SONY TA-E1 preamplifier clone

[viktor1986]

Victor, I want to assemble this power supply, and I have a couple more questions for you:
I don’t understand how stabilization of the voltage at the output of the power supply occurs. And what role does the TL431 with the BD140 transistor play? I am not familiar with the inclusion of TL431.
In the circuit of transistors Q1, Q2, Q3, which are connected in parallel, I also do not see voltage-stabilizing elements. I'm just trying to understand how critical this power supply is to the input voltage (AC 24V). In what range can the input AC voltage lie?

NPS1 is shunt power supply.

TL431 Shunt Regulator Circuits

NPS1 is very sensitive to the input voltage. For 22.5V DC output voltage, input voltage must be from 21 to 24V AC(depending to mains voltage) and try to keep voltage from emitter to collector(+V) Q1 in the range of 5 to 10V DC. CCS value is 65mA and is set with R11,R12,R13. If you multiply 65mA with 5V(emmitor-collector voltage Q1) you will get 325mW. Divide that with 3(3 transistors) and that is around 100mW for each transistor. If you have higher voltage difference, let's say 10V DC, then dissipation for each transistor(Q1,Q2,Q3) is around 200mW.

 

[Yuriy64]

Thank you, Victor, for the information. Most likely this scheme will not suit me. I need a not complicated power supply, which will be enough to power this pre-amplifier. Of course, I will not design PSUs with LM78 ** / LM79 **, or 317/337, most likely I will look for a circuit similar to NPS2, but a little easier.

 

[analog_sa]

What causes the interest in cloning this particular pre? It certainly looks nice, but so do hundreds of other designs... It may have been a premium model in Sony's line-up but then Sony is not exactly the first name coming to mind when one is shopping for anything high end.

Just trying to understand the attraction

 

[thimios]

Hi

It's still in the prototype stage but I think that this is final version.


I am currently working on assembling power supply boards.

I see empty pages only

 

[viktor1986]

Now?

I have problem with conversion from protel to pdf file. Problem is only when I want to convert pcb file to pdf file, with schematic file I do not have problem.

NPS2 in action...YouTube

 

[lung]

👍

All Files are now OK.
Big thanks.
Rolf

 

[Yuriy64]

Hello Victor. I am looking at the NPS2 power supply circuit. Please tell me what is the power of the constant resistors R3 ... R6, R7 ... R10 and R27, R28. I understand that the rest of the resistors can be set to 0.25W?

 

[thimios]

All Files are now OK.
Big thanks.
Rolf

Yes they are!
Thanks

 

[Vrystaat]

Thimios, have you finished the pcb's ?

 

[viktor1986]

Hello Victor. I am looking at the NPS2 power supply circuit. Please tell me what is the power of the constant resistors R3 ... R6, R7 ... R10 and R27, R28. I understand that the rest of the resistors can be set to 0.25W?

All resistors are 0.6W metal film