Re: Need advice (Benz Micro Ace Medium)
Due to the low output (0.8mV and not 0.8V as stated in your post), you might find that the Phonoclone configured to 75dB of gain might suit the cart better. 75dB gives an output of more than 4V, which is a bit on the high side, but the 40dB gain of the VSPS would give an output of 0.08V, which doesn't seem high enough.
If you're feeling a bit ambitious, you could lower the gain of the first stage, as long as you're using an opamp which is stable at lower gains (OP27 is stable down to unity gain). Adjust R2 according to the Phonoclone article. You'll be looking for a gain of 38dB or less from the first stage in order to output 2V, which is as much as your typical CD player, and more than enough to drive most amps to full power especially if you've got an active preamp. Check the gain of your preamp, and the sensitivity of your power amp if you're worried at all, but I wouldn't be.
good luck,
-d
Alabama978 said:
Due to the low output (0.8mV and not 0.8V as stated in your post), you might find that the Phonoclone configured to 75dB of gain might suit the cart better. 75dB gives an output of more than 4V, which is a bit on the high side, but the 40dB gain of the VSPS would give an output of 0.08V, which doesn't seem high enough.
If you're feeling a bit ambitious, you could lower the gain of the first stage, as long as you're using an opamp which is stable at lower gains (OP27 is stable down to unity gain). Adjust R2 according to the Phonoclone article. You'll be looking for a gain of 38dB or less from the first stage in order to output 2V, which is as much as your typical CD player, and more than enough to drive most amps to full power especially if you've got an active preamp. Check the gain of your preamp, and the sensitivity of your power amp if you're worried at all, but I wouldn't be.
good luck,
-d
Ooops
Yes it should have been 0.8mv
Thanks for the info, look forward to hearing from all the good members here, it's a great info resource. My amp is integrated you can see the spec here...
http://www.mystere-eu.com/ia21/index.php
Yes it should have been 0.8mv
Thanks for the info, look forward to hearing from all the good members here, it's a great info resource. My amp is integrated you can see the spec here...
http://www.mystere-eu.com/ia21/index.php
I am a phonoclone user since three years now. In conjunction with a DL103 and/or DL103R.
Today I got a refurbished EMT Tondose TSD-15, a moving coil cartridge, perfect for my EMT930 turntable.
Some weeks ago, a friend of mine showed up with a TSD-15. We where both surprised: between the DL103R and a TSD-15 is not a slight difference, there is a BIG difference in sound reproduction quality.
And now I converted my double mono phonoclone from 47R input R / 2.7k feedback to 180R input / 6.8k feedback, to get about 30dB gain from the first stage (TSD-15 internal impedance 27R).
And the phonoclone is still a perfect MC-preamp.
The only thing: a little bit noisy, when turning volume completely up and no sound is playing.
What I am thinking about (maybe should open a new thread):
Instead of the first stage with an opamp a low noise JFET gain stage attached to a VSPS.
Did someone already try this idea?
Franz
Today I got a refurbished EMT Tondose TSD-15, a moving coil cartridge, perfect for my EMT930 turntable.
Some weeks ago, a friend of mine showed up with a TSD-15. We where both surprised: between the DL103R and a TSD-15 is not a slight difference, there is a BIG difference in sound reproduction quality.
And now I converted my double mono phonoclone from 47R input R / 2.7k feedback to 180R input / 6.8k feedback, to get about 30dB gain from the first stage (TSD-15 internal impedance 27R).
And the phonoclone is still a perfect MC-preamp.
The only thing: a little bit noisy, when turning volume completely up and no sound is playing.
What I am thinking about (maybe should open a new thread):
Instead of the first stage with an opamp a low noise JFET gain stage attached to a VSPS.
Did someone already try this idea?
An externally hosted image should be here but it was not working when we last tested it.
Franz
Problem building phonoclone
Hi there,
Recently I finished the phonoclone after excellent results with the VSPS.
But as I've bought myself a Fidelity Research MC202 I needed a MC phonopre.
All works, but there is virtually no bass, and the top end seems slightly to load compared to the midrange.
So I've checked, double checked and triple checked the values for the RIAA caps. They are correct. 1nF for C1 and 2.2nF||0.68nF for C2.
Other details:
R1: 0R
R2: 1k
R3: 2k7
R4: 2k2
R5: 110k
R6: 750k
R7: omitted
R8: 47R
C3: omitted: coupling cap in pre amp
U1 and U2: OPA2134
All wired on strip board.
PS based on LM317 and 337
Can anyone please suggest me a way to isolate the problem?
any helps much appreciated.
Marco
Hi there,
Recently I finished the phonoclone after excellent results with the VSPS.
But as I've bought myself a Fidelity Research MC202 I needed a MC phonopre.
All works, but there is virtually no bass, and the top end seems slightly to load compared to the midrange.
So I've checked, double checked and triple checked the values for the RIAA caps. They are correct. 1nF for C1 and 2.2nF||0.68nF for C2.
Other details:
R1: 0R
R2: 1k
R3: 2k7
R4: 2k2
R5: 110k
R6: 750k
R7: omitted
R8: 47R
C3: omitted: coupling cap in pre amp
U1 and U2: OPA2134
All wired on strip board.
PS based on LM317 and 337
Can anyone please suggest me a way to isolate the problem?
any helps much appreciated.
Marco
Alabama
I still use the VSPS. It's a plug in board for my heavily modified Quad 33 (http://www.diyaudio.com/forums/showthread.php?s=&threadid=79794 ). The phonoclone lives in the turntable () itself so the low signal leads are short.http://www.diyaudio.com/forums/showthread.php?s=&threadid=109696
I can change arms on my turntable easily so I can both us an High Output MC (or MM) and low output MC.
MArco
I still use the VSPS. It's a plug in board for my heavily modified Quad 33 (http://www.diyaudio.com/forums/showthread.php?s=&threadid=79794 ). The phonoclone lives in the turntable () itself so the low signal leads are short.http://www.diyaudio.com/forums/showthread.php?s=&threadid=109696
I can change arms on my turntable easily so I can both us an High Output MC (or MM) and low output MC.
MArco
Hi Marco
About your missing bass response:
What do you use as psu bypass caps?
Do you have some bypass caps nearby the chips power supply pins to ground?
Did you try some input resistors? Just in series between the cartridge and the input. Values between 10 to 200R (maybe you must adjust the gain, adapting the feedback resistors value).
Kind regards
Franz
About your missing bass response:
What do you use as psu bypass caps?
Do you have some bypass caps nearby the chips power supply pins to ground?
Did you try some input resistors? Just in series between the cartridge and the input. Values between 10 to 200R (maybe you must adjust the gain, adapting the feedback resistors value).
Kind regards
Franz
Hello Franz,
I as well have the noise problems - these problems are not severe but I feel the OpAmp is noisy. I have sensitive loudspeakers and the noise is a little too audible when there is no playing.
I am also intersted in the Jfet because it is quieter. There is the Pass Phono that is all Jfet and people are happy but this must be used with the step transformer for impedance matching.
I would try if I had the time!
Good luck and listening,
MV
I as well have the noise problems - these problems are not severe but I feel the OpAmp is noisy. I have sensitive loudspeakers and the noise is a little too audible when there is no playing.
I am also intersted in the Jfet because it is quieter. There is the Pass Phono that is all Jfet and people are happy but this must be used with the step transformer for impedance matching.
I would try if I had the time!
Good luck and listening,
MV
mavallarino said:
If you're talking about the Pearl, our friend Promitheus has designed a MC pre-preamp for the Pearl. It seems to use nothing but jfets in the signal path - check it out here:
http://www.diyaudio.com/forums/showthread.php?s=&threadid=78441&highlight=pearl+phono
-d
