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Hi folks, I have taken the plunge and started my Triwatt head build. Chassis component installation has been going steady, but unfortunately I'm getting wrapped around the axle on the power switch orientation and wiring. I've been poring over past forum posts and seem to see the switch oriented both ways, and I'm having difficulty from the instructions understanding which wires should go where for my build.

Per the instructions, "On" is when the switch is pointed "down" toward the 4 lugs. However, the instructions also show the "On" position with the installed switch pointed at the top/intersection of the chassis. This doesn't seem to match my front panel, since this "up" position is labeled "Off." According to the diagram in the instructions, the angled lugs should be on bottom when I'm facing them, but with "On" correctly matching the front panel (i.e., "down"), the angled lugs are on top when peering into the chassis. Do I just flip the wiring diagram shown in the instructions, or am I missing something?

Interestingly, a sampling of others' photos shows the switch orientation and wiring both ways (see photos in "Triwatt Build - Almost Complete" and "Triwatt Build" from April for examples), though it seems maybe the combo version is reversed because the chassis is located at the top of the combo instead of the bottom of the head. Everybody building a head like me seems to have the switch backward from how I'm interpreting, but why would you want the "Off" label aligned with the switch "On" position? Hmm...

I had some issues with this as well.
Check my build pics in my previous topic.
Mine is placed with the angled lugs facing towards the chassis.
I've added two pictures for clarification.

Let me know if it helped.

Kind regards.

Thanks for replying! Yours was one of the builds I'd looked at

Can you confirm with that switch orientation that the amp power is "on" with the switch pointed down, toward the "Power" label? Since so many people have theirs oriented this way I figured I would just wire it that way (per the instructions) with a little extra lead in case I needed to rotate the switch after installation.

The easiest way to figure it out is just connect an ohmmeter to the lugs and see which way you have to flip the handle to get continuity. This is the "On" position. Then mount the switch so that position agrees with what's printed on the faceplate. Traditionally, down is "On" with English amps.

Mine is off like this.
Just check with an ohm meter like Mitch said.

Thanks guys, I figured it was something obvious I should have been able to figure out. Unfortunately at this point I'm good at following instructions, ok at soldering, and so-so at basic electronics know-how, so I appreciate the help!

No problem. Even well-written instructions aren't always easy for everybody to follow, so the only dumb questions are the ones you don't ask. That's how you learn, and we all had to learn this stuff sometime.

Following the instructions and good soldering skills are the keys to a successful amplifier build. Also it helps if you keep the wiring neat! Then check your work, double check it, then check it again. A good tip is to make a few copies of the layout drawing and use a hi-lighter pen to mark the wires and components as you install them and do your final checks.

I'm happy to share that after many hours, I completed my Triwatt build on Wednesday! Considering my limited knowledge of electronics fundamentals and the fact that it's only my third amp build (the other most complicated being a 5e3), it feels like a huge accomplishment--especially because it fired up after testing/measurements with no real problems and runs very quietly! There's only one strange issue that I wonder if anyone here has any thoughts about: the treble control does something weird in the final 1/12 or so of its travel (between ~5 o'clock and dimed). Up to this point, it performs as expected, but once it crosses this point there's a slight audible (through the speaker) pop, and the sound stays bright, but gets suddenly sort of choked or pinched sounding (though still bright). Seems strange, and I have no idea what kind of issue would cause this to only occur at the upper extreme of the knob's travel. I could live with it, but I'm OCD enough to want to chase down a cause.

In general, I'm really thankful to everyone who responded to my questions here and for all of the build topics on this forum that posted extremely helpful gut shots, particularly matt_garman's, Riise's, and Gertjan's. Seeing all of the super neat wiring was really impressive, and though I'm not really capable of getting it that clean, it certainly upped my attention to detail and end results.

A few general notes from my build experience that may impact others:
-Not enough keps nuts came to accommodate the terminal strips that attach to the bottom of bolts shared with tube sockets; a hardware store trip fixed this for me! I also received 2 more terminal strips than I needed. Hmm...
-Where did everybody else get enough red wire? I didn't end up having enough to hit all of the connections labeled red. I was a bit confused about the manual's up-front instruction about which type of wire to use for which type of connection, and I ultimately figured it wasn't going to be a huge deal, so I used leftover red from the braided heater wire for a handful of connections.
-The input jack situation, 16 ohm hookup, and a couple other linked ground connections are a little confusingly depicted on the layout; it was helpful to see others' solutions for these.
-Why are there 2 red test points for bias?
-I broke the bias selector switch on installation--clip off the vertical locator tab on the washer it includes and make sure to use it! Otherwise if you over-tighten it'll break apart. I bought a 5-pack of replacements and one overheated when soldering connections, so I'd caution to be careful with this part in general (in addition to using as much insulation on unused lugs and wiring as possible per the forum post that discusses switch arcing).
-My kit was missing the 470Ω resistor so I temporarily replaced with a metal film 1/4 watt I had lying around. Maybe this has something to do with my Treble knob issue? Doesn't really look too related in the circuit though.

The amp sounds great with my (W)eber FC12, but I have a host of other options I'm looking forward to trying and reporting on in the appropriate topic. Once I install the replacement resistor, I'll take more comprehensive internal shots. For now I'll leave you with a shot of the righteous cab that Stephen made for me (sitting on a very expensive stand...matching white 2x12 speaker cab to come!) and a quick-and-dirty internal shot.

Great build man.
Glad to hear that my pictures helped you out. Sometimes the instrcutions and lay-outs can be a little confusion/difficult. That's when the pictures of others on the forum will help you out.

The two red test points are for the two power tubes. One test point per tube. This way, you are able to verify that both tubes have the same bias set up, which should normally be the case when installing matched tubes.

I missed some red wire too. Not too much though. I ended up using another color for a few connections. Not a deal breaker as long as you take the right gauge or thicker.

Regarding the treble issue, I have know clue. My knowledge is not that advanced but the resistor does not seem to have anything to do with that part of the circuit. I could be mistaken though.

For now enjoy your freshly built amp! You will love it.

Thanks for the comments. We will take care of this for you and updated the manual as well.

http://www.trinityamps.com/docs/TriwattBuildersGuide3.pdf

1. Not enough keps nuts came to accommodate the terminal strips that attach to the bottom of bolts shared with tube sockets >> Quantity updated to 6, now there should be enough nuts. Mount others with 4-40 bolts & nuts
2. received 2 more terminal strips than I needed >> should be a pack of 5 (updated)
3. Where did everybody else get enough red wire? >>colours don’t really matter, they are really there to easily trace on the colour layout. Use high voltage transformer cutoffs you don’t need. However, we could ad a couple of feet of red stranded for this.
4. I was a bit confused about the manual's up-front instruction about which type of wire to use for which type of connection, and I ultimately figured it wasn't going to be a huge deal, so I used leftover red from the braided heater wire for a handful of connections. >> clarified in latest guide now.
5. The input jack situation, 16 ohm hookup, and a couple other linked ground connections are a little confusingly depicted on the layout; it was helpful to see others' solutions for these.>> this is hard to depict on the layout but we have updated it

6. Why are there 2 red test points for bias? So you can check bias of both power tubes.
7. I broke the bias selector switch on installation--clip off the vertical locator tab on the washer it includes and make sure to use it! Otherwise if you over-tighten it'll break apart. I bought a 5-pack of replacements and one overheated when soldering connections, so I'd caution to be careful with this part in general (in addition to using as much insulation on unused lugs and wiring as possible per the forum post that discusses switch arcing). >> these notes have been added to the manual.
8. missing the 470Ω resistor so I temporarily replaced with a metal film 1/4 watt I had lying around. >> This has nothing to do with the Treble knob issue. Sounds like the treble pot’s taper is not perfect at the extremes.

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

Good work, Elliot! Glad your Triwatt is working. It looks great in that white cabinet.

As for the treble issue, it's probably the pot as Stephen said. Try disconnecting the pot and measuring the resistance between the middle terminal and one of the outer terminals. It should vary smoothly throughout the shaft's entire rotation. With the shaft completely turned one way it should read close to 0 ohms. Completely turned the other way it should read close to 250K. If it fluctuates or stops changing before the shaft is completely clockwise or counterclockwise, the pot is either dirty inside or it's faulty.

Check the resistance between the middle terminal and the other outer terminal as you rotate the shaft, too. It should read the same as your previous readings, except reversed.

Also check the resistance across both outer terminals. It should be close to 250k.

Thank you! This is extremely impressive--having worked in manufacturing and technical writing, I've experienced firsthand that it can take ages for some companies to incorporate customer feedback, and for you to do so quickly and take into account people like me from the more "novice" end of the spectrum is greatly appreciated. I know it's a lot of work to write instructions for the "dummies" audience, but it probably makes the kits more accessible to a wider audience.


I think this is again a symptom of my lack of basic electronics/amp knowledge--not knowing exactly which connections are rectifier, etc.


It looks like the BOM disappeared from the latest manual rev--I cracked it open to try and identify the 250k pot for a replacement but the page is blank. If I wanted to buy a replacement, it'd be a 250k linear pot with a 1/4" wide shaft, right? Does brand matter?

Mitch, again, thanks for the super clear common sense advice, this is very helpful from a learning perspective!!

Looking forward to sharing more photos, clips, and impressions...

We have a new BOM system and they need to be incorporated into the manuals once they are verified.
The pot we use are Alpha . 1/4” shaft, 3/8” bushing.
Good idea to test the resistance.

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

Pulled out the treble pot today--far as I can tell the resistance looks right. I had also picked up a replacement, which also measured fine. I installed the new one and am still getting the same issue. It's not any kind of deal breaker, but is certainly perplexing. It doesn't occur when the overdrive knob is active--check out this video I uploaded. Apologies for the shaky phone camera work!

https://youtu.be/EAy6Kf-Azqg

It could be a coupling capacitor leaking a bit of DC at the high settings of the treble pot. Try changing C7 (220p) and see if that makes any difference.

Thanks for the video. We don't have one here to test. You can try measuring the DC voltage at the Treble pot wiper.

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

Yes, in a combo this is reveres but not in the layout, something we will need to remind combo builders!

Glad all is well and you learned a new skill.

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

Well, I swapped out C7 with a fresh cap and unfortunately the treble pot issue persists. It's not a serious impediment to enjoying the amp but I would like to find some way to resolve it eventually. Any other ideas out there? I appreciate the advice so


I'm attaching a not-so-great pic of the head with the matching 2x12 cab--in there I've settled on a Fane Crescendo-inspired W eber FC12 (the classic pairing for a Hiwatt, from what I understand) and a W eber CV123. The FC12 has a very distinctive sound that sounds great with certain guitars and amps and works with the Triwatt in all of the settings I've tried--it's got a lot of low mids and a really sticky sounding midrange. The big bottom can make it seem dark, but there's actually a nice top end too, it's just really full toward the bottom. The result is a very round, sweet tone that no other speaker I've tried sounds like. Naturally, with a profile like this, you really don't get super bright American tones. However, just because a speaker like this was traditionally paired with a Hiwatt doesn't mean the Triwatt doesn't sound great with other speakers (it does). It sounds great with my greenback, blue, and variety of American speakers too! I actually recently shot out 12 W eber speakers I own with a bunch of different amp tones, including 3 from the Triwatt. I will definitely be sharing the results in this forum whenever I get around to editing. The great news is that the Triwatt sounds great with a lot of speakers and its natural tone isn't heavily weighted in any one direction.

As for the CV123, I tried most of my speakers in conjunction with the FC12 and the main challenge was sensitivity--either the FC12 was too loud or the other speaker was too loud most of the time, with the result seeming like you're just hearing one speaker. I threw a hail Mary and picked up the CV123 specifically hoping it would pair with the FC12 and, for a particular sound (even more in that mid-heavy direction), I think they are extremely well matched--the CV123 is low on bass and has more upper mids than the FC12, so the result is a broader range but still with that syrupy mid emphasis, just a bit more 3-dimensional (and they are very well-matched volume wise).


I hope everyone is holding up ok out there...now would be a great time to be stuck at home, deep into a big amp project!

Thanks for the update. Glad you got to try the amp with so many different speakers and it sounds great with all of them.

With the treble pot, it has two fairly long wires heading back to the board. You could try re-routing them so they aren't so close to other wires.

And maybe it's just hard to see exactly where the wires go in the photo, but it looks like the wires heading back to the board from the treble pot and the bass pot are reversed!

Make sure the wire from the 220k resistor goes to lug 3 on the treble pot and the wire from the 47n capacitor goes to lug 2 on the bass pot.