OPT replacement ???

[jwrauch]

I have a Maggie 9300 series amp that has been updated and would like to improve the bass response. would new opt's make sense? JOHN

 

[jaymanaa]

What are the output tubes, 6V6, or 6BQ5?

 

[jwrauch]

6BQ5 output tubes. Sounds wonderful . Bass is OK but a little thin. JOHN

 

[jaymanaa]

I've had good luck tightening up bass in old Maggies by switching out the 6BQ5s to 6GK6s (a TV tube). I think there are 3 wires you have to move around on the socket, but I'd have to consult a tube manual if you want to try it.

 

[jwrauch]

Sounds like like something I'd like to try. JOHN

 

[Thespeakerdude8]

I've had good luck tightening up bass in old Maggies by switching out the 6BQ5s to 6GK6s (a TV tube). I think there are 3 wires you have to move around on the socket, but I'd have to consult a tube manual if you want to try it.

Why? Is there a technical reason behind this? Do these tubes have lower internal resistance, and thus better damping factor?

I noticed when taking them apart for cleaning, that on the 6v6 versions of this amplifier, the OT's appear to be gapped! They have an EI lamination instead of interleaved, and there is a thin piece of paper or wax separating them. This could help explain the slightly poor LF response. I would like to try interleaving the EI laminations some time to see if ti helps. :thmbsp: