op.9 wrote:

I chanced upon an interesting PSU arrangement for my 5842. I run a valve regulated powersupply at 210v and then drop down to 160v with an un-bypassed 8uf oilcap. Any more capacitance or bypasses seemed to be a step backwards in terms of pleasure. A nice side-effect of the regulator is much more consistency of sound from day to day. (I run my 5842 with a 2v lead acid cell in place of a cathode resistor)

I’m kind of debating how I will organize the PS. I am considering going for LCRLC with a lot of inductance and small capacitance to make the tube stage to “see” Bessel curve in PS…  Nevertheless, I do not know at this point… The LCRLC chain will be driving 4 RC parallel filers for each channel. (To keep the shot pass to ground for each stage). I do not know for now how it all will be organized from sonic perspective… In fact, considering my demands for compact size and the dimensions of the parts it become quite complex to built everything inside the Macondo’s frame.

I know that there are some people who would like to hear form me about my findings regarding the Singe-Stage Milq. I do not talk about it for a while but not because I do nothing in that direction. The decision was made to convert my 3 stages Super Milq into 6-chanls Super Milq featuring 3 full two-stages Milqs and 3 one-stage Milqs under one roof.

I have found all voltages, filaments all supporting thing – it do-able and it is all almost have done with one amp (you can see 6 driver tubes). There in nothing is connected yet internally as I have no out transformers for one-stage amp. The transformer are ordered and they will be ready within a month of so. The special attraction will be given to MF transformer the will be driving the main S2. I have recruited 4 transformer manufactures who will be making their versions of OPT according to my specification but utilizing this own implementation techniques. I will report which transformer will turn out the best (I will not report on the contestants). The budge that you see atop the Super Milq is the home for 3 new output transformers, currents meters and all supporting things. It should be very interesting…

op.9 wrote:

Thanks, look forward to hearing about your results. I am tempted to make some similar experiments myself - but all I have to hand is some 17.5:1's. I think I'll give it a go anyway..

Still the final number would depend from:

1) The ACTUAL impedance of your load in the bandpass of the given channel.
2) The plate current
3) The listening distance from the channel and how “live” your room at the bandpass of the given channel.
4) How your other channels are loaded
5) What kind driver are you using and what the driver’s natural harmonics
6) What frequency range you drive
7) How responsive your particular driver for damping
8) How far you are fro axes of the channel if you use horns
9) Reverberation time in your room.
10) How the transformer is made (it might have own 48282 parameters)
11).... esle

Generally I feel that for 6E5P anything from 10:1 to 20:1 into 15R might be useful in one way or another…

I got today my first pair of output transformers for the single-stage Melquiades.  They are 40ma, 5H, 42R primary, 15:1, Amorphous, with remapable secondaries made by Netherlandian Pieter Treurniet. I did not put it in use and heard them – probably it will take another two weeks but I need to say that this transformers made me to think sorry they the will be hosted inside of the Milq chassis, I never thought I would feel this way.

When I spoke with Pieter I asked him do not pot it into a can as it will be inside of amp, Pieter gave me a lot of reasons why he insist to pot it, fi9nishing with something like this: “I know hat I do. It will be potted”.

Well, the sad irony is that when I got those transformers the first thing that very impressed and surprised me was… their potting. It really feels deferens and I did catch myself that I actually experience a pleasure to hold the things in my hands. I am not kidding. It has a very strange quality of very precisely boiled egg, what a few seconds more would make it completely boils but a few second less will make the core too soft. Of cause the transformer has noting inside riddling of liquid but I constantly caught myself that I am wiling to shake it… Very abnormal feeling for me and I usually do not give a damn how the parts look and feel…

Can’t wait to put this baby into the use…

Romy,
It seem what with the tacttile pleasures of boiled egg potting compound sensations you are going a bit Sakuma yourself.

I will say this: I think Pieter is an absolute magician when it comes to iron; he's also a gentleman despite looking like Larry David's Dutch cousin.

I have to say, if there's any way an inanmiate component would capture some of the personality of its maker, it would be the output transformer. All that painstaking winding, layering, core assembly etc. I wonder if it's a coincidence that my fave OPTs all come from folks who are either pals or I get on very well with.

I hope they work well for you.

cheers
cv

The new 6-Channal Milq is up and running, I did manage to calibrate everything in the Macondo’s left channel and was listening it for a while. I might report somehow a controversial result. The MF drive with a single stage is incontestable king – it very clean and it cured the S2 from all its illnesses. Should I rejoice? Well, not real. Along with a phenomenal smoothness and cleanness the MF now exhibits a behavior that I do not like, in fact - hate. That all makes the enter sound absolutely not acceptable. Here is what I found very wrong:

1) With increased of dynamic the channel go thinner, the higher volume the thinner it goes. Extremely ugly!!!
2) The channel now too fast, inappropriately fast, faster then the rest of my channel. It is a way hyper-transient and  harmonically deficient – a typically overly idling tube
3) It sounds OK power vise only with full 8-9W dissipation on the tube – a very full power. Lowering power to 6W and the channel begin to loose in stresses.

Here are possible solutions that I am considering:

1) Heavier loading the tube that should eat some transients and add power.
2) Trying a different output transformer if it will not help
3) Change, S2’s impedance curve after 10K
4) Accept that a single stage amp was a dad idea.

Frankly I do not case about the wrong transient and harmonic balance - I will be able to deal with it by loading the tube it will also shell address the problem with power. However, I am VERY concerned about the increase of  thinness with rise volume… I afraid that it might be a characteristic of a sing-stage amp… I play that the effect will go away what I load the 6E5P much heavier.

The 5E6P is the same as my 5E5P only with more or less military ambitions and with congenital “western” pins layout. It has more fragile specifications and more tight tolerance then 5E6P but it is the very same tube. There is very very very minor sonic difference between then and it is why I used 5E6P for my MF and tweeter channel. Still, the 5E6P and 5E5P has the same character in sound and might be consider as the same tube.

However, the 5E6P has the identical pins lowing with another my favorite tube – the 7721 or D3a in European specification:

http://www.goodsoundclub.com/pdf/7721_D3a.pdf

The 7721 is from the same family as my beloved 7788 and they were made in the truly golden age of tube manufacturing. It is a bit more powerful then 7788 and it is much better driver then 7788. The 7788 is a king for microphones and MC cartridges, the 7721 is a next output state…

Now is the fan…. The 7721 and 5E6P have the same pins and pretty much interchangeable.  The 7721 won’t handle as much power as 5E6P but my interest to use it on tweeters what I need no power.  I drive the 5E6P at 200V and a good 5E6P pushes 1800mS under 30mA and with minus 4V on bias. The 7721 (as a triode) give the same transconductance at the same voltage and 12mA on plate.

What I need to learn how would 7721 sound driving my tweeter.  I also need twice lower plate impudence for my tweeter driver (do not ask why - it is classified). The 7721 does has lower impedance but a higher current. I wonder what would be the 7721’s plate impedance at 12mA.

I wonder what would be the 7721’s plate impedance at 12mA

op.9, cv and the rest folks at the previous page.

After a long debate and consulting with multiple parties it looks like I am incline to go for nickel-iron alloy (Mu-metal) transformer in my substitution of single-stage MF amps with DHT. The objective it to drop the core “speed” and decrease plate loading. Let wee it is was a right direction to go.

Be careful to relieve me if I am not impressed, many promised no one excelled. :-)

Chris, I do not think that you will see me to think about transformers for other channels. I do not think that what I do will be some kind of resolution for Amorphous vs. Nickel transformers: in my care it will be a different amp with different out tube and differently loaded. The subject of faster core vs. more idle plate is very interesting but I am not the one to address it. I do want to do for a SLIGHTLY slower core, but not too much slower, then increase damping and power, will see where it will lead. I have a hunch the it might be a good direction for a limited bandwidth

About the transformer. I was thinking about it a lot. It will be 70% Nickel with limited inductance to support 200 cycles  at 50mA. 20:1. It will load the ~1250R plate of YO186 to ~6K. I have no idea if it will be good and if the YO186 even the tube that will give any interesting sound. Here is what I was thinking:

In my priory list are the “small” 4V DTH tubes like RE604, AD1, PX4 and those ghost-like YO186 since they were damped to my head and might be a “cheap” replacement of the imposable to get good RE604, AD1, PX4. If my project with small DHT will go south then I will go for full-size DTH but the high-impedance, like 10Y. Many experiences people advised me that I will not see in those high-impedance tubes the “tacky” and “overly romantic” qualities that I do not like in some DHT. I kind of would like to have “clean” and “neutral” sound, the one similar in “cleanness” to 6C33C, sine it will be DSET I do not see any problem with high OPT ratio. If the 10Y will not go as well then I will jump into the common 2A3/300B/45 wagon. If all falls then I will return to my ½ 6C33C… that it absolutely securest assurance of the result that I accept.

So, how to put one ass to all DHT transformers? I find a solution. In fact I did not find it, it just came itself. I spoke with Dave Slagle, inquiring what he can do and he told that his design implies the field interchangeable coils and adjustable gaps. That is a very cool solution for me. He also assured me that the assembling and disassembling of his transformer is Morons-complained, which is perfect for me. So, he will wind a base transformer and I might just get from him more windings if I need them.

Regarding you to hear the installment? Be my quest. From what you heard before my playback nowdays is 342 light miles ahead and I am very comfortable to play it "as is" without any MF modifications and with the Amorphous  magnetiks. I afraid that MF modifications will do some downtime foe a month or so, unless my unicorn YO186 hit the mark from a first try…

cv wrote:

…. I'm not sure I believe the overall hypothesis, I think it is more a function of the particular high/low impedance tubes he was writing about (300B, 10, 45 etc). But how this translates to neutrality above "levels 1 or 2" is another matter entirely...I think the 6C33 is a complete outlier in this respect.

cv wrote:

Yes, well - I wasn't really saying much; just a vague hypothesis. There is some tendency for lower Rp tubes, (and somewhat related) tubes with a certain harmonic structure, to sound more romantic, and hence impart that quality to music regardless of the content, the 6C33 has the lowest Rp out there, and is not the most linear, and yet you've found that somehow it manages to keep out of the way of the musical expression, or even enhance it in some ways? It seems to polarise tube fans - many won't touch it, saying it sounds solid-state... ie they are missing the romanticism (despite it being not that linear....) Something like a 10Y is rather clear/lean sounding *and* measures it too... so - along the lines of some of your comments  - what exactly is the 6C33 doing? I don't have that much experience with either tube, so these are just some wishy-washy thoughts... sorry I don't have more time to elaborate more clearly!

I have heard criticism of some people that 6C33 sound like solid-state and missing some romanticism. I disagree, not to mention that I practically never heard any good sounding amp around 6C33 – not because the tube but because the people who cooked the tube. The 6C33, with all appeared simplicity, is a difficult tube to get good sound out of it. In fact among all 6C33 amps that I ever heard in my view only ML2.0 was able to get right sound out of 6C33: the ML2.0 had no even references to SS or to tube sound. The SS vs. tube is for AA or DIYAudio.com - level of audio, the ML2.0 was beyond it…

Anyhow, I am not a huge fan of romanticism-addiction that some many DHT fans look like have. Romanticism is great but if music is not call upon romanticism then what would you do? I understand that those people who complain that 6C33C has “missing romanticism” understand neutrality in a different and very primitively way, so who care what they think. A two-year old child might have an Opinion why Moon is moving 2” further from Earch each year. Does anybody care what this child thinks?

I do not know what 10Y does – I never used it but from comments of people who have the similar to me detaste for the tubey “artificial melancholy” and pulled out-of-ass phony romanticism I concluded that 10Y MIGHT be different then the other DHT’s casual suspects. I do not know how accurate it is.

Anyhow, I kind of stuck with 6C33C and her definition of neutrality - I am quite comfortable with it. I begin to question my move toward to a single stage, but this is whole other subject. BTW, I do not know if you have seen it but David have made a transformer for my YO186:

http://www.goodsoundclub.com/GetPost.aspx?PostID=9689

I know you were interested.