My Holy Grail of amplification found: Non-Polar electrolytic caps across power supply

[ygg-it]

another test

Why do you still have other capacitors in there?

This input and the following test wane any my theory, but strengthen my empirical outcome.

I got rid of the Polar 180uF/450V polar capacitor, in order to have a "pure" Non Polar (back-to-back) power supply and had a listening test: clean sound but deep bass have nearly disappeared!

So it is not a "pure" NP power supply which works the best, but the combination of Polar+NP which brings the best sonic results.

In fact again, when I resoldered the 180uF/450V polar capacitor in parallel to the NP, result was amazing again.

As I tested now all the possible combinations, I'm sure regarding the benefit of installing NP caps (given the fact that the polar sosbtitute with identical value was tested not to be as much pleasant), but it looks that the power supply and the SET amp still enjoy anyway the big Polar cap across the rail.

 

[ygg-it]

The Blackgate replacements will unlikely be outrageously expensive ( Audio Note owner is notorious for high prices)

Audio Note

Thanks! We could even take two NP 100uF/500V and put in parallel (but not clear if they make NP at 500V)

 

[ygg-it]

new web site

I've started to build a website around this my tube amplifier and about non-polar electrolytic capacitor usage.
You may find the development under:

The Sound Grail

Sorry still under construction, bear with me for about next two months...

 

[arnyk]

Proper observations the yours, as I had just compared Non-Polar vs No Cap: so I finally compared a bank of polars equal to 272uF/400V against the back-to-back 235uF/400V: the change of capacitors really does have an audible effect which I can translate as a minor listening fatigue, as stated before.

Thanks guys, now I'm firmly convinced that is not a placebo effect!

So you did some proper DBTs? That's the only reliable way to answer questions about placebo effects.

 

[AndrewT]

Or he can measure the performance before and after and post the results.

 

[arnyk]

Or he can measure the performance before and after and post the results.

While that is a great idea and would address questions about technical performance improvement, unless the numbers were really bad, it would shed very little light on questions of audibility.

Modern test gear is orders of magnitude more sensitive to most common performance problems than the ears.

 

[DF96]

Changing capacitor values in a SET PSU is audible, especially when the listener knows it has been done because he did it himself. Who would have thought it?

 

[arnyk]

Changing capacitor values in a SET PSU is audible, especially when the listener knows it has been done because he did it himself. Who would have thought it?

LOL!

That all said, a technical analysis suggests that if one wanted to hear the effects of changing PSU caps, a low feedback SET might be a fertile place to start listening. Of course the listening would need to be done intelligently, and that means doing DBTs.

I have learned from practical experience that conventional high-feedback class AB power amps playing music aren't real encouraging that way.

 

[AndrewT]

While that is a great idea and would address questions about technical performance improvement, unless the numbers were really bad, it would shed very little light on questions of audibility.

Modern test gear is orders of magnitude more sensitive to most common performance problems than the ears.

and may well prove that there is no performance benefit to making the modification.
Or prove that the performance benefit is so enormous that his results will be enough to convince every Member to copy the technique.

On the meantime all we have is some uncomparable subjective view through rose tinted glasses.

 

[arnyk]

and may well prove that there is no performance benefit to making the modification.
Or prove that the performance benefit is so enormous that his results will be enough to convince every Member to copy the technique.

On the meantime all we have is some uncomparable subjective view through rose tinted glasses.

Exactly. Reading audio construction forums reminds me of a footrace where the participants determine the winner by arguing over who felt he ran the fastest.

 

[ygg-it]

some measurements

Attached some measurements at 60 Hz -30dB. I have repeated @ 100Hz.

The polarized one refers to the back-to-back capacitors which have been shorted, so each results in one polarized capacitor with double the capacity.

The NP one refers to my three couples of back-to-back capacitors without been shorted: the bypass one, the ultrapath one and the power supply decoupling one.

(Giving the generous size of the 3 caps, there is no difference at 60Hz for the fact that the two tests compare a double capacitance in the circuit.)

I cannot see any important difference, even if I'm just using my PC soundcard and not professional tools.

That means two important things for me: first that the good sonic performance of NP caps is not justified by any measurement yet.🙁

But most important (as many folks believed the contrary): the reverse biased capacitors, which should act as a diode, do not produce any visible harmonic distortion increment! And, this is at least very good for me!🙂

 

[Cal Weldon]

Racial profiling and innuendo is taboo here. Post(s) removed.

 

[ppl]

I Tried THIS


I used these

 

[Bigun]

ygg-it,

Nice thread, I've had an interest in NP caps for awhile since using them in the signal path for a couple of amps - as input capacitors. The sonic results from these amplifiers were very good from my subjective evaluation but I didn't do much in the way of comparisons I trusted the fact that large value caps generate vanishingly small a.c. voltages across them for small signals so distortion will be low and therefore preferred a largish value NP cap to either a small value non-electro or a large physical film cap for all the hassles that the size of those things bring to the table. I haven't tried NP's in the power supply - something I might add on my to-do list for my next project.

Of course, it's not unusual to have some interesting sonic changes that are difficult to measure and as hobbyists we often don't have the equipment to do the job adequately. Nevertheless, I have found simple listening tests to be invaluable for comparing different parts and topologies in my own experiments. All in all it has been a very rewarding part of the hobby and I like to read about the experiences of others like yourself.

 

[arnyk]

I Tried THIS


I used these

What light on the topic was obtained?

 

[29285]

What light on the topic was obtained?

how to clear the fat wallet😀

 

[arnyk]

how to clear the fat wallet😀

Exactly. Relying on sighted evaluations can help with that, too.

 

[ygg-it]

ygg-it,

Nice thread... I haven't tried NP's in the power supply - something I might add on my to-do list for my next project.

Thanks for the input: try back-to back electrolytic. I'm running since at least 300 hours and everything is still running cold and quiet.
Safety for me is now the ultimate aspect (as sonically are excellent): I think my is the first longest test over the web, running back-to back over DC.

I'm only just waiting for someone here who has professional equipments that can measure for me harmonics of back-to back electrolytics over DC as I didn't find any differencs (by using my sound card analyser).

In the mean time I will continue to finish my web site The Sound Grail Tube amplifier Schematic

Cheers!

 

[ygg-it]

I Tried THIS


I used these

Thanks for the indication (diameter size allowing...good for future design) and your project looks excellent.

Regarding the cost, I' don't think it is so much as these cover the whole power supply: I see more people here spending hundreds of bucks on Mundorf, just in signal path...

Pay attention: C4D serie should run maximum 70°C even if 85° labelled

 

[ticknpop]

Cyril Bateman tested electrolytic capacitors extensively and shows in his article that bipolar electrolytics have the lowest distortion of the electrolytic type, also that the higher the voltage the electrolytic is rated for the lower the distortion. Cyril also shows film caps are generally lower distortion than electrolytics of any type. Also read Marsh/ Jung's artcles on capacitors for further information.

Pro Audio Design Forum • View topic - Cyril Bateman Capacitor Sound Archive

Classic Articles Page | Walt's Blog 2014

(go half way down the Jung page to the 2 part ' Picking Capacitor articles)

My system is all Borbely jfet/fet totally direct coupled from phono input to speaker with servos on each stage and DC monitoring of the preamp and power amp with turn on delay and offset shut down relays. So no coupling caps of any type anywhere. All the compensation caps are polystyrene, the RIAA network caps are 1% Relcap teflon and the local power supply bypass caps on all stages are Blackgate N and NX bipolars. The power amp uses 720,000 uf in an CLC filter with the final 90,000 uf all Blackgate FK and N series.

The speaker (full range electrostatic) crossover is all MIT Film and foil polystyrene and polypropylene. After 40 years of building and modding equipment improving coupling caps, reducing the number of them, and finally eliminating them with fully symetrical direct coupled Jfet/fet circuits has improved the sound significantly.