KT77's (or 88's) in a BE-100?

[JerEvil]

Dumb question I'm sure but my understanding was that 77's are a pretty safe swap for EL34's. Anyone try them in the BE100? Any point in trying? Also, would KT88's make it blow up?

 

[RACKSYSTEMS]

No issues with either. Just bias.

 

[JerEvil]

No issues with either. Just bias.

Nice. Thanks Dave!

 

[JerEvil]

So has anyone here tried either of these in their BE?

 

[fusedbrain]

I've tried JJ kt77s in my BE100, as well as a few other el34 amps. I find the Kt77s give you a little more bottom end, are a little brighter, and sound / feel less compressed in the midrange vs el34s. More modern if you will. They drop right in and bias up no problem.
I would suspect kt88s would be a similar sonic change, but possibly even more pronounced than the 77's. KT88s will also require considerably more bias voltage, so I would expect to have to modify the bias circuit with a resistor swap.

 

[MetalHeadMike]

Got a quad of KT77s coming for the QR!

 

[JerEvil]

I've tried JJ kt77s in my BE100, as well as a few other el34 amps. I find the Kt77s give you a little more bottom end, are a little brighter, and sound / feel less compressed in the midrange vs el34s. More modern if you will. They drop right in and bias up no problem.
I would suspect kt88s would be a similar sonic change, but possibly even more pronounced than the 77's. KT88s will also require considerably more bias voltage, so I would expect to have to modify the bias circuit with a resistor swap.

Yeah I’ve never tried 77’s. Maybe I’ll give them a go.

Got a quad of KT77s coming for the QR!

Man let me know how they sound in there. Hopefully that gets it sorted.

 

[CrazyNutz]

Dumb question I'm sure but my understanding was that 77's are a pretty safe swap for EL34's. Anyone try them in the BE100? Any point in trying? Also, would KT88's make it blow up?

I have a quad of GL kt77's I might try them in a BE circuit. Everything else I've tried kt77's in (Swapping from el34's) It gets more low end, and more highs, sounds more like 6l6, not as mid focused like el34's. The mid focus is what I like about el34's which is why I typically stay with them.

As for kt88's those have too much headroom (IMHO), when I've tried them in other amps, I feel like I'm just plugging the preamp section in to a hifi power amp. YMMV