Replacement tube for my H&K Rotosphere???

[pjackso]

What brand of tube would you recommend as a replacement for the stock 12ax7 in my Hughes and Kettner Rotosphere?
Thanks...

[Peter Snowberg]

You may want to try more than just one. I have no idea what they came with, but any decent 12AX7 would be fine I'm sure. Try a JJ 12AX7 or a Sovtek 12AX7LPS.

Good luck,
-Peter

[EdJ]

I`d say JJ if you want to buy a new one;Phillips if you want to buy NOS and live in/near the Netherlands.
Greetings,Ed
p.s.do you perhaps have a schematic for that one?

[bwanasonic]

I seem to remember reading some people had good results with lower gain (5751 or 12AT7) tubes in there. I would try as many as you can, as different tubes behave differently in different circuits. The aforementioned JJ and Sovtek LPS are about the only current production tubes I  use.

Kerry M

[The Tone God]

I've tried a bunch of different tubes in a couple and to be honest I didn't notice a huge amount of difference be it NOS or production. Just about any decent tube, meaning no China or Sovtek WX* tubes, will do. The tube seems to be used only for some buffering and doesn't really do much.

As for a schematic I would imagine it would be way too sophisticated. There are two BBD sections (rotor and horn) and something like 9 quad opamps. Thats alot of stuff.

Just my opinion.

Andrew

[pjackso]

Andrew,
I'm not familiar with Sovtek WX* tubes???