Pre Amp Tubes for Herbert - Which Ones?

[Jim86]

I have a Herbert and last I knew was to use the following

V1 -12AX7AC5HG+ 678
V2 - 12AX7AC5HG+
V3, V4, V5, V6 - 12AX7AC5HG

is this correct?

I do have 6 of the 12AX7AC5HG+ 678...........would I be better to use the 678s for all the
pre amp tubes?

Thanks

Jim

 

[Peter Diezel]

No need to spend extra money, Jim.

Your information is perfect.

Cheers,
Peter

 

[Jim86]

Thanks for the reply Peter.

Couple of more quick questions, I already have 6 of the 678 but I have not taken them out of the box yet. I could also exchange them to get the exact ones listed because I work at a music store. What is the main difference between the 12ax7s 678 and the other 2 types of 12ax7s? Would having all 678's sound different than having the configuration listed above?

Thanks

Jim

 

[Peter Diezel]

The only difference is the micro phonic rating, Jim.

Best,
Peter

 

[Jim86]

Peter,

So the 678's are just less microphonic and no difference in tone or voltage rating etc?

-Jim

 

[Peter Diezel]

Yes

 

[Jim86]

Thanks Peter.........I will let you know how I make out. Im still waiting for my KT-77s to come in then I am going to re-tube the entire amp.

Jim