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…

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?

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…

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 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

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.

the subject of the intermediation is kind of complex

hagtech wrote:

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.

Jim, I do not think that it is the question. There is no argument that “no ripples at all” is better than ripples and no one argue that sonic effects of the ripples, no meter what it would be, is altogether negative. However, there is also a negative effect of the mechanism that minimizes ripples – the capacitance.  So, the quest is where the negative impact of ripples would be “competing” with the negative impact of the capacitance. Perhaps you took me too literary what I said about that “ripples do not meter”. So far in Super Milq I use huge a huge amount of capacitance with having absolutely microscopic amount of ripples – I would like to revise it for the HF one-stage amps. Not the least reason, and perhaps the main reason, is because, as I said before “larger capacitance makes HF harder”. Actually I even being to question if I even need a second cap in amplifier itself. In all my 2 chassis units, including the Super Milq I have the LC with a bleeder in PS and then RC in control unit. I usually try to keep the last cap as close to load providing the shortest DC path to ground. If I keep the last cap of small value on the PS side then I lose bass and Dynamics. Now, I wonder if I need to worry about it in context of HF one-stage amps. It might be that I will be go away with just one single LC on PS side with a small cap of very good quality (not metalized). I might be interesting if it turn out to be true… It always will be easy to add the second cap on the amp side to short the ground locally… BTW, since it will be effectively a high-pass filter and since I do not do LF it one-stage amps then might be a very small cap, perhaps the Teflon values…

I am trying to think about this power supply from a perspective that less is better.

Which caps exactly did you decide to try?  I don't recognize the big black jobbies.  Are they oilers?  Are they 200V?

Sticking with the Hammond chokes?

Best regards,
Paul S

Paul S wrote:

Which caps exactly did you decide to try?  I don't recognize the big black jobbies.  Are they oilers?  Are they 200V?

I did not “decide” but went with what I had in my hands. They are the Ansars from the picture few post above, Metallized Polypropylene, 100uF/450V. I use two in parallel.

Paul S wrote:

Sticking with the Hammond chokes?

Sticking with whatever I need. The Hammond chokes are the bias chokes 40H.  I like Hammond chokes BTW, they are better then many others. The 6C33C chokes are Toroidal 10H/400mA custom made by Toroidal Maryland. The first stage is Maryland custom as well.  The single-stages choke is 15H/150mA Lundahl. I was trying to use it before and hate it – never was able to make it to sound/measure good. It was literally a trash choke… until 2 weeks ago I paid attention that it has absolutely unintuitive marking of the coils and that I connected in past the cols … against each other. What a Moron!!! Anyhow I pulled it literally from a trash box and it works very well now.

hagtech wrote:

.  You have 30mA bleeder for each output?  Seems like a lot of draw.

Nope. It is not for each output. The Second stages do not use bleeders; the tubes suck enough current to warm up the chokes – 250mA-300mA against 10H. The bias chokes are 40H and each solder draw 20mA. I bleed another 8mA from each side. The first stage is 3 X 6E5P by 17mA each against 15H. I bleed 30mA extra.  The single-stage is 3 X 6E5P/6E6P by 30-35mA each against 15H. I bleed 8mA. All supplies with exception of bias are shorting on 50R resistor when the power is off. (I disconnect the tweeter that has a transformer with B+ aboard) The 12V is CRC full wave, completely lifted from chassis. I am not convinced that I will stay with the current single-stage configuration. My initial draft will be the second RC filtering stage in the amp side – 250R and 100uF the same Ansar cap to introduce a local path to ground. Well, will see how it works out…