G&W 2006TX PreAmp upgrade • Rice Inside •

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Oh,the OP is used in the PSU..

Malefoda said:
Right now I've no OPA2604 to try, maybe my next sample ;)
I've the LM4562 wich works nice and better than NE5532. I don't know if I still need to do the mods you said for regs PPA?
Maybe later I'll go for s-regs anyway.
Here is the LM on the tulip socket.
An externally hosted image should be here but it was not working when we last tested it.

I know this since your picture.
As the OP is not used in PSU, you needn't use high quality OPs in it. NE5532 is good enough.
This is the circuit.
 

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you could put a 2.2k resistor between the 7815 out and the ground and also an other 2.2k resistor between the 7915 out and the ground. This is a fast upgrade that reduces the regulators distortion because the regulator's output stage currents polarization is greater.
 
often the IC op amps have a small quiescent currents (power supply currents) and so the regolators work with a few mA but increasing this current the regolators work from class A to class AA and so the sound is often more kindly than when they work without the resistances.
 
Ah...I made a mistake

Malefoda said:
Ok, here I go for some 2.2k res. This time I understand ;)
But still, why "As the OP is not used in PSU, you needn't use high quality OPs in it. NE5532 is good enough" ?
Is the LM4562 a waste or even a problem? It's from sample program, I've many in hand.
Can you explain please?


"As the OP is not used in PSU, ..." is wrong,

:)
Correct it as "As the OP is used in PSU,...."

The OP is used in the PSU in oder to reduce the high frequency noise,so that the PSU is more clear and pure. But the OP is not used in the Audio siganl path, I think the NE5532 is good enough.

regards

bbp
 
It's from sample program, I've many in hand

If it's possible to know , what's " sample program"?

For the super reg , I have seen the schematic , I think that you could use AD8599 without problems. I'm referring to the electrical compatibility with the regulator's circuit.
 
It's more if it has any sense between the use of the opamp and the noise rejection very high with the AD8599.

Companies such as TI, National Semicoductors or Analog Devices offers people to have a try on some of their products, so you can as for some components free in order to try them in your designs. It's mainly for companies engineers, but as my company is in industry they allow my mail to be check as "serious potential customer": they send me free many opamps. It's their try, aka sample program.

Please my chinese fellow what do you think of using the AD8599? (140dB CMRR vs LM4562 120dB vs NE5532 100dB).
 
AD8599 is a good OP since to the DATASHEET

Malefoda said:
It's more if it has any sense between the use of the opamp and the noise rejection very high with the AD8599.

Companies such as TI, National Semicoductors or Analog Devices offers people to have a try on some of their products, so you can as for some components free in order to try them in your designs. It's mainly for companies engineers, but as my company is in industry they allow my mail to be check as "serious potential customer": they send me free many opamps. It's their try, aka sample program.

Please my chinese fellow what do you think of using the AD8599? (140dB CMRR vs LM4562 120dB vs NE5532 100dB).

But since I haven't test it before,I have no idea whether the AD8599 is better than the LM4562 or not. To my diy experience,it must better than the NE5532. You can replace the NE5532 in your 2006TX.
For more, I think if you replace the A1015/C1815 with A872/C1775,it will sounds better more.
 
Re: Re: AD8599 is a good OP since to the DATASHEET

Malefoda said:


Thanks but what does that means ?

Thanks both of you for helping. (And Simon of course ;) )
I'm sorry that my english is so silly ^_^
I meant that the transistors(A1015 and C1815) used in the preamplifier board is not specially design for audio.
actually,2SA970/2SC2240 from Toshiba is a pair of audio.
I think 2SA872(A)/2SC1775(A) from Hitachi is also an audio product.And,both them can be seen in Hi-Fi and Hi-End amplifiers.
 

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