7236 vs 6AS7 ?

[atmasphere]

Ali,

That message shows in our email box, plus that we responded. Not sure what's up, but anyway you have your answer.

All the Best, -Ralph

 

[toptip]

Oh, well, it is a relatively inexpensive experiment ($100, all in), I will try and report back.
I am surprised though that a tube (outside of reliability, arcing, etc., concerns) can make such a difference in sound: amps are driven more by their feedback circuits than the traits of the components, ate they not?

 

[toptip]

No problem. Goes to show e-mails do get lost. Many thanks.

 

[Shoog]

Oh, well, it is a relatively inexpensive experiment ($100, all in), I will try and report back.
I am surprised though that a tube (outside of reliability, arcing, etc., concerns) can make such a difference in sound: amps are driven more by their feedback circuits than the traits of the components, ate they not?

Mine has local feedback around the output triode. Other than that it has no feedback. Its a very simple directly coupled circuit which means that each components sound comes through.
I am certain that an amp with more Global feedback would be relatively immune to output tube selection.

Shoog

 

[atmasphere]

The 7236 sounds OK. You just need speaker fuses, something our amps don't normally need!

 

[Bigun]

Good luck finding a quantity of the 7236, they seem relatively difficult to find. I got one unit some time ago and that supplier shows them out of stock for a year now.

 

[toptip]

Well, the 6080s in the Atma-sphere S30 MkIII was a failure and, perhaps, a near disaster -- even after a few days of keeping the filaments warm, two of the tubes arced almost immediately with the volume turned up a bit. The fuse blew even as I attempted to turn the power off. Luckily no speaker damage. Back to the Coke bottles... May be some day there will be a slim tube that works in this amp!

 

[atmasphere]

Well, the 6080s in the Atma-sphere S30 MkIII was a failure and, perhaps, a near disaster -- even after a few days of keeping the filaments warm, two of the tubes arced almost immediately with the volume turned up a bit. The fuse blew even as I attempted to turn the power off. Luckily no speaker damage. Back to the Coke bottles... May be some day there will be a slim tube that works in this amp!

6080s are dicey. Some have very small grid heatisinks, like the 6AS7A. That type should be avoided. The kind with the larger grid heatsinks like the 6AS7G seem to work better.

 

[toptip]

I got 5 RCAs and a mixed bunch of Sylvanias and Raytheons as parts of my order. I installed the RCAs together and it was two of them that arced. The mixed bunch seemed OK.

 

[atmasphere]

The Sylvanias always seemed to hold up well. OTOH the RCAs seemed quite fragile. It did seem to help then though if they were preconditioned for 72 hours.