trinityamps.com

I noticed I put, what I think is the VRM low limit resisitor, as 100K as per the manual. But the diagram shows a 220K which was a change in 2014, I don't think this would be my issue so I'm not going to swap that out unless someone think's it's the cause.

Update: I've got some sound with humbuckers, though very low. Single coils even lower. I have to turn the level and volume up to at least half before I hear anything. Maybe a speaker issue? My ET10 hasn't come in yet I'm using the speaker from a Peavey Blazer 158 (little solid state practice amp) 15W, 7.7V RMS, 4 OHMS -- it's what I had around that I could easily access the speaker.

I measure voltage around the board, to match the layout diagram measurements. I annotated one of the photos, some voltages seem low, off the 12AX7 socket.

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I'm no amp tech, just a Tramp owner cheering on a fellow Tramp builder, the first thing I would suggest is to post up your various voltages and that may point straight to a trouble spot. For comparison here are mine from when I first powered up my build. Also I'm not sure why the 100k off the VRM was changed to 220k (mine is 100k since my amp was built in 2012 and I haven't changed it). Maybe Stephen can elaborate on the change.

"I recorded some voltages for other builder's reference, especially for anyone else building the amp to run off 240 Volt mains like mine.
These were all recorded to ground with the VRM B+ dialled to 400VDC at the positive side of C12.

6V6
pin 2 = 3.3 VAC (fillament)
pin 3 = 397 VDC
pin 4 = 395 VDC
pin 7 = 3.3 VAC (fillament)
pin 8 = 28 VDC

12AX7
pin 1 = 179 VDC
pin 3 = 1.84 VDC
pins 4 and 5 = 3.3 VAC (filament)
pin 6 = 178 VDC
pin 8 = 1.6 VDC
pin 9 = 3.3 VAC (fillament)


For reference I also took the following B+ readings for the various numbered positions of the Power Level (VRM) control. (Mine was marked as "A" taper)

VRM B+ measured at positive side of C12
position Idle = 40 VDC
position 4 = 50 VDC
position 5 = 75 VDC
position 6 = 95 VDC
position 7 = 116 VDC
position 8 = 146 VDC
position 9 = 259 VDC
position 10 = 382 VDC
MAX = 427 VDC


Snowy"

Neat build. Everything looks good in your pictures.

Running the amp without a load for a minute or two probably wouldn't hurt it too much. The idea of always having a load is to protect the output transformer. With no load, the transformer could arc internally and become damaged.

Actually the only time you need a load is if you have the output tubes installed. You can test the amp with no tubes, or with just the preamp tubes, without having a load.

Filaments and heaters are the same thing in tube amp terminology.

The red wires from the power transformer are the high voltage AC leads. After the diodes it's DC.

When you say there is no sound, you hear a faint hum or hiss coming out of the speaker, or is there dead silence?

Check your speaker cable again. Plug it into just your speaker and measure the resistance at the other end of the cable. It should read about 4 ohms.

Check all your connections in the amp again, too. If there is no sound at all pay special attention to the connections to the output transformer, the impedance selector and the output jacks.

I just noticed you listed the voltages on your last pic and they seem good to me, mine were quite similar.

As mitch points out check all connections related to the OT, Jacks and selector. With speaker connected, and both volumes and VRM turned up, poke around those various output related connections with a wooden chopstick and see if it causes any noises/crackling. (Remember Safety First!, one hand behind back, etc).

Possibly also check/operate the Tweed/'Tude pull switch to see if there still the same low level sound in either position.

Just another idea but other common trouble spots seem to be the shielded cable run from the input jack to C1 and the shielded cable run from the Tweed/'Tude switch to the 330k R6/Pin 7 of the 12AX7. Preparing the shielded cable properly without creating a short seems to catch a few people.

Tweed mode seems fine, just low volume, almost nothing for single coils. Tude mode crackles a lot when I adjust the gain pot, sometimes without even that. Sometimes Tude works fine, I think it may be the switch. I'll take more voltages later today.

I recall when soldering the 220K resistor to the gain SPDT I needed to desolder and re-bend the lead, the process resulted in too much heat and the SPDT lug for that resistor end up a bit loose. The switch resistances seem not to have been affected. Hrm, now that I recall I had suspected a snipped lead may have disappeared into that pot's innards, but at the time I dismissed that as probably didn't happen -- now I wonder.

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Went to two electronic shops looking for a 500K audio/logarithmic pot with push-pull SPDT switch and no luck -- turns out Long & McQuade had some in their guitar repair department. After swapping out the old one with a wiggly pin, everything seems to be in order! I'll have to wait for my son to finish his nap before I crank it and really check though

Confirmed, everything working, sounds fantastic even through this crappy speaker.

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Good news, congrats, what are your plans for cab and speaker?

I've got a WGS ET10 on the way, going to build the cab myself, though if anyone wants to share plans for a simple 10" dovetailed cab for this thing it would help! These ones for a 5e3 should work size-wise, no?

http://music-electronics-forum.com/atta ... heet_1.pdf
http://music-electronics-forum.com/atta ... heet_2.pdf
http://music-electronics-forum.com/atta ... heet_3.pdf

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Contact Stephen about the Tramp cab plans, As a Tramp customer I am sure he would confidentially share the Trinity plans with you, I'm pretty sure this used to be the policy, not sure if it still holds though, certainly worth asking him.

Here's how this one turned out. My motivation was to build the amp itself, the cabinet was a necessary evil and therefore has a couple of issues. Overall I'm please with the result being my first tube amp build, and first cabinet build, plus, when it sounds as good as it does you can't fault it too much

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Nice work, I have zero cab building skills so I take my hat off to you for building your own.