trinityamps.com

All:

I was recently given a Plexi 18W Trinity amp kit that was partially completed by someone back in 2015. They purchased the prebuilt Plexi component board and the remainder of the kit components. I'm in the process of doing an inventory so I can determine if I'm missing any parts. The kit came with V.2.5 of the builders guide but I just printed out V3.1. There are several changes and I'm trying to determine if they are corrections, or modifications to component substitutions by Trinity over the years. If they are corrections, then I need to use V3.1. If they are reflective of component substitutions by Trinity, then I need to use the older version that reflects the actual parts that I have.

These are the changes from the version I have to the latest version.

2.6 - 23Feb15 EF86 Pin out diagram changed - I don't think this affects me
2.7 - 23Dec15 Impedance switch updated - what changed here? I'll photo the switch I have if that helps.
2.8 - 14apr16 BOM update with Impedance switch and knob - what changed here?
2.9 - 24Sep16 Updated v6 layout to piggy-back output tube bias design - I don't think this affects me
2.92- 2Mar17 Updated BOM to reflect correct voltages - ok
3.0 - 26Apr18 Updated new Power Transformer Primary wiring - Is the transformer I have wired differently than the new one? What changed?


Can you guys help me determine how to deal with these changes. Keep in mind that I have the prebuilt Plexi board circa 2015 as a starting point. I have never built an amplifier before.


- Jason

Coco would be the best to chime in

But if it came with 2.5 that would be the best to go by since its the era of the amp

The impedance switch was changed at some point after the era of your amp . but a pic would help to tell if its old or new style

The transformer wiring change I think was more for 240 wiring and yours looks to be 120 so I don't think there an issue there

The good news it looks like all the components are all there. You just need to finish up one input the tone knobs and a couple of missing grounds

If you can print off the latest layout take a highlighter and mark every thing out comparing to what you have

The impedance switch was changed to the current black HD model. The PT primaries were changed to add more international voltage support.
Nothing else has changed really. We could probably send you a document closer to your kit if you didn't get a manual or diagrams with the kit.

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

I have the older style transformer with the 117V taps.

I have the newer style impedance selector switch.

I found a copy of the V2.5 guide and drawings so I think I am ok with using those for now. My soldering station arrived today so we will get started soon.

We finally fired up the amp last night. We had a bad jumper configuration on V2 that threw the voltages off, but it has been repaired now.

There is a problem with the Cliff jacks on the normal and TMB sides. The normal side is noisy and the TMB side has a severe loss of signal. It looks like I"m taking those apart this weekend to redo them.

Any issue with using shielded 24ga instrument cable for the Cliff Jack wiring?


- Jason

Shielded cable isn't overly critical for short runs carrying audio signals. Light gauge cable with a foil or braided shield works best.

The shield connects to ground only at one end of the cable. The layout drawings show the shields connected to ground at the jacks. The other ends are usually covered with heat shrink tubing to make sure the shields can't touch the chassis and create a noisy ground loop.

I got the normal channel working by redoing the connections. The TMB side is still intermittent, which is the side where I used guitar cable because I didn’t have enough RG174. I am going to redo that side tomorrow when the 174 I ordered comes in.

This thing is loud. Wow. I am going to have to get the VRM kit for sure.

Finished it. Sounds great. Had some extra oak plywood around so we made a case for it also.




- Jason

Looks good

Glade you got it working

Good job. Always harder to pick up someone elses work!

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