[MisterX]

What does the DC offset measure with no op-amps installed?

 

[Pars]

MisterX is correct. The opamps are only for the DC servo. The amp should be adjusted for lowest possible DC offset with the servos disabled (opamp out). They could be fried, but you need to take things one step at a time and get the basic amp working before you worry about the servos.

 

[Pars]

It might also help to refer back to the Dynalo construction thread (here), as well as this nice pdf that dgardner put together showing the correct operating points in a Dynalo.

 

[Paragon]

Make sure the capacitors are still good.?

When you changed all the transistors, you basically changed the whole board so you may have to go back and re-zero (or as close as you can to zero) the DC output via the LEDs before you rely on the servo opamp. It can only handle so much DC and if you rely on it to zero out too much, I thought it sorta goes haywire.

 

[kfaiman]

Before I could try replacing all the LEDs and capacitors, I fried the amp again. Same way, plugged in the wrong cable...

This time my power supply fuse quickly blew. I tried replacing the LEDs, hoping the transistors didn't fry. But, both rows of 2SC1815s get scorching hot. So, I will try matching and replacing all the transistors again.

I will install sockets for all transistors this time. Constant desoldering is tearing up the traces.

I will also heed everyone's advice and install different connectors for the power cables.

To easy my pain, does anyone have a Dynalo board to sell me? Populated or not.

 

[MisterX]

that sucks.

Quote:

To easy my pain, does anyone have a Dynalo board to sell me? Populated or not.

Check the link I posted earlier.

( http://www.djgardner.com/headphone/gilmore/ )

 

[jarthel]

that is why XLR is NEVER suitable as a power connector

 

[Pars]

If Dan doesn't have any or you can't get ahold of him, I probably have one that I could part with. Dan also has the FETs and probably has a bunvh of the transistors as well. Sorry about your problems.