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  »  New  Super Melquiades Amplifier...  About the Super Melquiades Bass....  Melquiades Amplifier  Forum     29  188938  07-16-2005
  »  New  Fun with transformers?..  Re: An amplifier is not a subject but a service.....  Melquiades Amplifier  Forum     7  66227  10-21-2005
  »  New  Building Melquiades: Chronicle of full-range..  VR2 issue leading to jump in current on 6C33 tube...  Melquiades Amplifier  Forum     44  254241  06-09-2006
  »  New  5 Channel Version of Melquiades..  Very easy....  Melquiades Amplifier  Forum     21  169188  07-23-2006
  »  New  RAAL “Water Drop” tweeter for Macondo...  Your comment takes me by surprise...  Horn-Loaded Speakers Forum     77  675876  02-16-2007
  »  New  The one-stage Melquiades...  Tubes vs. Speakers vs. FR...  Melquiades Amplifier  Forum     73  465286  04-21-2007
  »  New  The single-stage Milq and power Supplies...  Just the tank...  Melquiades Amplifier  Forum     10  64860  05-03-2007
  »  New  A DSET is better then an expensive SET..  DIY Stradivarius...  Audio For Dummies ™  Forum     41  254150  09-21-2007
  »  New  Amplification and Consciousness...  Freedom of expression vs. something to say...  Playback Listening  Forum     15  75632  01-07-2008
  »  New  My (Amplification + Acoustic System): what is next?..  Macondo and Melquiades in the NEW room....  Audio Discussions  Forum     41  207124  01-10-2008
  »  New  All Active! A DSET and multi-way acoustic system...  Hahaha...  Audio Discussions  Forum     14  81437  01-31-2008
  »  New  The Melquiades' "Remote Biasing"..  The Melquiades' "Remote Biasing"...  Melquiades Amplifier  Forum     0  14753  02-05-2008
  »  New  A proper implementation of low-pass filters..  Low Pass...  Melquiades Amplifier  Forum     4  33833  02-18-2008
  »  New  Incorporating active crossovers into DSET..  Thanks...  Melquiades Amplifier  Forum     2  30412  07-22-2008
  »  New  Single-stage Melquiades vs. DHT amps..  A hallucination?...  Melquiades Amplifier  Forum     397  2597920  11-22-2008
  »  New  If you’re multiamping then use passive-line lever cross..  Crossover and DSET?...  Audio For Dummies ™  Forum     3  37217  01-21-2009
  »  New  The DSET perspective examines the Herb Reichert article..  Are you still in Reutlingen, Germany?...  Melquiades Amplifier  Forum     5  68320  07-01-2009
  »  New  Training amplifiers..  The Milq's demands for burning...  Melquiades Amplifier  Forum     16  81745  03-20-2006
  »  New  Think ahead how to measure the DSETs gain...  The calibration mode is for DSETs not for SET....  Audio For Dummies ™  Forum     2  19014  09-17-2009
  »  New  Amplifiers heat… a real-estate solution?..  I have seen this simular concept...  Melquiades Amplifier  Forum     1  15445  09-18-2009
  »  New  About DSET-driven multi-way acoustic system maintenance..  About DSET-driven multi-way acoustic system maintenance...  Horn-Loaded Speakers Forum     0  18216  11-01-2009
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10-27-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 51
Post ID: 5747
Reply to: 5745
The contrasts…
Speaker vs. line

Many benefits, Paul, it was well covered at my site along with many others places.

Cap vs. coil

Truly huge, only this would well-worth the admission ticket of the line-level. Do not also forget that in high-pass situation a coil works as shunt filter vs. cap as a series filter. In this case the signals in passband does not flow though the filter...


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-01-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 52
Post ID: 5780
Reply to: 5744
Super Milq 6 channels diaries: I am through

Ok, now it is done and it is official as I see nothing available for conceptual improvement in the crossover circuit. Interestingly this version offers the most interesting sound as well, since the circus was tune for sound, not vise-versa, it is what was expected. The below is the last version and I am intend to leave it as is. There were no strategic changes since the last version but there was minor playing with loadings and gain to shape the sound in a way I feel it should be.

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=5765

Here is the brief online:

1) Lover Bass Channel:  the crossover point was moved to 78Hz
2) Upperbass Channel: the plate of the ½ 6C33C was loaded against 4000R instead of 1100R. The drop in the voltage divider was changed accordingly.
3) Injection Channel: was added mechanical frame to the speaker for precise time-aliment and fixation of the found position. The references setting is from minus 14dB to minus 10dB
4) Fundamental Channel: the high pass slope was moved to slightly higher
5) MF Channel: nothing was changed, was good as is.
6) “Water Drop” Channel: The tube was converted into triode and the Bessel 12dB per octave at 13kHz was implemented. The reference setting is from minus 7dB.



Above is the HF's high-pass filter for the "Water Drop"

It is it. In the two channels stages the drivers are at 205V, the output tube of LF channel (full tube) at 230V/200mA, the Injection and Upperbass output tubes are at 200V/150mA (half tube). The single stages tube are at 205V/32mA. I will make a picture when I close the amp up. Now I need to convert the second amp… I do not whant even to start it... to much work...

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
11-02-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 53
Post ID: 5788
Reply to: 5780
Super Milq 6-channels diaries: the final pictures.
Ok, the 6-channels super Melquiades is done, closed up and I made a few pictures of the beast. I have to admit that I do like how it amps turn out to be packaging-wise: the layout turned out to be very good for 3 channels as well and for 6-chennals. It looks and feel like Soviet military helicopter form 60s – well is what it is… As now there are no major further changes that I am planning to do. Among the minor things I would need sometime in future to put my Schottky diodes on larges heat sinks and to experiment with 2 alternative transformers for MF channel that I have (currently I use Pieter Treurniet’s Trebute for MF). I will do it after, when the right channel of the 6-ways Super Milq will be done. I think it will take another month of two. Also, I would need to found a good-sounding regenerator for the amps: 388W each monoblock

 So far, enjoy the Super Milq porn…




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-03-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 54
Post ID: 5791
Reply to: 5788
The new filtering capacitors for my tweeter channel.




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-04-2007 Post does not mapped to Knowledge Tree
Antonio J.
Madrid, Spain
Posts 272
Joined on 08-16-2004

Post #: 55
Post ID: 5792
Reply to: 5791
What are those?

I had never seen anything like that. I like their looks. Do they "sound" as expected? I'm fascinated for your efforts with your system. I think I don't have the endurance to go throughout all that, provided I had the time, space, resources and knowledge, which of course I don't have. Good luck Romy, I hope you get where you want to arrive.

11-04-2007 Post does not mapped to Knowledge Tree
drdna
San Francisco, California
Posts 498
Joined on 10-29-2005

Post #: 56
Post ID: 5793
Reply to: 5791
Why the vacuum caps?
The question in my mind Romy is: why?  I will be interested to hear your comment on what your goal was to learn about your system in introducing these and what the results are.  After the extent to which you have described the sound of your system, it will be very instructive to hear your comments.

I have toyed with the idea of using these for RIAA circuits in a phono preamp, since the required pF values are appropriate and they should offer minimal distortion.
11-04-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 57
Post ID: 5794
Reply to: 5793
Capacitors are like cholesterol - migh be good and bad.

 drdna wrote:
The question in my mind Romy is: why?  I will be interested to hear your comment on what your goal was to learn about your system in introducing these and what the results are.  After the extent to which you have described the sound of your system, it will be very instructive to hear your comments.

I have toyed with the idea of using these for RIAA circuits in a phono preamp, since the required pF values are appropriate and they should offer minimal distortion.

Well, prior to personably bitching about capacitors let define what we are fighting in capacitors. Capacitors are like cholesterol: there are good capacitors and there are bad capacitors. The good or bad status is however is not only determined by the type of capacitors but primary by the why how the cap is used. If cap is a coupling capacitor (or PS capacitor) then it is squashed from both sides by differences of DC potentials and the dielectric of the capacitor has been already polarized. The small amounts of AC signal the flows over the cap has not significant strength to repolarize the cap’s dielectric. Why it is important? Because the what AC attacks the cap’s dielectric the dielectric acts like a cone on miniature loudspeaker, crating electro-mechanical vibration and consequentially the microphonic noise. However, in case a cap use no or little DC (as in line-level filter of feedback filter) then each single milivolt of AC forces the dielectric into re-polarization. Better dialectic less exposed to this event but what would be if the dielectric …is vacuum or air? In this case there is no dielectric of any kind. available for re-polarization. I was looking for year the right vacuum cap and all that I have seen with right fixed values were aluminum caps. Now I have eventually found a pure cupper cap. Will it be better than an air cap? I do not know but I will try, and I think this is the only way to answer the question.

Pay, attention the Melquiades nowhere uses the “bad-type” (location) capacitors. Wherever the circuit is called upon such a cap the amp uses RL filters or the caps with no dielectric (air, vacuum)

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
11-04-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 58
Post ID: 5797
Reply to: 5788
The new Super Milq and the old Super Milq.
On Friday a guy that I invited long time ago shut me email informing that he should be in Boston this weekend. I have just one freshly cooked 6-ways Super Milq and just right functional Macondo channel. I did not wan to brash him off and I connected the old 3-ways Super Milq to temp just-made crossovers and decided to run it along with the hew 6-way Milq-Macondo assembly. None- of the 9 channels were calibrated yet and there was many aspects of sound that I do not like but to my big surprise the general imaging was not absolutely destroyed. The installation did not do it’s customary “kinky” things - like curve the presentation in parabola – but the imaging was much better then I anticipated form a playback driven by essentially different amps.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-24-2007 Post does not mapped to Knowledge Tree
op.9
Planet Earth
Posts 68
Joined on 01-26-2007

Post #: 59
Post ID: 5939
Reply to: 5780
Bias confusion
Romy,
Could you help me understand your biasing scheme with this version? I thought I understood the original Milq circuit - but the only channel that looks like that to me is the D channel. I don't get A and B at all! what is the 50 ohm resistor doing? is it just a grid stopper? I assume you can adjust bias and 0v at input in each stage - but don't the two red legs (on channel B for example) work against each other?
Thanks in advance!
james



everybody used to call me James in my past other-worldly life.
11-24-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 60
Post ID: 5940
Reply to: 5939
The Super Milq’s input: electrical perspective.

 op.9 wrote:
Could you help me understand your biasing scheme with this version? I thought I understood the original Milq circuit - but the only channel that looks like that to me is the D channel. I don't get A and B at all! what is the 50 ohm resistor doing? is it just a grid stopper? I assume you can adjust bias and 0v at input in each stage - but don't the two red legs (on channel B for example) work against each other?

Sure.  Let live aside of idiosyncrasy of sound with gas tube driving fixed biased 6E5P. I have written about it in many places:

http://www.GoodSoundClub.com/TreeItem.aspx?PostID=5533

…and it would be totally different subject.

Let look at the Super Milq’s input just from purely electrical perspective. The basic premise is to get rid of a DC blocking capacitor at input. To do it we pit a series dose ohms resistor and then apply a contra-collage on another side to keep the DC balance at input at zero volts. Then we need to put at each channel own filter.

Here is the initial filtering idea.

SuperMilq_6Ch_5.jpg

I intentionally kept all drafts on the site to show progress and how one thing flew into another. Eventfully the series capacitors were replaced with RL filters and it make too many series resistors in signal pass, so the objective was to combine the filtering and biasing duty of the resistors together.

So look with what we end up:

Channel A: Has RC (substitute for L) filter at input and the 30K filter resistor is used as yellow biasing resistor. Look at the Draft 3. R14 and R27 are the same resistor and if so then we do not need R17 (red), the purpose of Red resistors is apply positive contra voltage on the left side of bias resistors but in the final draft on the left side of 30K resistor there is a common B+ voltage share be all channels. Surely, since we have much less positive voltage “sipping” through the new bias resistor (30K is more then 12.1K) then we need to apply much less negative voltage to the grid, or to increase the value of greed resistor. The 50R resistor is grid stopper; it might or might not be there – does not matter for THIS circuit. (The need of grid stopper for fast tubes is another subject all together)

Channel B: The identical story with the Channel A only instead of 30K series resistor we have a voltage divider that from a prospective of filter/bias is the same fixed series resistor. Pay attention that of I can the cable on the left side of the divider, disconnection the Channel B then I would need to change value of the Red 402K resistor at the bottom of the image as the total balance of positive (coming from 402K resistor) and negative (returning back from each channel) will be changed.

Channel C: this is practically standard Milq configuration with L-pad at input – there is not filter in here. You would ask me why I did not use the same approach as I used in Channels A and B – getting rid of Yellow and Red and letting voltage to pass via the attenuator to common positive. The reason is because my L-Pas is laden type, what has constant input impedance and variable output impedance. So, the circuit balance the 0V dc on left and right from the L-pad, making the channel DC do not care about the L-Pad. If in my L-pad I would flip not 2 resistors but 4 and the output impedance was constant then I would employ the same approach as I did in the channels above.

Channel D: This is quite complex. We can’t used the approach as above as the DCR of filtering coil is too low (250R) and the negative bias voltage shorts itself to ground via the coil. So, we need here a fill scale biasing Yellow resistor to keep the tube happy. What happened at left side of the Yellow resistor? Some voltage comes from positive bias, via 36.6K resistor and across 250R of coil to ground. So, why do we care, we juts  adjust the voltage of common positive bias and it will be it.

Channel E: The RL filter, the situation is identical to the Channel D. It might be a concern that I have we have too high series resistance in a grid chain. In practice is dos not sound as HF-challenged. That impedance with Miller capacitance of the 6E5P makes ~ over 100K low-pass filter … not so damaging for a fast, oscillation-incline tube.

Channel F: It has input cap that does not transmit DC, so we should not vary about anything and juts run one green resistor with negative bias supply. However, some voltage drift via coil to ground, passing through the L-Pad with variable output impedance… Eh, Not good! So we need to put a Yellow “bias stopper” into the game and to get 0VDC on the left side of the Yellow resistor. Then positive will not flow to coil because it will be blocked by the cap and negative will not flow anywhere because it balanced by red resistor. This way flipping the L-Pad affects nether bias nor impedance. Not that the L-Pad has constant input impedance against which the CL filter is written (it is Bessel). It was very important and a change if the attenuator impedance would lead to change of crossover point and subsequentual throwing the tweeter off the time aliment.

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
12-16-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 61
Post ID: 6132
Reply to: 5780
The Super Milq’s electrons pool.
Yesterday I woke up and suddenly I feet liking to convert my second Super Milq in 6-chennals Super Milq. I kind of did not want to touch it for almost 2 month and yesterday it “got” me. So, I started: took all the unnecessary 3-chennals Super Milq guts out, changed the needed to be changed transformers, drilled the need holes and begun to-hook up input stage. It is kind of dirty and messy inside but it dives an idea about the grounding schema I use of the first stage. Pay attention that the local +400V terminal also has 8ga local cupper “buffer”.

I am not trying to pose myself as some kind of DIY guru, in fact I have little interest in the DIY knowledge but my objective is to make the Super Milq as silent as it could be. The first 6-chennals Super Milq, where I use absolutely the same techniques is not just quiet but it is absolutely silent in each channel, even if I stick my head inside the horns (people who use 110dB sensitive installations know how it works “usually”) - it is absolutely imposable to say if amp is on or off by listening the sound coming from Macondo. So I presume I do something right.


The “local” large copper mass in B+ does NOT do a “huge affect” but I feel that it does makes sound more “moisture” very slightly. I have no explanation why. A friend of mine call it “electrons pool” (he uselessly refer to electrons pool on cathodes) but I do not subscribe this explanation as I feel that electrons do not exist and the bogus believe about electrons was invited by Franz Kafka’ imagination while he was writing his chemistry papers during his sophomoric years.

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
12-16-2007 Post does not mapped to Knowledge Tree
Wojtek
Pinckney (MI), United States
Posts 159
Joined on 09-01-2005

Post #: 62
Post ID: 6134
Reply to: 6132
It looks very good to me ..
Bare ,tick 400V B+ wire does look a little  scary .Those noval sockets are  very nice -are those teflon ones ??
Bud Purvine is also using "electron pool" concept but I think the application is a little different ;0)
RGRDS, W
12-18-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 63
Post ID: 6143
Reply to: 6132
The Second Super Milq: it is coming.
To my surprise it is going along not painful. I do it a half hour per day – only when I am in a mood - and I do not feel abusive with it at all. At this point the half of the bias chain of the third of the filters have installed. If it go further so smoothly then I might have the second Super Milq at Charismas semi-operational and instead of humiliating myself in Chinese resonant I might actually try to listen this thing…




"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-23-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 64
Post ID: 6180
Reply to: 6143
Super Milq: trying to do it last time + caps for PS.

I was slowing mingling the conversion of the power supplied of my second Super Milq from 3 channels into 6 channels and I ask myself: is anything in that amp is made in the way that would allow me to close it up and never review it. Sure if I move in very large space then my Macondo would need more power but it will be another story as it  might be a different Macondo then…

Anyhow, in the 6-channel Super Melquiades I found there is one moment that I feel might be done differently. Currently I have the single-stage amps powered anode supplies that power the Injection channel’s 6C33C. Since the Injection channel is a lot of dB down the plate voltage is very stable. Also the last cap in that supply is 15.000uF, so an extra 100mA that the 3 single-stage amps draw are not a big deal. Still, I feel it is a half ass solution I decided to change it while I am revising the amp. I do not know if the dedicated supply would make any sonic difference, I have no problem with sound of the single-stage amps as now, but it to have the single-stage amps power from own supply would be intellectually more pleasing. The most important it would keep the 6-channel Melquiades logically compile and eliminate the itch to thing about the dedicated supply in future.

So, I will be building-in (thankfully I have space and additional wire in the connector between the PS and amp) a new power supply for single-stage amps. It will be a full scale: 220V/250mA separate power transformer, Schottky full-wave bridge, LCRC filtration. I also contemplate, since the single-stage amps do not care any low frequency to make the power supplies only with film capacitors. I think it might be interesting in HF section of DSET. Does anyone know any low voltage (250V-300Volts), 100uF-300uF film capacitors? Do not propose Solens – they sound like crap. I have some 100uF Ansers but they are 650V – too big…

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
12-23-2007 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,157
Joined on 10-12-2006

Post #: 65
Post ID: 6181
Reply to: 6180
Not to start a run on them,
but Auricaps are plainly better than Solens, and they also come in the larger values (partsconnexion.com).

I can't say that the Solens are "good", ever, really, but I can say they are better when I use them a lot, ie, they are less of an "issue" when I keep them juiced up.

I am slowly phasing over to Auricaps, however; it would be done by now but for the boutique prices.

Best regards,
Paul S
12-23-2007 Post does not mapped to Knowledge Tree
hagtech


Hawaii
Posts 117
Joined on 02-13-2006

Post #: 66
Post ID: 6182
Reply to: 6180
Ferret them out?
So what is with the ferrite beads?  Do you find they are necessary?  Seems to me the resistors right on the socket would be good enough.  Especially with the grounding of the center pins.  I run beads all the time in my digital signals, but avoid as much as possible for analog.

jh
12-23-2007 Post does not mapped to Knowledge Tree
Wojtek
Pinckney (MI), United States
Posts 159
Joined on 09-01-2005

Post #: 67
Post ID: 6183
Reply to: 6182
DIYHiFi Supply from HK
has supposedly very nice Obbligato line of film HV caps . I personally bypass Solens with vit. Q and they are OK to me but for you it'll be probably summit of known what.
Rgrds, W
12-24-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 68
Post ID: 6184
Reply to: 6182
The con and pro of 6E5P anti-oscillations measures

 Wojtek wrote:
has supposedly very nice Obbligato line of film HV caps .

Thanks, the high nominals the have only 630V and they are larger than I would like to have. Does anyone know how those Obbligato sound in PS?

 hagtech wrote:
So what is with the ferrite beads?  Do you find they are necessary?  Seems to me the resistors right on the socket would be good enough.  Especially with the grounding of the center pins.  I run beads all the time in my digital signals, but avoid as much as possible for analog.

As you can see I did not leave ferrite beads out and I did use 47R grid stopper at all channels. I even put 2 ferrite beads on MF channel (you can see it on picture). I have to admit that I did use Milq without ferrite beads and without the grid stopper (still keeping 50R between the screen and grid that serve the same anti-oscillation purpose). I did not detect any oscillation-related problems… but only with good tubes. I did not play with “too life” tube in the situation when I did not use stoppers. Also, I did not detect or research that the ferrite beads affect sound in negative way. I do not think they should…

The good 6E5P/6E6P are oscillation-free would it be with ferrite beads or not. They might have some minor oscillation for a few minutes after the start while they are cold and then when they reach their cruise temperature the oscillation should be gone. What is interesting that the 6E5P/6E6P’s oscillation is much softer and less annoying (even dangers) then the oscillation of other UHF 100-300MHz tubes. The WE417A, the WE437A, the 6842 when they got aroused were very atrocious. The 6E5P/6E6P oscillations very mildly and gently – it is like a difference between the Plinian and Hawaiian types of volcano eruption. The 6E5P/6E6P when it age might develop some minor HF noise – it is an easy sign to spot and identify a worn up tube. BTW, I did not detect any oscillation pattern differences between 6E6P-DR – the military and tighter tolerance and the regular 6E5P.

So, the story is that I keep the ferrite beads in there. I do not know if it is necessary. My behavior with the ferrite beads is more like the behavior of that nun who said “Good protect anyone who protect themselves”, while she put a condom on her candle….

Can I stay without the ferrite beads and grid stopper? Probably I can. The grid “bias” resistor is very high that forms with Miller capacitance of the tube a near 100kHz filter. The bias voltage the come directly to the grid is from gas tube. The gas tube voltage is not regular voltage but very “slow” voltage and it might do the additional comforting of the grid. So I might go away without ferrite beads and the grid stopper... but the question is why would I need it?  There are some “protective” benefits from them but are they the course of any problems?  Did you detect that a ferrite beads affect sound in any negative way? If so, then might it be the size and the type of the ferrite beads?

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
12-24-2007 Post does not mapped to Knowledge Tree
hagtech


Hawaii
Posts 117
Joined on 02-13-2006

Post #: 69
Post ID: 6185
Reply to: 6184
Bead to Me
I have not experienced any ill effects from ferrite beads myself.  That is why I asked.  Some report sonic degradation issues (like CH at Ayre).  Some say they can get magnetized.  Listening to the masses I am unable to put together an accurate picture of reality.  Yet.  Detecting a pattern of concensus from within the noise is not happening.

jh
12-24-2007 Post does not mapped to Knowledge Tree
cb
Posts 5
Joined on 03-14-2007

Post #: 70
Post ID: 6186
Reply to: 6180
Caps for PS
Came across these at Madisound.

ClarityCap 100μF 250vdc PX Range Polypropylene Capacitors. I have no experience with them though.

Rgs, Charles
12-24-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 71
Post ID: 6187
Reply to: 6186
The Metallized Polypropylene vs. something better.

Yes, thanks Charles and thanks for everyone who sent the direct amps on this subject.

The ClarityCaps, similar to the Canadian Solens, British Ansars Supersound, the French MKP, and a few others proposed, are all Metallized Polypropylene caps. I am not a big fan of them generally. There are also an Oil-Impregnated Metallized Polypropylene caps like Siemens/EPCOS MKV, V-Cap, Vishay, ASC, GE, Sprague and a few others –  the motor’s start up caps - I am not a huge fun of them ether. I did not try all of the in PS but I did play a lot with Metallized Polypropylene on speakers and in line-level coupling application and I did not like the results.  So, I have large 100uF Ansars that I will use for now but I will keep my eye open for more “intellectually interesting cap”.

Also, I reach a pathetic point of my live when I decided to build a new PS for my amps and… and … and  … and I  accidently have all parts that I need right in my home – very troublesome symptom. So, the PS will be a 300mA torpid with 220V secondary, Schottky full-wave bridge, inputs choke 15H/150mA and 40mF and then RC with 100uF.  I should be arriving at 200V, 110mA of 3x6E5P and most likely I will bleed extra 20-30mA through the choke – I do not know exactly now – I will measure the choke performance when I build it.

 hagtech wrote:
I have not experienced any ill effects from ferrite beads myself.  That is why I asked.  Some report sonic degradation issues (like CH at Ayre).  Some say they can get magnetized.  Listening to the masses I am unable to put together an accurate picture of reality.  Yet.  Detecting a pattern of concensus from within the noise is not happening.

Hm, interesting. I remember a long time ago I did tried to detect the sonic influence of ferrite beads on my 7788-7721 phonostage. At that time I was listing the 7788 with and with the ferrite beads and I did not detect any sonic impact. I did it only once and never thought about it again. I never tried in with Melquiades. I do not know who CH is but I do like the Ayre as a company, so I presume that whoever CH is he is not an idiot. Still, if CH is correct and the ferrite bead gets magnetized with time (it is not difficult to measure with a gausemeter) then why should it affect sound? I really do not know the answer. It would be a good idea to remove the long-worked ferrite beads and to listen if the sound was changed. Unfortunately in my case if the ferrite bead was working for a long time then to physically access to it in the Milq would require an archeological expedition…

The Cat

PS: BTW, what I do not is another advantage of DSET topology:  http://www.romythecat.com/Forums/ShowPost.aspx?PostID=5344


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
12-24-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 72
Post ID: 6188
Reply to: 6187
The PS for the single-stage amps: trying to disregard ripples.

Trying to take full advent age of DSE and contusing the thoughts that I developed in the flowing thread:

http://www.romythecat.com/Forums/ShowPost.aspx?postID=4328

http://www.romythecat.com/Forums/ShowPost.aspx?postID=4743

I would like to try making this PS for single-stage amps with absolutely minimal capacitance. It will be very interning experiment something that was planning for a very long time.  Let presume that no switching pulses Silicon Carbide Schottky Diodes are free from any problems and will produce right sound (that would make me do not try the damping diodes) then what we have left – the filters. The first LC chain is not filtrating chain but rather filter entering chain (set right Q + current stabilization). It will very-very slightly reduce the ripples but very slightly. The ripple killing is done with the second RC chain where the last cap is usually is very large in my supplies.

Now we have a DSET where the single-stage amps have just 2.8W and care just MF and HF. This opens a very interning opportunity. I have been saying for a while, perhaps incorrectly, those ripples have no affect to sound. Sure they affect noise but if the noise is not auditable then ripples are not important. So, it will be fun: 120Hz ripples against the HF single-stage 2.8W, 35 times gain amps, 109dB sensitivity. I am going to tell you honestly I will not even planning to measure ripples and juts will be listening the noise from the speakers (I will not use my compression drivers but a full range speakers to hear the LF wobbling to assure the absents of Doppler problem in my compression drivers)

So, I ma planning to find the absolute minimal values of the last capacitance necessary for my application. I hope that I will be able to go away with LCRC were the fist cap will be a couple dozen uF and the last cap will be a few dozen uF. I will be reporting the results.

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
12-25-2007 Post does not mapped to Knowledge Tree
hagtech


Hawaii
Posts 117
Joined on 02-13-2006

Post #: 73
Post ID: 6189
Reply to: 6188
Ripples All The Way

The issue I see is that of intermodulation distortion on the biasing of the output tube.  It will effectively change HF operating point per supply ripple.  Easy to understand if one imagines a gross ripple of 50V.  Same thing happens with 0.5V ripple, just to a lesser extent.

In my latest ongoing amp project I re-discovered an easy way to deal with some ripple.  The stage runs large bypass cap from B+ to cathode to keep output loop small.  Only thing left is grid.  I drive the grid through an interstage tranny, and set the common mode of the secondary to ground via 50k resistor.  This is for dc bias.  The trick now is to run a 1uF or so cap from B+ to the common mode of the secondary (in my case a center tap).  Thus, any ripple on B+ is also exactly seen on cathode and grid.  The tube has no idea anything is going on, as it only sees a constant dc bias at all terminals.  I got this idea from a WE92A schematic.  It works incredibly well.  My noise floor (on proto) dropped maybe 20dB or more.

jh

12-25-2007 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,545
Joined on 05-28-2004

Post #: 74
Post ID: 6192
Reply to: 6189
Sometimes ripples are not only ripples.

 hagtech wrote:
The issue I see is that of intermodulation distortion on the biasing of the output tube.  It will effectively change HF operating point per supply ripple.  Easy to understand if one imagines a gross ripple of 50V.  Same thing happens with 0.5V ripple, just to a lesser extent.

Jim, I do not know – it is not so clear to me. First of all the subject of the intermediation is kind of complex.  The contemporary ceramic dives in soft runner suspension have intermediations (via Doppler) order of magnitude higher then compression driver and it doses not prevent them to accepted by morons as “good drivers”. I was thinking abut it before and I do admit that in the case of high ripples the modulations might take place from DC ripples  on plate to AC plate but to which degree I do not know. From one point it is very easy to measure the change of intermediations with change of ripples but from another point I do not know what that measurement would mean. Also I do not know where the subjective problem of intermediations would compete with subjective benefit of lowering capacitance. My objective is to find purely subjectively an equidistant between the minimal capacitance (with presumption that smaller cap would allow to use better cap) and the negative subjective sensation that high ripples might be resulted).  With full a range Milq the minimal capacitance of the last 6C33C cap was 750uF but it was restricted purely by noise. In biasing of 6E5P the minimal capacitance after gas tube is 10uF and it is purely sonic value. I was experimenting in there with everything, starting from no-capacitance and ending with 100uF and in there it is MUCH more critical as I is right on grid). For whatever reason the 10uF was a dead spot where everything come together… So, I presume and hope that the 6E5P plate, in my application, might have own max tolerable ripples and min capacitance. I am not certain in it but I do have a hunch that it might be much smalls capacitance then I ordinarily put in…

 hagtech wrote:
In my latest ongoing amp project I re-discovered an easy way to deal with some ripple.  The stage runs large bypass cap from B+ to cathode to keep output loop small.  Only thing left is grid.  I drive the grid through an interstage tranny, and set the common mode of the secondary to ground via 50k resistor.  This is for dc bias.  The trick now is to run a 1uF or so cap from B+ to the common mode of the secondary (in my case a center tap).  Thus, any ripple on B+ is also exactly seen on cathode and grid.  The tube has no idea anything is going on, as it only sees a constant dc bias at all terminals.  I got this idea from a WE92A schematic.  It works incredibly well.  My noise floor (on proto) dropped maybe 20dB or more.

Yep, the idea to have the enter tube to “float on ripples” is elegant but from my point of view it is not the way to fight with problems the ripples might course. You might make the tube impervious to ripples but look how much you pay to do so: pollution of cathode, pollution of grid… in the case of DH you would need to pollute the filaments… Is it worth it, Jim? BTW, some of aspects of your “float on ripples” idea, viewed from a dissimilar angle, is something that Dima and I recently “re-invented” for a VERY different and for almost “revolutionary” application. I am sure the readers of my site will be reading about it in a coupled mouth if the implementation demonstrates itself sonically positive.

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
12-25-2007 Post does not mapped to Knowledge Tree
hagtech


Hawaii
Posts 117
Joined on 02-13-2006

Post #: 75
Post ID: 6193
Reply to: 6192
Floating Ripples
the subject of the intermediation is kind of complex

It's difficult for me to guess exactly what the possible sonic effects of the ripples would be.  I see a tube operating at a fixed point, having a particular distortion spectrum.  Say -42dB 2nd harmonic.  Then, the ripple pushes it to a new operating point, giving -40dB 2nd harmonic.  So the treble signal is modulated where distortion fingerprint changes at a 120Hz rate.  Is that audible?  What does it sound like?  Maybe I am chasing ghosts.

Similarly, we have the same thing with DHT, as the operating point of tube changes with the temperature of the cathode, heating and cooling at 60Hz. 

Maybe this is so far down in the noise floor we cannot hear it yet.  There are other peels to the onion that must be removed first.

jh
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