Head-Fi.org › Forums › Summit-Fi (High-End Audio) › High-end Audio Forum › The Stax Thread III
New Posts  All Forums:Forum Nav:

The Stax Thread III - Page 164

post #2446 of 4575
" Frank, are they only a problem when in the signal path? So if electrolytics are used in the psu for example, there are no negative effects on the sound?"

In solid-state amps, because of the large capacitances required, there is usually no practical substitute for electrolytics in the power supply. In tube amps, substitution of film caps for electrolytics in power supply filters is usually an audible improvement. Of course film caps of appropriate voltage and capacitance values are much bulkier and more expensive than equivalent electrolytics, hence are rarely employed in commercial products.

Another traditional but non-optimal use of electrolytics in tube amps is the cathode bypasses. Film caps (or better yet solutions that don't involve capacitors at all) are better here as well. Again space and economics are the overiding factors.

Oops! Screwed up the quote. Sorry about that.
Edited by FrankCooter - 5/22/14 at 6:12pm
post #2447 of 4575

Thanks Joachim,

 

I have that schematic - but the circuit board in here does not look like that schematic.

 

It looks a lot more like the SRD5 schematic with the 50k resistor on the power input (with a switch which replaces the 50k with a 250k to switch from 100V to 240V... on the SRD5, the SRD7 has no such switch).

 

Hence my question ! - this appears like an earlier circuit layout, more closely related to its SRD5 predecessor.

 

I may just have to trace it

 

bye for now

David

post #2448 of 4575

ES amps being balanced have much less sensitivity to PS - as long as both outputs are affected equally any PS "error" doesn't cause a difference signal to hear

 

PS electrolytics are even used by the Stax mafia - but they do usually insist on regulation too


Edited by jcx - 5/23/14 at 7:17am
post #2449 of 4575
Quote:
Originally Posted by jcx View Post
 

ES amps being balanced have much less sensitivity to PS - as long as both outputs are affected equally any PS "error" doesn't cause a difference signal to hear

 

PS electrolytics are even used by the Stax mafia - but they do usually insist on regulation too

 

True as far as it goes, but I wasn't talking about error correction. Electrolytics, in the signal path (like the last capacitor in the power supply) generate artifacts that in some cases can  be heard and subjectively described as adding a "glare" or "sheen" to the amplifier. The advantage of Black Gates was the minimization of these artifacts. Regulation won't affect the inherent properties of the filter caps. Whether the sonics of any particular amp or circuit is affected by the type of capacitors employed in the power supply I couldn't say.

 

BTW, not all electrostatic amps are fully balanced.


Edited by FrankCooter - 5/23/14 at 9:30am
post #2450 of 4575

I was using "error" to include anything that might color the sound - assuming the usual physical materialism point of view that anything about amps/circuit components that can be "really" be heard (under controlled conditions, with Blinding protocol, by more than one person...) has a technical circuit cause, involves measureable V or I changes in the headphone drive

 

and can you name a "High End" ES headphone amp that isn't balanced Stator drive?


Edited by jcx - 5/23/14 at 9:51am
post #2451 of 4575
Quote:
Originally Posted by jcx View Post
 

I was using "error" to include anything that might color the sound - assuming the usual physical materialism point of view that anything about amps/circuit components that can be "really" be heard (under controlled conditions, with Blinding protocol, by more than one person...) has a technical circuit cause, involves measureable V or I changes in the headphone drive

 

and can you name a "High End" ES headphone amp that isn't balanced Stator drive?

 

So if I'm understanding you correctly, all component differences and artifacts in a balanced power supply, such as diode switching noise, recovery times, capacitor ESR, frequency ratings, etc. are cancelled out along with I and V errors? And if this is so, then why do we even need to regulate a balanced supply at all? Not saying you're wrong here, just curious.

 

All ES amps of course have balanced stator drive. Not all ES amps are "fully balanced" as you stated. Maybe it's not "high end", but I use a three stage 845 amp to drive ES headphones. It's all single-ended up to the output transformer, which then splits the signal into balanced mode.

post #2452 of 4575

never said any such thing of course - less sensitive is not totally immune - and PS with just rectification and filtering without regulation for the output stage is common in audio amps - even SE - but push-pull balanced output drive is a lot more immune to PS Ripple, Sag, non zero impedance...

 

push-pull balanced output drive is the standard for direct drive ES amps - easy to name a 1/2 dozen balanced push-pull ES headphone amp designs, to one that isn't

 

I was mostly objecting to the seeming categorical dismissal of electrolytic caps - they work well enough that you find them in most $k ES headphone amp power supplies - even at these levels few want to spend for brick sized film caps needed to give similar technical performance

 

sometimes diminishing returns are really not worth pursuing - there really are audible thresholds below which differences can't be heard

 

 

as a conceptual art project 100s of uF of kV rated film caps could be justified for the "infinite" life - but using films as PS reservoir caps fails coming close to audibility thresholds from the engineering numbers for electrical circuit performance effects vs electrolytic caps, particularly with regulation, added immunity of balanced push-pull output

 

@100db100V sensitivity you need 1 V across full size Stax headphones to even be at the human hearing threshold after minutes of adaptation in an anechoic chamber - compare to:

Quote:
 KG on the KGSSHV PS:

Tests indicate about 12 microvolts of noise at full power. Its when the diodes turn on, and
using the 35ns soft recovery diodes, even ceramic caps across them make no difference.
Over the range 10C to 50C and under full load the power supply voltage changes only 1.2 volts.
Measuring this is not at all easy. So i'll call it a better than -140db power supply and be done with.

 

derated modern electrolytics ran cool will last decades and occupy a fraction of the volume and price - the volume and price advantage giving plenty of scope for adding circuitry to improve actual performance - which may well involve smaller film caps where they do make a difference


Edited by jcx - 5/23/14 at 2:22pm
post #2453 of 4575

Hi guys!

 

Birgir and Kevin have done us all a solid, and I'm gonna need some help getting electrostatic cans in for measurement.

 

Really the easiest way to tell you about it is just to point you here:

 

http://www.innerfidelity.com/content/stax-mafia-makes-unrefusable-offer-and-i-begin-electrostatic-headphone-measurement-program

 

Looking forward to a bunch of new estat measurements! 

 

 

Thanks Birgir and Kevin! Imma make good use out of the KGSSSRE.

post #2454 of 4575
Quote:
Originally Posted by Tyll Hertsens View Post
 

Hi guys!

 

Birgir and Kevin have done us all a solid, and I'm gonna need some help getting electrostatic cans in for measurement.

 

Really the easiest way to tell you about it is just to point you here:

 

http://www.innerfidelity.com/content/stax-mafia-makes-unrefusable-offer-and-i-begin-electrostatic-headphone-measurement-program

 

Looking forward to a bunch of new estat measurements! 

 

 

Thanks Birgir and Kevin! Imma make good use out of the KGSSSRE.

Enjoy! 

 

I love the KGSS and KGSSHV! That one looks like a real beauty! 

post #2455 of 4575
Quote:
Originally Posted by Tyll Hertsens View Post

Hi guys!

Birgir and Kevin have done us all a solid, and I'm gonna need some help getting electrostatic cans in for measurement.

Really the easiest way to tell you about it is just to point you here:

http://www.innerfidelity.com/content/stax-mafia-makes-unrefusable-offer-and-i-begin-electrostatic-headphone-measurement-program

Looking forward to a bunch of new estat measurements! 


Thanks Birgir and Kevin! Imma make good use out of the KGSSSRE.

Very exciting! I can't wait to see how the vintage models measure.
post #2456 of 4575

Frank

 

Couple things I'd like your opinion on-

 

Have you found that using a film cap  as the last cap in the PSU is sufficient, or do you need to replace all the electrolytics with film?

 

I've seen quite a few designs where the aluminum electrolytics in the PSU  and the on-board "demand" electrolytics in solid state amps are bypassed with one or two film caps- does that ameliorate the sonic problems caused by electrolytics or is it just wishful thinking?

 

And last but not least-  Black Gates are gone, but there are now other "audio grade" electrolytics - Silmic & Cerafine from Elna, and Muse from Nichicon - have you heard  these? Do you think they offer sonic benefit over the regular good quality but otherwise garden-variety Panasonic caps?


Edited by milosz - 5/24/14 at 12:29am
post #2457 of 4575

Hello,

 

My first foray into electrostatics is happening as I type this. I just received an SR-007 Omega  MK ii and a SR-007t on audition and can buy if I like the combo. Needless to say, I am definitely buying (wow).....

 

Here is the question I have for you guys, Does the SR-007t take the Omega MK ii to the height of where it can go sound wise? , or should I just buy the headphone end of this deal (an offer he gave me ) and look to another amp?

 

Budget(within reason) is not an issue, so any suggestions if I should not buy the whole combo would be appreciated.

 

 

Thanks!

post #2458 of 4575
Quote:
Originally Posted by Fearless1 View Post

Hello,

My first foray into electrostatics is happening as I type this. I just received an SR-007 Omega  MK ii and a SR-007t on audition and can buy if I like the combo. Needless to say, I am definitely buying (wow).....

Here is the question I have for you guys, Does the SR-007t take the Omega MK ii to the height of where it can go sound wise? , or should I just buy the headphone end of this deal (an offer he gave me ) and look to another amp?

Budget(within reason) is not an issue, so any suggestions if I should not buy the whole combo would be appreciated.


Thanks!
I'd guess you'd be better off with 717 or 727. Question is, where does the 323 stand against the 007t?
post #2459 of 4575

The SR007 with SRM007t sounds very dark with uncontrolled bass and muddy medium. 

post #2460 of 4575
Quote:
Originally Posted by Hun7er View Post

The SR007 with SRM007t sounds very dark with uncontrolled bass and muddy medium. 
Yet it must sound more controlled than 006/t1?
New Posts  All Forums:Forum Nav:
  Return Home
  Back to Forum: High-end Audio Forum
Head-Fi.org › Forums › Summit-Fi (High-End Audio) › High-end Audio Forum › The Stax Thread III