trinityamps.com

After longing to build my own amp for many moons, I’ve finally decided to jump into the amp building pool with both feet. This is my first amp build. I’ve built many guitars and pedals so I feel up to the task. I’ll say I looked at just about every kit out there and Trinity kept coming up over and over at the forums across the interwebs. Kudos for a good name! I wanted to build a 2061 clone, but I only found one kit available out there (at another site) and there were no details other than a layout to follow. Not good for a first timer! As a Van Halen fan, I was hooked on the Plexi MK II when I came across the thread here about unimind’s build and his “brown” layout. So without further ado, I present the beginning of my Plexi MKII build. I'm going to add the VRM and Cascade mod with switch. I'm also utilizing the boost switch too. I opted for the SOZO caps.



I started by sorting all the caps and resistors. The caps are self explanatory with the printing on them but the resistors took me a minute to translate. I decided to tape them to a sheet of paper labeled for quicker access when soldering starts.

Next, I populated the hardware ie pots, tube sockets, etc......

I do have some questions.

1. I mounted (3) terminal strips but I have one left over. Is it an extra if doing a different model or where does it go?

2. The BOM listed (4) #4 nuts which I have. However, I don't have one for the #4 chassis ground located near the cliff jacks on the chassis underside. I used the (4) #4 nuts mounting the terminal strips. Did I miss something? I can do down to the hardware store and get one, just wondering if it's an oversight or if I just missed some detail.

3. Speaking of nuts, BOM listed (1) #6 nut which I used for the #6 chassis ground but the pictures of the build shows nuts under the cap can. I know the chassis is drilled with threads here so probably don't need them. Is the picture in the reference section just outdated?

4. The boost switch has a "keyed" washer like the impedance switch. However the hole on the back of the chassis for the boost isn't keyed. Is this ok? Just turn the washer around backwards so it will mount?

5. I'm adding the cascade switch and VRM. It looks like you drilled the holes in the chassis for me Stephen to mount in the back. Based on layout and wiring, which holes should I used to place each one? Cascade switch next to boost switch? VRM between output and impedance? Looks like I may have an extra hole?

1. its for the screen resistor for power tubes

2. might be a miss count but going to hard ware store is always good

3 see 2

4.just flip it

5. cascade switch closest to v2 . might want to build without vrm first and best option would be to replace the power switch or by the impedance switch


for 1 see Paul g's picture

I've got some heater wiring questions...

1. Does it matter which lug on the 5 lug terminal strip adjacent to the transformer the red/black twisted heater wire attaches to? I've seen what looks like red connected to the lug closest to the front of the amp and black on the lug next to it, black and red soldered together on a lug, etc. Which wire goes on which terminal lug?

2. When daisy chaining the heater wires across the preamp tubes, are the red wires tied together and pins 4 & 5 jumpered or does one red go to pin 4 and the other to pin 5? And then jumpered or no jumper?

For the heaters it doesn't matter which lugs you use on the terminal strip as long as you don't use the ones bolted to the chassis. Red to one lug, black to another lug. According to the layout drawing, they use two lugs near the middle of the strip. Nothing connects to the grounded lugs and another lug is used for the AC neutral connections to the power transformer.

Also according to the layout drawing, at the sockets for the EL84 output tubes, red goes to pin 4. Black goes to pin 5.

At the sockets for the 12AX7 preamp tubes, red goes to pins 4 and 5. Black goes to pin 9. With the red wires, if there are two of them at a socket, you can connect one to pin 4 and the other to pin 5 and jumper the two pins together. But I find it easier to connect both wires to pin 5 and leave enough bare wire to run to pin 4.

Ahhh, thank you! I was wondering about striping off enough of the insulation to run both wires across pin 4 and 5 for the preamp tube sockets. I had noticed some others using a jumper but the diagram looked like one to both. Thanks for the clarification!

I have too many projects going so my pace has been slow. Should have more time now. Been building a guitar and a pedal. Too many irons in the fire!

Finally got the heater wires done. Very tedious work but I wanted to do it the best I could. Pretty good for a first timer? See any potential hum issues?

Looks good. There shouldn't be hum issues. I like to keep the insulation pretty close to the terminals to minimize the bare wire. But you have to be careful soldering then, so you don't melt the insulation. You might want to get the insulation a bit closer to the terminal on the red wires at V3. Bare wire between terminals 4 and 5 is OK, of course.

You have some cool looking EVH guitars on Photobucket, too. What's the little box going to be? Looks like it's made from walnut and maple.

It is! It's going to be a cigar box guitar with a resonator cone. Trying to figure out how best to mount the neck. I did one before with an actual cigar box and mounted the neck all the way through the old school way. Made actual cigar box amp too. 9v, sounds good.

Got busy at Thanksgiving and haven't had time to do much but I did get to learn how to braid! Hopefully I'll have some time this weekend to move forward. Welcome to the world's longest build.

Had some "life" come up, and after a 7 year break, I'm picking my project back up. I decided to pick-up with the board. I have populated it and am running my bus wire on the top across the turrets. There is what looks like a jumper going from the turret to a wire that leads to the gain pot. (See pic, circled in red) I'm not sure what to do with it.