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Woo Audio Amp Owner Unite - Page 2056

post #30826 of 30965

Nice! :tongue_smile:

 

I found the driver tubes supplied by Woo underwhelming (YMMV). There are better deals to be done out there for both NOS and new production driver tubes. The teflon adapters, however, are very nice.

 

New production tubes can cop a lot of flack here at HeadFi and elsewhere, but I am having a lot of fun tube rolling with them and getting some very good results.

post #30827 of 30965

Pretty much agree with you here but with the WA6 (non-SE)

Love the SP 274B and for me, best paired with either the stock Westinghouse 6DR7 but am now enjoying it with JAN Sylvania 6SN7 WGTA with the Woo adaptors.

Tube compliment in your pics looks exactly what I have in my WA6 ;)

 

Quote:

Originally Posted by Stereolab42 View Post
 

For the most part, SQ differences between tubes are less than I expect based on the price differences. Like some others I find it counter-intuitive that the tube most removed from the final signal -- the rectifier -- seems to have the most effect on SQ. 

 

 

 

 

Actually, out of 4 sets of 6DE7 (or comparable tubes), I have, I found the stock ones the best so I went the Woo stock 6SN7 adaptor/tube set.  Not impressed until I got some Sylvania 6SN7's.

 

Quote:
Originally Posted by TonyNewman View Post

I found the driver tubes supplied by Woo underwhelming (YMMV). There are better deals to be done out there for both NOS and new production driver tubes. The teflon adapters, however, are very nice.

 

post #30828 of 30965

Is it possible for choice of output tubes to drastically affect how hot the WA22 runs?

post #30829 of 30965
Quote:
Originally Posted by Stereolab42 View Post
 

Is it possible for choice of output tubes to drastically affect how hot the WA22 runs?

 

Depends on your definition of drastic.  Are the transformers getting to hot to touch?  If so, that would be a concern.

post #30830 of 30965
Quote:
Originally Posted by bonesnv View Post
 

 

Depends on your definition of drastic.  Are the transformers getting to hot to touch?  If so, that would be a concern.

 

Was playing around with two Sovtek 6AS7Gs (yes, I know... suffice it to say I ordered a wide range of stuff) and it was causing the rectifier to blaze about twice as brightly as my Woo stock and upgrade 6080s. Now one of the tubes is bad, with lots of noise and a cloudy look, and they are going back, so perhaps that is that cause. I have other 6AS7Gs and 6080s coming so I'll soon be able to do more comparisons, but I'd rather stick with tubes that will run the amp as cool as possible.

post #30831 of 30965

Think I've figured it out after getting more tubes in and finding some old posts in this thread... the TS 7236 just runs cooler than 6080s or 6AS7Gs (40 degrees cooler on the rectifier according to my Fluke), and they appear to be more efficient too... I get more volume from the same dial location. They seem rare enough I'm inclined to go ahead and get a bunch of backups from Woo...


Edited by Stereolab42 - 9/2/14 at 10:03pm
post #30832 of 30965
Quote:
Originally Posted by Stereolab42 View Post
 

Think I've figured it out after getting more tubes in and finding some old posts in this thread... the TS 7236 just runs cooler than 6080s or 6AS7Gs (40 degrees cooler on the rectifier according to my Fluke), and they appear to be more efficient too... I get more volume from the same dial location. They seem rare enough I'm inclined to go ahead and get a bunch of backups from Woo...

 

 

The 7236/5998 have more gains than 6080/6AS7G.  Just wait til you try a GZ34, it is the hottest rectifier in WA22.

post #30833 of 30965
Quote:
Originally Posted by jc9394 View Post
 

 

 

The 7236/5998 have more gains than 6080/6AS7G.  Just wait til you try a GZ34, it is the hottest rectifier in WA22.

 

But can an output tube have more gain but run cooler? That's specifically my experience with the TS 7236 versus other 6080s and 6A7SGs. Gain and efficiency appear to be semi-independent variables here. (As if rolling tubes wasn't complicated enough!)

post #30834 of 30965
Quote:
Originally Posted by Stereolab42 View Post
 

 

But can an output tube have more gain but run cooler? That's specifically my experience with the TS 7236 versus other 6080s and 6A7SGs. Gain and efficiency appear to be semi-independent variables here. (As if rolling tubes wasn't complicated enough!)

 

 

It really depends on what rectifier you are using, yes it can be done.  the coolest running rectifier i tried is gz32 but you should not look for the coolest running tubes.  what you should be looking for is the best tube combos for you liking regardless of how hot/cool they run, the nos tubes will last a long time.  some of them are design to run hot to get the optimum performance from it.

post #30835 of 30965
It runs cooler because it biases at a lower current in a typical cathode bias circuit. Measure the voltage across the cathode resistor and you will see it is much lower. I mentioned this in the 6AS7 tube rollers thread a while back. In my WA3, the PS sits around 190V depending on the tube. What I've measured is substantially different operating points in my amp when various tube types bias up in the output circuit...which I found interesting based on comments people make on how the different tubes "sound". The 6080 and 6N13S bias up around 38mA with 57V on the cathode resistor. 5998A and 7236 settle around 21mA with 32V on the cathode resistor. The 5998 is at the other extreme with only 18.6mA current and 28V on the cathode resistor.
Quote:
Originally Posted by Stereolab42 View Post

But can an output tube have more gain but run cooler? That's specifically my experience with the TS 7236 versus other 6080s and 6A7SGs. Gain and efficiency appear to be semi-independent variables here. (As if rolling tubes wasn't complicated enough!)

Edited by GrindingThud - 9/3/14 at 7:48pm
post #30836 of 30965

OK, I guess I need to understand more of the theory here. First, I am not 100% clear on the different roles of the driver (input) and power (output) tubes. This is after reading at least one thread here dedicated to the subject and Googling around. The role of the rectifier is obvious -- AC to DC. Then, the DC is fed to the cathode of the driver tube, and the audio line signal is fed to the grid of the driver tube. This amplifies the VOLTAGE of the audio line signal, and the amplified voltage proceeds out the anode, right? Now, what exactly does the power tube do and how? I've heard "amplify current" is the answer but I don't understand how a vacuum tube amplifies current instead of voltage.

post #30837 of 30965
Quote:
Originally Posted by Stereolab42 View Post
 

OK, I guess I need to understand more of the theory here. First, I am not 100% clear on the different roles of the driver (input) and power (output) tubes. This is after reading at least one thread here dedicated to the subject and Googling around. The role of the rectifier is obvious -- AC to DC. Then, the DC is fed to the cathode of the driver tube, and the audio line signal is fed to the grid of the driver tube. This amplifies the VOLTAGE of the audio line signal, and the amplified voltage proceeds out the anode, right? Now, what exactly does the power tube do and how? I've heard "amplify current" is the answer but I don't understand how a vacuum tube amplifies current instead of voltage.

 

My understanding (probably wrong) is that both the driver (e.g. 6SN7) and output (e.g. 300B) tubes are amplification tubes - doing the same job in a very similar way. The original signal is fired across from anode (+ve) to cathode (-ve) across a large steady current. As the signal passes through the steady current it amplifies the changes in the original signal. Result = amplification of the original signal.

 

Driver / output / power tubes are all amplification tubes. In the case of a small amp like the WA6, the driver tubes alone are enough. For thumping big headphone amps, like the WA5, there are 2 drivers and 2 output tubes, one set per channel (?). I like to think of the 6SN7s acting as pre-amps to the 300Bs i.e. amplifying the source signal that is further amplified in the 300Bs.

 

I hope I have this close to right. I would be very happy if someone with more knowledge than me could chime in and correct and/or add to this.


Edited by TonyNewman - 9/4/14 at 12:20am
post #30838 of 30965

Just wanted to post a pic of this tube combination on WA22, that I have found is universally outstanding on all the HP's that I have tried (HD 800, T1, XC, TH 900 ).

 

WE422A + WE421A + Mullard CV 181

 

 

This the most dynamic sound that I have heard from the WA22, big sound stage , deep punchy bass , extended treble, very dynamic. Not for people who prefer overly warm,romantic, lush sound.


Edited by punit - 9/5/14 at 1:48pm
post #30839 of 30965
Quote:
Originally Posted by punit View Post
 

Just wanted to post a pic of this tube combination on WA22, that I have found is universally outstanding on all the HP's that I have tried (HD 800, T1, XC, TH 900 ).

 

WE422A + WE421A + Mullard CV 181

 

 

This the most dynamic sound that I have heard from the WA22, big sound stage , deep punchy bass , extended treble, very dynamic. Not for people who prefer overly warm,romantic, lush sound.

 

 

Did I just saw you posted your kidney for sale?  Glad you finally found a go to combo.  :beerchug:

post #30840 of 30965
Hahaha.....yes definitely not a combination for sane reasonable people. which sane person will spend an amount nearly equal to the cost of the amp on tubes ;-). Some people do drugs..I do tubes.
Edited by punit - 9/5/14 at 2:22pm
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