Anyone out there run KT77s in your Traynor YBA-1 or YBA-1A Bass masters?

[timrichter9]

Hey all-

I have scored a pair of Traynor Bass Masters (one YBA-1, one YBA-1a (with the internal fan).
Just wondering if anyone out there is running KT77s in one of these (or did do so, and yanked them out with displeasure).
Would love to chat off list to get your impressions on the experience.

I have not dived into these, but they have huge iron and are supposed to be close to a Bassman circuit with some slight tweaks.
I have heard that the KT77 is more of a 6L6 sounding EL34 substitute and that intrigues me.


Thanks
Tim

[soundmasterg]

I haven't used the JJ KT77's in a Traynor but I have used them in a Vox AC100 clone that I built. I like them....good sound and hold up well. I have to get the coolest running ones for the Vox build as it runs them really hot.

Greg

[big_teee]

I haven't used the JJ KT77's in a Traynor but I have used them in a Vox AC100 clone that I built. I like them....good sound and hold up well. I have to get the coolest running ones for the Vox build as it runs them really hot.

Greg

I've used the JJ KT77s in my Clone JCM800 2204.
They had good harmonics.

[madkatb]

I've seen YBA1's with 6L6's. Just need to change resistor values in the bias circuit to get the right bias.

[timrichter9]

Thanks for your responses. As far as putting 6L6s in the Traynors, MADKATB, I have several vintage amps with 6L6s (actually, most of my amps are vintage Fenders, so 85% of my collection is 6L6). Unless someone tells me that the YBA-1s are AMAZING with 6L6s, I will probably experiment with various 6Ca7s, EL34s, KT77s etc.

[g1]

Unless someone tells me that the YBA-1s are AMAZING with 6L6s, I will probably experiment with various 6Ca7s, EL34s, KT77s etc.

Not sure about the "amazing" part, but the original YBA-1's used 7027 power tubes, which are pretty much 6L6's that are supposed to handle higher plate voltages than regular 6L6GC's. Some people really like the 7027 version, some prefer the EL34's. Depends what kind of sound you are looking for.
Here's a link to a pdf of schematics with several YBA-1 versions.
http://www.lynx.bc.ca/~jc/YBA1Schems.pdf

[Ted]

I'm guessing your using them for guitar.

I've tried them in a YBA4 Bassmaster combo used as a bass amp.. The EL34s I replaced were so tired that anything would have been an improvement. I thought the KT77s sounded OK - quite pronounced mids with a rather pleasant dirty breakup. But I eventually replaced them with 6550s which I definitely preferred - almost gave a sort of "mini-SVT" tone.

But the fact is that these aren't great bass amps. When I get time I'm going to play about with the porting and maybe try a different driver.

[KevinOConnor]

Hi Guys

True 6CA7s which were used in YBAs are built the same as a 6L6, so sound like a 6L6 even though the bigger heater makes them smell like an EL-34.

If you wanted true flexibility from this amp, you would install meter jacks and individual bias pots. This would allow easy change of tubes and you could mix tubes. Since the amp was wired to accept 6CA7, it has heater capacity for all the tube types you mentioned above. Contrary to this, amps spec'd for 6L6s have nominally less heater current available and you are taking a chance wrecking the PT by plugging in higher-heater-current tubes.

Have fun