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PostPosted: Mon May 30, 2022 10:11 pm 
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I ordered my kit ages ago. In fact, it shipped to me with a cover letter on the instructions dated October 14, 2019. That’s admittedly 2.5 years ago. I kept the whole package safe and secure until I was ready to start building.

In truth, I had to prioritize remodeling my ENTIRE HOUSE over an amp build. I did find time to finish up some minor guitar projects. But those are small potatoes compared to an amp.

Disclaimer: This is my second Trinity amp. First was a sIIIv6. And I also built three Allens: Old Flame, Chihuahua, and Encore.

I sat down to build today and noticed immediate potential issues:

1) My builder’s guide shows v3.5 on the cover, although the version control table on page 8 only goes up to v3.4, dated 15Oct19. So it makes me wonder what I have.

2) I started to “Install the Hardware” per page 24. The #4 bag contains only one 4-40 Keps nut. In fact, there are no other 4-40 nuts. But there are 20 4-40 x 5/16 machine screws. But there are also zero 4-40 x 7/16 screws.

3) Page 24 talks about a 5 lug terminal strip. There is no such strip in the kit. In fact, the kit has a bag with four 3 lug terminal strips and another two 3 lug terminal strips in another bag.

4) The included color layout shows no 5 lug strips.

5) The layout shows one terminal strip on the v1 tube socket screw closest to the circuit board (near tube pins 4 and 5). But the build photos on the website show it on the side, near pin 8. Which is correct?

6) Just spending a few minutes poking around, there are a few other differences between the build pics on the Trinity Support page and what I see in my color layout. How do I know which is correct?

Other than super easy steps, I feel like I need to stop before doing anything I will need to fix later. Any guidance on determining the cirrec5 instructions?

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PostPosted: Tue May 31, 2022 1:34 pm 
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Sometimes life gets in the way of these projects, but its good to hear you are finally able to get around to this build.

My advice is to use the most recent builders guide, schematic and layout as posted on the trinity support website. Anything that is different from 2019 is probably there for a reason, whether to improve tone or reduce hum, or whatever. I'd make a list of any parts/components differences between your revisions and also any missing hardware. You could then email or PM Stephen and see what he could do for you, or just source the parts yourself. The #4 nuts and screws are generally hard to come by at Lowes or Home Depot, but many online amp parts stores has them, like AES, Tube Depot, and Hoffman.

For the grid stopper resistors for V1, the mounting of the terminal strip depends on how you run your heater supply. If you do it "Fender style" as shown in the build pictures where they are floated above the sockets, then I'd mount the terminal strip as shown in the photo. If you do them Marshall style where they are tucked against the corner of the chassis, I'd mount the terminal strip between the socket and the board.


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PostPosted: Tue May 31, 2022 2:52 pm 
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Thanks for the response.

Later today, I will go through my Builder's Guide and the one online page by page. I will try to use the one online as best I can. Yes, it makes sense that any changes were probably clarifications and/or improvements.

As expected, I had no luck at Home Depot with 4-40 Keps nuts. I was able to call the local hardware store just before closing time. They claim they have #4 and #6 Keps. I'll stop by today right after work. Hope they have them like they said. Otherwise, it's online. Ugh!

I see that there are two different drawings online for the Relay board layout:
- "3V OD RELAY LAYOUT" - This design connects directly to the 6.3 VCT heater supply.
- "5V OD RELAY LAYOUT" - This design requires a separate transformer to supply the AC to the relay board.
There is a Zettler Magnetics transformer in my kit, along with a bag of parts that includes the relay board and a few other parts. I assume that's the one that goes with the 5V OD layout. But I suppose I have some time before I reach those steps.

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PostPosted: Tue May 31, 2022 4:24 pm 
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I did not do the relay board with my build, but I would suspect that you would go with the 5V relay layout. You may want to build the amp without the relay first, just to make the initial troubleshooting a little easier. Once you get any issues worked out, you can wire in the relay board later. However, I'm sure there are a lot of people who do the build all the way through with the relay board installed before powering it up for the first time.


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PostPosted: Wed Jun 01, 2022 12:59 pm 
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Stopped by the hardware store after work to pick up some #4 and #6 locking washers and keps nuts. So I was sort of back on track with some of the hardware assembly.

I decided to compare my build guide with the one online (wife trying to print it for me, but had a printer glitch) to note the differences. I'll stick to the current one wherever possible. If I run into a discrepancy, I'll give it as much thought/research as possible before making a misstep.

One thing that jumped out at me, and perhaps it will get explained in better detail later, is the bit about the overdrive switch/pot on page 18. It provides instruction on how to do it and not do it if you are doing the relay board. But the instructions aren't crystal clear.

Before installing the Overdrive switch, pre-wire the switch with a 100K resistor
as shown.
Note: * This step not required when the relay board is being used for the
footswitch option. Also not required if you have mounted the 100K on the tube
socket pin 2 directly.
This modification requires a jumper where the 100K is
shown in the layout diagram.


I have a relay board and footswitch in my kit, so it seems clear that I do not need to pre-wire a 100K resistor. Okay, makes sense.
But after that, I don't know they are talking about. It says pin 2. But I'm guessing they really mean pin 2 and pin 7, since those are the two pins that the 100K resistor would engage with the switch pushed in. I assume that I can ignore that 100K entirely (whether on the tube pins or the switch), since I'm doing the footswitch thing.
What I'm not clear on is the red text. Do I need a jumper here? Or is that only if you do the 100K on the tube socket pins?

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PostPosted: Wed Jun 01, 2022 3:59 pm 
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you will use the jumper in place of the 100K resistor on the switch ONLY if you mount the 100K directly to the tube socket. If you are using the relay board, you will not use a jumper. Instead, follow the builders guide for the 5V Relay board: http://www.trinityamps.com/docs/TRIWATT_OD_Relay_Manual_5V.pdf

Since you mention you not sure what is going on, I'll try to describe the overdrive circuit.

Each half of V1 serves as the preamp for the bright and normal channels. The signals come off the plates of V1 (pin 1 and pin 6) to the respective volume controls, and then to the two 470K mixing resistors (R9 and R10). From there, the junction of these two resistors serves as the input to the next stage. The OD switch is basically routing this input through V2b (pin 7) and then to V2a (pin 2), which then goes to the tone stack ---OR--- bypassing V2b and going straight to pin 2. Thus, V2b (pin 6,7,8) serves as the OD circuit, as the signal from this circuit is cascaded into V2a (pin 2) when the switch is engaged (pulled).

As I mentioned, the second triode of V2 serves as the cascaded OD circuit....the signal input is pin 7 (grid), and the output is the plate (pin 6). From pin 6, the signal goes through a coupling cap (C4), then on the the 1M pot (OD control; VR3), and then to the 100K resistor (R47). The switch, when pulled, connects the other end of the resistor to the shielded wire leading to first triode of V2 at pin 2, the grid. The end result is cascading the mixed signal from V1 into V2b, then to V2a, then to the tone stack.

When the switch is in the off position, the "other end" of the 100K resistor (R47) is not connected to anything, so anything that happens in V2b has nowhere to go. At the same time, with the switch in the off position (pushed in), the mixed signal coming from V1 (where the two 470K resistors are; R9 and R10; orange "straight line" wire) is sent directly to V2 pin 2. This results in a bypassing of V2b. You can see that when the switch is pulled (OD is on), the signal coming to the switch from the mixing resistors along the orange wire has no place to go, and instead takes the closed path from the mixing point straight to pin 7 via the shielded wire, where it travels as described in the preceding paragraph.

The 100K resistor (R47) is only connected to V2, pin 2, when the overdrive switch is engaged. R47 is not at any point connected to V2, pin 7.

I know I suggested earlier to perhaps build the amp without the relay board in order to simplify troubleshooting, but on second thought you may want to proceed with installing the board right off the bat. That way you don't have to rewire anything. Doing it this way will result in the 100K resistor being moved to the relay board, and you will wire everything as described in the 5V relay board builders guide.

The Triwatt is a great amp but probably the most complicated build I've done. Take your time and quadruple check everything. As with any amp, good lead dress and wire routing are critical. But the cascaded OD circuit can be a source of gremlins. Use the shielded wire as recommended and minimize wire length whenever possible.

Good luck!


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PostPosted: Thu Jun 02, 2022 12:15 pm 
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PharmRock wrote:
you will use the jumper in place of the 100K resistor on the switch ONLY if you mount the 100K directly to the tube socket. If you are using the relay board, you will not use a jumper. Instead, follow the builders guide for the 5V Relay board: http://www.trinityamps.com/docs/TRIWATT_OD_Relay_Manual_5V.pdf

Since you mention you not sure what is going on, I'll try to describe the overdrive circuit.

Each half of V1 serves as the preamp for the bright and normal channels. The signals come off the plates of V1 (pin 1 and pin 6) to the respective volume controls, and then to the two 470K mixing resistors (R9 and R10). From there, the junction of these two resistors serves as the input to the next stage. The OD switch is basically routing this input through V2b (pin 7) and then to V2a (pin 2), which then goes to the tone stack ---OR--- bypassing V2b and going straight to pin 2. Thus, V2b (pin 6,7,8) serves as the OD circuit, as the signal from this circuit is cascaded into V2a (pin 2) when the switch is engaged (pulled).

As I mentioned, the second triode of V2 serves as the cascaded OD circuit....the signal input is pin 7 (grid), and the output is the plate (pin 6). From pin 6, the signal goes through a coupling cap (C4), then on the the 1M pot (OD control; VR3), and then to the 100K resistor (R47). The switch, when pulled, connects the other end of the resistor to the shielded wire leading to first triode of V2 at pin 2, the grid. The end result is cascading the mixed signal from V1 into V2b, then to V2a, then to the tone stack.

When the switch is in the off position, the "other end" of the 100K resistor (R47) is not connected to anything, so anything that happens in V2b has nowhere to go. At the same time, with the switch in the off position (pushed in), the mixed signal coming from V1 (where the two 470K resistors are; R9 and R10; orange "straight line" wire) is sent directly to V2 pin 2. This results in a bypassing of V2b. You can see that when the switch is pulled (OD is on), the signal coming to the switch from the mixing resistors along the orange wire has no place to go, and instead takes the closed path from the mixing point straight to pin 7 via the shielded wire, where it travels as described in the preceding paragraph.

The 100K resistor (R47) is only connected to V2, pin 2, when the overdrive switch is engaged. R47 is not at any point connected to V2, pin 7.

I know I suggested earlier to perhaps build the amp without the relay board in order to simplify troubleshooting, but on second thought you may want to proceed with installing the board right off the bat. That way you don't have to rewire anything. Doing it this way will result in the 100K resistor being moved to the relay board, and you will wire everything as described in the 5V relay board builders guide.

The Triwatt is a great amp but probably the most complicated build I've done. Take your time and quadruple check everything. As with any amp, good lead dress and wire routing are critical. But the cascaded OD circuit can be a source of gremlins. Use the shielded wire as recommended and minimize wire length whenever possible.

Good luck!


Thank you so much for that! What a great explanation. Really makes it clear and completely understandable.

Knowing how the whole cascading halves of V2 work now makes it so much easier to understand. And yes, I'll definitely wire it up using the relay board right off the bat. That way, no messy rewiring.

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PostPosted: Tue Aug 23, 2022 12:46 pm 
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Thought I'd chime in again and say the build is going well, albeit constantly interrupted by life! I'm moving cross country in a few days, from California back to Ohio. So in between the various selling a house, buying a house, working my actual day job, hundreds of phone calls and emails, I did what I could to get the darn thing built as far as I could to prepare for the move.

As always, I'm trying to stick as well as I can to the controls as well as those build pictures on the Trinity site. So I installed all the major hardware, wired up the heaters, did the full circuit board, and got partway done with some of the off board component wiring (off tube strips, some front control stuff, etc.). So far, so good. Although I will say that getting some of the parts UNDER the heater wires is a royal pain. V3 in particular was a PITA! A cap and resistor go across the tube socket, under the FOUR heater wires. Took some trickery to get it to all work right.

As of now, the entire thing is in a big locked plastic bin, waiting for it's cross country trip.


One other note. We have four dogs: Gibson and Taylor are almost 12 year old male Spoodles (half Field Spaniel, half Standard Poodle. About 60 lbs each. Marshall (male) and Trinity (female) are Cavachons (half Cavalier King Charles Spaniel, half Bichon Havanese). Trinity had some major health issues for her whole life. She passed about two weeks ago. So I kind of need to build this amp as a sort of weird tribute.

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PostPosted: Mon Dec 05, 2022 5:06 am 
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I really appreciate that. What a wonderful justification. makes everything incredibly plain and understandable.

Now that you understand how V2's cascading halves function, understanding it is much simpler. And certainly, I will immediately wire it up using the relay board. This will prevent messy rewiring. gartic phone


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