Woo Audio Amp Owner Unite

[Yitaro]

Wow....10 grand for a headphone amp!!!!!!  The main reason why I got into head-fi is the price/performance ratio.  I can get a really nice set up for a less than a grand.  For 10 K, I would happily move back to a YBA / Martin Logan combo where more than one person can enjoy the music at one time. 
 

 

[bobeau]

 
Quote:

The NOS tubes seem to be made of "tougher stuff" so we apparently never get to see an EML tube arc, it just dies.

My EML 274b solid arc'ed like a tesla coil when it died.
 

 

[bobeau]

     Quote:

Wow....10 grand for a headphone amp!!!!!!  The main reason why I got into head-fi is the price/performance ratio.  I can get a really nice set up for a less than a grand.  For 10 K, I would happily move back to a YBA / Martin Logan combo where more than one person can enjoy the music at one time. 
 

Anyone surprised by a $10k headphone amp as some new frontier hasn't been around here long enough.
 
Singlepower used to sell a variant of the SDS that I believe exceeded that and a few head-fiers had that setup circa 2004-2006 timeframe.
 
As far I can tell nothing's really changed in the head-fi game... if anything the current state of the economy probably has made things pull back a bit.  I find it odd that for instance an R10 will linger around the FS for weeks before being picked up.  Usually they would sell almost immediately, as well as any orpheus, HE60, K1000, qualia, rare audio technica woodies... just about any difficult to find TOTL discontinued headphone, and many times at prices exceeding what people are asking today. 

 

[dannie01]

Quote:

From what I see they use the same timer that charges the capacitor through a resistor at turn on then jumps out the resistor after 10sec or so.
Also It looks like they have the two 5U4 filaments are in series then hooked to ten volts they do this with the 6SN7s and hook them to 12 volts
This would mean that only one 5U4 is burned out If one burns out the other tube will go out like series connected Christmas lights.
I would go to someone that has a tube tester and test them to see which one is bad  also do this with the ECC32s.
If you have a ohm meter you can check them for continuity between pins 2 & 8 on the 5U4s and pins 7 & 8 on the ECC32s to see which one is bad.
I would say that only one of the 5U4s are bad.
I wouldn't put the EML that is good in the amp along with a Russian rectifier at the same time these two different tubes might draw different filament current  that would cause one to light brighter when series connected. 
 

Thanks Glenn. Just checked with a DMM with ohm testing as advise to measure pin 2 & 8 of the EML 5U4G, one of the tube without any reading but in the other tube I have a reading in 0.4ohm shown in the meter. Is that mean the one without any reading was a bad tube?
 
For the ECC32, one with reading in 1.0ohm and the other in 1.1ohm, are they fine with these reading?
 
Anyway, I will try to take both tube to test with a tube tester.
 

 

[Icenine2]

When I did have my WooWA22 the EML 5U blew after about 5 months.  George from TubesUSA replaced it without issue (thanks again George!)  At the time George had build questions about the WA22 which I couldn't answer and he said he'd ring up Jack.  Voltage questions too.  Do other amps have the same issue's w/EML's?  I'm just glad I'm done with all that since I've got the Liquid Fire now.  

 

[rosgr63]

Testing rectifiers is not the same as driver/power tubes.
 
I recommend this article by a good friend Bob Putnak of tubesound.com
 
http://tubesound.com/2010/08/25/testing-a-balanced-rectifier-on-a-tube-tester/
 
 

 

[dannie01]

Quote:

Testing rectifiers is not the same as driver/power tubes.
 
I recommend this article by a good friend Bob Putnak of tubesound.com
 
http://tubesound.com/2010/08/25/testing-a-balanced-rectifier-on-a-tube-tester/
 
 

Noted with thanks, Stavros. I ask someone who have a tube tester to have them tested. 

 

[Xcalibur255]

Quote:

 


 The WA6 output tubes draw allot less current then these larger amps.
 
How can I explain this  OK If you think of the electricity as water and the input capacitor as a tank . The rectifier changes AC to pulsating DC the amp needs pure DC
so it fills the capacitor/tank the more the amp draws the more it takes out of the tank. So the tank/capacitor is refilled 100 times a second 120 times a second in the US.
This to large tank your WA6 only takes a little out of the tank so not much has to be replaced through the rectifier. But in the bigger amps it empties the tank more that
gets replaced in less then a 100th of a second. This causes a large inrush of current that is going over current for the 5U4.
This is why there is a max rating for the input capacitor so this over current doesn't happen especially at turn on when the capacitor is completely discharged / empty tank.
 
I hope this explains to you why you are getting away with a 274B in a WA6 with a in proper input capacitor.
  
 

Thank you for the excellent explanation Glenn, it makes perfect sense.  So assumedly there are side benefits to oversizing the cap in this position, as you mentioned a bit back in the thread it can smooth out line hum for example.  It can't be a coincidence that the majority of EML tube failures are from WA22 amps though, and in an amp as expensive as it is it couldn't have been a big deal to include the necessary filter choke to eliminate the line hum so perhaps there is another reason or more variables than has been brought to light. 
 
I personally feel this is one of those situations where Jack Wu should clarify things for the owners to prevent assumptions and mis-information from being spread around, but maybe I'm out of line to say such a thing.
 

 

[Clayton SF]

There are some Woo amps that have ss rectifiers. The WA3 and the WA4. There must be advantages to ss rectifiers then. Is it possible to burn out ss rectifiers, too?

 

[Silent One]

 
 
Somewhere inside this thread it was reported last year that George approached Jack and presented his concerns regarding the EML Glass failures in WA22 amps. And that Jack informed George the WA22's design was fine and not responsible for the premature deaths (failures? not strong enough word!) of EML 5U4G rectifiers. Anyone remember this discussion? Maybe this came on the heels of Icenine2's experience...

 

[jamesnz]

So is there any news on the DAC yet? inputs/outputs? If it has 2 optical going in and an xlr and rca out (like DACmagic), I'll be in with a grin.

 

[grokit]

^ Vaguely. I also remember something about a SS rectifier in a tube form factor that could be used in a WA22, as I remember the impressions were mixed on the sound.

 

[Xcalibur255]

Quote:

 
 
Somewhere inside this thread it was reported last year that George approached Jack and presented his concerns regarding the EML Glass failures in WA22 amps. And that Jack informed George the WA22's design was fine and not responsible for the premature deaths (failures? not strong enough word!) of EML 5U4G rectifiers. Anyone remember this discussion? Maybe this came on the heels of Icenine2's experience...

This previous discussion is what I was getting at before.  I really would like to just take the statement as truth and move on, but real world experiences of the users seems to suggest that the WA22 and EML tubes have a compatibility issue that remains unresolved.  On the one hand we have the designer saying the pairing is fine, and on the other we have users complaining that their tubes keep failing prematurely.  I'm the sort of person who really wants to have some specific explanation on why or why not when it is asserted that a problem does or does not exist.  We've had some very knowledgeable and experienced users bring some information to light suggesting there might be an issue, but no detailed information to reinforce the assertion that the pairing is safe to use other than the simple statement that "it is." 
 
Also, with that, I'm done beating on the drum.  It'd be nice to hear, definitively, that the EML tubes are technically safe to operate in the amp, but I doubt anything I write here will affect the chances of getting such a confirmation.  If the tubes in question weren't nearly $300 a pop it wouldn't be such a big deal, but they should be expected to last out their normal operational lifespan for such a price and if it is the amps' fault for this not being the case I think owners should be very concerned about that.
 

 

[Xcalibur255]

Quote:

^ Vaguely. I also remember something about a SS rectifier in a tube form factor that could be used in a WA22, as I remember the impressions were mixed on the sound.

I vaguely recall reading something about SS rectifiers not being safe to use in the Woo which are designed for tube rectifiers.  No idea if I'm recalling that right or not so take it with a huge grain of salt.  At the very least it would probably result in a more SS-esque sound due to the lower voltage sag.

 

[2359glenn]

 
Quote:

Thanks Glenn. Just checked with a DMM with ohm testing as advise to measure pin 2 & 8 of the EML 5U4G, one of the tube without any reading but in the other tube I have a reading in 0.4ohm shown in the meter. Is that mean the one without any reading was a bad tube?
 
For the ECC32, one with reading in 1.0ohm and the other in 1.1ohm, are they fine with these reading?
 
Anyway, I will try to take both tube to test with a tube tester.
 

Yes the one without the reading is the bad one the other one is still good.
The ECC32s i suppose are still lighting up I hadn't gone back far enough to see what the problem with these were. I guess they just started to sound bad?? 
Well this isn't as bad you just have to buy one EML and not two