Looking for an excellent circuit for some Heathkit W6 trannys

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dak

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Apr 19, 2018
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Hi all, I am helping a fellow diy'er with making a Push pull 6550 amp utilizing some legendary Heathkit W6 amps transformers. Any suggestions is much appreciated.
 

abbey road d enfer

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I am not sure since there are reports of that circuit causing a low lifespan of the 12bh7 driver tube, which hard to source NOS tubes that are reasonable and consistently available.
That is quite surprizing since the later versions used a 12AU7 in this position without any changes in the operating point. The 12AU7 has a lower rating than the 12BH7. Are these later versions considered also unreliable?
 

dak

New member
Joined
Apr 19, 2018
Messages
3
That is quite surprizing since the later versions used a 12AU7 in this position without any changes in the operating point. The 12AU7 has a lower rating than the 12BH7. Are these later versions considered also unreliable?
Hi, yes, I think it is better with the 12bh7. I heard that there is a a schematic which is on Glass Audio? that is supposed to be an improved circuit but i have not been able to find that schematic.
 
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