Thanks. I will use 500 mA.
Nordic: I am not a big fan of toroidals, either. I will use EI one for this project.
Nordic: I am not a big fan of toroidals, either. I will use EI one for this project.
I'm using the Phonoclone BE with much joy and am happy with it. No particular problems. I know the saying "Don't fix if ...".
Having said that, I'm always looking for areas to improve. Noise could be a little lower, just as sensitivity to RF pickup. This is my current setup, built by the book with a 50VA trafo. Could I improve on the wiring, parts, the case of somewhere else based on experiences of newer iterations?
Ralph
Having said that, I'm always looking for areas to improve. Noise could be a little lower, just as sensitivity to RF pickup. This is my current setup, built by the book with a 50VA trafo. Could I improve on the wiring, parts, the case of somewhere else based on experiences of newer iterations?
Ralph
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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.
An externally hosted image should be here but it was not working when we last tested it.
Hi Ralph,
I don't see any smoothing in the PSU case.
I think first stage smoothing must stay in a very tight loop with the rectifier and transformer secondary wiring.
Your second stage smoothing/decoupling can be on board with the circuit.
I don't see any smoothing in the PSU case.
I think first stage smoothing must stay in a very tight loop with the rectifier and transformer secondary wiring.
Your second stage smoothing/decoupling can be on board with the circuit.
I'm sure RJM will step in here, but IIRC, I asked this and was told not to use any smoothing at the Tx, just bring the raw rectified DC to the phonoclone.
Fran
Fran
Not having build a phonoclone I cannot say if your interpretation will sound nicer, but this philosophy of bringing the rectified half waves (and the very short charging pulses) to remote smoothing caps brings all the pulse currents into the very sensitive areas of the circuitry.woodturner-fran said:
I would at least try the compact TINY loop area method to prove it one way or the other.
I consider it very important to keep the transformer secondary and rectifier and first stage smoothing in a very tight loop area configuration and if possible to keep all the interconnections between these three PSU components short.
This is true, but it also put all the resistance (and inductance) of the lead wire between the cap and the diode, which if it does anything improves the filtering and dampens the diode spike. It avoids having, from the point of view of the op-amp, a capacitor sitting a long way from the power pins behind a significant inductance. Anyway trust me it sounds much better without capacitors in the power supply box itself. But you are welcome to do the test yourself.
Richard
What about keeping the caps and regulators in the psu box, and then putting some caps near the power pins of the opamps as well?
Filtering
Hello.
A few months ago I build my last version of Phonoclone I use till now. This is total dual mono. Each opamp on the pre pcb has each own regulators (lm317/337). Second opamp is biased to class A by adding a 2k resistor (supply is 2x15V). Filtering: 70 000uF/25V & 8 inductors 10mH/1A for each channel. I bypassed also schottky (1N5819 1A/40V) in rect by a small cap.
http://img170.imageshack.us/my.php?image=phonoclonee002fs8.jpg
Chassis .... I called it The Tower 🙂...why .... see the pictures:
1. http://img502.imageshack.us/my.php?image=thetower002xp4.jpg
2. http://img517.imageshack.us/my.php?image=thetower003zu9.jpg
Sound for me and friends who listened that version is wonderfull. Bigger, deeper bas, incredible soundstage. High freq are also beatiful. This isn't cheap improovement but I can recommend it for everyone.
Krzysztof
Hello.
A few months ago I build my last version of Phonoclone I use till now. This is total dual mono. Each opamp on the pre pcb has each own regulators (lm317/337). Second opamp is biased to class A by adding a 2k resistor (supply is 2x15V). Filtering: 70 000uF/25V & 8 inductors 10mH/1A for each channel. I bypassed also schottky (1N5819 1A/40V) in rect by a small cap.
http://img170.imageshack.us/my.php?image=phonoclonee002fs8.jpg
Chassis .... I called it The Tower 🙂...why .... see the pictures:
1. http://img502.imageshack.us/my.php?image=thetower002xp4.jpg
2. http://img517.imageshack.us/my.php?image=thetower003zu9.jpg
Sound for me and friends who listened that version is wonderfull. Bigger, deeper bas, incredible soundstage. High freq are also beatiful. This isn't cheap improovement but I can recommend it for everyone.
Krzysztof
I realize I am late reading this thread but would anyone have any spare VSPS boards they would be willing to sell?
If the value of R2 in the input buffer was lowered would it be possible to use the PHonoclone with a lower level MM cartridge?
Re: Filtering
Wow that's pretty impressive. I just started building mine today and it will be dual mono as well. I got one channel finished and it worked the first time, I can't wait to finish the other channel.
🙂
ahaja said:
Wow that's pretty impressive. I just started building mine today and it will be dual mono as well. I got one channel finished and it worked the first time, I can't wait to finish the other channel.
🙂
has anyone done any experiments with lower noise supplies than the LM317 series regs for these preamps?
any differences?
mlloyd1
any differences?
mlloyd1
I use my pc with superregs and different opamps and slightly enhanced topolgy (output servo)
Much better.
Rüdiger
Much better.
Rüdiger
Zener diodes. Two for each rail. 12V/3W. For each opamp. 🙂
Is much better than any LM .... I got these diodes and only resistors for I load (about 70R). V sec from toroid I got 2x16,92V (after rect and filtration).
Here is the calculator: http://www.opamplabs.com/zenerreg.htm . Try it 🙂.
Krzysztof
Is much better than any LM .... I got these diodes and only resistors for I load (about 70R). V sec from toroid I got 2x16,92V (after rect and filtration).
Here is the calculator: http://www.opamplabs.com/zenerreg.htm . Try it 🙂.
Krzysztof
Because I don't need any additional gain recently my Phonoclone is driving only a passive pre, nothing more than a DACT CT2 100K volume pot. Does this have any sonic penalties?
Ralph
Ralph
Thats a hard one to call.
I can tell you this:
I had a passive pre that I thought sounded great (and it did) but then I changed it to active with an aikido circuit.
What a difference - I realise now so much was missing
YMMV
Fran
I can tell you this:
I had a passive pre that I thought sounded great (and it did) but then I changed it to active with an aikido circuit.
What a difference - I realise now so much was missing
YMMV
Fran
My pre amp is originally an active transformer coupled tube one. I just bypassed everything from the pot to a spare set or RCA's. I meant penalties in the impedance-matching/frequency response kind of way.
No, there is no penalty for this since the Phonoclone can drive the pot directly even if it has a relatively low impedance, like 5k or less. The purpose of original gain/buffer stage before the pot would have been to present a very high impedance to the input source device, so as to be compatible with tube tuners and so forth incapable of driving low impedance loads.
Hi Richard, I made another VSPS, because my original was "taken away" from me... I really love the VSPS. Thanks!
I made two inputs this time, switchable with DPDT switch, but everytime I wire with the switch, I get a buzz. With one input hardwired, silent as before.
Any tips on wiring for two inputs, specially grounding route?
I made two inputs this time, switchable with DPDT switch, but everytime I wire with the switch, I get a buzz. With one input hardwired, silent as before.
Any tips on wiring for two inputs, specially grounding route?