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12-03-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 51
Post ID: 9060
Reply to: 9059
Brewing, thinking and heating
fiogf49gjkf0d

 nl wrote:
Gordon Rankin of Wavelength Audio did a series of one-stage DHTs with a step-up transformer input about ten years ago. I think they were called the Mercury series. By all accounts, they sounded good, but of course had limited gain, not much power and had to be driven by a powerful preamp, which involves at least one and probably two stages if you use tubes.

I did not know it. I wonder how your DHT people consider the sound of one-stage Wavelength compare to the multi-stage. Did the Rankin’s one-stages amps had the DHT coloration that you admit exist in other DHT amps. Anyhow, I feel that those Wavelength Mercury series might not be even illustrative if DHT might do really “clean” sound as I am sure Gordon targeted mass-market with this full-range addenda. In DSET configuration it shall be a different amp. The inductance of input transformer shell not be nearly 100H and the output transformer might have a LOW of less turn. That all shell greatly improve HF end. Also, 10 year back Gordon most likely did not use amorphous core that I found a very good thing to do for HF DSET.

 nl wrote:
I think using a DHT amp only over 3000hz would be somewhat self-defeating. I would try to use it at least over 600hz,

Why?

 nl wrote:
… and use a 45 tube, not a 300B. The 45 is a wonderful tube for running compression drivers. If you use a 45, however, you probably won't have enough gain even with a 1:4 stepup.

I most certainly not going to go with 300B if I decided to go there. Most like it will be 2A3 or anything else with sub 1000R on plate that would allow me to use my currant OPT transformer. If I find the DHT idea worth for me to stick with then I might order a dedicate OPT and then I will be open for high-gain high impedance DHT. At this point I do not know how it all meaningful. Perhaps I need to take 6V.3 6A3 and juts plug in on 6C33C filenames with a regulating resistor and to see where it would go. I mean there are many ways to implement the thing but do not looking DIY project but for a sensible sonic result.

 nl wrote:
Personally, I would forget about the input transformer, and just use a 6SN7 driver. RC coupling is fine. Many people like carbon comp resistors for the plate load, and paper/oil capacitors for the coupling cap here. PIOs take some time to break in. You might later try substituting an inductor for the load resistor. Of course you want to use a good 6SN7, not a new-production Russian or Chinese model.

I do have a very good driver (my 6E5P if I wish to go two stages). I did when in past from 2 stage Milq to one stage Milq I did like the new level of “laconic clarity”. I would like do not lose it.  Also, it is HF only DSET that need juts 1W? What do I ever need two stages? Well, I might need but juts do not know about it, will see. At list the idea of transformer and DHT is worth to try before to go for 2 stages a, coupling, DC stability, sound of the driver and all the rest. I also not really not willing to modify the 6-ch Milq as whatever it does now is fine. So, to do some work on it I really need to have evidence that DH will be advantageous for my MF driver.

 nl wrote:
A nice 6SN7-45 amp, RC coupled with carbon comp/PIO, and a decent powersupply that doesn't sound drecky (which probably means NO cheap high-value industrial grade electrolytics, or at the very least a film cap that is isolated from the electrolytics with a resistor or choke), and whatever tricky bias schemes turn you on, would be a good intro into the sound of DHTs.

I do not know. I hardly ever see heard not drecky low power DH amps. All of them sounded very dead to me those idiotic full-range amps and the idiotic music that they looks like constantly play.  I have seen a few DH with stupidly made high-sensitively systems with horns- but it you read my site then you know my attitude toward sound of stupidly made horns. So,  I do not know which ingredient was wrong in the DHT that have seen before – I think most like it was the awareness of the amp builders but it another subject.

 nl wrote:
Pay attention to the quality of the filament supply. The Tent Labs boards seem to get some acclaim, but I shy away from IC regulators in this position. You can try an IC current source filtered with a cap and choke such as Hammond 159ZC, which is 60mH and 2A, 0.7R.

Interning as you are today a second person who insists in DC filament supply. It is pretty me everyone strongly  in past suggested me to use AC on filaments. Can you elaborate on it?

 nl wrote:
  Then, I would use it on your S2 driver in the 600-12000 range, and turn off your other S2. I would also turn off the "injection channel." That would give you a better idea of how it sounds.

Come on, of course when try to evaluate how my MF sound in with different amps then I turn off my "Injection Channel”, how with it? To use the S2 driver in the 600-12000 range is another subject, I would like do not go there at this thread. BTW, the 6E5P with the "Injection Channel” might be very much make the DHT triode journey not necessary. I do not have a position about it at this point. Well, you are local from east cost, right? So, feel free to bring your single DSET and to see how injected Macondo work against DHTed Macondo. I wish I spent more time (or had more time) to evaluate THIS aspect when I had my 300B. I am planning to do this try again.

 nl wrote:
  Lastly, put in a line-level filter at the input instead of using a speaker-level crossover. The same circuit as is used with your 6E5Ps would be fine.

I a not intending to use speaker-level crossover. I am not going to put a resistor in primary of input transformer, using the transformer shunting inductance as a second order high-pass. Probably I would need to add some coils in parallel with primary….

 nl wrote:
  Given that you are using a solid-state preamp with presumably lots of driving power, you might consider a 1:4 stepup and use of either an EML 20B tube or the AVVT AV8 tube. That might get you enough gain. I think Rankin used the 20B in his Mercury amps. The 20B would take a rather special output transformer, as it has an Rp of 3200. I think Rankin used a parafeed output here. A typical 5K:8 OPT could also work, on the 16 ohm drivers, as the reduced inductance is not so much a problem since it would be used above 600hz. The AV8 is somewhat more forgiving, with an Rp of 1500. The new TJ PX25 has a gain of 8 and an Rp of 1500, another possible choice here.

Thanks, I will look at those tubes and will consider them. I am not convinced but I might use this input transformer:

http://www.lundahl.se/pdfs/datash/1544a.pdf

… that can go up to to 1:6…

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-03-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #: 52
Post ID: 9061
Reply to: 9057
Physical characteristics of electronic devices
fiogf49gjkf0d
 nl wrote:
The 45 is a wonderful tube for running compression drivers.

Many people like carbon comp resistors for the plate load, and paper/oil capacitors for the coupling cap here.

PIOs take some time to break in.

Of course you want to use a good 6SN7, not a new-production Russian or Chinese model.

...a decent powersupply that doesn't sound drecky (which probably means NO cheap high-value industrial grade electrolytics...

Pay attention to the quality of the filament supply...the 26 takes a VERY high quality filament supply. I use batteries with a cap and choke with my 01As.
This is my point. We often say these things, like "use a paper/oil cap or air cap here or there" and we think about capacitance, inductance, resistance, etc. but we ignore all the other physical characteristics of the device and how it interacts in the circuit. Like judging a house we are going to buy from the number of bedrooms and bathrooms, when we should be thinking: it is poorly insulated so we need a good furnace for it; or it has a large garage so we have plenty of extra storage space.

I would be interested if we could think about WHY we make these choices and have these preferences, and see if we can formulate some experiments to confirm it. It might give us a lot of power in tuning a system.

I would like to hear people's ideas. Smile

Adrian
12-03-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 53
Post ID: 9062
Reply to: 9061
I see the things differently.
fiogf49gjkf0d
Hm, it might be wider topic then the subject of this thread but don’t you think that the "use a paper/oil cap or air cap here or there" are very much comments about “why we do it” instead of the comment about “what we do”. I see more interest not in the wondering of why we make choices but rather in the questing what choices might be made in order to accomplish this or that effect. I kind of know where to do but I very frequency might not know how to go.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-03-2008 Post does not mapped to Knowledge Tree
nl
Posts 14
Joined on 06-15-2008

Post #: 54
Post ID: 9063
Reply to: 9060
Don't waste time being "creative"
fiogf49gjkf0d
There is no "one tube DHT amp." There are only amps with gain in one box or two boxes.

Your 6E5P tube is not so special. People have been making WE437 spud amps since the 1960s. There is a class of amps that use a high-gm tube driver and a DHT output. Gordon Rankin has done this for about twenty years, and still does. However, I would suggest moving away from the high-gm driver, simply because the point is to try something new.

I will reproduce Jim de Kort's findings with the 437 spud, which roughly mirrors my own results. He used an amorphous Tribute transformer.


17-05-2001
All the wiring was done, double checked and then hooked up the amp. Everything reacted as I though it would. The 437's bias themselves nicely at 205V/25mA. I did some listening even though it is not wise to make a judgement just yet. All the parts are brand-new and take a while to play in (200 hours minimum). First impression: WOW!!!! Very direct sound, right in the middle of the music. The first minute it sounded like crap but eventualy started to turn around. Sound is a bit closed and rough around the edges, but this should change after it has been playing for a few hours.

19-05-2001
I made some measurements on bandwidth and power output. Better than I expected really. Bandwidth is 18Hz - 225kHz at -3dB. The low end was expected to be higher as the OPT's were designed for 50Hz and up (midrange), they don't have the inductance to go lower. As the 437A was intended to power my horns, the 20Hz is better than I expected to get anyway. Power output is 0.7W before any visible rounding of the sine, 1W max with clear signs of clipping/distortion. Square wave response is excellent even at 1W output, down at 60Hz is really the limit on the square wave test, very rounded. For those building this amp and wanting more power, use a 3K or 3K5 OPT.

The sound is becoming ever more open and clear. Another experiment that has paid off. The compromise with DHT's is that I need three tubes and acompanying transformers/chokes to get the same level of output (0.5-1W). This project proves that an IHT with high mu might be a compromise by itself when used in an audio chain, but I think the right tube used on it's own can sound better than three great tubes strung together to perform the same task. The key factor with this amp is that I can do with 0.5W perfectly. I don't have 90dB speakers that need at least 3-5W to come to their rights. I think this amp might even stay in my system for a long time to come. I'm almost thinking of not continuing my Exodus amps Smile Nah...

25-05-2001
Playing-in the parts sucks big time!!! Highs are getting smooth, low is getting tight, but mids are too woolly and agressive. I hope it will pass. I've only been playing for about 50 hours now, anybody have a time machine?! Soundstage is very good, precise placing of the voice etc. Depth is wonderfull.

03-06-2001
Visited Bert Doppenberg and took my "amps" with me, also a nice benefit of a small amp Smile Bert is very sceptical on anything that is not his, so I knew he would complain as ussual (grapje!). I was kind of worried that he didn't say anything just after hearing the first notes coming out of the amp. After a few minutes it was obvious he liked this amp, or he would have honestly told me his thoughts. So, now I am not the only one to agree this little amp sounds good.

The amp still has a lot of hours ahead of it to burn in all the parts, but it is getting better each day. I didn't think this idea would be anything else than a nice little replacement amplifier that I could put on a shelf if I didn't need it anymore. It just may up becoming my favorite amp Smile Funny how things work out.

06-09-2001
Ai, Cold Turkey... I hooked up my system this weekend (finally). It hadn't played since the ATF2001, yes yes, I am ashamed of myself. I didn't want to hook up the Exodus amp as it was a lot of hastle with the batteries etc, so I just used the 437A amp. A friend called that evening saying he would drop by and wanted to hear my new setup (just got a new CD transport). Heck, now I really had to hook up the Exodus amps, ah well, it was a good excuse to get my ass off of the couch and get everything playing.

The tubes were lit up again, the 10 sticking out ofcourse with it's bright glowing tungsten filament. Always a nice sight!!! In went the CD, click... out came the music. What?! Couldn't believe my ears. Was the 437A really that bad??? It was like the music opened up a door and let in the air. Everything wa so smooth compared to before, it was music again. I really didn't notice with the 437A as I hadn't heard the good old DHT's in a while (due to all the rebuilding). I have gotten a big slap in the face again waking me up to the difference between a directly and indirectly heated tube.

Even a single tube performing all the tasks can't come close to my three tubes per channel DHT amp system. There is no getting around the immense difference in sound. Yes, the 437A and 6S45P sound incredible and perform a unique task, but compared to a DHT it really can't hold water. I was doubtful about the comparisson before, but now I am fully convinced. Even three stages of (good) DHT's can't be beaten by a circuit using only one IHT.

Basta!
12-03-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #: 55
Post ID: 9064
Reply to: 9063
The audiophile attitude
fiogf49gjkf0d
 nl wrote:
simply because the point is to try something new.
To me this is entirely NOT the point. The results of High Gm tubes vs DHT you posted are pretty typical of audiophiles, who tend to fixate on the novelty of the sounds coming from a different stereo component, without fixed ideas about specific goals and objectives for the Sound and a system. The next amplifier is always the best one.
Adrian
12-03-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #: 56
Post ID: 9065
Reply to: 9062
The where and why of design choices
fiogf49gjkf0d
 Romy the Cat wrote:
I see more interest not in the wondering of why we make choices but rather in the questing what choices might be made in order to accomplish this or that effect.
It is true that conjecture can be a false path without confirmation. That is exactly why I specified that the formulation of hypotheses must be followed by experiments to validate them.

 Romy the Cat wrote:
I kind of know where to do but I very frequency might not know how to go.
Exactly, and if we know WHY then we know HOW.

Otherwise it is purely blind trial-and-error experimentation and apocryphal anecdotes on design choices. I hate to think that audiophiles and DIY'rs are proceeding like the proverbial thousand monkeys at a thousand typewriters.

Adrian
12-03-2008 Post does not mapped to Knowledge Tree
nl
Posts 14
Joined on 06-15-2008

Post #: 57
Post ID: 9066
Reply to: 9064
Blah blah blah
fiogf49gjkf0d
Yes, well, in this case, it wasn't a new amplifier, it was his old amplifier!

At the end of the day, he tried it and came to a personal conclusion. I also tried it and came to a personal conclusion. Romy is still just farting into the air.

This is Romy's site, so I suppose in the Kingdom of Romy only single-stage high-gm amps sound good, and the 6E5P is the "perfect" high-gm tube, and that is that. I offered to be of assistance, as I have a little experience in these matters, but assistance is not appreciated so I will be leaving the Kingdom of Romy for more productive environments.


12-03-2008 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,577
Joined on 10-12-2006

Post #: 58
Post ID: 9067
Reply to: 9065
Laconic Clarity vs. Comfort vs. Nostalgia
fiogf49gjkf0d

Yes,  the laconic clarity is too rare and too worthy to let go.  My limited experience suggests that the 45 may have this very special ability, taken alone.  Conversely, the "good" 6SN7 is wonderful with respect to tonality and tonal integrity, both.  The good 6SN7 also has acceptable clarity, but I have not heard it developed specificially for this.  Neither have I worked with the 437A, although in years gone by I heard lots of whining about the troubles with finding good ones.  I know nothing about the new production WE tubes except that their saga reads like a soap opera.

I am a little suspicious of the Allen Bradley Club mentality, including vintage (carbon comp) resistors, transformers, caps, etc.  When I have bothered to listen, I have often chosen "selected", "non-inductive" wire wound R for plates and "selected" tantalum R for cathodes and other RCs, etc.  My objective in the trials has been to retain the capability to sound hard and correctly dirty, when that's what is wanted.  Care with stacking, grounding,and other issues goes a long way toward calming things down to allow for a proper "hardness potential" without consistent hardness.  This may also be a factor in the "randomness" capability, which is really only freedom of movement, and not "randomness", per se.

I have read a few DIY posts where guys claim to have solved AC filament noise on 45s by putting a small coil right on the tube pin, or what have you.  I cannot comment on this.  The AC 45s I heard, buzzed and, looking back, I think only certain qualities of those old amps are worth recreating; and not many, at that.  But, I am no longer interested in the vintage sound, at all, that's for sure.

Best regards,
Paul S

12-03-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 59
Post ID: 9068
Reply to: 9066
Do I need to be hissing?
fiogf49gjkf0d

nl,

 nl wrote:
I offered to be of assistance, as I have a little experience in these matters, but assistance is not appreciated so I will be leaving the Kingdom of Romy for more productive environments.

where did this come from are you crazy your master have eventually took over you?

 nl wrote:
This is Romy's site, so I suppose in the Kingdom of Romy only single-stage high-gm amps sound good, and the 6E5P is the "perfect" high-gm tube, and that is that.

Ironically you are so much off. I have no vision on the subject; in fact the whole notion of DHT vs. single-stage high-gm amps is created by you. My quest was my about my specific single-stage Milq vs. DHT, there is different if you can see it.

 nl wrote:
At the end of the day, he tried it and came to a personal conclusion. I also tried it and came to a personal conclusion. Romy is still just farting into the air.

At this point the person who is farting into the air is you. You did not say that you trued you’re a single-stage approach, at list you did not pass any sharable comments about your observations of the result in order the people who you would like to learn were able to make own assumption about the sincerity of your findings. You pretty much bark conclusion but they worth as much as anyone’s else barking - I do not think that you care about my conclusion if I do not provide you with soothing that resonates with what YOU know is truth is. However, you were the people who during initial introduction of you position brought the evidence: “However, even Lamm is now using the GM70 for his $140,000 statement amplifier.” nl, I am sorry those arguments is not soothe that sane people bring up. Not to mention that I might hit under the belt and reply that “many people around (and it is fact) the world who can afort the most sophisticated, kinkiest and advanced DHT through their DHT away after they were exposed to Lamm ML2.0.” Oh, did I mention that it was IDHT?

 nl wrote:
Your 6E5P tube is not so special. People have been making WE437 spud amps since the 1960s. There is a class of amps that use a high-gm tube driver and a DHT output. Gordon Rankin has done this for about twenty years, and still does. However, I would suggest moving away from the high-gm driver, simply because the point is to try something new.

The 6E5P/6E6P and WE437/6C45P have absolutely nothing in common besided the people who did not deal with them decided to label them as "high-mu tubes". Hey, the WE437 and 811 tubes are probably the same as well, the both have grass… The really is that thee is a lot of special about the 6E5P/6E6P. it is completely up to you to discover it. in contrary to you I do not feel insulted if you do not support my poinjt of view…

 nl wrote:
  I will reproduce Jim de Kort's findings with the 437 spud, which roughly mirrors my own results. He used an amorphous Tribute transformer.

Thanks, for posting it. It was interning but absolute not educational in my view. I do not know who Jim de Kort is but leading a dairy of a person with a shovel who decided to turn over all sand in Sahara juts because he has no map where the treasures are. This is a typical DIY syndrome – I do not like those. The Jim de Kort say nothing about sound, nothing about own objective, nothing about what he is would like to accomplish, nothing about why he want to accomplish it. He has the damn solder gun and ability to solder – it never was enough to make sound.

 nl wrote:
  Even a single tube performing all the tasks can't come close to my three tubes per channel DHT amp system. There is no getting around the immense difference in sound. Yes, the 437A and 6S45P sound incredible and perform a unique task, but compared to a DHT it really can't hold water. I was doubtful about the comparisson before, but now I am fully convinced. Even three stages of (good) DHT's can't be beaten by a circuit using only one IHT.

And It is possible that you are correct – I just do not know and it looks you are not able to provide more justification of your view beside your desire for your readers to kiss you in your ass just because you express own views. That is fine; after all it is poorly voluntary sharing. You might be correct – but I would like to get my own answers, similar that if this subject were your curiosity then you would not be satisfied with my answers. I also do not belie that you experiments were “kosher” (let start from the fact that you used apparently used 6C45P, which is very crapy tube, partially as an out tube – many Russians build headphones with it). My quest is very limited and and I do not care what can't and can hold water compare to what.  I have Milq sound that I am comfortable. The recent 300B amp that I tried did have some minor tonal advantage that kind of evaporated when Macondo was injected. The DHT amp did have the “pace randomness” advantage, something that you with all your apparent DHT experience did not know, or might be do not know or perhaps will not even know. I did appreciate this DHT’s randomness a lot and I would like my amp to be able to do the trick. Do not worry it will. If my 6E5P/6E6P driver will not be able to handle it then I will try the DHT – I have no agenda in it. it is possible that the randomness  did come from the DHT, even though I have no evidence about it as no other DHT user repost it. I just need to learn how to make DHT if I got for it to sound as accurate, as “clean” as dynamic as my 6E5P/6E6P…

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-03-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 60
Post ID: 9069
Reply to: 9067
...associated with lack of neutrality and colorations.…
fiogf49gjkf0d
 Paul S wrote:

I am a little suspicious of the Allen Bradley Club mentality, including vintage (carbon comp) resistors, transformers, caps, etc.  When I have bothered to listen, I have often chosen "selected", "non-inductive" wire wound R for plates and "selected" tantalum R for cathodes and other RCs, etc.  My objective in the trials has been to retain the capability to sound hard and correctly dirty, when that's what is wanted.  Care with stacking, grounding,and other issues goes a long way toward calming things down to allow for a proper "hardness potential" without consistent hardness.  This may also be a factor in the "randomness" capability, which is really only freedom of movement, and not "randomness", per se.
Isn’t it a bit ironic and said the in most of the cases the folks who stick to low power HDT ether are users of Moronic full-range loudspeakers that are superbly not neutral of the subordinates of the “Allen Bradley Club mentality”. It would be very interesting to see a company or individual who would have an adjective to make clear and neutral DHT. Interning that some people with whom I talk the last few day via emails and why have a lot of experience with DHT subjects told me that a properly made DHT is not necessary is associated with lack of neutrality and colorations.…

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-03-2008 Post does not mapped to Knowledge Tree
mumford
Posts 10
Joined on 06-10-2008

Post #: 61
Post ID: 9070
Reply to: 9069
John Broskie's Partial feedback amplifier
fiogf49gjkf0d
You can eliminate the driver stage and drive a DHT in just one stage, because your source or preamp is sand based and has plenty of current drive.

Page 10 of the PDf showed an example of driving a 300B DHT to full output with just +/- 4ma.


http://www.tubecad.com/march2001/2001_03.pdf


12-04-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 62
Post ID: 9071
Reply to: 9067
Randomness vs. freedom and the Homework # 4334
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 Paul S wrote:
This may also be a factor in the "randomness" capability, which is really only freedom of movement, and not "randomness", per se.

OK, is it “randomness” of “freedom of movement”, the question is not about juts semantics. Since Paul said I have been thinking about is and I have to admit those thought fascinate me. The “randomness” would imply the will of amplifier vs. “freedom of movement” would imply the transparency of amplifier to external source of pace randomness. It is very much not the same.

I feel Pail was wrong and I still would insist that it is not “freedom of movement” but randomness. I never experience in live music neither “freedom of movement” nor randomness, the pace of live music whatever it is and there is not reference in my mind to some kind of pace-setting framework. What I question a pace of live event I equation it in context of musical idea and the “program” of the piece. What I question a pace of reproduced muss invent then in addition to original performing pace I recognize the pace aberrations of playback. If so, and if we take the pace aberrations out of repentances of attention then we can see that the timing aberrations are not connected to the timing of original events and can’t be called “freedom of movement”. The “freedom of movement” implies high amplitude of obedience of aberrations to the original pace but the original pace doe not exist.

So, what we have here is not “freedom of movement” but rather a randomness of amplifier’s timing self-control. I think that this randomness comes with randominisation of error. It like when we have frequency-centric noise injected into sound then we recognize it as “harmonic problem” but if we have more or less white noise then we do not feel that the noise interact with sound. A good example is a LP record noise. It is random my nature then we play record and have no problem. However, if the record has scratch on one side and each turn of the record we have a click that come at the same “pace” then it annoys us tremendously…. Now pretend that an amplifier somehow might take this non-unsystematic click from this scratch and spread it appearance at random moments. Then we will me bother but the click much less as then the click will be not interacting with the pace of the plays musical material.

 Romy the Cat wrote:
OK, here is an easy homework: how to randomize elections flow but do not create microscopic? The answer is actually contains in the question. The answer is one of the solutions that my first thing that I will be trying sometimes.

Now, in context of what I expressed in the first part of the post I am planning tonight to make some actual experiments with my single stags IDHT driver, trying to “randomized” the electrons flow, it is not truly randominisation but insertion of something soft of geometrical  errors. If it works (a big question!!!) then I will post explanation of how it was done. If it works it might be interesting to see what ease it might affect. It is very possible that it will destroy the tube itself, so I will dedicate one of my 6E6P as the Pavlovian Dog… If it does work then it is very interesting to see if the effect would be the similar of what I have experience with the DHT last week. On another side it all might open who knew can of worms and to alter the ways how tubes might be operating..

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-04-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #: 63
Post ID: 9072
Reply to: 9071
What is randomness?
fiogf49gjkf0d
 Romy the Cat wrote:

 Paul S wrote:
This may also be a factor in the "randomness" capability, which is really only freedom of movement, and not "randomness", per se.

OK, is it “randomness” of “freedom of movement”, the question is not about juts semantics. Since Paul said I have been thinking about is and I have to admit those thought fascinate me. The “randomness” would imply the will of amplifier vs. “freedom of movement” would imply the transparency of amplifier to external source of pace randomness. Romy the Cat


In my mind, there are at least three possibilities, and they must be interpreted by experiment with caution:

1. irregular fluctuations in signal (I will call this "noise") result in irregularities in output signal we listen to and find pleasant; it adds to output signal a quality of "random pace" we like. It should not duplicate itself exactly on multiple listenings.

2. "Noise" acts as analog dithering, to enhance ability of listener to interpret low-level information about pace, emotional content, etc. It should make a low-resolution system sound like a higher resolution system, yet still the sounds will retain many elements of lower resolution, couterintuitively.

3. "Noise" sounds less irritating than IDHT (where the regularity of signal may be more like constantly repeating record "ticking"). The sounds may still be unchanged but the ability to relax and listen is enhanced. Music may sound "less strained" or "more natural."

I look forward to the results.

Adrian
12-04-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 64
Post ID: 9073
Reply to: 9072
Those least three possibilities…
fiogf49gjkf0d

 drdna wrote:

In my mind, there are at least three possibilities, and they must be interpreted by experiment with caution:

1. irregular fluctuations in signal (I will call this "noise") result in irregularities in output signal we listen to and find pleasant; it adds to output signal a quality of "random pace" we like. It should not duplicate itself exactly on multiple listenings.

2. "Noise" acts as analog dithering, to enhance ability of listener to interpret low-level information about pace, emotional content, etc. It should make a low-resolution system sound like a higher resolution system, yet still the sounds will retain many elements of lower resolution, couterintuitively.

3. "Noise" sounds less irritating than IDHT (where the regularity of signal may be more like constantly repeating record "ticking"). The sounds may still be unchanged but the ability to relax and listen is enhanced. Music may sound "less strained" or "more natural."

I look forward to the results.


Those least three possibilities might describe something only if the entire notion of “elections behavior” was responsible for randomness of DHT. Then my “Homework # 4334” experiment will be (or will not be) able to mimic it. There is another “ugly” possibility. This DHT’s randomness might not be due to “elections behavior” but rather due to electrons quality.  I mean the material of cathode or the mater of the coating that was used in let say 1942 was very different then what we use today and therefore the electrons that were evaporating from those old DHT cathodes juts were different type of electrons. If it’s the case then there is nothing that might be done. I know that there is a group of people ho do hunt what they call “period tubes” and who swear that they better.  I would like aside my entire attitude toward to the “vintage sufferers” who persistency demonstrates very poor sound and just would say the following. If that tube from let say 1942 does have “different sound” then it is not well known to me if it was because the contraction or material (under material I imply the tie of vacuum and the rest of the things).

This is why I think it is very interning something like Emission Lab Company that makes the “period tubes” with contemporary production. If they are smart, and I presume that they are, then they shell be able to make even better DHT tubes then what was made 60 years back. The key is to have these tubes properly evaluated sonically in context to the vintage tubes. This will give an idea if the alleged advantage in randomness for DHT tubes derives from the “behavior” of electrons or from their “quality” of electrons. Did anybody heard a sane and without hype analyses of the sound the Emission Lab’s tubes (or the tubes of a similar serous re-manufacture) compare to the sound of “period tubes”?

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-04-2008 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,577
Joined on 10-12-2006

Post #: 65
Post ID: 9079
Reply to: 9073
Randomness and Music's Prerogative
fiogf49gjkf0d
Given enough time (and enough distance), most "randomness" adopts (or appears to adopt) some sort of a "pattern" or patterns.

This appears at the rote level to be yet another variant of the old "musical versus accurate" conundrum.  Yes, the idea of true "freedom of movement" via hi-fi seems far-fetched, unless it is understood that we are speaking in purely relative terms.  Of course I am speaking in relative terms, ie, not all amps do this equally well, to allow the music to go where it will.  Meantime, I still find it hard to wrap my mind around the idea that we can introduce "random" noise that will not eventually be perceived as a constant/distortion  or some kind of limiting or merely ancillary factor.

I certainly do not hear music as "random" just because it is +/- "unpredictable" at a certain level, as it unfolds.  I still think the an amp's ability to "get out of the way" is an important marker in "allowing" music, and I do hear this best accomplished by SETs, and, yes, DHT SETs.  Further, I have always heard this "strength" as the flip side of the SET "weakness", that it lacks the ability to "facilitate" what it "allows".

If I were not so cheap and lazy, I would be trying to get more energy from/in the lower-mids on down, and I would also like to get the "proper discontinuity" between the mids and HF that I hear in live music, where the upper mids/lower treble seem to be kind of "random" in a "spike-y" sort of way.  But I aim to do this primarily with speakers, not amplifier "effects".

Despite my current facination with the ML2, I am very leery of amplifier effects, which I feel take away the Music's "prerogative".

To close with one of my patented full-twisters, I do acknowledge the remote possibility that even an audible "randomiziing" effect of the sort we are discussing here might yet have enough of a desirable effect to offset it, like the ML2's effects still work for me (with good electricity).  To this end, I would at least make a serious try for the AC filament.  Buzz notwithstanding, this seemed to have the "aliveness" thing down, anyway.

Best regards,
Paul S
12-04-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 66
Post ID: 9083
Reply to: 9053
It works, … sort of. The revolution is canceled.
fiogf49gjkf0d
 Romy the Cat wrote:
I have to admit that the idea of the “second solution” looked to me superbly promising. The “second solution” would allow modifying the amount of 2nd and 4th harmonics on a driver without change loading, volume or inflicting of any negative effect to sound. It is not even a harmonic correction circuit but rather a new revolutionary and COMPLETELY NATURAL way to manage second harmonics in respect with volume. I was implemented last night - the “second solution” - well, it did not work, I mean it did not work at all. Sucks!!!
Ok, I found why my “second solution” did not work and I fixed it. Well, it is not that I fixed but I rather used less own moronity while I was implemented it and it stated to work. Did I mention that it shell be a “revolutionary tool” that allow to surgically modify lower even harmonics without affecting anything else and and the most important without affecting the loading. It looks like it does though I did not look deeper how harmless it is. Despite that the “second solution” looks like works I am not so pleased as it does not lead my MF driver to the direction I would like it to be. In fact, running my MF driver up to scale of 2nd harmonics, and the “second solution” also to do it very prissily I realized that my MF channel was loaded perfectly, I kind of knew about it. Adding the lower even harmonics just changed Sound but in my view all in worth direction. So, the revolution is canceled and it looks I have no use from it.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-06-2008 Post mapped to 2 branches of Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 67
Post ID: 9095
Reply to: 8932
Thorsten Loesch’s article about DHT SETs
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Here is Thorsten’s very good article about different opinions for DHT SETs

http://www.fortunecity.com/rivendell/xentar/1179/theory/seamptheory/SEAmplifiertheory.html

Quite good writing and quite good thinking.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-07-2008 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,577
Joined on 10-12-2006

Post #: 68
Post ID: 9107
Reply to: 9095
A Beautiful Mind
fiogf49gjkf0d
Lots of good information in there, if one has some idea of what it means in terms of sound and how it might be integrated into a system.  However, some of the guys who are the smartest with respect to circuit design seem to have no discernable sense of direction with respect to music or the sound they are after with respect to their musical objectives.

The Monkey Circuit is very attractive on paper, with basically nothing but wire and the tubes themselves in the "signal path".  Of course, as Thorsten points out, the signal winds up as +/- part of the tank, which basically shifts many of the "usual problems" to the power supply.

It might be nice to use a 45 OT and some sort of comparator for the PS, like the ML2.  It might not be necessary to use feedback, IF you could keep the tank quiet apart from input signal, and if it was kept well clear of clipping at all times.  IOW, unlimited, perfect DC.

Thorsten refers to Chimera Labs' "Kyra" amp, and its PS, but I like the way the same guys did a "no-cap" "mega-tank" similar to the Monkey with their "Axiom" amp.  This one does use (tube) diodes, however, and although they say, "no feedback", it looks to me like there is, in fact, what I call "deniable feedback", where the diodes act +/- as follower/comparitors.  I have not heard it, but in any case they ran their listening tests with "FR" Lowther BH, or similar...

Hard to say what any of this stuff would sound like if subjected to more stringent tests.

Only one way to find out...

Best regards,
Paul S
12-09-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 69
Post ID: 9120
Reply to: 8932
Some summary and conclusions from the first phase.
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I would like to overview the content of my thoughts on the subject. I feel that the first phase of my interest in single-stage Milq vs. DHT is over and I can make some observations.

 The subject turned out to be more interesting and more changing then I expected but it was also more fruitful then I expected. It is important to understand that the subject was not about the DHT vs. High Mu tubes as “nl” put it. I have no interest to make general concussions and my curiosity is much more egocentric – I egotistically care about the sound of my Milq-Macondo and frankly less care about compliance of violation to some kind of DHT practice out there. So, what I discovered?

It looks that there are some very interesting characters in sound of DHT tubes. However, I do not know for now how to capitalize on them in the applied sound  as Macondo is multi-amped system and I have no idea at this point  what would be cone and pros  of DHT used if I mix DHT and IDHT amplification with Macondo. I do not anticipate any problems but some corrections of Macondo or Milq operation most likely will be warranted. Admitting that there are some interesting moments in DHT I also observe some negative moments (lost dynamics, lack of clarity, deficiency of intelligibility, lessen articulation, colorations) that I do not like. I think  to move further in the discovery process it would be necessary to built a “clean” brand new DHT amp and to see if the DHT’s negative moments will be gone.

Thinking about positive properties of DHT sound and analyzing the differences of DHT and IDHT some observation and proposals were made how to “tweak” the sound of IDH tubes and to take their performance taken slightly in another dimension. The proposals were tried. One of them was natural injection to the sound of IDHT the harmonic context that is atypical for IDHT. Even though it did not lead to sound improvement in the direction that I would like it to be but the method itself turned out to be VERY interesting and promising. I am planning to experiment more with it and when I have conclusive observations about the ways to do the things and benefits of it s use then I am planning to post all information about it at my site. The second proposal was the randominisation of elections flow and I have to say that the result was instantaneously extremely positive. In fact it was so positive that I feel the method has quite high commercial value as the result were very good and anything like this never was done before. I pitched this idea to an industry-involved friend who might take it farther commercially. So, for a time being the second proposal will not be discussed further.

So, does mine IDHT single-stage Milq, improved by the above motioned “proposal” and become “competitive” to DHT? I have no idea. I do not even know if the DHT would be competitive to single-stage Milq in general sense. I think a “clean” DHT shell be made to take this debate anywhere further in practical and relevant terms. Talking about practical and relevant terms is very important for me as I would not like to change anything in Milq-Macondo. This weekend I was listing a live broadcast of Handel and Haydn Society’s Messiah. The electricity was not bad and the general sound was fine. I turned my attention to “target listing” and was trying to observe specifically the sound of my MF channel, trying to assess what I would like to improve. I did not experience any frustration with the sound as it was; in fact I liked it a lot. There was in it some kind of “super correctness” with no character of own. When sound had to be ugly it was ugly, when it had to be beautiful it was beautiful, when it had to be brute it was brutal, when it had to be gentile it was gentile, what it had to be elastic with flexibility to change of meaning with volume or tone then it was. It was exactly where I need it to be.  So, I do not particularly have any motivations hypothetically to ruin what it is with DHT rubes. Might it be no “ruining” but advancing – I do not know yet, in some aspect it might be. I do not know at this point how valuable will be those “advancing  aspect” and how much effort and compromise I would need to sacrificed to get this alleged or factual  “DHT advancing  aspects”.

So, decided to calm down with this whole DHT saga and to see what happened next. It might be another “cleaner” DHT will come my way. It might be I will build or buy some kind of DHT prototype where I would able to look at the DHT sound deeper and more in context of the whole Macondo-Milq integration. I would like do not do a lot of work with it myself, so I might get some kind of DHT kit that would give a necessary ground for further observations. I was looking for Japanese Sun Audio VT25 and 2A3 kits but they are too expensive juts for experiment. To make them to sound OK it would take another $500-$1000 – too much money and work as if the DHT turns out to be a good direction for my MF channel to go then the prototype DHT will be trashed and a new DHT will built in inside the 6-ch Melquiades.

So, let see if the Second Phase of my DHT curiosity kick in and if it does then let see where it would lead me.

Rgs, Romy the Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-24-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 70
Post ID: 9257
Reply to: 8932
Second phase: revising requirement for my DHT objectives.
fiogf49gjkf0d

In context of the recent changes in my playback regarding the electricity and the consequential effects: 

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=9252

I have revised and reinstated my interest in the DHT experiment. In addition to anything I need gain and transients now, so the single-stage DHT with input transformer might not work.

I did not have a line of people with DHT who know in my door with offers, so I need to do it my own. I bought a Sun Audio SV-2A3 kit juts for a sake of prototyping the sound I would like to get and when I found what I like I will implement it in Milq MF channel (if the DHT turn out to be a direction to go).

Sometimes after the New Year and will put the SV-2A3 kit together, with necessary changes and perhaps will convert it to 6E5P-2A3, Milq-type amp. The kit is very flexible, has multiple filaments voltages and multiple primaries and secondarys in on output transformers. In addition to those generic Tamuras I have a couple of my  transformers that are more HF optimized and can handle 2A3, 6A3, 300B, 45 and the rest of them with plate user 2K.

My mild concern with DHT was that they are costly and fragile in live but I have a tendencies to run my Melquiades’ for many hours and days without caring about the live-span of the tubes. Then I figured that in a few days the pilot Mini-Me speaker will be done (my mash saps bed the end of the year) and if it tune out to be good then it might take a lot of dally tube load out of the Melquiades shoulder…

Well, let see what happen next. Who knows if the modified Sun Audio SV-2A3 kit turn out to be an OK full-range amps then I might sell it after I found right MF configuration for myself. In meanwhile, if anyone has any proposal what tube to try in the Sun Audio audio kit’s output stage then let me know. The only condition I have at this point is that I would like to drive the output heater with AC. I think it might be extra fun to drive the DHT heater with good sounding sinusoid. The next step will be driving the 2A3 filament with 44.1 kHz…

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-24-2008 Post does not mapped to Knowledge Tree
JJ Triode
Posts 99
Joined on 09-12-2007

Post #: 71
Post ID: 9258
Reply to: 9257
Tubes for your DHT amp
fiogf49gjkf0d
Romy, I have had good experiences with the Shuguang 2A3C. There are plenty of comments in the Sewer about this tube. They cost about $80/pair and seem quite stable so they are a good choice if you leave your amps on a lot. superTnT.com is out of them now, I got mine from another China reseller, hkadelie.com.

I have also used the Sovtek 2A3, it is OK but a bit dull. I have extra Sovteks if you would like a pair.
12-24-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #: 72
Post ID: 9259
Reply to: 9257
Abandoning Milq?
fiogf49gjkf0d
 Romy the Cat wrote:
In meanwhile, if anyone has any proposal what tube to try in the Sun Audio audio kit’s output stage then let me know.
You want a suggestion for a good 2A3? Get Ricardo Kron's (KR Audio Enterprises) KR 2A3. Very rugged, overbuilt. There is no comparison between this tube and all other 2A3's, and I tried many of them. The sound is more dynamic, the timbre is more lifelike, the transients are more accurate.

Does it mean with the PP2000, you will abandon the Melquiades and go for DH SET instead now?

Adrian
12-24-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 73
Post ID: 9261
Reply to: 9259
Will see how it goes....
fiogf49gjkf0d

 drdna wrote:
You want a suggestion for a good 2A3? Get Ricardo Kron's (KR Audio Enterprises) KR 2A3. Very rugged, overbuilt. There is no comparison between this tube and all other 2A3's, and I tried many of them. The sound is more dynamic, the timbre is more lifelike, the transients are more accurate.

The audio Kit comes with Sovtek tubes that are might be expectably bad. The Shuguang 2A3 are single plate that might be interesting. I have difficult time to hear the comments of other about the DHT tubes as they uselessly drool about its LF extension. I so much care less about the 2A3’s bass. It will be used than it will sit behind a 3200 Hz crossover in DSET configuration with an ultra-fast transformer with minimum amount of turns. I do not see anybody comment about the DHT tubes in DSET application… I have those Sovtek tube that she be good to measure operational parameters. I have a pair of new Tang Sol 6A3 from 1944 and a pair of new RCA from 1942. I think they might be a good enough to try for start. If the DHT will turn out a good direction to go then for the channel the will be built-in in the 6Ch Milq I might go for older single pate tubes with thoriated Tungsten heaters. I do not know yeat. The Sun Audio amp will be a good and comfy play-ground for those things.

 drdna wrote:
Does it mean with the PP2000, you will abandon the Melquiades and go for DH SET instead now?

Actually I do not how going for DH DSET would constitute the abandoning of Milq. Melquiades idea was two-stages, both with grounded cathodes amp where the Milq-style biased 6E5P drives output stage. The output tube is not part of Milq idea at all. The uniqueness of 6E5P (besides sonic characteristics) that it can give high gain - output 100V and have pump enough current to push the next tube capacitance. This gives a unique opportunity to swing the out tube juts with one gain stage where mostly people use two stages. There is/was a Milq with 6C33C, 6C41, GM70, 6GL and even with SS output stages. So, I do not see if the out stage will be 2A3 then it will be any departure from Milq. BTW, whatever I m talking about I mean the MF channel only as I other channels in my view perform fine and I intend to keep them as they are

BTW, I have no desire to glue myself to Melquiades or to not Melquiades. Whatever works! Whatever sound I will be able to get with 2A3 of any other DHT it will be competing with what I currently have. I still am not convinced that the DHT will be better solution. It looks that I would like to have more gain at my current MF channel; I would need 1-2 db more or more if I change loading. I do not know yet, it will be seen as time goes by…

The caT


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-26-2008 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,052
Joined on 05-28-2004

Post #: 74
Post ID: 9268
Reply to: 9257
Single-stage Milq vs. Sun Audio VT-2A3
fiogf49gjkf0d

I was playing lately with the Single-stage Melq and the DHT amp driving MF channel. It turned out that the Sun Audio VT-2A3 was very simple kit and it 2-3 hours to make it working. There is a lot in this kit that I do not like and some revisions will be made in it. Still, even in the “as is” state it is obvious that 6SN7-2A3 and 6E6P direct have very different character. My Sun-Audio VT-2A3 amp is not where I might comfortably talk about it’s sound, I think it will take a week or two to make this amp to sound better in a way it shell. Still, I wonder if those DHT might sound “light”.

Pretend that you are walking on water. You do not need to be a god to do so, you just need to walk very fast, let say 500km/hour, and then the surface tendon will keep you atop the water not allowing you to submerge. So, the Milq 6E6P has a good balance where to lower own speed to 150km/hour and to let the feel to submerge for 1/3 or where to run at 700km/hour not letting the feet to even to indent the water surface. The 2A3 it feels like heavy-sunk time of tube and it constantly run a fully submerged. It has seriousness but it does not look at this point that it has lightness.

Mind you that I am very ignorant with DHT and this is firth amp with 2A3 that I own. So, I need some time to figure out how to cook this tube in order to make it able to do the “lightness” tricks. It is very possible that I need to drive 2A3 with the 6E6P to get the right “acceleration” characteristics... I will be posting my further observations.

Rgs, The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-26-2008 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 526
Joined on 10-29-2005

Post #: 75
Post ID: 9271
Reply to: 9268
Topology and 2A3?
fiogf49gjkf0d
 Romy the Cat wrote:
It is obvious that 6SN7-2A3 and 6E6P direct have very different character. The 2A3 it feels like heavy-sunk time of tube and it constantly run a fully submerged. It has seriousness but it does not look at this point that it has lightness.
I also use the 6SN7-2A3 DHT for my system (except subwoofer). Did you use the Electrocubes for the coupling capacitors? Was the internal wiring regular copper?

The coupling capacitor is critical, of course.

Also, I will say that silver wire, which many people hate: the fact is that it is a better conductor. My opinion is that the silver wire reveals a problem that is creating harshness and brightness from the OTHER parts of the system, perhaps from bad electricity as well.

In my amplifier, careful choice of the coupling capacitor and using silver wire in the signal path corrected the problem of the sound being syrupy like in a dream where you are running is low motion.

Adrian
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  »  New  The one-stage Melquiades...  It's time, what amorphous opt...  Melquiades Amplifier  Forum     74  659581  04-21-2007
  »  New  The single-stage Milq and power Supplies...  Just the tank...  Melquiades Amplifier  Forum     10  96402  05-03-2007
  »  New  The 6E5P tube data...  Bartola Valves: 6e5p beam tetrode SPICE model...  Melquiades Amplifier  Forum     44  466936  07-23-2007
  »  New  6 Channel Version of Super Melquiades..  The first Milq screw up....  Melquiades Amplifier  Forum     131  1210427  08-08-2007
  »  New  My (Amplification + Acoustic System): what is next?..  Macondo and Melquiades in the NEW room....  Audio Discussions  Forum     41  303264  01-10-2008
  »  New  Incorporating active crossovers into DSET..  Thanks...  Melquiades Amplifier  Forum     2  44301  07-22-2008
  »  New  About the life-expectancy of the new production tubes...  Stressing the damn contemporary tubes....  Audio Discussions  Forum     9  90249  12-29-2008
  »  New  Small SET’s bass, besides everything- is it about power..  Importance of OPT and type of tube for SET amp bass per...  Audio Discussions  Forum     4  83209  01-12-2009
  »  New  Macondo: new horizons. A few thoughts in context Zander..  What does make a playback to stop?...  Playback Listening  Forum     9  72815  02-02-2009
  »  New  The period DHT tubes and Swastika..  Maybe there is another solution...  Melquiades Amplifier  Forum     1  27510  04-30-2009
  »  New  Some thoughts about Milq’s MF filter..  High-Pass RL Filter calculator....  Melquiades Amplifier  Forum     2  33642  05-02-2009
  »  New  The DHOFT topology? Do not try it home...  A medley of slow-cooked triodes....  Melquiades Amplifier  Forum     3  47004  05-04-2009
  »  New  Why the tubes shall be the same?..  Not optional anymore?...  Melquiades Amplifier  Forum     7  62403  05-11-2009
  »  New  Valve Technology Timeline..  A good video about tubes making....  Audio Discussions  Forum     5  95685  06-18-2006
  »  New  The DSET perspective examines the Herb Reichert article..  Are you still in Reutlingen, Germany?...  Melquiades Amplifier  Forum     5  94458  07-01-2009
  »  New  About the Critical Audio Tune ™..  “Critical Audio Tune” bay-leave in the soup......  Playback Listening  Forum     5  51027  08-29-2009
  »  New  A full-range quality-triode? Does Size mater?..  A full-range quality-triode? Does Size mater?...  Melquiades Amplifier  Forum     0  17064  12-02-2009
  »  New  About Stupid Dynamic..  Misplaced dynamics....  Playback Listening  Forum     1  21130  08-21-2011
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