Tube selection for Simul-Class Mesa Mark III++ (troubleshooting content now)

[ners]

Haven't been happy with the way this was sounding lately so I decided to test some tubes and seems like the inner 6l6s (STR 445 yellows) were worn down. Blindly ordered some more but got sent STR 448 Greens by accident...are these worth keeping?

Consulted my friendly AI which seemed to suggest they're actually a better choice (448 > 445 & green > yellow) but now it feels like a whole tube rolling rabbit hole...

EDIT: Welp, said fuck it and threw them in. It sounded glorious for about 1min before it blew a fuse...so onto troubleshooting I guess.

 

[Techdeth]

Bad power tube
My 3++ simul blew a second cap

 

[DanTravis62]

Yeah sounds like the tubes weren't the issue in the first place

 

[ners]

Ran out to buy new fuses since of all the ones I have lying around none were the right fit. Amp plays just fine with the outer EL34s so yeah sounds like a DOA tube.

So back to my original question, what 6l6s are folks using for this beast?

 

[Holy-diver]

I have been getting “mesa rated” JJs from ruby that work super well for me, in an HRG III++ though so it’s slightly different

 

[ners]

Finally got in a replacement set of tubes from Mesa. Popped them in, let them heat up on standby for 4-5mins. Played it for a minute then started getting a smokey smell...

Anything easy to check before I just say fuck it and take it to a tech?

 

[schnarf]

Any chance you're willing to share some gut shots of the III++? I'm really curious about them! Might also be able to see if anything obvious looks off. I had a Mark IV which was blowing fuses coming out of standby and there was a snubber cap that had gone bad: https://www.rig-talk.com/forum/threads/mesa-mark-iv-snubber-cap-not-on-schematic.340894/

 

[ners]

Any chance you're willing to share some gut shots of the III++? I'm really curious about them! Might also be able to see if anything obvious looks off. I had a Mark IV which was blowing fuses coming out of standby and there was a snubber cap that had gone bad: https://www.rig-talk.com/forum/threads/mesa-mark-iv-snubber-cap-not-on-schematic.340894/

So I'm probably too lazy right now take new gut shots as even if it is as simple as a burnt resistor or blown cap as I don't trust myself enough to fix it anyway.

But here's the gut shots from Mike B when he did the mod late last year.

 

[Brain Becker]

So I'm probably too lazy right now take new gut shots as even if it is as simple as a burnt resistor or blown cap as I don't trust myself enough to fix it anyway.

But here's the gut shots from Mike B when he did the mod late last year.
View attachment 457760View attachment 457761

I think schnarf wants photos of it as it is now so he can troubleshoot.

 

[mentoneman]

still love my blue III

often forget how versatile it is.