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REVIEW: Decware Select Zen CSP2 Tube Headphone Amp - Page 27

post #391 of 558
Quote:
Originally Posted by longbowbbs View Post

......

 

any perspective on these?  http://www.sophiaelectric.com/pages/se/274b.htm

 

BTW, when swapping tubes, how long do you wait for them to cool down before you take one out and replace it with another? Cool to touch? Just wondering....

 

popcorn.gif

 

I vaguely recall Skylab over here having experimented with really expensive rectifiers like the 274b.

 

The conclusion was that it would be better to stick to 5Y3 rectifers coz the CSP2+ was designed around it.

 

As for swapping tubes, there was some discussion before on the Decware forums.

Steve actually confirmed that you can yank out the hot tube whilst the CSP2+ is still running.

 

I'm the more cautious type and would prefer to wait about 10 mins.

post #392 of 558

I can see the "Decware Insulated Glove" order form on their site...biggrin.gif

post #393 of 558
Thread Starter 
Quote:
Originally Posted by Lord Soth View Post

I vaguely recall Skylab over here having experimented with really expensive rectifiers like the 274b.

The conclusion was that it would be better to stick to 5Y3 rectifers coz the CSP2+ was designed around it.

As for swapping tubes, there was some discussion before on the Decware forums.
Steve actually confirmed that you can yank out the hot tube whilst the CSP2+ is still running.

I'm the more cautious type and would prefer to wait about 10 mins.

The Sophia rectifiers are fussy beasts and I didn't like them in the CSP-2 for a variety of reasons. I really do think the 5Y3 family is best in it.
post #394 of 558

^ Indeed. Two days ago I substituted the RCA 5Y3GT tube MadDude included with my CSP2. My first change from the stock JJ 5U4G.

 

According to Steve Deckert's audio paper Lord Soth directed us to, these are the changes to expect:

 

As the voltage changes on this circuit the signature changes from very euphoric and smooth to having more force and weight. Think of the 5Y3GT giving you the most type B [euphoric and smooth] signature possible and a 5U4 tilting the scale to somewhere between a type B and type A [more force and weight], similar to the original circuits signature.

 

Early days for me with the CSP2 but like Skylab, I personally prefer the 5Y3 out of these two tubes.

 

When I substituted a Tung Sol 5Y3GT for the same 5U4G in the Taboo, there was an immediate and distinct gain in transparency and immediacy. The RCA seems to have a similar effect with the CSP2 to my ears. Maybe type B just happens to be the right fit for my hearing!

 

BTW, Steve's paper also points out this ingenious feature: The two output tubes like before are dual triodes, but now are wired using only one side of each tube. And the left tube uses the left side, while the right tube uses the right side. This means that after your tubes wear out you can simply swap the left for right channel and you have a fresh set of tubes again! Twice the tube life.

post #395 of 558
Quote:
Originally Posted by AiDee View Post

.......

 

BTW, Steve's paper also points out this ingenious feature: The two output tubes like before are dual triodes, but now are wired using only one side of each tube. And the left tube uses the left side, while the right tube uses the right side. This means that after your tubes wear out you can simply swap the left for right channel and you have a fresh set of tubes again! Twice the tube life.

 

I believe that one of the famous Dodd amps are also built like that.

 

I don't mean any offence but one thing which I can't still come to grips with is that the tubes are akin to light bulbs.

A dual triode would be equivalent to having 2 light bulbs, one on each side.

AFAIK, one cannot shut down only one side and leave the other light bulb on.

As long as the filament for both sides are heated, wouldn't the life span of the so called other "not in use" side be decreased as well?

 

I hope that some tube guru out there can help explain away this nagging doubt of mine. smile.gif

post #396 of 558
Quote:
Originally Posted by longbowbbs View Post

I can see the "Decware Insulated Glove" order form on their site...biggrin.gif

Yes, in the audio industry, it is the audio accessories which bring in the high margins and big bucks! wink.gif

post #397 of 558
Custom Silver Litz insulated gloves...biggrin.gif
post #398 of 558

After reading positive reviews of the Visseaux French 5Y3GB, I managed to get hold of one such rectifier and installed it in my CSP2+.

The Visseaux 5Y3 is a lovely rectifier with French aesthetics and reminded me of the Eiffiel Tower.

 

Unfortunately, the rectifier refused to be turned on. It was basically dead on arrival "DOA".

My CSP2+ was not damaged in any way though.

 

I put back my trusty old Tung Sol 5Y3GT and the CSP2+ continued to work as usual.

 

BTW, this has only proven that the CSP2+ can't be damaged by a DOA rectifier.

 

However, should the rectifier blow up after installation, there might still be a chance of the CSP2+ being damaged.

In such a situation, I would expect the fuse to be blown 1st before any other components are taken out.

post #399 of 558
Quote:
Originally Posted by longbowbbs View Post

Custom Silver Litz insulated gloves...biggrin.gif

Yes, they must be the Super Cryoed Lambskin gloves which allow audiophiles to tube roll with absolute impunity.

The silver litz prevents the fragile tube markings and etchings from ever being removed. tongue.gif

post #400 of 558
Quote:
Originally Posted by Lord Soth View Post

Yes, they must be the Super Cryoed Lambskin gloves which allow audiophiles to tube roll with absolute impunity.

The silver litz prevents the fragile tube markings and etchings from ever being removed. tongue.gif

You saw the same ad!

 

I need them now...Look what showed up this afternoon!

 

 

 

Naturally I have to leave for work until Friday night....So a quick listen then I have to leave for a couple of days. This amp was finished right before Zenfest so Steve had it burn in for about 70 hours with the shipped tubes. biggrin.gif

 

DSOTM sound glorious.....Dang..work SO gets in the way of better things.....biggrin.gifbiggrin.gif

 

I'll post some more pics tonight when I get to the hotel....Only 306 miles to go.....


Edited by longbowbbs - 10/16/12 at 2:17pm
post #401 of 558

BTW, it arrived with a USA Made 5U4G (GE) and 3 Chinese Shin-EB 6N1P-EV tubes....

post #402 of 558

I'm sure no-one's offended.

 

Good point!

 

I tried googling "tube life". The three main causes of tube-wear seem to be cathode burn-out (the material that supplies the electrons is used up); shorting (potentially disastrous for the rest of the amp); or air entering the tube through an imperfect pin seal.

 

All these causes seem pretty terminal!

 

Looking at my 6N1Ps power tubes, both filaments are switched on for sure. I wondered if there had to be voltage (potential difference) at the anode before the cathode would emit its electrons? If so, the cathode coating would not be used up.

 

From my reading, no! Seems if the filament's turned on then electrons are freed and cathode material is getting used up, even though nothing useful may be happening eek.gif

 

The paper I quoted is dated 2004. There's another from 2006 which mentions the revisions that turned the CSP2 into CSP2+. My guess is the 'feature' of only running one side of each power triode got dropped - i.e. both sides were needed again.

 

Don't know for sure though - a question for the Decware forum, unless anyone here knows the answer?

 

Quote:
Originally Posted by Lord Soth View Post

I don't mean any offence but one thing which I can't still come to grips with is that the tubes are akin to light bulbs.

A dual triode would be equivalent to having 2 light bulbs, one on each side.

AFAIK, one cannot shut down only one side and leave the other light bulb on.

As long as the filament for both sides are heated, wouldn't the life span of the so called other "not in use" side be decreased as well?

 

I hope that some tube guru out there can help explain away this nagging doubt of mine. smile.gif

post #403 of 558
Thread Starter 

If you are actually lighting up both filaments, simply not passing a signal through one of the two will not improve the life of "one section".  If you were literally not firing one of the two filaments in a dual triode, then of course, you would be preserving that "section". But when I had the CSP-2 (not +), both filaments on all tubes were lit.

post #404 of 558

Thanks Skylab - makes sense and is what I figured. A nice feature but sounds like it was only implemented for a short time.

post #405 of 558
Quote:
Originally Posted by longbowbbs View Post

BTW, it arrived with a USA Made 5U4G (GE) and 3 Chinese Shin-EB 6N1P-EV tubes....


I don't think the Chinese made the 6N1P-EV; this is Soviet Military production.

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