SE 6L6GC amp in triode mode

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While waiting on stuff that I ordered from Dynakitparts.com for my MKII-to-MKIII conversion/restoration project, I thought I'd build a SE amp with 6L6GCs + 6SL7. I bought these 6L6GCs for my ST-70, but I wasn't crazy about how they sounded. They were not bad, but preferred EL34s.

The amp sounds pretty good and it worked perfect the first time I fired it up. That never happend before! I am using 7.5k 5W Valve Junior OPTs and, after some experimentation, I like 4 ohms tap with 8 ohms load the best. I haven't decided what to do with the base yet. Probably go with wood. Here are some pcitures.

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[Shannon Parks]

Where did you get the VJ OPTs? Cool project.

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Thanks. I got three of those on eBay brand new for the price of one. It was a greal deal. Perfect for small projects like this. Apparently I biased those 6L6GCs pretty suitable for 6V6s as well. I plugged 6V6s in and the amp sounds real nice.
BTW, I want to add a switch for operation in pentode mode. How to you do this? My guess is that you would wire no. 2 grid to B+ before OPTs with a resistor, since you want the grid volt to be less than the plate? What would be the resistor value? I strapped 100 ohms for a triode mode.

More pictures with a metal base. Do those base and power switch/IEC socket look familiar, Tom?

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[TomMcNally]

Hi Min -

Yeah glad to see that box find a good use - a friend made it
for me back in the 80's for a project I never got around to.

Nice job - how many amps have you build now ? Like 10 ?

... tom

[Sal Brisindi]

Min,
Nice job, can you post a schematic of it?

Regards,
Sal Brisindi

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Thanks, Sal. I will be back home from my water-skiing trip to Lake Powell on Sunday, so I will post it then. -Min

[77seriesIII]

ok so trolling through the site and I found this...Did the schematic make it up and I missed the link? I've got 4 6l6gc's and I'm itching to do something with 'em... Yellow_Light_Colorz_PDT_16

[hembrook]

6L6 I LOVE in a good guitar amp.

The comment about 6V6 is appropos, they have similar ratings for power and such, so are swappable, just the 6V6 gives half the power. Nice swap in guitar amps.

That said, I love 6L6 in guitar amps, because you can set them so that as you dig in, you kit the "kink" in the curve. That is what the "KT" series of tetrodes was for, to eliminate the kink. So I think people find pentodes to sound nicer than tetrodes, as it worked for Dynaco using 6CA7/EL34s rather than 6L6.

Lemme know how it works out.

P.S. Tetrode to Triode switches are easy. Can't make a 6L6 go Pentode, however Yellow_Light_Colorz_PDT_12