VSPS 17a preview
Here's the preliminary revision of the VSPS PCB. Generally it brings the VSPS features into line with the Phonoclone boards introduced last time: thicker traces and poly fills, and fixed regulators replaced with adjustable types. The size and general layout are unchanged.
notes:
The filter and bypass capacitors sizes have been adjusted slightly.
No, there is no room for protection diodes. On the up side, there is also no room for enough capacitance on the output to damage the regulator anyway!
Richard
Here's the preliminary revision of the VSPS PCB. Generally it brings the VSPS features into line with the Phonoclone boards introduced last time: thicker traces and poly fills, and fixed regulators replaced with adjustable types. The size and general layout are unchanged.
notes:
The filter and bypass capacitors sizes have been adjusted slightly.
No, there is no room for protection diodes. On the up side, there is also no room for enough capacitance on the output to damage the regulator anyway!
Richard
Attachments
Questions about DL-160 Cartridge
I want to use Denon DL-160 cartridge on my table. Which of the phono amp is suitable? VSPS or VSPS ultra? The denon catalouge states that the cartridge can be used with a normal MM phono amp as it is a high out put MC. Any sugessions?? I had bulit VSPS a year ago for my dad to be used with MM cartridge and was very pleased with the results.
thanks
Dinesh
I want to use Denon DL-160 cartridge on my table. Which of the phono amp is suitable? VSPS or VSPS ultra? The denon catalouge states that the cartridge can be used with a normal MM phono amp as it is a high out put MC. Any sugessions?? I had bulit VSPS a year ago for my dad to be used with MM cartridge and was very pleased with the results.
thanks
Dinesh
Hey Richard, that looks quite a bit better, I never liked the ground arrangement on the other boards too much...
My VSPS is in a PVC case, and I noticed that if no record is playing it will produce noise as my hand comes closer to the unit...
Dinesh, as far as I know the VSPS is almost as simple as they could make it. For that reason the phonoclone probably performs better, but you will probably have to wait for Richard's reply on that...
The way I see it I would leave VSPS to low output cartridges and those who don't want to go through the extra few miutes of soldering for the phonoclone.
My VSPS is in a PVC case, and I noticed that if no record is playing it will produce noise as my hand comes closer to the unit...
Dinesh, as far as I know the VSPS is almost as simple as they could make it. For that reason the phonoclone probably performs better, but you will probably have to wait for Richard's reply on that...
The way I see it I would leave VSPS to low output cartridges and those who don't want to go through the extra few miutes of soldering for the phonoclone.
Thanks for the reply. I do not have OP27 but have the following opamps.
opa2134, lm6172, opa627, opa637
which will be the best for VSPS? I have used OPA2134 before. Also what is the recommended dc blocking cap to be used(4.7uf)? Any options other than black gates? Can this cap be eliminated if I use it along with a preamp which has a DC blocking cap at the input?
thanks again
Dinesh
opa2134, lm6172, opa627, opa637
which will be the best for VSPS? I have used OPA2134 before. Also what is the recommended dc blocking cap to be used(4.7uf)? Any options other than black gates? Can this cap be eliminated if I use it along with a preamp which has a DC blocking cap at the input?
thanks again
Dinesh
Hi Dinesh, you have quite a few questions there...
I'll answer one... I have removed my 4.7uF caps, DC output was not all that high, and I'm sure the input cap on my amp is dealing with it just fine as I am not smelling smoke, and the speakers are just fine. It just cleaned up the sound a little, but I found it a positve move.
Cheers
Nico
I'll answer one... I have removed my 4.7uF caps, DC output was not all that high, and I'm sure the input cap on my amp is dealing with it just fine as I am not smelling smoke, and the speakers are just fine. It just cleaned up the sound a little, but I found it a positve move.
Cheers
Nico
Batch Order no 5
I will be taking orders for the next batch (Batch 5) of PCBs, parts, and kits from now until Saturday, June 24th. The PCBs are priced as follows, including shipping worldwide:
Phonoclone B.E. set: PCB only. $45 for two boards.
Phonoclone Mini set: PCB only. $20 for two boards.
VSPS set: PCB only. $20 for two boards.
Additional components are available as add-on packages:
Black Gate N output coupling capacitor 4.7uF/50V. +$8/pair.
Voltage regulator pack: 2 each LM317, LM337. +$10
VSPS op-amp pack: 2x OP27 and sockets. +$10
Phonoclone op-amp pack: 4x OP27 (Analog Devices or Burr-Brown/TI), and sockets. +$20
Kits include the PCBs and all its components, but not the power supply, chassis, hardware, etc...
Phonoclone B.E. kit: $110
Phonoclone B.E. assembled PCB: $175
Phonoclone Mini kit: $85
Phonoclone Mini assembled PCB: $140
(VSPS kits are not available at this time.)
additional information can be found on the web page. The Phonoclone BE and Phonoclone mini are unchanged from last time. The VSPS board has been updated to use the LM317 and LM337 adjustable regulators.
/rjm
http://www.geocities.com/rjm003.geo/rjmaudio/diy_pcb.html
I will be taking orders for the next batch (Batch 5) of PCBs, parts, and kits from now until Saturday, June 24th. The PCBs are priced as follows, including shipping worldwide:
Phonoclone B.E. set: PCB only. $45 for two boards.
Phonoclone Mini set: PCB only. $20 for two boards.
VSPS set: PCB only. $20 for two boards.
Additional components are available as add-on packages:
Black Gate N output coupling capacitor 4.7uF/50V. +$8/pair.
Voltage regulator pack: 2 each LM317, LM337. +$10
VSPS op-amp pack: 2x OP27 and sockets. +$10
Phonoclone op-amp pack: 4x OP27 (Analog Devices or Burr-Brown/TI), and sockets. +$20
Kits include the PCBs and all its components, but not the power supply, chassis, hardware, etc...
Phonoclone B.E. kit: $110
Phonoclone B.E. assembled PCB: $175
Phonoclone Mini kit: $85
Phonoclone Mini assembled PCB: $140
(VSPS kits are not available at this time.)
additional information can be found on the web page. The Phonoclone BE and Phonoclone mini are unchanged from last time. The VSPS board has been updated to use the LM317 and LM337 adjustable regulators.
/rjm
http://www.geocities.com/rjm003.geo/rjmaudio/diy_pcb.html
Hum Problem
I built the VSPS with onboard regulation as suggested on the VSPS Web site here -
VSPS Web site
The power coming into the VSPS is unregulated 32.5 VDC, which also powers my linestage (hybrid tube/mosfet circuit). I am using 15 volt fixed regulators 7815 and 7915. I have 470mfd for input caps and 100 mfd for output caps as recommended.
With this setup, hum is noticeable at normal listening levels. If I use a separate regulated power supply, the hum goes away. I think I need more filtering through the regulator circuit, but I am not sure how to proceed. Do I add more capacitance at the input or at the output? The unregulated DC comes from a power supply kit from Welborne Labs with schematic here:
WelborneLabsPS5
Should I add filtering to this supply?
I can build separate supplies (one per channel) but the cost is quite high. I am hoping I can add PS filtering to quiet the hum.
Thanks for any help.
Lindsay
I built the VSPS with onboard regulation as suggested on the VSPS Web site here -
VSPS Web site
The power coming into the VSPS is unregulated 32.5 VDC, which also powers my linestage (hybrid tube/mosfet circuit). I am using 15 volt fixed regulators 7815 and 7915. I have 470mfd for input caps and 100 mfd for output caps as recommended.
With this setup, hum is noticeable at normal listening levels. If I use a separate regulated power supply, the hum goes away. I think I need more filtering through the regulator circuit, but I am not sure how to proceed. Do I add more capacitance at the input or at the output? The unregulated DC comes from a power supply kit from Welborne Labs with schematic here:
WelborneLabsPS5
Should I add filtering to this supply?
I can build separate supplies (one per channel) but the cost is quite high. I am hoping I can add PS filtering to quiet the hum.
Thanks for any help.
Lindsay
The PS5A should work fine. Increasing the capacitance isn't going to solve the problem - most likely it will make it worse - you have to find and eliminate the ground loop.
The current pulses caused by the ripple voltage are getting into the input signal through some shared length of ground wire. When you use a regulated supply there is no ripple voltage and no current pulses so no audible hum, but any noise from the power supply is still being coupled to the output in the same manner. So its a bad layout and you should fix it... a regulated supply isn't the solution.
Until I see what layout you are using I can't comment further. Could be a simple matter of how you connected the chassis to the circuit common .. not using insulated RCA jacks for the input and output for example.
Grounding order must be followed precisely: see image below.
Once you've fixed the problem, try removing the eight filter capacitors from the PS5A, just leave the 470 uF and 100 uF on the VSPS board. Should sound even better then.
rjm
The current pulses caused by the ripple voltage are getting into the input signal through some shared length of ground wire. When you use a regulated supply there is no ripple voltage and no current pulses so no audible hum, but any noise from the power supply is still being coupled to the output in the same manner. So its a bad layout and you should fix it... a regulated supply isn't the solution.
Until I see what layout you are using I can't comment further. Could be a simple matter of how you connected the chassis to the circuit common .. not using insulated RCA jacks for the input and output for example.
Grounding order must be followed precisely: see image below.
Once you've fixed the problem, try removing the eight filter capacitors from the PS5A, just leave the 470 uF and 100 uF on the VSPS board. Should sound even better then.
rjm
Attachments
rjm - thanks for the great visual on how to wire the grounds.
I have rewired the grounds as shown in the attached a diagram. This has reduced the hum, but it is still unacceptably loud.
Each module in the diagram has onboard regulation. For the VSPS and the DC Protection circuit, it is the regulation circuit on the VSPS Web site. The line stage modules use the LM317T and LM337T regulators with 15 mfd caps on the incoming power lines. I get no hum from the line stages.
If the shield of the phono input is only connected at one end, I get very loud hum. When the shield is connected from the chassis to the VSPS the hum is reduced below the level it was before I rewired the grounds. However it is still unacceptably loud.
I removed the caps from the power supply and the hum got much worse.
At this point, I think the only ground loop would be through the phono input shield, but if I remove it the hum gets much worse. If you have any other suggestions it would be greatly appreciated.
I have rewired the grounds as shown in the attached a diagram. This has reduced the hum, but it is still unacceptably loud.
Each module in the diagram has onboard regulation. For the VSPS and the DC Protection circuit, it is the regulation circuit on the VSPS Web site. The line stage modules use the LM317T and LM337T regulators with 15 mfd caps on the incoming power lines. I get no hum from the line stages.
If the shield of the phono input is only connected at one end, I get very loud hum. When the shield is connected from the chassis to the VSPS the hum is reduced below the level it was before I rewired the grounds. However it is still unacceptably loud.
I removed the caps from the power supply and the hum got much worse.
At this point, I think the only ground loop would be through the phono input shield, but if I remove it the hum gets much worse. If you have any other suggestions it would be greatly appreciated.
Attachments
Unfortunately you cant use the same power supply for both the line stage and the VSPS.
The ground loop is being made through the signal common between the preamp and VSPS modules, as I've tried to illustrate in the attached image.
The only real solution is to use a separate power transformer for each module. Fortunately, you already have the answer in front of you: Since you already have two in the PS5A, which you are currently trying to use in dual mono but shared between the VSPS and line stage, all you have to do is re-connect the power supply to use one output for both channels of the VSPS and the other for both channels of your line stage.
-Richard
The ground loop is being made through the signal common between the preamp and VSPS modules, as I've tried to illustrate in the attached image.
The only real solution is to use a separate power transformer for each module. Fortunately, you already have the answer in front of you: Since you already have two in the PS5A, which you are currently trying to use in dual mono but shared between the VSPS and line stage, all you have to do is re-connect the power supply to use one output for both channels of the VSPS and the other for both channels of your line stage.
-Richard
Attachments
![preampground[1].gif](/community/data/attachments/71/71983-e4a7a2b22bf14b601cc4d46e5ce21a41.jpg)
![preampground[1][1].gif](/community/data/attachments/72/72123-50c391a1c94eb6bb8f7fbb1b9b4e2d1d.jpg)
rjm - Thanks for your quick reply.
I understand your drawing, but there is no ground connection between the VSPS modules and the line stages. All grounds run through the power grounds. In other words only a single wire connects the VSPS signal out to the line stage. However both modules are connected to a single ground through the ground wire from the incoming power. There is a ground loop from the shield of the incoming signal cable to the VSPS since it is connected to the chassis ground and to the signal ground on the VSPS module. However, unless that shield is connected at both ends I get very loud hum. I have not tried removing the power ground on the VSPS, which would eliminate the ground loop, but would use the shield as the power ground. I don't know if this is an acceptable approach.
There is an Alps Blue Velvet potentiometer that I did not show in my diagram. The case of the potentiometer is connected to the pre amp case, but the ground connections on the pot are connected to signal ground in the line stage modules.
I have used two supplies for right and left channel to maximize separation. If I re-wired the supplies as you suggest, wouldn't that reduce the channel separation? Since I already have the regulator circuit, I could probably build a dual supply for the VSPS for under $125 US including a case.
Thanks for any further suggestions. And thanks for the VSPS design. It was fun to build and exactly meets my needs.
I understand your drawing, but there is no ground connection between the VSPS modules and the line stages. All grounds run through the power grounds. In other words only a single wire connects the VSPS signal out to the line stage. However both modules are connected to a single ground through the ground wire from the incoming power. There is a ground loop from the shield of the incoming signal cable to the VSPS since it is connected to the chassis ground and to the signal ground on the VSPS module. However, unless that shield is connected at both ends I get very loud hum. I have not tried removing the power ground on the VSPS, which would eliminate the ground loop, but would use the shield as the power ground. I don't know if this is an acceptable approach.
There is an Alps Blue Velvet potentiometer that I did not show in my diagram. The case of the potentiometer is connected to the pre amp case, but the ground connections on the pot are connected to signal ground in the line stage modules.
I have used two supplies for right and left channel to maximize separation. If I re-wired the supplies as you suggest, wouldn't that reduce the channel separation? Since I already have the regulator circuit, I could probably build a dual supply for the VSPS for under $125 US including a case.
Thanks for any further suggestions. And thanks for the VSPS design. It was fun to build and exactly meets my needs.
![untitled[1].jpg](/community/data/attachments/72/72314-48b255e29c4d0bf0552cbb6924b70243.jpg)
And that's precisely why you've got hum. The signal common between VSPS and preamp is connected through the very noisy power ground line. The solution is to sever the power common connection by using separate power supplies, as I illustrated above.
A ground loop isn't a loop. Sorry I confused the issue back there because I assumed you had the signal commons between VSPS and preamp connected - as you should have had, by the way: That connection is required, while the connection through the power supply is required to be absent.
While it is technically possible to re-wire all the grounds so that the VSPS+preamp system shares a common supply, if you have two supplies moving to a shared power supply between channels is by far the easiest and best option - even though it will lead to some loss of separation. The cost-no-object alternative is four supplies... and the do-it-no-matter-what answer is rebuilding the layout from scratch, basically, so the whole VSPS+preamp system is designed as one unit...
Since it is easy to do I urge you to just re-connect the power supply - remembering to connect the VSPS and preamp signal commons - and check. I'm fairly sure it will cure all the hum issues, even the one regarding the shield on the VSPS input cable.
/rjm
P.S. To actually go dual mono shared between VSPS and preamp, the layout would have to look something like the attached diagram. Having the different elements separated by long lengths of wire will problematic, even if you were to follow this plan exactly. That's why I'm trying to discourage you since your VSPS and preamp are on two separate boards...
Attachments
![vsps_grounding[1].gif](/community/data/attachments/72/72382-e80780abf3645092fd68b10066f3ad03.jpg)
Please clarify, I don't understand what you are doing here.
The input to the VSPS are the four wires from the phono cartridge. There is a fifth wire which connects the turntable chassis to the VSPS/preamp case. So far as the external connections are concerned that is the end of the matter, since the VSPS input commons are connected to the case later on in the circuit.
Attachments
![preampground[1][1][1].gif](/community/data/attachments/72/72403-92fee57dc9b2b4a32bd7171538fe5d6c.jpg)
rjm - I think your latest diagram makes it clear.
The RCA connector grounds are all connected to the case, no insulators were used. I plan to correct that in the future, but that is how the JC2 was originally wired.
Re-wiring per your newest diagram will be relatively easy to test as a solution. To rewire the PS5 to supply the line stages using one supply and the VSPS using the other supply is almost as much work as adding separate supplies for the VSPS. And the additional supplies will preserve the separation I've come to enjoy with the current set up.
So to confirm I understand your diagram my plan is to:
1. Break the ground in the VSPS after the regulators and filter caps
2. Leave the phono input shield connected at both ends
3. Add ground connections from the VSPS to the line stages
4. Disconnect the power supply grounds from the case
5. Break the ground in the DC protection circuit in the same way as the VSPS, after the regs and filter caps
6. Connect the DC protection circuit ground to the chassis
This will result in the VSPS signal ground being connected to the case through the input cable shield. The VSPS signal ciruitry will not be connected to the power supply ground accept through the line stage. The VSPS signal ground will be connected to the line stage signal ground and hence the power supply ground. The power supply ground will not have a separate connection to the case. I believe that follows your diagram except for the RCA jack grounds being connected to the case.
I will also try disconnecting one end of the phono input shield and connecting the VSPS signal ground to the chassis with a separate wire to see if there is a difference.
Thanks for your help. I'll let you know my results.
The RCA connector grounds are all connected to the case, no insulators were used. I plan to correct that in the future, but that is how the JC2 was originally wired.
Re-wiring per your newest diagram will be relatively easy to test as a solution. To rewire the PS5 to supply the line stages using one supply and the VSPS using the other supply is almost as much work as adding separate supplies for the VSPS. And the additional supplies will preserve the separation I've come to enjoy with the current set up.
So to confirm I understand your diagram my plan is to:
1. Break the ground in the VSPS after the regulators and filter caps
2. Leave the phono input shield connected at both ends
3. Add ground connections from the VSPS to the line stages
4. Disconnect the power supply grounds from the case
5. Break the ground in the DC protection circuit in the same way as the VSPS, after the regs and filter caps
6. Connect the DC protection circuit ground to the chassis
This will result in the VSPS signal ground being connected to the case through the input cable shield. The VSPS signal ciruitry will not be connected to the power supply ground accept through the line stage. The VSPS signal ground will be connected to the line stage signal ground and hence the power supply ground. The power supply ground will not have a separate connection to the case. I believe that follows your diagram except for the RCA jack grounds being connected to the case.
I will also try disconnecting one end of the phono input shield and connecting the VSPS signal ground to the chassis with a separate wire to see if there is a difference.
Thanks for your help. I'll let you know my results.