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Hello All -

I am new to Trinity Amps, I am building a Tramp, because it is awesome

Question: to add EL34 functionality I wire up a DPDT switch as in the lower right corner, correct? Is this a substitute for the existing 6v6/6l6 switch?

Thanks!

Mike

Hi Mike. Welcome to the forum!

The optional switch shown in the box on the schematic is an impedance switch. It lets you use the transformer's 2.5K tap on the primary which is a better match for an EL34 output tube.

You still need the 6V6/6L6 switch. It sets the bias for the output tube. The 6L6 position is the higher setting so use that with EL34.

Good luck with your build.

Thanks, Mitch, that makes sense. I'm about half-way through, I expect to finish by the weekend

Spot on mitch, thanks!!

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Glad to help. I've never actually built a Tramp but I've been reading lots of great things about them on this forum and the demo clips sound great, too.

I recently got an old Bogen PA amp. 10 watts, 6L6 single-ended output, two-stage preamp. I'm going to mod it into something Trampish!

That will be fun!! If you need latest schematic / layout, let me know.

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Finally had a chance to sit down and finish. Wow! What a nice amp!

When I first put the tubes in the 6v6 was red-plating Strange since all the voltages were correct and everything seemed in place. Turned it off, took out tube, redid voltages, and all OK No shorts, no funny smells, all looks good. Huh. Is it the tube? Swapped in a KT66, moved the switch to 6L6 and let it rip. No red plate and absolutely gorgeous beautiful tone through an external cab. I looked around for an extra 6v6, swapped the switch back, and no red plate. So, bad tube!

One issue remains: the power scaling doesn't work. No difference at Idle vs Max. I will trouble shoot using the guide and shout if I need any help.

Otherwise, what an nice amp!

Mike

*EDIT* Now waiting for the cab, the WSG ET65 came Friday!

And fixed it: I had the lead to the 10W 5W resistor coming from the Source, not the Drain. All is well. Very well, in fact I tried a 6L6 in there and that's going to stay. I might roll a few !2ax7's through, though...

*EDIT* er, I mean the Drain, not the Source

I was about to suggest the wiring. I think you're pretty lucky the FET didnt blow!
A 6L6 totally rocks this amp!! But gets away from our low power style!
Glad you're liking the Tramp!

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Thanks, Stephen. It is much louder now, but with power scaling working it is somewhat mitigated. The power scaling is tricky, but it is really good. I played with it a bunch tonight and I can dial in really great tone at reasonable volume. Great stuff

The MV works very well too!

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Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

Yes! That's what I'm finding. They both have their place, but I'll tell you what: cranking that thing and making the speaker, the power tube and the preamp all work hard makes for some awesome tone. Find a place to crank it!

And all done! Cabinet here, sounds wonderful! ET65 really works for this configuration of this amp

So I've been looking at modding the amp to use an EL34 and I think I've found an error in the layout diagram. The graphic for the mod says to take the middle lugs of the switch out to PIN 8 of V2. This should be PIN 3, right? The schematic says pin 3 and that seems like the right thing.

definitely pin 3.
pin 8 is for the bias resistor switch.