I had a chance today to do some careful comparisons with PS and as suggested earlier, I did remove C3/C4 across current source: the sound become noticeably better without those caps (less coloration). I also removed C5/C6 and further improvement was observed. I tried without C9/C10 as well, but circuit actually sounded better with those caps in place. Nichicon FG was preferred here over BG STD, something I suspected already. BG N 10-47uF could be another good choice, although not that much better than FG.
I also did some testing with constant current regulator types. I really liked the old production ON Semi, National was second, then the new production ON Semi while Linear Technology LT317 was the worst; nice sound but too technical, ON Semi was OTOH much more musical.
Attached is updated PS schematic.
I also did some testing with constant current regulator types. I really liked the old production ON Semi, National was second, then the new production ON Semi while Linear Technology LT317 was the worst; nice sound but too technical, ON Semi was OTOH much more musical.
Attached is updated PS schematic.
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I know you fooled around with batteries a few years ago, have you tried it with this? It's a big difference on the B1.
Regards,
Chris
Properly grounded and shielded, the circuit is very quiet.
Presently, I stay away from batteries. I tried them briefly with Ono and wasn't happy with results at all.
Presently, I stay away from batteries. I tried them briefly with Ono and wasn't happy with results at all.
Banned
Joined 2002
Shielding
I ONCE saw some one wrap a thin small piece of wire around a twisted pair and ground it on one end only to remove hum, it worked very well.
Peter, as always DAM NICE WORK,! have such brilliant ideas and clean and easy flowing boards.
J'
I'll have to follow up with some pics at some point as I have mine all nicely boxed up in one of Peter's integrated/amp enclosures. My hum was virtually all but eliminated by grounding my tonearm to AC/Chassis ground. Now it seems I will be playing around by removing some caps, but at this point I have already replaced my Pearl with Ono MC stage, very happy with the sound out of this phonopre. Thanks Peter!
I don't think it would have that much influence, there are many well regarded phono preamps with toroids.
My main reason for using Hammond 229D24 was convenience: I wanted to keep the phono board in a same format as DACs, I wanted transformer to be pcb mounted and most of all, it all had to fit inside 2x3 aluminum tubing.
I'm pretty sure toroid will work here quite well too.
My main reason for using Hammond 229D24 was convenience: I wanted to keep the phono board in a same format as DACs, I wanted transformer to be pcb mounted and most of all, it all had to fit inside 2x3 aluminum tubing.
I'm pretty sure toroid will work here quite well too.
transformers designed like the hammond test to have less high frequency coupling between primary and secondary, so likely provide some helpful line noise filtering.
mlloyd1
mlloyd1
Another completed
First, very nice work by 04dgmsilv! I use similar RCAs (Vampire PCB2F/S), and your technique of mounting the PCB directly on the jacks never occurred to me - great idea.
My unit is just now running breaking in, but already sounds great.
I used Peter's recommended parts for the power supply, but in the audio circuit I used 1% film and foil polystyrene caps I had on hand, along with PRP resistors. I found some 1" by 2" square aluminum stock for Peter's suggested heatsinks which work out great. They barely get warm.
I measured the frequency response of mine (using the Hagerman inverse RIAA) and its very flat (well within the 0.25db tolerance of the Hagerman) except for the very high end, where mine measured up 1.1db at 20Khz. It could well be a measurement error.
My unit draws 5.3 watts of power when on.
I'm using it with a high outpur moving coil - a Dynavector 10x4, so the gain is a bit low (2.5mv, 270 ohm impedance), but only a bit lower than with the ARC PH-3.
Thanks to Peter for all his work on this project and his help sourcing parts!
Mike
First, very nice work by 04dgmsilv! I use similar RCAs (Vampire PCB2F/S), and your technique of mounting the PCB directly on the jacks never occurred to me - great idea.
My unit is just now running breaking in, but already sounds great.
I used Peter's recommended parts for the power supply, but in the audio circuit I used 1% film and foil polystyrene caps I had on hand, along with PRP resistors. I found some 1" by 2" square aluminum stock for Peter's suggested heatsinks which work out great. They barely get warm.
I measured the frequency response of mine (using the Hagerman inverse RIAA) and its very flat (well within the 0.25db tolerance of the Hagerman) except for the very high end, where mine measured up 1.1db at 20Khz. It could well be a measurement error.
My unit draws 5.3 watts of power when on.
I'm using it with a high outpur moving coil - a Dynavector 10x4, so the gain is a bit low (2.5mv, 270 ohm impedance), but only a bit lower than with the ARC PH-3.
Thanks to Peter for all his work on this project and his help sourcing parts!
Mike
An externally hosted image should be here but it was not working when we last tested it.
An externally hosted image should be here but it was not working when we last tested it.
Thanks Peter, for the kit, I have been using it with my Denon 103R and am very happy with the result.
A side note, I have a couple of MM phono amps (Project Tubebox SE II and Yaqin MS-12B) that I would like to downsize/sell. Which MM phono amp kit can you recommand so that I can have something for my nice MM cartridges as well?
A side note, I have a couple of MM phono amps (Project Tubebox SE II and Yaqin MS-12B) that I would like to downsize/sell. Which MM phono amp kit can you recommand so that I can have something for my nice MM cartridges as well?
I would recommend this circuit: http://www.diyaudio.com/forums/audi...hip-amp-kits-dacs-chassis-78.html#post1123520 with shunt regulators as in MC phono project.