Finally operational!
Received and installed the replacement parts that were necessary due to my previous ham handed efforts. Everything checked out and all seems well.
The result is VERY quiet. Even better than I hoped and especially impressive considering the the gain is ~70 dB. The Parasound phono pre that I used before was practically "shouting" noise by comparison.
It is noticeably brighter than the Parasound. This may be due to the cartridge itself, an Audio Technica OC9 MkII. They are known to be strong on the top end in some situations. I have only ever used it with the Parasound, so I have no other comparison.
Other than the increased brightness, everything is simply superb. We will have to see if I get accustomed to the top end. If not, it may be new cartridge time.
Thank you for an outstanding design and all of the help, RJM!
Received and installed the replacement parts that were necessary due to my previous ham handed efforts. Everything checked out and all seems well.
The result is VERY quiet. Even better than I hoped and especially impressive considering the the gain is ~70 dB. The Parasound phono pre that I used before was practically "shouting" noise by comparison.
It is noticeably brighter than the Parasound. This may be due to the cartridge itself, an Audio Technica OC9 MkII. They are known to be strong on the top end in some situations. I have only ever used it with the Parasound, so I have no other comparison.
Other than the increased brightness, everything is simply superb. We will have to see if I get accustomed to the top end. If not, it may be new cartridge time.
Thank you for an outstanding design and all of the help, RJM!
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I have been using phonoclone for about 10 years.
I used LM317/337 for +/-15V power supply for a long time.
I changed power supply from 317/337 to Salas shunt regulator last year.
The Salas regulator does improve phonoclone sound very much.
I don't use coupling capacitor. I use dc servo instead. I have tried both, but I prefer dc servo. I love currently setup very much. The phonoclone is fantastic.
The first stage OP of phonoclone is AD797, the second and dc servo OP are OPA627.
Sorry to Richard. I use my own board to build the phonoclone.
I used LM317/337 for +/-15V power supply for a long time.
I changed power supply from 317/337 to Salas shunt regulator last year.
The Salas regulator does improve phonoclone sound very much.
I don't use coupling capacitor. I use dc servo instead. I have tried both, but I prefer dc servo. I love currently setup very much. The phonoclone is fantastic.
The first stage OP of phonoclone is AD797, the second and dc servo OP are OPA627.
Sorry to Richard. I use my own board to build the phonoclone.
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.
Here is my phonoclone module. Some parts are located on the backside of PCB.
An externally hosted image should be here but it was not working when we last tested it.
Yes, I was wondering where it was in your first post. Without the coupling caps or regulation, the board can be made very small.
Looks great. Clearly a lot of work on your part so I'm glad you like it!
Looks great. Clearly a lot of work on your part so I'm glad you like it!
Yes, #3409 was my first post in this thread.
The board was designed for Blackgate N as coupling. It was pretty compact with Black N.
Blackgate N did make sound good. Besides Blackgate N, I also tried RIFA PHE450 4.7uF, Auricap 4.0uF PP. Those are all good capacitors, but the sound of those capacitors can't satisify me till I try dc servo.
Phonoclone is an inverting amplifier, hence I use an inverting integator. (only two capacitors for stereo)
I use Duelund 0.47uF CAST PIO as dc servo capacitors. For sound, they are awesome. I have compared with Auricap 0.47uF PP in dc servo position, Duelend won.
Compared with coupling capacitors, dc servo has better soundstage, deeper bass, better dynamic and details. Phonoclone and dc servo match pretty well in my system.
The board was designed for Blackgate N as coupling. It was pretty compact with Black N.
Blackgate N did make sound good. Besides Blackgate N, I also tried RIFA PHE450 4.7uF, Auricap 4.0uF PP. Those are all good capacitors, but the sound of those capacitors can't satisify me till I try dc servo.
Phonoclone is an inverting amplifier, hence I use an inverting integator. (only two capacitors for stereo)
I use Duelund 0.47uF CAST PIO as dc servo capacitors. For sound, they are awesome. I have compared with Auricap 0.47uF PP in dc servo position, Duelend won.
Compared with coupling capacitors, dc servo has better soundstage, deeper bass, better dynamic and details. Phonoclone and dc servo match pretty well in my system.
Hello all,
new VSPS builder here...
I already ordered VSPS kit from Richard, he was kind enough to give some suggestions concerning the transformer for the PSU, but I have more questions...
Would this enclosure be big enough for the VSPS -
1455C801BK HAMMOND, Metallic Enclosure, 1455 Series, Extruded With Metal End Panels, PCB Box, 23 mm, 54 mm, 80 mm | Farnell element14
Or maybe this one -
1455K1201 HAMMOND, Metallic Enclosure, 1455 Series, Extruded With Metal End Panels, PCB Box, 43 mm, 78 mm, 120 mm | Farnell element14
I think the PCB might just fit into the first one, but with all in/out connections...
About the transformer for the PSU, guess this one will do -
MCFM32/12 - MULTICOMP - Toroidal Transformer, 24mm x 43mm, 3.2 VA, 2 x 12V, 133 mA, Panel | Farnell element14
And last but not least, the rectifier bridge, will this be O.K. ?
KBPC102. VISHAY, Bridge Rectifier Diode, Single, 200 V, 3 A, KBPC, 1.1 V, 4 Pins | Farnell element14
If anybody has sourced mentioned parts for the VSPS from Farnell, can you please let me know what you ordered?
Shipping costs from Mouser for EU are quite high compared to Farnell.
Regards,
Davor.
new VSPS builder here...
I already ordered VSPS kit from Richard, he was kind enough to give some suggestions concerning the transformer for the PSU, but I have more questions...
Would this enclosure be big enough for the VSPS -
1455C801BK HAMMOND, Metallic Enclosure, 1455 Series, Extruded With Metal End Panels, PCB Box, 23 mm, 54 mm, 80 mm | Farnell element14
Or maybe this one -
1455K1201 HAMMOND, Metallic Enclosure, 1455 Series, Extruded With Metal End Panels, PCB Box, 43 mm, 78 mm, 120 mm | Farnell element14
I think the PCB might just fit into the first one, but with all in/out connections...
About the transformer for the PSU, guess this one will do -
MCFM32/12 - MULTICOMP - Toroidal Transformer, 24mm x 43mm, 3.2 VA, 2 x 12V, 133 mA, Panel | Farnell element14
And last but not least, the rectifier bridge, will this be O.K. ?
KBPC102. VISHAY, Bridge Rectifier Diode, Single, 200 V, 3 A, KBPC, 1.1 V, 4 Pins | Farnell element14
If anybody has sourced mentioned parts for the VSPS from Farnell, can you please let me know what you ordered?
Shipping costs from Mouser for EU are quite high compared to Farnell.
Regards,
Davor.
The 23mm case is not high enough. Even with the other there will only be 20 mm clearance front and back for the connectors. Suggest 100x150x50mm minimum, or much larger if you put the transformer in the same case.
The diode / bridge is fine.
The transformer: if you are going to pay 17 euro for a 3.2 VA model, might I suggest you pay 5 euro more and get this 30 VA model instead? 10x more power for 20% more cost seems like a pretty good deal.
The diode / bridge is fine.
The transformer: if you are going to pay 17 euro for a 3.2 VA model, might I suggest you pay 5 euro more and get this 30 VA model instead? 10x more power for 20% more cost seems like a pretty good deal.
Hi guys!
It's been about a year since I built my stereo VSPS, and I have enjoyed every bit of it. As a reminder, that is what it looked like a year ago:
Today I just upgraded it with rjm's own b-boards to buffer its outputs! Layout was a challenge since the enclosure I used is rather compact, but I really wanted to keep that way, and I somehow managed to fit everything without getting a larger enclosure.
And despite the transformer being so close to the boards it is completely silent! Some pics:
Thank again rjm for the great designs!
Cheers! [emoji2] [emoji41]
It's been about a year since I built my stereo VSPS, and I have enjoyed every bit of it. As a reminder, that is what it looked like a year ago:
Today I just upgraded it with rjm's own b-boards to buffer its outputs! Layout was a challenge since the enclosure I used is rather compact, but I really wanted to keep that way, and I somehow managed to fit everything without getting a larger enclosure.
And despite the transformer being so close to the boards it is completely silent! Some pics:
Thank again rjm for the great designs!
Cheers! [emoji2] [emoji41]
Thanx Richard! Yes, the wiring is kind of messy and cramped... Especially the grounds, I was too lazy (!) to drill a new better placed hole so I reused an old one for the ground!
I also had to make the leads longer than necessary in order to solder them to the boards before screwing everything in the box...
But it works!
Skickat från min Nexus 5X via Tapatalk
I also had to make the leads longer than necessary in order to solder them to the boards before screwing everything in the box...
But it works!
Skickat från min Nexus 5X via Tapatalk
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Hi!
A while ago, I noticed a thump when switching inputs on my amplifier, from or to the VSPS signal. I realized looking at the speakers while doing so that I might have an issue with DC offset.
After a quick measurement (at the VSPS outputs, before the b-boards), it turns out I have about -949 mV on one channel and -1365 mV on the other one!
I tried several things like rolling opamps, lifting the connection GND to earth, with no benefit whatsoever.
It then occurred me to take a measurement directly at the opamp outputs, and I get around -6 mV on one side and -70 on the other one! Much better, although still a big difference between channels... Measuring across the output caps (C3) confirms all of the above and gives the same potential difference of about -0,9 and -1,4 volts.
Power supply is at a rock solid +18,32 and -18,32 at the rectifiers output, so perfect symmetry there.
What is going on here? Should I try other coupling caps, or just bypass them? The ones I have are the ones supplied by Richard (Rapport audiocap 2,2 uf).
Thanks for any suggestions!
A while ago, I noticed a thump when switching inputs on my amplifier, from or to the VSPS signal. I realized looking at the speakers while doing so that I might have an issue with DC offset.
After a quick measurement (at the VSPS outputs, before the b-boards), it turns out I have about -949 mV on one channel and -1365 mV on the other one!
I tried several things like rolling opamps, lifting the connection GND to earth, with no benefit whatsoever.
It then occurred me to take a measurement directly at the opamp outputs, and I get around -6 mV on one side and -70 on the other one! Much better, although still a big difference between channels... Measuring across the output caps (C3) confirms all of the above and gives the same potential difference of about -0,9 and -1,4 volts.
Power supply is at a rock solid +18,32 and -18,32 at the rectifiers output, so perfect symmetry there.
What is going on here? Should I try other coupling caps, or just bypass them? The ones I have are the ones supplied by Richard (Rapport audiocap 2,2 uf).
Thanks for any suggestions!
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This is easily solved.
The bboard buffer has a DC offset equal to the input offset current multiplied by the DC impedance seen by the base of Q1,Q2.
What you need to do is reduce the value of R7 on the stereo VSPS, which the BOM value sets as 68 kohms. You need to change it to about 10 k or simply add another resistor in parallel say 22k, since 22k||68k = ~10k or that ballpark), attached either between OUT+ OUT- of the VSPS or IN+ IN- of the bboard.
That should reduce the offset from ~1 V you have now to about 100-120 mV. If that's still too high for your application then you'd need to add coupling capacitor (and drain resistor 50k~100k) to the output of the bboard.
The bboard buffer has a DC offset equal to the input offset current multiplied by the DC impedance seen by the base of Q1,Q2.
What you need to do is reduce the value of R7 on the stereo VSPS, which the BOM value sets as 68 kohms. You need to change it to about 10 k or simply add another resistor in parallel say 22k, since 22k||68k = ~10k or that ballpark), attached either between OUT+ OUT- of the VSPS or IN+ IN- of the bboard.
That should reduce the offset from ~1 V you have now to about 100-120 mV. If that's still too high for your application then you'd need to add coupling capacitor (and drain resistor 50k~100k) to the output of the bboard.