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Well i finished my build tonight and everything looked pretty good so i decided to plug it in, no smoke, no sparks. Good right? Plugged some tubes in and they all lit up, still no smoke or sparks but unfortunately no sound either. Dead quiet...Where should i start? Input jacks?

I forgot to mention I tried all 4 inputs and nothing out of any of them. Also i dont have a 5ar4 so I used a 5y3. I also have a 5u4 but im not sure if thats a good idea to use that one.

Well, at least no smoke is a good sign.

Do you hear any hum or hiss coming out of the speaker? If so do any of the pots affect it?

Is the VRM installed yet? The reason I suggested not installing it until you know the amp works normally is because it can complicate troubleshooting.

Yes, check the input jack wiring for shorts especially where there is shielded cable. I assume you have checked and rechecked all the wiring.

Also measure and post the voltages at all the pins on all the tube sockets.

The 5Y3 should work but the voltages will be lower.

There is a very faint hum, volume affects it slightly.

The VRM is installed. I already had it mounted and all connected aside from the b+ in and out.

Measure voltages with tubes?

Thanks for the help

If the AC voltages look good. Measure voltages with tubes. Try the 5Y3 but voltages will all be lower

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

I found part of the problem. The wire from pin 6 of the ef86 was missing. That channel is working! Still no sound on the normal channel.

Here are the voltages with a 5Y3

V1 EF86 pin 1 = 66V, pin3 = .3v, pin 6 = 79v and pin 8 = 1.5 v

v2 12AX7 pin 1 = 115, pin 3 = 1.5 pin 6 = 115.8 pin 8 = 1.03

v3 12AX7 pin 1 = 134.7, pin 3 = .91, pin 6 = 218.1, pin 8 = 134.7

v4 12AX7 pin 1 = 210, pin 2 = 31.2, pin 3 = 46.2 , pin 6 = 209, pin 7 = 31.2, pin 8 = 46.2

v5 & 6 EL84 are identical pin 3 = 5.7v, pin 7 = 294 volts and pin 9 = 190v Do the matching voltages mean the power tubes are matched? Theyre 2 old Mullard el84s i picked up many years ago as a lot that I never got around to using. I also have a bunch of 6V6s which is another reason for wanting to build a TriWatt.

V7 5Y3 pin 8 = 299V

Also the large capacitor voltages are 297 v on the left and 283 on the right and when i power off the voltage drains out fairly quickly. Is this normal?

I think im enjoying the trouble shooting more than the actual building. Haha

Pins 3 and 8 on V1 should read the same voltage. 1.5V in your case. They are supposed to be connected together with a jumper on the socket. Other than that, the voltages there look reaonable considering you are using a 5Y3 for the rectifier.

Pins 3 and 8 on V2 should read the same, too. They are also connected together with a jumper on the socket.

V3, V4, V5 and V6 look good. The identical readings on V5 and V6 are a good indication that the tubes are matched.

All your voltages are low but that's because you aren't using a 5AR4.

I assume you made these readings with the VRM up full. Does the VRM lower the B+ if you turn it down?

Looks like the EF86 channel is working. Just check to see why pins 3 and 8 on V1 read differently.

The phase inverter (v4) is working. So is the power amp and the power supply. You are almost done!

As for the 12AX7 channel, the voltages on V2 and V3 look reasonable except for the difference between pins 3 and 8 on V2. See why that is happening. Also keep checking your wiring on that channel for errors, shorts or opens. Follow the layout drawing or the schematic and trace it through with an ohm meter to make sure there is continuity between everythnig that's supposed to be connected and nothing is accidentally shorted to ground.

It's normal for the main filter capacitors to discharge to a low voltage fairly quickly when you power the amp off.

Yes the voltages are with the VRM turned all the way up and it does change the B+ voltage.

I will check all my connections and pin voltages again tonight. Unfortunately work gets in the way of all my fun. Haha

I have also ordered a Ruby 5AR4

Thanks to everyone for your help. Im actually glad it didnt work on first power up. Ive learned quite a lot and I could use this towards my next build.

Why do the filter caps discharge so quickly? I've always read that they hold a charge and can actually recharge from all the other capacitors in the circuit.

If you leave the standby on they will discharge more quickly through the circuitry. Good trick to know.

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

It's working perfectly and the tone is amazing! Thanks to everyone for your help. I had a great time building this and am now saving up for a triwatt.

Way to go frank!!

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

Congratulations, Frank!

Glad you got it working. It should sound even better when you get the 5AR4.

What was the trouble on the 12AX7 channel?

I wired the input jack incorrectly. Once i took care of that, it was good to go. I will be waiting patiently for the 5AR4.

I also have a 5u4 but im not sure if thats a good idea to use that one.


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