I'm still in the process of testing my version, but haven't seen any oscillation with very light loads. If anyone else would be willing to help, I think I have a few more board sets.
Hello friends
I build an NS10 with apassgear schematic http://www.ptsoundlab.com/temp/ns10/ligne.jpg (thanks to him !!!) and with my PSU http://www.ptsoundlab.com/temp/ns10/alim.jpg
The sound is marvelous ! Very good details and dynamic, beautiful basses. A very pleasant preamplifier.
I tried to add to it a RIAA stage, I included original components in apassgear schematic (see in black) http://www.ptsoundlab.com/temp/ns10/riaa.jpg
At the same time, I added the head amp for MC http://www.ptsoundlab.com/temp/ns10/prepre.jpg
The result is very very good, no audible noise and a very good integrated preamplifier.
BUT, I have an issue. The line stage give a lot of basses and is perfect, but the RIAA stage don't give realy enough basses. It seems that the RIAA curve is respected but with basses behind.
Treble seems ok but the lack of basses give me the feeling that they are a little high.
Could someone have an idea of why ? what is the error in my schematic ? or how can I improve basses ?
Thanks a lot in advance if you can help me.
Cordially
Pascal
I build an NS10 with apassgear schematic http://www.ptsoundlab.com/temp/ns10/ligne.jpg (thanks to him !!!) and with my PSU http://www.ptsoundlab.com/temp/ns10/alim.jpg
The sound is marvelous ! Very good details and dynamic, beautiful basses. A very pleasant preamplifier.
I tried to add to it a RIAA stage, I included original components in apassgear schematic (see in black) http://www.ptsoundlab.com/temp/ns10/riaa.jpg
At the same time, I added the head amp for MC http://www.ptsoundlab.com/temp/ns10/prepre.jpg
The result is very very good, no audible noise and a very good integrated preamplifier.
BUT, I have an issue. The line stage give a lot of basses and is perfect, but the RIAA stage don't give realy enough basses. It seems that the RIAA curve is respected but with basses behind.
Treble seems ok but the lack of basses give me the feeling that they are a little high.
Could someone have an idea of why ? what is the error in my schematic ? or how can I improve basses ?
Thanks a lot in advance if you can help me.
Cordially
Pascal
Dear Pascal,
This reply refers to you noticeing a lack of bass in the sound produced by the NS10 RIAA stage. When I examined the schematic posted at your website (PT Soundlab), I noticed that your schematic has two series-connected 301k resistors shunting the RIAA network. This shunt results in a rather severe reduction of bass, as compared to the original RIAA curve. Removing the shunt may give you the bass which you are missing.... 😀
May be the shunt is a modification of the original NS10 circuit, in order to attenuate subsonic garbage from warped records. But I guess the action of the shunt is rather too severe. Perhaps the father (auctor intellectualis) of the NS10 circuit, Nelson Pass, may comment?
These are my five cents from The Netherlands (I have run some PSpice simulations which indicate that the statements I made above are correct).
Best regards,
Aren van Waarde (aka Arens Attic)
This reply refers to you noticeing a lack of bass in the sound produced by the NS10 RIAA stage. When I examined the schematic posted at your website (PT Soundlab), I noticed that your schematic has two series-connected 301k resistors shunting the RIAA network. This shunt results in a rather severe reduction of bass, as compared to the original RIAA curve. Removing the shunt may give you the bass which you are missing.... 😀
May be the shunt is a modification of the original NS10 circuit, in order to attenuate subsonic garbage from warped records. But I guess the action of the shunt is rather too severe. Perhaps the father (auctor intellectualis) of the NS10 circuit, Nelson Pass, may comment?
These are my five cents from The Netherlands (I have run some PSpice simulations which indicate that the statements I made above are correct).
Best regards,
Aren van Waarde (aka Arens Attic)
Thank you very much Aren
I will try tomorrow and let you know the result.
Otherwise, without this issue with RIAA, this preamp is a killer, very nice sound with F5 amplifier.
I'm a fanatic of valve amplifiers and preamplifiers, and I don't love a lot solid state,... except Nelson jobs, I love all Nelson amplifiers and preamplifiers.
Cordially
Pascal
I will try tomorrow and let you know the result.
Otherwise, without this issue with RIAA, this preamp is a killer, very nice sound with F5 amplifier.
I'm a fanatic of valve amplifiers and preamplifiers, and I don't love a lot solid state,... except Nelson jobs, I love all Nelson amplifiers and preamplifiers.
Cordially
Pascal
Hello Aren
the issue is the same with or without 301K resistors, lack of bass
So now i see two possibilities
- false RIAA network
- bad capacitors in RIAA network
I will order new capacitors to verify. For the RIAA network, it is the one I saw in all schematics.....
http://www.ptsoundlab.com/temp/ns10/sl10-riaa.gif
http://www.ptsoundlab.com/temp/ns10/RK%20Ronningstad's%20version%20of%20the%20NS10.pdf
I tried with 18,2K like RK or 16,5K like original and it's the same
http://www.ptsoundlab.com/temp/ns10/sl10-sch.gif
...., so I think it is good ?
If I don't make mistake, RIAA Network is made by 16K5//4,7nF 301K//15nF
Thank you for your help
Cordially
Pascal
the issue is the same with or without 301K resistors, lack of bass
So now i see two possibilities
- false RIAA network
- bad capacitors in RIAA network
I will order new capacitors to verify. For the RIAA network, it is the one I saw in all schematics.....
http://www.ptsoundlab.com/temp/ns10/sl10-riaa.gif
http://www.ptsoundlab.com/temp/ns10/RK%20Ronningstad's%20version%20of%20the%20NS10.pdf
I tried with 18,2K like RK or 16,5K like original and it's the same
http://www.ptsoundlab.com/temp/ns10/sl10-sch.gif
...., so I think it is good ?
If I don't make mistake, RIAA Network is made by 16K5//4,7nF 301K//15nF
Thank you for your help
Cordially
Pascal
NS-10 Preamp service manual / original schematics
Does anyone have a copy of the original NS-10 service manual, or at least the original schematic? Urgent! .... DIY AUDIO Member: "Robert the cat"
Does anyone have a copy of the original NS-10 service manual, or at least the original schematic? Urgent! .... DIY AUDIO Member: "Robert the cat"
Need help with missing chip
No Service manual ever existed that I know of.
If any one with an NS 10 could look under the hood for me I would be grateful.
I need to know about a 14 pin DIP near the right front of main board. This early unit has a one piece gain circuit PCB. The 14 pin socket is next to a FT 317 w/ heat sink. What is the chip and the orientation? Any help mucho appreciated.
No Service manual ever existed that I know of.
If any one with an NS 10 could look under the hood for me I would be grateful.
I need to know about a 14 pin DIP near the right front of main board. This early unit has a one piece gain circuit PCB. The 14 pin socket is next to a FT 317 w/ heat sink. What is the chip and the orientation? Any help mucho appreciated.
Sorry that I don't have the info.
It may be that the 14 pin dip is a quad op amp used for the offset. You
can find that out by examining the connections of the pins or by seeing
whether the op amp is present on the individual gain modules.
😎
It may be that the 14 pin dip is a quad op amp used for the offset. You
can find that out by examining the connections of the pins or by seeing
whether the op amp is present on the individual gain modules.
😎
Even more so inside the 400A. I am sitting here looking into it like some doctor of medicine wondering shall I just close it again? Well, I am going to close it. But I will do some surgery on it, maybe replace some vital parts. I'll find a 400A thread and post the pictures maybe.
So the picture of the damaged inside is here: http://www.diyaudio.com/forums/pass-labs/95067-repair-question-re-threshold-400a-47.html#post4034628
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