If you are contemplating building something as complicated as that circuit, why not build a valve phono amp. There are some really elegant designs out there which are almost bound to sound better than a transistor phono amp.
Failing that I would say that using top quality opamps (such as the OPA627) will probably give a better result. I am currently using the VSPS with OPA627's and it sounds great. I will eventually replace it with a valve phono preamp.
Thats my thoughts anyway.
Shoog
Failing that I would say that using top quality opamps (such as the OPA627) will probably give a better result. I am currently using the VSPS with OPA627's and it sounds great. I will eventually replace it with a valve phono preamp.
Thats my thoughts anyway.
Shoog
Might have enough closed loop gain for moving magnet but not enough for moving coil. Probably needs "diamond buffer" between collectors of T17,T18 and output node for enough open loop gain for the feedback RIAA but then RIAA eq would change without new values for C4,C5,C6,C7,R15,R17. Input should have low voltage noise but probably has high current noise so overall noise for MM is probably inferior to NE5534. Feedback loop is DC coupled with high DC gain so stable DC operating point is difficult without DC servo.
I would try this if I had limited component selection, lots of time and lots of BC550/560 to match. A better choice is Werner's circuit, 2SK117 is probably ok for MM, you could use NE5534 with larger C3 and smaller R5.
I would try this if I had limited component selection, lots of time and lots of BC550/560 to match. A better choice is Werner's circuit, 2SK117 is probably ok for MM, you could use NE5534 with larger C3 and smaller R5.
Don't do that!
Hello,
I would not suggest to build this amp.
Reasons:
- A phono preamp with passive RIAA EQ ALWAYS sounds better. Why? I do not want to explain here, but if you really interested, send me an e-mail and we can discuss it.
- The sound quality of preamps are very much depended on the PSU. This one needs a complicate one that is costly and difficult to build ( I mean a parallel regulation circuit required).
OP amps may be operated with much simpler PSU. The simpler SOUNDS BETTER. You can use two rect.bridges + 2 x 68.000 mF Siemens Sikorel Military Caps (best ever) and then two Dale series resistors with a simple Zener stabilization for each IC's.
Forget 7812 and alike.
Two inverting AD OP amps in each channel with a passive RIAA between the two do the trick.
You can save a lot of work for nothing serious.
Regards: Gabor / Budapest
gabor@zeppelin-audio.hu
Hello,
I would not suggest to build this amp.
Reasons:
- A phono preamp with passive RIAA EQ ALWAYS sounds better. Why? I do not want to explain here, but if you really interested, send me an e-mail and we can discuss it.
- The sound quality of preamps are very much depended on the PSU. This one needs a complicate one that is costly and difficult to build ( I mean a parallel regulation circuit required).
OP amps may be operated with much simpler PSU. The simpler SOUNDS BETTER. You can use two rect.bridges + 2 x 68.000 mF Siemens Sikorel Military Caps (best ever) and then two Dale series resistors with a simple Zener stabilization for each IC's.
Forget 7812 and alike.
Two inverting AD OP amps in each channel with a passive RIAA between the two do the trick.
You can save a lot of work for nothing serious.
Regards: Gabor / Budapest
gabor@zeppelin-audio.hu
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