advice: 6L6 hextet for SUper Twin head for bass guitar

[JRGuitarGuy]

at least with 6l6 you have a wider range of options/different ones you an try etc. I'm not bashing JJs I'm just scared of them I have had too many nightmares maybe its just bad luck with me lol

[ArcticBreaze]

i hav bought about 30 pairs of jj 6l6's from AES plus HEAPS of ecc83's and ecc803's and even after being shipped all the way to New Zealand (kicked around buy couriers, droped and fumbled by customs, etc) still not a single dead'un out of the box and no one has reported a failure in any of the amps i hav fitted em to.

The = C= are sopssed to hav about the best sound, but twice the price.

JR If the ECC83 sounds abit dull try an ECC803 its the long plate version, sum people prefer them. I hav 803's in my harp amp and like the tone, ....but i guess tone is a personal thing.

[cyclecamper]

So what's a = C=

[cyclecamper]

I guess my quietion is more that I'm not really comfortable with mis-matched construction in parallel push-pull; these tubes look quite different inside.

[cyclecamper]

Originally Posted by JMFahey

...how much it's actually putting out. Anything above 120W RMS is excellent...

If I only get 120 watts I'll replace them all. I used to get a real 130 out of a silverface bassman 130 with only 4 6L6s (ultralinear seems to give a few extra), I want to get the real rated 180 out of 6 6L6s in this ultralinear.

I need to look carefully at the super twin schematic compared to its closely related sister the Studio Bass. I know the centers for the EQ are different, but I don't know whether there are any other differences in the bass model, like size of coupling caps, bright switch, etc.

[cyclecamper]

A sextet of 7581A could give as much as 210 watts in the right circuit, but they're almost $700 for a low-hours used set.

[JRGuitarGuy]

Yeah I heard good things about the Ecc803 and I tend to actually like long plates, I have them old Sylvania 12AX7 those sound pretty good, Not sure what I am after tone wise maybe some more Edge/clarity and bite but I still find lots of the long-plates have a nice 3D presentation I really liked. I would like find a nice gainy short-plate that still has a more lively open sound to it. I keep thinking I need to try a Mullard I61 or an Amperex BB, or else something with amazing harmonic content.

[JRGuitarGuy]

Them old Chinese "silver specials" were hot as hell but I found they still retained like a nice sound-stage/bite etc I wish I would of hung on to a few of them lol. Now I understand they have the 8th and 9th gens 12ax7a/b etc I haven't tried em yet but guys say they are nothing like the old ones.

[GeorgK]

Originally Posted by cyclecamper

If I only get 120 watts I'll replace them all. I used to get a real 130 out of a silverface bassman 130 with only 4 6L6s (ultralinear seems to give a few extra), I want to get the real rated 180 out of 6 6L6s in this ultralinear.

I need to look carefully at the super twin schematic compared to its closely related sister the Studio Bass. I know the centers for the EQ are different, but I don't know whether there are any other differences in the bass model, like size of coupling caps, bright switch, etc.

I recently changed O/P tubes in a studio bass and it reached about 170 WRMS. I used chinese ones from TAD. 120 Watts in fact would be weak.

btw, ultralinear will not give you extra power, rather less than conventional pentode operation. To get most out of the amp you could try to convert the output stage. But the ultralinear transformer certainly gives the amp something special. Wouldn't want to play guitar with this one though

If you have the super twin with the infamous 6C10 then the preamp is different in some ways but they share the same output stage.
Just curious, how will you measure output power without a scope?

[bernification]

Regardless of valve type, the studio bass and silver face super twin will only be rated to give 180 w by the output transformer.
Going beyond this will drive the amp into transformer saturation and/or output stage distortion (which may or may not be your cup of tea- but you did state previously that breakup modes were not what you were after).
Driving this excessively will cause undue heating and possible damage to an old transformer, so beware.
I'd personally try to measure current draw between both sides and balance the valves to get the best indication of that.
Then play the bloody thing. All this talk about what valves they are or aren't, or other peoples experiences with different brands doesn't matter if you can balanced current draw and it sounds good and works!