Mpp - Page 637

Joachim Gerhard · 25th July 2012, 06:07 PM

Did you build your pre- and power-amp yourself ?

Stefanoo · 25th July 2012, 06:09 PM

really nice work!

Stefanoo · 25th July 2012, 06:13 PM

Quote:

Originally Posted by Joachim Gerhard

Did you build your pre- and power-amp yourself ?

I have only built the pre.
I have in mind for future development a Power Amp that I will probably design once the Phono Stage is over.

I am not as great as you guys so it took me a long time to develop this Phono.
I did a lot of measurements a lots of listening test I went through a series of Board's revision.
I am not that great! I have to say though that the phono sounds very nice so far, I can't wait to try this new Paradise V2.

Maybe you overlooked it, just in case, I can still offer some evaluation on the Beta version if needed.

Joachim Gerhard · 25th July 2012, 06:14 PM

You can order R2 Beta Boards from Hesener. Best you send him a PM:

Stefanoo · 25th July 2012, 06:21 PM

Will do.

Stefanoo · 26th July 2012, 09:54 PM

Joachim

Reading this thread I have seen you posted several designs for buffer and said that your favourite one is the one copied here.
I wanted to ask you if after all this time is passed since you posted that, are you still with the same opinion?
Also, I am trying to design the servo around the buffer to use to correct the DC offset of the gain sage before that.
Unfortunately I wasn't able to make it work on the simulator.
Could you please give me some advice on this?

Thank you very much.

Stefanoo · 26th July 2012, 09:56 PM

here is the file...

Joachim Gerhard · 26th July 2012, 10:30 PM

Yes, that is my favorite BJT buffer still. It really sounds amazing. In the Paradise R2 we went to the simpler floating cascode J-Fet buffer because we thought that the BJT buffer could be responsible for the oscillation we found at 40 MHZ. At the end we found that it was the layout, especially the decouplig of the mirrors so the BJT buffer is not suspicious any more. In fact i use this buffer in a commercial product for L`Art du Son called Buffalo Bill without any problems.
I see that you earthed the connection between R11 and R14. How should the servo then work when you shunt the output to ground ?

Joachim Gerhard · 26th July 2012, 10:33 PM

The current sources J1, J2 should not be necessary. You can try them of cause.

Joachim Gerhard · 26th July 2012, 10:36 PM

One way is simply trimming the offset. You can use 3.5kOhm for R11, R14 and put a 1kOhm trimmer in between, wiper to ground.

25th July 2012, 06:09 PM	#6362
Stefanoo diyAudio Member Join Date: Apr 2006 Location: italia - ora USA -WI	really nice work! __________________ Stefano

25th July 2012, 06:21 PM	#6365
Stefanoo diyAudio Member Join Date: Apr 2006 Location: italia - ora USA -WI	Will do. __________________ Stefano

26th July 2012, 09:54 PM	#6366
Stefanoo diyAudio Member Join Date: Apr 2006 Location: italia - ora USA -WI	Joachim Reading this thread I have seen you posted several designs for buffer and said that your favourite one is the one copied here. I wanted to ask you if after all this time is passed since you posted that, are you still with the same opinion? Also, I am trying to design the servo around the buffer to use to correct the DC offset of the gain sage before that. Unfortunately I wasn't able to make it work on the simulator. Could you please give me some advice on this? Thank you very much. __________________ Stefano

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25th July 2012, 06:07 PM	#6361
Joachim Gerhard diyAudio Member Join Date: Mar 2009	Did you build your pre- and power-amp yourself ?

25th July 2012, 06:14 PM	#6364
Joachim Gerhard diyAudio Member Join Date: Mar 2009	You can order R2 Beta Boards from Hesener. Best you send him a PM:

26th July 2012, 10:30 PM	#6368
Joachim Gerhard diyAudio Member Join Date: Mar 2009	Yes, that is my favorite BJT buffer still. It really sounds amazing. In the Paradise R2 we went to the simpler floating cascode J-Fet buffer because we thought that the BJT buffer could be responsible for the oscillation we found at 40 MHZ. At the end we found that it was the layout, especially the decouplig of the mirrors so the BJT buffer is not suspicious any more. In fact i use this buffer in a commercial product for L`Art du Son called Buffalo Bill without any problems. I see that you earthed the connection between R11 and R14. How should the servo then work when you shunt the output to ground ?

26th July 2012, 10:33 PM	#6369
Joachim Gerhard diyAudio Member Join Date: Mar 2009	The current sources J1, J2 should not be necessary. You can try them of cause.

26th July 2012, 10:36 PM	#6370
Joachim Gerhard diyAudio Member Join Date: Mar 2009	One way is simply trimming the offset. You can use 3.5kOhm for R11, R14 and put a 1kOhm trimmer in between, wiper to ground.