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Slowy wrote: ↑Mon Feb 06, 2023 8:50 am Sometimes, I think I'm a monkey with a machine gun

I changed the valves in Optimus from 6L6 to 6DZ7. So far, so good.
Then in a moment of inspiration I replaced V1 with one of my old Mullard ECC83s

Switch on amp and Mullard explodes. Seriously, broken glass everywhere.
Today's job is to remove amp from chassis and visually check for circuit damage but I suspect I won't find anything.

No smoke or smell was present, the glass just shattered.
No fuses blown.

So what should I do? check there's no visual damage, replace the tube and switch on?
Or not?

Jay wrote: ↑Mon Feb 06, 2023 9:56 am You know the amp's maker. Why not ask him?

Was the replacement EeC83 pin compatible with what was there before?

Happy to check the voltages before you try a new valve

Anyway, one change at the time....
Go back to the 6L6 (after full visual inspection) and original V1. Check amp.
If it goes, you can start experimenting again, but read up on things first.

sizzlingbadger wrote: ↑Mon Feb 06, 2023 10:30 am I'm not too sure the 6DZ7's will work that well as a direct plug-in replacement, depends on the original wiring on the socket I guess. If pin 1 & 5 (grids) are joined together and 3 & 6 (anodes) then it would run both pentodes in parallel, if not then only one pentode would be active.

clubhouse wrote: ↑Mon Feb 06, 2023 10:13 am Dunno the specifics of the amp involved but a 6DZ7 is a twin power pentode. The incorporation of two pentode sections in one envelope makes it especially suitable for compact stereo systems. It’s essentially electrically equivalent to two EL84s in a single glass envelope…check substitution validation for the 6L6(G/GT/GB/GC/STR?) beam tetrode power valve.

Didn't even know there were twin pentode, single package valve types! I know of ECL types (triode/pentode combos) but twin pentodes...wow!

If it’s handling the 6DZ7 as a sub, it sounds like a cool as hell build…tres curious…care to share anymore about it, please? Is it substantially louder, compressed or quicker to break-up with a 6DZ7 than a 6L6? Do you change speaker loads to accomodate?

Slowy wrote: ↑Mon Feb 06, 2023 12:34 pm
And I love the power chord insulation used as spacers!

RectifiedAmps wrote: ↑Mon Feb 06, 2023 1:02 pm Wow, it’s hard to imagine a situation where a preamp would be under enough electrical stress to explode. What was in V1 before? If it was an EF86 or some oddball valve, the mismatched pinout could’ve caused this, but just a guess really.