[ygm]

From my experience with a VAC PA80/80 (a push-pull tube amp with manual bias adjustment) under/over biased tubes sound perceptably worse than optimally biased ones.

The amp designer indicated that the 5998 would be up to 40% underbiased in the wa22 circuit. If, however, as Seamaster has indicated, the 6AS7G is already underbiased then the 5998 would be even worse off.

 

[ygm]

On a side note - I went back to the stock Sovtek rectifier and have to admit that I like it a lot more than the NU 5U4G. Much more dynamic presentation. The NU is a bit tooby for me: loose bass and rolled-off highs.

I can't spring for the EML 5U4G mesh yet - any other rectifiers worth considering? Maybe a Svetlana 5C3S Black Plate circa 1959?

 

[yilmaz196]

What about mullard gz34? Good rectifier i think but alittle expensive.

 

[ygm]

I take it back. I was listening to some SKA and the snap/sizzle of the sovtek fitted the music to a tee. Moving to some jazz I found the sovtek underwhelming (and thats an understatement)

I'm going to try a JAN RCA 5r4GY and a Tung Sol 5U4G while I save up for the EML. =)

 

[grokit]

Okay tube newbie here bumping another thread, trying to understand how each kind of tube on the WA22 affects the sound signature. The only thing I really get at this point is that using a different power tube, like the Sylvania 7236 over the GE 6AS7, can increase the output level of the amp.
 
But could someone please explain in simple terms how the power, rectifier and driver tubes interact with each other, and how each one affects the SQ individually?
 
Thanks in advance to anyone who attempts to answer this stoopid-sounding question

 

[Skylab]

Here is a good thread to read regarding the power tubes...
 
http://www.head-fi.org/forum/thread/410326/for-6as7g-tube-rollers-here/

 

[grokit]

Any idea what happened to the "tube tutorial" sticky, did it get "lost in the cloud"?

 

[Seamaster]

As far as WA22
 
Driver tubes affect the sound the most, then rectifier. Power tubes affect the sound the least. For example: I you get too drunk, you would not tell the difference between GEC 6080 and GEC 6AS7G

 

[Double F]

Is there a difference between the 6080 and 6as7g  GEC.  I am not drunk at the moment

 

[Skylab]

Quote:

Is there a difference between the 6080 and 6as7g  GEC.  I am not drunk at the moment

Electrically, they are the same.  Physically, not the same. 
 
6080:
 

 
6AS7G:
 

 

[grokit]

 
Quote:

As far as WA22
 
Driver tubes affect the sound the most, then rectifier. Power tubes affect the sound the least. For example: I you get too drunk, you would not tell the difference between GEC 6080 and GEC 6AS7G

Thank you very much for that simple yet informative response Seamaster, it is what I have been looking for!
 
And thank you Skylab, for the link. Threads like those (and this one) are quite interesting and informative as well, but they do assume some basic knowledge that I do not currently have. The books that I have looked into seem to want to educate me on how to build my own tube amp, which is not my objective. I would be most interested in something like "headamp tube rolling for dummies".
 
Which leads me to another silly question, inspired by a post on that thread:
 
Is the input tube the same as the driver tube, or the power tube?
 

 

[Skylab]

I did post quite a bit of information on the 6AS7G and its variants here:
 
http://www.head-fi.org/forum/thread/324469/review-four-6as7g-based-home-tube-headphone-amps-reviewed-and-compared
 
And yes, input = driver, for all intents and purposes.

 

[Seamaster]

 
Quote:

Is there a difference between the 6080 and 6as7g  GEC.  I am not drunk at the moment

GEC 6080 is little darker than GEC 6AS7G, little lack spark on the top compare to also. 6AS7G is little brighter and resolving, which may give you a sense of more dynamic also. The difference is small but audioble. Cans like Grado or HD-800 are actrullay benifit from using GEC 6080.


 
Quote:

Electrically, they are the same.  Physically, not the same. 
 

Sonically also



 
Quote:

 

Thank you very much for that simple yet informative response Seamaster, it is what I have been looking for!
 
 

You are welcome
 

 

[grokit]

Does anybody know the output impedance of the WA22 as far as the HI / LO impedance switch goes?
 
Obviously a 32 ohm headphone would be used on LO and a 600 ohm on HI, but what about those in between cans, like a 50-75 ohm, or a 100-250 ohm?
 
I know it says, "Headphones impedance: 8-600 Ohms", and "Output: 810 mw with 6080, 2 watts with 7236 power tubes", but what doeas that mean for nominal output impedance?
 
That shouildn't change with the power tube selection, right?

 

[nututubes]

Quote:

Does anybody know the output impedance of the WA22 as far as the HI / LO impedance switch goes?
 
Obviously a 32 ohm headphone would be used on LO and a 600 ohm on HI, but what about those in between cans, like a 50-75 ohm, or a 100-250 ohm?
 
I know it says, "Headphones impedance: 8-600 Ohms", and "Output: 810 mw with 6080, 2 watts with 7236 power tubes", but what doeas that mean for nominal output impedance?
 
That shouildn't change with the power tube selection, right?

Exactly my question at the moment. My WA22 won't be here for a month, but I still would like to know now. The headphones are Senn HD800.