Can Astorias handle running KT88's

[Dave W]

Has anyone tried them?

If no one has run them, then with the specs and tolerances of the amps could KT88's hypothetically work?

I want to try them at some point if it sounds like they can be run safely. I have a Classic and a Custom incase that matters as far as the specs and tolerance of those amps may be different.

Thank you!

[SteveD]

I never tried KT88s during development so can't really make an informed comment.

[surfnorthwest]

I tried them they work, sound like shit. Best way I can explain it if I remember right is the amp lost some distortion but the sound was "woofy". Also the dynamics of the amp when sustaining a chord was not as "tight" The good of them is there seemed to be more clean headroom.

I rolled 5 different power tubes in the amp before deciding on some old RCA 6L6s in it, those sounded best to me and are still in the Custom.

I also tried

- KT66 Pretty good, might have gone this way if I were only playing blues with less gain
- EL34s They were new Mullards, not bad but not as nasty as the 6L6s
- KT88s see above
- KT77 ......Much like the EL34s
- 6L6 I liked the cleans and the total overdriven sound

[Dave W]

Cool. Thanks guys! That helps. I have 6L6, KT77, EL34 so will roll them when I get time. Still curious how KT88 would sound in the Classic, maybe some day when I get time but not sure its worth the $80-90 to try them since they did not fair well in the Custom.

[TM1]

I have some slightly used M.O.Valve KT-88’s, slightly used Mullard EL34 from the 70’s, some NOS Mullard EL37’s & NOS M.O.Valve KT66’s. I’ve tried the EL37’s and didn’t like them compared to the KT66’s. I haven’t tried the KT88’s. I’d like to try the old RCA 6L6’s I have as well as the NOS 5881’s...

[ASM31500]

Can you swap from different tubes without bias ? I means at least 6L6 or EL34 ?
Does it means the Astoria is self bias ?

Thanks for clarification

[Roger]

Can you swap from different tubes without bias ? I means at least 6L6 or EL34 ?
Does it means the Astoria is self bias ?

Thanks for clarification

Yes. You can swap them without set the bias. The Astoria range is self bias.
I use Tung Sol 5881 on power tubes.

[surfnorthwest]

Can you swap from different tubes without bias ? I means at least 6L6 or EL34 ?
Does it means the Astoria is self bias ?

Thanks for clarification

Like Roger said, you can change to any other power tube without setting the bias. The amp was designed to work with EL34s, but Marshall shipped them with KT66s.

I run two 6L6 RCA power tubes.

[TM1]

I think the issue with the KT88's is an impedance mis-match versus the output valves and the output tranny.