ThermalTrak+TMC amp

[Cambe]

Dado,

[dadod]

Cambe, how is going with the PCB for the regulator, do you need the PSU PCB too?
dado

[Cambe]

Ordering parts now for reg and amp. Yes, please post PSU PCB.

[dadod]

PSU
dado

[dadod]

Originally Posted by dadod

Here it is.
dado

I found an error on the PS regulator PCB. There was missing connection between Q9 emitter and the ground. Here are correct pdf files.
dado

[dadod]

This is new PS Regulator Layout, made to follows the role for less interference with the power lines (at list I hope, comments wellcome). The schematic is not changed.
Next step, better layout for the amp, hopping to get even better performance for this TT amp.
dado

[keantoken]

Shouldn't there be a diode from output to input of the regulator so output caps don't discharge through the pass transistors and hatever else? Also, R28 seems redundant, as the collectors of Q4 and Q2 ill have scores of kR impedance and only several pF of capacitance. Because of their high impedance R28 ill not matter much, like it ould if Q15 ere driven by a lo-impedance source.

[dadod]

Originally Posted by keantoken

Shouldn't there be a diode from output to input of the regulator so output caps don't discharge through the pass transistors and hatever else? Also, R28 seems redundant, as the collectors of Q4 and Q2 ill have scores of kR impedance and only several pF of capacitance. Because of their high impedance R28 ill not matter much, like it ould if Q15 ere driven by a lo-impedance source.

Thank your for the comments. A diode across power regulator transistor could not help to much as at the input of the regulator are big caps in the PSU, so smaller caps at the output or on to amp board will discharge faster thtough the amp and R22, R23, R122, R123.
R28 is redundant and I put it there just in case, it does not do any harm. This PS regulator(old layout) is in working amp and behaves as expected. It could be better for sure, but until now I never received any comment. Could you suggest more, also what about the new layout?
dado

[keantoken]

Actually I really like that layout.

For the circuit, if you have an experimenting spirit and a good signal generator, you can do a lot. But only if you ant to. If you are satisfied ith the regulator I see no reason to improve it.

For one thing, I think regulators are somehat misapplied. A regulator too fast ill make you unable to use local decoupling or lo-ESR capacitors. This isn't necessary and quite possibly hurtful. After all, 1 inch of decoupling alays does better than 6 inches of trace beteen the regulator and the circuit. A regulator that bites off more than it can che ill oscillate ith films inches aay.

So it is important to kno hat causes oscillation into capacitive loads and ho to make a regulator that is benign. Your regulator looks like it's pretty slo, not high-performance, so it probably fits this profile.

Using a regulator does not mean you have to use small output capacitors. It shouldn't anyays, this can be fixed in design. But you need a good signal generator to be able to verify and adjust in real life.

I have a Tektronix FG504. I've had to fix it several times but it's all I could ask for. Do you have a good one?

[dadod]

I have two, a Tektronix 475(one channel is not working, I have to fix it, but alwais lack of time) and much slower ITT OX 710C.
dado