Hi Richard,
Sorry for late reply, great to know that everything is alright in Kyoto.
Well performance of phonoclone is superb regardless of price. I am happy with it.
Just my observation.
I was listening to the "said fm" phono stage again last week, and noticed something very strange.
Normally I assume a phonostage would amplify any signals from the cartridge say from 20hz-20khz, and one can expect to hear the clicks and pops and surface noise when the stylus hits the vinyl.
When someone say its a quiet phonostage, in general I believe they mean the noise generated in the system before the stylus hitting the vinyl groove.
Now this "said fm" phonostage is dead quiet even when the stylus hits the vinyl and tracking the groove until the music comes about.
So I suspect that it has employed some kind of band stop filtering network to filter out certain frequencies, and therefore it is super quiet.
Anyhow, thanks for the good work.
Regards.
Sorry for late reply, great to know that everything is alright in Kyoto.
Well performance of phonoclone is superb regardless of price. I am happy with it.
Just my observation.
I was listening to the "said fm" phono stage again last week, and noticed something very strange.
Normally I assume a phonostage would amplify any signals from the cartridge say from 20hz-20khz, and one can expect to hear the clicks and pops and surface noise when the stylus hits the vinyl.
When someone say its a quiet phonostage, in general I believe they mean the noise generated in the system before the stylus hitting the vinyl groove.
Now this "said fm" phonostage is dead quiet even when the stylus hits the vinyl and tracking the groove until the music comes about.
So I suspect that it has employed some kind of band stop filtering network to filter out certain frequencies, and therefore it is super quiet.
Anyhow, thanks for the good work.
Regards.
I doubt that it has a bandpass (notch) filter, not in the audio band anyway, that would be too hard to achieve with any semblance of transparency. On the other hand I do agree with you that some phono stages seem to exaggerate groove noise and some seem to hide it, and I don't fully understand why this should be the case.
If you look at the run in before the music starts on a track, the broadband noise level is typically quite high, 20-30 dB above the phono stage noise baseline when I measured it. This is stylus, turntable and record-dependent of course. You can barely hear it, but the presence or absence will be sensed as more or less "blackness".
My guess is that a phono stage with a -1 dB rolloff at 20 kHz will make this noise a lot less apparent than one which has a +1 dB peak at the same frequency. The change in the noise volume will be more apparent than the change in the music even, since the noise is broadband with considerable energy at 10 kHz to 20 kHz, where music is,for the most part, centered at much lower frequencies.
If you look at the run in before the music starts on a track, the broadband noise level is typically quite high, 20-30 dB above the phono stage noise baseline when I measured it. This is stylus, turntable and record-dependent of course. You can barely hear it, but the presence or absence will be sensed as more or less "blackness".
My guess is that a phono stage with a -1 dB rolloff at 20 kHz will make this noise a lot less apparent than one which has a +1 dB peak at the same frequency. The change in the noise volume will be more apparent than the change in the music even, since the noise is broadband with considerable energy at 10 kHz to 20 kHz, where music is,for the most part, centered at much lower frequencies.
Refer to the link,
????????: 2009/10/14
Someone in Taiwan has done some reviews on Op-amps, I would like to check if you have any idea whether ADA4627, OPA111 are directly interchangible with op027 on IC 1-4 position.
Appreciated.
????????: 2009/10/14
Someone in Taiwan has done some reviews on Op-amps, I would like to check if you have any idea whether ADA4627, OPA111 are directly interchangible with op027 on IC 1-4 position.
Appreciated.
Neither are available in DIP8 packages, so cannot be considered drop in replacements.
Both op amps are JFET input types. They can be used in the phonoclone circuit if you insist, but are not as well suited for the application as bipolar input op amps like the OPA27. They are noisier and have higher offset voltages.
JFET opamps are good for high impedance applications. The Phonoclone is a low impedance circuit.
Both op amps are JFET input types. They can be used in the phonoclone circuit if you insist, but are not as well suited for the application as bipolar input op amps like the OPA27. They are noisier and have higher offset voltages.
JFET opamps are good for high impedance applications. The Phonoclone is a low impedance circuit.
VSPS300 Power Supply Info
I am just beginning my setup stage for the VSPS300 Phonostage and have noted that the power supply info states that the power supply should be separate (which makes much sense.) I am wondering though which board is used from RJM Audio? There is no offering for a separate power supply PCB that I have been able to find. I searched on "VSPS power supply" but got no results. Help would be appreciated. I am thinking it is the same board but am not sure. Newbie to phonostage here...
I am just beginning my setup stage for the VSPS300 Phonostage and have noted that the power supply info states that the power supply should be separate (which makes much sense.) I am wondering though which board is used from RJM Audio? There is no offering for a separate power supply PCB that I have been able to find. I searched on "VSPS power supply" but got no results. Help would be appreciated. I am thinking it is the same board but am not sure. Newbie to phonostage here...
From the construction guide, which is supposed to gives the details of the "non-board" sections of the Phonoclone and VSPS.
I didn't actually state that there is no power supply board. Sorry, that could be made clearer. I've flagged that section for review.
Thanks,
Richard
I didn't actually state that there is no power supply board. Sorry, that could be made clearer. I've flagged that section for review.
Thanks,
Richard
Attachments
Thank you Richard. Now all i have to do is decide how much i want to spend on a transformer. I think though that I will go with the basic recommended unit that is mentioned in the construction guide. If i went with a Plitron, is there a recommended unit from that manufacturer? There are so many choices, I could use help with a specific model number if i decide to spend the extra money.
Thanks for any help,
Jerry
Thanks for any help,
Jerry
You just need something with two 12 VAC secondaries. The size is not critical, 25-180 VA.
There are the low profile PC mount 700XX series from AMVECO if you want to put everything on a circuit board. AMVECO (formerly Talema) also has the miniature low profile 620XX series which have a potted core for convenient bolt-through mounting. These are sold at Digikey. I often use the 62062. Much the same thing is available from Mouser as the Triad VPT24-1040, without the potted core. I've given 25VA examples, but you could go with 35VA or 50VA.
If you want something bigger, Hammond comes to mind, and of course Plitron. Plitron is great if you live in Canada. The pricing is such that buying anything smaller than 160VA makes no sense, so consider the 160 VA model 057012201.
The Plitron transformers you really want are the custom units with the electrostatic screen and magnetic shield. Unfortunately they don't sell them in anything less than 5 unit batches, last I checked - it was some years ago now.
There are the low profile PC mount 700XX series from AMVECO if you want to put everything on a circuit board. AMVECO (formerly Talema) also has the miniature low profile 620XX series which have a potted core for convenient bolt-through mounting. These are sold at Digikey. I often use the 62062. Much the same thing is available from Mouser as the Triad VPT24-1040, without the potted core. I've given 25VA examples, but you could go with 35VA or 50VA.
If you want something bigger, Hammond comes to mind, and of course Plitron. Plitron is great if you live in Canada. The pricing is such that buying anything smaller than 160VA makes no sense, so consider the 160 VA model 057012201.
The Plitron transformers you really want are the custom units with the electrostatic screen and magnetic shield. Unfortunately they don't sell them in anything less than 5 unit batches, last I checked - it was some years ago now.
Testing Question
I have built the Phonoclone 3 with Xreg and I am testing it. At this point I do not yet have my MC cartridge and I am testing with a Grado moving magnet cartridge. It plays at about the same volume as with my MM Preamp (VSPS), but with very little treble. Is this to be expected due to the mismatched impedance?
Thanks for your help.
Lindsay
I have built the Phonoclone 3 with Xreg and I am testing it. At this point I do not yet have my MC cartridge and I am testing with a Grado moving magnet cartridge. It plays at about the same volume as with my MM Preamp (VSPS), but with very little treble. Is this to be expected due to the mismatched impedance?
Thanks for your help.
Lindsay
Help troubleshooting...
I finished putting my VSPS300 (thanks Richard for the boards/parts) together and just tested it two nights ago with a pair of computer speakers. Sounded great but had hum, which I was going to write to the forum for help on what to check.
Last night I hooked it up to my main system and it would not play at all, and to add insult to injury, the hum was still there...
So I have two problems now, no sound and the same hum.
The only fuse in the setup is built into the IEC and it did not blow. The power supply is outputting 15.8vdc+/- (measured at the xlr connector).
What should I check next?
Thanks in advance.
I finished putting my VSPS300 (thanks Richard for the boards/parts) together and just tested it two nights ago with a pair of computer speakers. Sounded great but had hum, which I was going to write to the forum for help on what to check.
Last night I hooked it up to my main system and it would not play at all, and to add insult to injury, the hum was still there...
So I have two problems now, no sound and the same hum.
The only fuse in the setup is built into the IEC and it did not blow. The power supply is outputting 15.8vdc+/- (measured at the xlr connector).
What should I check next?
Thanks in advance.
If it was working before, and not now, the mostly likely thing is a simple mistake involving the input connection.
The VSPS does not hum, but hum can be picked up by the MM cartridge. Hum will also be present if you don't properly connect the turntable and tonearm grounds to the VSPS COM/chassis.
To comment further, it would help to see a photo of your finished VSPS.
The VSPS does not hum, but hum can be picked up by the MM cartridge. Hum will also be present if you don't properly connect the turntable and tonearm grounds to the VSPS COM/chassis.
To comment further, it would help to see a photo of your finished VSPS.
The RCA's common are isolated from the chassis.
An externally hosted image should be here but it was not working when we last tested it.
I had time tonight to hook it up again. The hum was from a loose grounding lug in the back of the turntable.
The no playing *both* channels was a bad RCA cable.
But I do have a problem with one channel not playing. I swapped the out right/left cables and the silent speaker changed, so it is a board that is producing no output. The silent channel has a slight hum to it, whereas the sound producing channel does not.
I will go through the components on that board tomorrow to make sure nothing died from the first time I played and both channels played.
Any suggestions are still welcomed...
The no playing *both* channels was a bad RCA cable.
But I do have a problem with one channel not playing. I swapped the out right/left cables and the silent speaker changed, so it is a board that is producing no output. The silent channel has a slight hum to it, whereas the sound producing channel does not.
I will go through the components on that board tomorrow to make sure nothing died from the first time I played and both channels played.
Any suggestions are still welcomed...
talema
Dumb question but can someone please tell me how to hook up a talema 62072 for 120v mains? I tried tying the yellow to red and black to violet on the input side and green/red and brown/blue to the rectifiers. Is this correct? Unless I'm measuring wrong(very possible) I get a much higher dc reading on my multimeter than I should and no sound. I had it hooked up and running a couple years ago and only unhooked the transformer when I put it away.
Dumb question but can someone please tell me how to hook up a talema 62072 for 120v mains? I tried tying the yellow to red and black to violet on the input side and green/red and brown/blue to the rectifiers. Is this correct? Unless I'm measuring wrong(very possible) I get a much higher dc reading on my multimeter than I should and no sound. I had it hooked up and running a couple years ago and only unhooked the transformer when I put it away.