Simplistic NJFET RIAA - Page 261

disco · 2nd November 2009, 05:00 PM

Quote:

Originally Posted by Salas

... Don't manipulate the ground BTW.

For stability of the regulator that is?

Salas · 2nd November 2009, 06:19 PM

It will change the loop characteristics and will be susceptible to kinds of noises too. If it can lead to further problems, this is only with hands on measurement in each build so to say.

RCruz · 3rd November 2009, 05:11 PM

First PSU mod completed... I just swaped the 25v tx by the block RK 30v one.

I am reading 40V in for 28vout in the shunts.

Major improvements in spatiality.... everything got bigger and more detailed (I also notice a reduction in noise ... maybe the block TX is more silent).

Of course there is much more heat inside the case so next I will try to reduce the voltage in 4 volts..... Hope this does not affect the soundstage size.

massimo · 3rd November 2009, 06:27 PM

v1 or v1.1, Ricardo?

RCruz · 4th November 2009, 08:29 AM

V1

massimo · 4th November 2009, 09:01 AM

So you got such improvements simply replacing the xfrm..... The german toroids must be quite good then.
Are you going to upgrade the shunt to v1.1? Until Salas will release the v1.2 he's working on

RCruz · 4th November 2009, 09:25 AM

Yes.... I believe my issues with the v1.1 where related with low input voltage.

Now I am ready to try again.

massimo · 4th November 2009, 10:08 AM

I need an help from you, guys.
Before ordering all the parts I need and designing a suitable RIAA pcb, I would like to ask Salas, Ricardo, Disco and others their findings about the right capacitors.

> C out (3.3uF): the suggested type seems to be Obbligato Premium copper or gold. Good sound, nice price I read.
Did anybody try Mundorf Supreme which is more or less in the same price category?

> C 4 (0.1uF): here a huge russian teflon cap (ft-2 or ft-3) seems mandatory. Not expensive and very transparent you reported.
Again, did anybody try an alternative? Obbligato, Mundorf, etc.? What about smaller polypropylene film & foil?
I have some nice old blue Ero KP 1838/63V 2.5% that might fit.

> RIAA Caps (47 & 16 nF) most of you suggest some bulky russian silver mica. Are those really different (read better) from the modern dipped ones? And what about polypropylene film & foil such as the tiny green Wima FKP2 or even Teflon? Not easy to find in the right value, but it's always possible to // them and get the desired values.
I have a lot of FKP2/63V 2.5%, but even some 1% capacitors branded "Madrigal" (most probably teflon) pulled out from and old ML No.25 cannibalized board.
As far as polystyrene, I don't like them too much. They are now cheap and unrealiable. Unfortunately the good silver axial ones manufactured by Philips are no longer available. Not to mention the ps film & copper foil caps manufactured by the Japanese company known for the Noble pots that Hiraga was using many years ago in his Kaneda preamp! Absolutely unobtainable nowadays.

Contibutions highly welcomed!

nicoch58 · 10:36 AM

I'm looking on cheap hammond 155/159 choke price is 10 to 20€ Cruz to try on raw psu....

Massimo look at amphom from audicap/hicollective very good sound at decent price....

RCruz · 4th November 2009, 11:00 AM

I am using a 47nF obbligato gold in the riaa and it proved to be much better than russian PIO.

4th November 2009, 10:34 AM	#2609
nicoch58 diyAudio Member Join Date: Oct 2004	I'm looking on cheap hammond 155/159 choke price is 10 to 20€ Cruz to try on raw psu.... Massimo look at amphom from audicap/hicollective very good sound at decent price.... Last edited by nicoch58; 4th November 2009 at 10:36 AM.

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2nd November 2009, 06:19 PM	#2602
Salas diyAudio Chief Moderator Join Date: Oct 2002 Location: Athens-Greece	It will change the loop characteristics and will be susceptible to kinds of noises too. If it can lead to further problems, this is only with hands on measurement in each build so to say.

3rd November 2009, 05:11 PM	#2603
RCruz diyAudio Member Join Date: Sep 2006 Location: Saxon Blog Entries: 1	First PSU mod completed... I just swaped the 25v tx by the block RK 30v one. I am reading 40V in for 28vout in the shunts. Major improvements in spatiality.... everything got bigger and more detailed (I also notice a reduction in noise ... maybe the block TX is more silent). Of course there is much more heat inside the case so next I will try to reduce the voltage in 4 volts..... Hope this does not affect the soundstage size.

3rd November 2009, 06:27 PM	#2604
massimo diyAudio Member Join Date: Dec 2002 Location: Milan, Italy	v1 or v1.1, Ricardo?

4th November 2009, 08:29 AM	#2605
RCruz diyAudio Member Join Date: Sep 2006 Location: Saxon Blog Entries: 1	V1

4th November 2009, 09:01 AM	#2606
massimo diyAudio Member Join Date: Dec 2002 Location: Milan, Italy	So you got such improvements simply replacing the xfrm..... The german toroids must be quite good then. Are you going to upgrade the shunt to v1.1? Until Salas will release the v1.2 he's working on

4th November 2009, 09:25 AM	#2607
RCruz diyAudio Member Join Date: Sep 2006 Location: Saxon Blog Entries: 1	Yes.... I believe my issues with the v1.1 where related with low input voltage. Now I am ready to try again.

4th November 2009, 10:08 AM	#2608
massimo diyAudio Member Join Date: Dec 2002 Location: Milan, Italy	I need an help from you, guys. Before ordering all the parts I need and designing a suitable RIAA pcb, I would like to ask Salas, Ricardo, Disco and others their findings about the right capacitors. > C out (3.3uF): the suggested type seems to be Obbligato Premium copper or gold. Good sound, nice price I read. Did anybody try Mundorf Supreme which is more or less in the same price category? > C 4 (0.1uF): here a huge russian teflon cap (ft-2 or ft-3) seems mandatory. Not expensive and very transparent you reported. Again, did anybody try an alternative? Obbligato, Mundorf, etc.? What about smaller polypropylene film & foil? I have some nice old blue Ero KP 1838/63V 2.5% that might fit. > RIAA Caps (47 & 16 nF) most of you suggest some bulky russian silver mica. Are those really different (read better) from the modern dipped ones? And what about polypropylene film & foil such as the tiny green Wima FKP2 or even Teflon? Not easy to find in the right value, but it's always possible to // them and get the desired values. I have a lot of FKP2/63V 2.5%, but even some 1% capacitors branded "Madrigal" (most probably teflon) pulled out from and old ML No.25 cannibalized board. As far as polystyrene, I don't like them too much. They are now cheap and unrealiable. Unfortunately the good silver axial ones manufactured by Philips are no longer available. Not to mention the ps film & copper foil caps manufactured by the Japanese company known for the Noble pots that Hiraga was using many years ago in his Kaneda preamp! Absolutely unobtainable nowadays. Contibutions highly welcomed!

4th November 2009, 11:00 AM	#2610
RCruz diyAudio Member Join Date: Sep 2006 Location: Saxon Blog Entries: 1	I am using a 47nF obbligato gold in the riaa and it proved to be much better than russian PIO.