trinityamps.com

I’ve started in on a tweed build... I’ve got some experiencing soldering from other hobbies and like to try things myself while at the same time not afraid to ask questions along the way. I’m finding myself reading the directions over numerous times to try and figure things out so hoping the forum can help me along the way so I’m not driving Stephen too crazy with emailing my questions and maybe some else can learn something too.

First question... which way do I orient this switch? So I have it in the 4ohm or 8ohm position based on them picture?

Roar, it doesn't matter which way the switch is oriented. What matters is how you connect the wires, that is the center lugs will go to the output jacks and if you imagine a diagonal line through the lever(toggle) it will point to the lugs you want connect the 8 ohm wire to. In your picture, for example, with the toggle up you would connect the 8 ohm wire to the bottom lugs of the switch and with it down you would connect the 4 ohm wire to the top lugs. Does that make sense to you? It's easier to show than to explain Also you can check the Tramp guide, V.3.51, pg.47 for a good explanation by Coco. Hope this helps and doesn't confuse the issue

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"The only problem with being retired is you never get a day off"

Thank you Hankules... I think I understand what you’re saying and I’ll look in the tramp guide too. Then I’ll wire it up and post another picture to see if I got it right.

Hi Roar, welcome to the forum!

Like Hank said, these little switches connect their center lugs to the lugs opposite to where the toggle is flipped. You can see this for yourself with an ohmmeter. Look for which lugs have continuity and which way the toggle is pointing.

The layout drawing (at least the one online) shows how to wire the switch. Here's the side view of the switch:



And here's a view showing the back of the switch :



The speaker jacks go to the center lugs, the green 4-ohm wire goes to the lugs closest to the top of the chassis and the yellow 8-ohm wire goes to the lugs closest to the speaker jacks.

Good luck with the build!

Thanks for the help folks... the ‘diagonal’ guidance allowed me to visualize how to mount it much better... and of course constant scanning of the documentation helps too.

I believe I’ve got the power transformer all wired about and close to ready to test but the last step on page 40 of the 3.4 guide says to connect a wire from the other side of the standby switch to the eyelet board.... I haven’t even begun my eyelet board so I’ve got nothing to wire it to... from following along with the guide i didn’t think it was time to do that yet... do need my whole eyelet board wired up before I can test my power section?

One other observation (fear I’ve done something wrong) that has me surprised is this whole thing appears to be grounded to the chassis... once I wired up my pilot light to ground wires on the transformer all my wires leading to the tubes now ground to the chassis. When I do continuity checks with my meter all the tube wiring buzz out when touched to the chassis or each other.

Pictures attached to see if anyone sees anything glaring wrong.

Go to pg. 40 of Tweed build guide (v. 3.4 is what I have). Set your multimeter to VAC. DO NOT INSTALL ANY TUBES Then follow the steps and write down the voltages you get next to each step, check outlet voltage first, then heater voltage between the green wires at the indicator (pilot) light, then check the voltage between the yellow wires on the rectifier socket and finally the voltage between the red wires on the rectifier socket. These voltages will be higher than listed because there is no load on them from the tubes the heater voltages probably will be around 10 to 20% higher. Pretty straight forward after you've done it As Coco states in the beginning, BE VERY CAREFUL Some of the voltages can SERIOUSLY HURT or KILL YOU EDIT: After reading Mitch's excellent reply,and to clarify his post a little, AC voltages are not measured to ground (chassis) in this case.

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"The only problem with being retired is you never get a day off"

Transformer windings and light bulbs have very low DC resistance. And the transformer's center taps connect to chassis ground. So it could appear that all your heater pins on the tube sockets connect to ground, too.

The wiring looks good. I didn't see anything accidentally shorted to ground, but double-check just to make sure. Then continue with the AC voltage tests as Hank said. You won't get any DC until the rectifier and filter capacitors are in place.

Well I’m feeling good about myself

Not sure what MAINS are so I just measured the line IEC Line lug and ground and got the expected 110, then I measured across the lugs on the light and got a little better than 6.3, then about 5.5 on pins 2 and 8 and then around 710 on pins 4 and 6... so feeling good! On to the next steps.

Good on ya, mate P.S. A lot of countries use the term Mains for Line voltage (USA), that is, voltage from the wall outlet and electrical box.

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"The only problem with being retired is you never get a day off"

Sounds good. On to the front panel wiring and board assembly now.

We sometimes call the power coming out of the wall Mains in Canada, but it's mainly a British term. We usually call it Line Voltage, at least here in western Canada.

Yours is a bit on the low side at 110, but sometimes it changes throughout the day. Once the tubes are in place the heater voltage should read around 6.3 VAC.

Moving along with things... wiring up the impedance switch lacked fun... wasn’t sure where to get the right wire from, ended up using the off cut from the transformer wire but now I’ll be short on the wire to run from the board over to the standby switch... that is future problem though

Question... substitutes provided in the kit I assume are fine? Diagram indicates 16uF 450V and I’ve got 16uF 475V. Then on the 1uF 400V side I’ve got big orange ones that say CDE716P600V.

The black 16uF 475-volt capacitors are good. It's always OK to go higher with the voltage rating on capacitors.

The orange ones are .1uF 600-volt. You should have four of them. The 104J code tells the value. It means 10 pF followed by 4 zeros, which works out to .1uF. The J means the tolerance is +/-5%. Look up "capacitor codes" online if you want to know more about how they work.

It's OK to use leftover wire from the transformers for the speaker jacks. You should have received enough solid core wire with the kit to hook up all the B+, tube sockets, and pots.

Lots of wire in the kit for sure...

I’ve found a resistor that appears out of spec... the 100K 1/2 (Brown Black Yellow) is measuring 93.5 and another is measuring at 108.7... I assume the 108.7 is okay because greater than 5% is okay... should I replace the one that is less than 5%?

Also on the diagram on page 44 there appears to be a 56K resistor right in the middle that isn’t marked to be checked off... it’s not dashed so I assume it is required and is just missing the check box for it?

Resistors are rated (+) or (-)%. That's to say +/- 1%, +/- 5%, etc. Also, if it's a carbon composition (chocolate brown body), those 100K and above are usually rated +/- 10%, below 100K at 5%. Carbon comp resistors usually "drift" in value when they warm up, supposedly giving the amp it's "mojo" character

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"The only problem with being retired is you never get a day off"

For future reference, resistors with dark brown bodies are are carbon comp (CC), light brown are carbon film (CF) and blue are metal film(MF). Small 1/4W, 1/2W medium and 1W large bodies. Power resistors 2W and 3W are metal oxide (MO) usually gray or blue with a rough, kinda pebbly surface, 5w and above are usually cement or tubular types. Don't get me started on capacitors film, mica, electrolytic, ceramic disc, can, tantalum, ad infinitum And, as Mitch stated you can go higher than specification , but not lower on caps and resistors.

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"The only problem with being retired is you never get a day off"

Good that you are measuring the values of your resistors. You can go higher with the voltage rating on capacitors and resistors, but you should stick pretty close to the desired values for their resistance and capacitance. The two 100k resistors you mentioned are within 8% so they are OK to use.

The 56k in the middle of the board is definitely needed. The phase inverter won't work without it. I looked at the manual online and there is no checkbox for it there either on the drawing on page 44. Actually it's pretty hard to even see it!

I thought it was the last colour band that determined the % with gold being 5% and silver being 10%... thank you for all the details though, I’ve soldered hundreds of resistors without knowing all that detail so good to have more detail.

My kit didn’t come with any blue or yellow 20 gauge and I’d like my wiring to match the diagrams so I’ll probably track some down and pause till they arrives. Slowly but surely things are coming along.

Mitch, I noticed the 56K omission in the board stuffing guide, too. Maybe you could PM Coco and let him know. Roar, if you are in the US Apex,Jr in California has pretty good deals on PTFE wire, however the PTFE insulation on the wire is thinner than what Coco supplies and may not be an aesthetically pleasing match in diameter. Will handle the voltage, tho.

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"The only problem with being retired is you never get a day off"

Yes, gold means the tolerance is +/- 5% if it's the last band on a 4-band resistor. If those 100k resistors have gold bands they should be within 5000 ohms of 100K. The values aren't off enough to cause any problems being used as anode resistors.

Trinity's documentation is very good, and it's always improving. When I built my Tweed seven years ago, the manual had a layout drawing for the board but it didn't have any checkboxes for the components. But there have been a few minor glitches over the years. I'm sure Coco will add the missing checkbox to the diagram once he finds out.

I’m not in the states so not sure where to track down some wire. Went to Sayal as they are my go to for electronics and they stock 18 and 22 gauge in all the colours but no 20. There is a reasonably priced kit on amazon.ca but it is stranded not solid.

Documentation is really great, having to read things multiple times is on me and because of my lack of understanding, not the fault of the documentation .

Edit: just saw this on amazon

Silicone Wire Kit CBAZYTM Electric Wire Hook up Wire Kit (Solid Wire) 20 Gauge 6 Colors 19.6 feet Each Wires 20 AWG https://www.amazon.ca/dp/B07924YBNL/ref ... 0DbKESAYXH

That might do the trick. Only rated for 300V though.