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Hi all,

Just finished my amp and there is no sound at all, no pop when plugging guitar cable in etc. All of the voltages seem in scope so I'm confused. There is no change to the the power hum when increasing volume or VRM.

Power in = 640
50uf cap = 448

Preamp
Pin6= 181
Pin 1 = 188
4&9 = 3.5

I tested with a known working speaker and cable with same issue = no sound. How do I isolate this - could it be the volume (tude) switch wiring? I can't get any pops etc to start with.

Chris

Measure and Post all the voltages per manual.
Check for continuity from tip of plugged in guitar cable to grid resistor .
Make sure coax cables are not internally shorted to ground.

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

As follows - voltages seem off

All measured in DCV with 6L6 tube

V1
P1= 188
P2= 181
P4=3.5
P9=3.5

V2
P7 & P2 = 3.5
P8 = 431
P3 = 434

With ground to chassis and tubes in
-1st 50uf cap = 429 to 435 as vrm is turned up
- 2nd 50uf cap = 436 but does not increase when vrm turned up

Cathold voltage
- it's at 426 DC and should be 29 ???

There are two other areas to measure 1.7 in the schematic and these are at 1.85.

And for the stupid question- where is the grid resistor for checking continuity.

Thanks,

Chris

I think I missed the ground wire that goes from the first 50uf cap to the main power ground. Should this help!

And how do I drain the cap so I don't electrocute myself?

Chris

I was just posting that. It will absolutely.

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

1. check you have a ground connection to your cathode resistors (750R/560R) and all the caps (50, 50, 1000uf).
2. check the polarity of all the filter capacitors points to ground.

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

And how do I discharge the cap!

And final question - assume I can add the ground to top of board vs. Underneath as will be easiest method?

Thanks Stephen
.

If you installed the 220K 2W resistors, they will discharge automatically. Just measure B+ to be sure it is safe to work on inside.


Under or over, it doesn't matter. I like to go under.

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

And the last dumb question - where is B+

At the +ve end of the first 50uF filter capacitor.

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

For reference. Just measured our head here and updated it. Yours will be a little different because you are using 6L6.

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

Hi Stephen - now have blissful sound but...

- 1st 50uf cap @ idle = 78DCV, and at full power = 410 DCV

- 2nd 50uf cap @ idle = 443DCV and at full power = 418DCV

I read in manual that the second should adjust DCV with the power increase and that idle on the first one should always be over 400.

It's getting there!

Chris

The second filter cap on the board (is the first on one the schematic btw) is constant voltage where the first cap on the boards and the 3rd, 4th are variable.

So the 1st PHYSICAL 50uf cap on the board @ idle = 78DCV, and at full power = 410 DCV seems right on!

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

SPAM!!