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Hi all,

I've been lurking on here for a while, ordered a TC-15 a few years ago, and finally had time to start building. Anyone who has built the "red board" version, please check out my pics and let me know if anything is amiss.

All my pictures are located here:
http://anthonycravero.com/gallery/index.php?level=picture&id=279

The questions that I have on it so far are:
1. The three "25uf/25v" caps (as listed in the build specs) near the rightmost large cap are all 22uf/50v, because those were the only 3 caps close in size/value/type to what was in the wiring diagram. Will these be okay, or should I order 25uf/25v?
2. I don't have a cap with the value .0015uf, which is why that one is missing in my build so far. The other caps I have are below in the pic. Can I use a 152k cap in this spot? Is that the same value? If so, is there a conversion chart somewhere online?

Anything else you notice, please feel free to let me know. I'm colorblind, so the resistors were particularly challenging, but I had my son match them to values online, and hopefully those ended up right.

Just a note--I'm planning to clean up the solder joints when I add the lead wires to the rest of the amp.

1. I do believe the ones your talking about three small electrolytic s (have a + and - side) all cathode caps 22uf just fine 50v more than enough. Think the amp has evolved over time but the difference between 22uf and 25uf is probably not even gonna be audible

2.
Think your 152k is a .0015 cap



and if you go to this page you will see that 1500pf = .0015uf

http://www.justradios.com/uFnFpF.html

Sazafraz,

Thank you for your quick response! I couldn't interpret what the 152k meant on some other sites...your link helped a lot.

The board is now assembled & soldered...on to the chassis. Unfortunately, after removing the protective plastic, I just discovered that my chassis was labeled on the wrong side. All the inputs have the output labels and the output side has no labels. The faceplate will cover the mislabeled side, but the back of the amp is blank. Does Trinity Amps make a rear plate for this amp with the labels on it? I could write them on with a sharpie, but that wouldn't look too professional.

Current Trinity amps chassis are silk screened on the back. Original ones had a rear panel but no longer do. There might be a rear panel somewhere, but not sure it would fit your chassis .
As for colourblind / resistors, you can measure them to check they are the correct values.

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

One change you might want to implement is the voltage divider for Ch. 2 feeding the PI is now 220K/220K instead of 100K/220K. This better balances the two channels for volume.

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

Thanks for your response, coco. I just kept building because I'm itching to get this amp running soon. I also discovered that it looks like I got two of the varitone pots-- one black and one white-- but, I think that I'm missing the 3 way impedance selector. Is there a brand/number for this part? I'll try to post a pic of the pots on my site tonight.

I'll look into that other 220k resistor, as well.

Thank you!

Lorlin switches came in two colours. They may both be switches. check them out.

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

Thanks for your responses so far! I have uploaded pictures of the inside front & inside back.

Here is a view of the inside/back - http://anthonycravero.com/gallery/index.php?level=picture&id=293

And here is the inside/front - http://anthonycravero.com/gallery/index.php?level=picture&id=292

You can enlarge by clicking the photos on the site. Check out the two pots (varitone & impedance selectors) and let me know if I need to get a different part for one of them. They both look similar, and I believe are the "Lorlin" switches you're talking about.

Thanks!

Looks like you have the two rotary switches right. My TC-15 is the same vintage as yours and on mine the 6-position Contour switch has a black and white body, too.

Mitch

Hi Mitch,

Thank you for posting! Do you have any pics of how you wired up the impedance selector for the speakers? I don't understand how I'm supposed to wire it up & don't want to make a mistake.

Thank you!

Which Lorlin switch are you using for the impedance switch. in the manual, it describes how to set the switch to 3 positions and how to wire the terminals. A picture of the back of the switch might help, but we need to know if its one pole or two as a start.

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

Coco, thanks for your response.

Attached is a pic of the Lorlin switch that I have currently mounted in the back of the amp for the impedance switching. It's hard to tell because of the wires, but there are two terminals in the center of the pot.

I don't recall seeing how to wire this particular switch up in my manual, but I will check again when I get home. It does show which wires to attach from the OT and where, but the switch shown in the manual only has 3 inputs and one output.

In the meantime, if anyone has a pic of how they did it, please feel free to post it.

Hi korngold,

Here are a couple of pictures of the impedance switch in my TC-15. If you have a two-pole switch this might help with your wiring.

You can tell how many poles (individual sections) the switch has by how many terminals it has near the center of its body. A one-pole switch will just have a lug labeled "A". A two-pole switch will have lugs labeled "A" and "C". A four-pole switch will have lugs labeled "A", "B", "C" and "D". These are the common terminals and will be connected to the numbered terminals near the outer edge of its body depending on the position of its shaft.

It's a bit confusing until you get used to working with rotary switches. This switch style can be anything from a one-pole 12-position to a four-pole three position.

First you have to use the tang washer to limit the switch to three click positions as it says in the manual. I used pole A on the switch, so the lug marked "A" is the common terminal. I wired that lug to the speaker jacks.

I wired the yellow (4 ohm) lead from the output transformer to lug 1 on the switch, the green (8 ohm) lead to lug 2 and the orange (16 ohm) lead to lug 3.

If you have an ohmmeter you can verify that with the shaft fully counter clockwise, lug A has continuity to lug 1. The next click clockwise should connect lug A to lug 2. The next click clockwise should connect lug A to lug 3. This should be as far as you can click the shaft clockwise if you have the tang washer in the proper position.

I hope all this makes sense!

Thanks for the help Mitch. There is a section in the Manual on how to set the switch to 3 position in case you need help.

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

Here is a pic of how I wired mine that shows the speaker jack connections as well as the rotary switch. Hope this helps!

Cigarman, Mitch, & Holy Ghost--

Thanks for the help! I found it in my manual (I hadn't read far enough), and your photos really helped me to understand how to wire it up.

So, I decided to look through the rest of the manual. :-) I saw something in there about "coaxial" cable? I can't find any with my kit stuff, but keep in mind I've stored it for 2-3 years. So, I probably misplaced it. Is that cable necessary or can I just use the 600v solid core? Also, the manual mentioned something about using stranded wire for certain power connections. Are those shown in a specific color on the wiring diagram?

Thanks again for all your help, everyone. I can't wait to get this amp finished!

Glad you got the Impedance switch figured out.

Yes, you must use coaxial cable where it's called for. These runs are very sensitive to stray electrical fields and must be shielded. If you can't find the shielded cable that came with the kit, in a pinch you could cut up a spare good-quality stereo patch cord (the kind with RCA plugs at each end).

Note that the shields on these cables are connected to ground at one end only. This is done where they connect to the input jacks or potentiometers on the front panel. The shields at the other ends should be trimmed off and the ends covered with heat shrink tubing. To avoid ground loops the shield at this end must not be able to touch the chassis.

The stranded wire is used for the AC connections. Also for the Standby switch, but this could be solid core if you want. The AC wiring is shown in black and dotted black on the layout drawing I have. The Standby switch wiring is shown in red.

Good suggestion on the stereo coax, but there should be some black RG175U labelled wire in the wire package. It is important to use coax for noise, but it will work without it.

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