AC/DC & POWERSTATION KIT BUILD THREAD

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AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Sun Jun 14, 2009 10:38 pm

Please note that the AC/DC Ver 2,3 & PowerStation Ver 2,3 PCB's have a extra jumper at the front edge of the PCB to allow the 48v rail to be generated from a Doubler or Tripler
When using a single or dual 22vac to 25vac winding transformer strap D to the centre pad to generate the right volts for the 48v rail. (Shown in photo below)
When using a single or dual 15vac to 18vac winding transformer strap T to the centre pad to generate the right volts for the 48v rail.
All kits now come with 1000uF 50v 105 degree low ESR caps which are 1" (25mm) tall by 0.5" (13mm) diameter.
All kits now have NO 36v 1w Zener as it has been replaced with a 1N4007 for easier setup.

Circuits
Circuit of JLM AC/DC (Ver. 4) 3 rail Power supply PCB (JLM AC/DC Ver. 4 PCB)
Circuit of JLM Power Station (Ver. 3) 5 rail Power supply PCB (JLM POWER STATION Ver. 3 PCB)

Parts list
BOM of JLM AC/DC (Ver. 4) 3 rail Power supply PCB (AC/DC Ver 4 Power Supply Kit.txt)
BOM of JLM Power Station (Ver. 3) 5 rail Power supply PCB (Powerstation Ver 3 Power Supply Kit.txt)

ALL 120/240v mains wiring MUST be done by a Qualified Technician.

What Power Transformer secondary volts do I need?
The transformer secondary AC volts needed depends on the +/- dc regulated voltage rails wanted. If you want +/-34vdc regulated for 99v you will need 37v to 40v unregulated which would need one or two 26vac to 28vac transformer secondary windings. This might sound like a odd voltage value but in reality when you take the fully loaded voltage and add the regulation percentage specified by the transformer manufacture to get the no load voltage it all works out. So if the voltage output of a transformer is stated as 25vac at full load by adding the 10 to 20% regulation amount you will end up with 27.5vac to 30vac unloaded with is perfect. Also if you use one 25vac winding then the refresh rate to the large storage capacitors will be 50 or 60Hz depending on the country you are in. If you use two 25vac windings or a 50vac centre tapped winding the refresh rate will be 100Hz or 120Hz which will almost half the amount of ripple on the large storage caps. Also the dual 25vac has symmetrical ripple.

NEW JLM Audio Power transformer VA wattage and Heatsink C/W rating calculator
http://www.jlmaudio.com/ACDC%20Calculator.htm
(Hold down shift and click on link to open in new window)

PowerStation PCB and kit of parts
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All PowerStation Ver 2 & AC/DC Ver 2 PCB's have been bare board tested for shorts and breaks in tracks but it is always worth having a good look over the PCB for any damage before starting to assemble.
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1.Install all resistors in there correct locations using chart to the left or better still by using a multimeter with no leads fitted and bending the legs of the resistor and putting them in the meter sockets to double check you have the right value before putting it into the PCB. Fit all resistors before soldering them as this can also help check that you haven't put a resistor in the wrong place.

2.Install all diodes which all face in one direction. (Grey band lines up white white band on PCB)
Note. Leave out D1 to D4 if using the 4 to 6A bridge rectifier

3.Install 0.1uF bead cap which can go in either way around.
Image

4. Install the 5 x 5k trims pots with adjust screws closest to the large caps as shown.
Image

5. Install 10 x 10uF 63v caps all with there positive long leg to the left as shown.
Image

6. Install the 3 x LM317 positive regulators in the 3 left positions and the 2 x LM337 negative regulators in the 2 right positions. Now is a good time to use the mounted regs to mark up the 5 mounting holes in the heatsink or metal case side panel. You can also put the regulators legs in from under the PCB if you want to bolt the regulators to the same surface as the PCB mounting holes
(AC/DC has 2 x LM317 to the left and 1 x LM337 to the right)
Image

7. Install 10 x 1000uF 50v caps all with there positive long leg to the top as shown.
Image

8. Slide terminal blocks that sit beside each other into each others tongue and groove joint and then write with a permanent black pen what each terminal is on the terminal block before installing them to the PCB. (eg 0v +48 +24 +18v -24v -18v)
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9. The PowerStation PCB with terminal blocks fitted.
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10. You now need to jumper either T (Tripler) to the centre pad if you are using a 15vac to 18vac transformer or D (Doubler) to the centre pad if you are using a 22vac to 28vac transformer to get the pump charge for the 48v rail to work.
Image

11. Check the underside of the PCB for any shorts between any solder pads. Also recheck all parts are in the right way around. You can now connect the 15vac to 28vac transformer to the left side AC connections. Sit the power supply on a rubber mat and connect a volt meter to 0v and +48v DC outputs. Stand back and turn on. If there is no smoke and the meter reads about 27vdc to 33volts dc all is looking good. If you get higher than 48v on power up there is a short somewhere on the PCB. Use a small screw driver to adjust the 48v 25 turn trim pot until you have 48v. Turn off and move the volt meter to +V1 and turn on. Adjust for the voltage you need and repeat for all dc outputs.
(If any output voltage does not follow the trim pot up or down smoothly or seem stuck on full voltage do not just keep turning the trim pot as there is a fault and if you keep winding the pot down it will burn the 5k trim pot and 120R resistor)(Trim pots come set to half way when new and no not need any adjustment before first power up)
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12. Once all voltages are set you are ready to bolt the power supply to the metal case or heatsink. Peal the white paper backing of the stick on insulators and stick then on to each regulators metal tab. Make sure there are no sharp edges around the holes drilled into the case or heatsink that will cut the silicon insulators. The grey silicon washers do not require thermal paste at all.
(We use the 3 or 5 reg bolts to hold the PCB in place to the back or side panel in our full mic pre kits but add 2 x 10mm hex threaded standoffs to the front edge of the PCB to stop the PCB from tilting. We do not bolt the standoffs to the bottom panel as this allows the top and bottom panel to be removed easily for servicing. A small piece of stick on foam on the top of the 1000uF caps pins the power supply between the top and bottom panel securely)
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13. The 3 x 10mm bolt will go through the metal case or heatsink then through the insulator and regulator tab. Slide the white bush down the bolt so the thin tube part slide inside the regulator mounting hole. Fit lock washer and nut and do up firmly but do not over tighten. Check with a ohmmeter that the regulator metal tabs and heatsink or metal case are not shorted together.

14. Turn on and test that the DC outputs are still adjusted ok before connecting up DC outputs and Case ground to right hand front bolt hole on the PowerStation or the Bolt hole above the smiley face on the AC/DC.
(If the 10ohm resistor burns up when power is turned on there is a short on one of the regulator tabs to the heatsink or metal case)
Image

Photos of 4Amp or 6Amp bridge fitted to Powerstation Ver 3 PCB. Leave out D1 to D4 if using 4A bridge.
(Fit the Bridge so it stands with its top at the same height as the 1000uF caps as shown below)
Image
Image
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Sometimes the in phase wire of the secondary windings are shown with 0v which can be confused with the PCB 0v but it must be wired to the AC/DC or Powerstation kit as shown below.
Image

Spendor
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Joined: Thu Sep 03, 2009 11:37 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Spendor » Thu Sep 03, 2009 12:20 pm

Hello there. I've put together and AC/DC power supply. I'm using an RS transformer 30VA 25-0-25 . I'm getting 31V ac into the supply which seems a bit high, but perhaps OK under load? my problem is I'm getting +/- 40v and 80v for phantom. Trim pots are not operational. I've looked over the PCB 20 times with a magnifying glass and I can't see any shorts. I'm slowly going mad - can you help out with troubleshooting this problem?

Cheers!

chrisp
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Location: Sydney, Australia

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby chrisp » Fri Sep 04, 2009 9:35 am

Where are you based, Spendor? There's many JLMers would be happy to meet up and take a look at the board with you to see what's going on.
Chris P
---------------------------------------------------------
I do lots of things. I believe eclectic skills are best.

Spendor
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Joined: Thu Sep 03, 2009 11:37 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Spendor » Fri Sep 04, 2009 10:37 am

unfortunately I'm across the ditch in NZ. I've checked and double checked the orientation of caps and diodes, so it must be a short somewhere. Is there a way I can narrow it down to find the offending area?
Cheers

chrisp
Posts: 184
Joined: Sun Mar 04, 2007 11:46 am
Location: Sydney, Australia

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby chrisp » Fri Sep 04, 2009 3:01 pm

What jumpers (if any) do you have on the doubler / tripler pads
Chris P

---------------------------------------------------------

I do lots of things. I believe eclectic skills are best.

Spendor
Posts: 5
Joined: Thu Sep 03, 2009 11:37 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Spendor » Fri Sep 04, 2009 6:09 pm

I'm using the doubler - I think this is correct?
Cheers

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Sun Sep 06, 2009 10:23 am

Hello there. I've put together and AC/DC power supply. I'm using an RS transformer 30VA 25-0-25 . I'm getting 31V ac into the supply which seems a bit high, but perhaps OK under load? my problem is I'm getting +/- 40v and 80v for phantom. Trim pots are not operational. I've looked over the PCB 20 times with a magnifying glass and I can't see any shorts. I'm slowly going mad - can you help out with troubleshooting this problem?

OK did you leave the pots in there new middle position for power up which is best or did you wind the pots fully down to 0v? As if you have the pots fully wound down and too high a voltage coming in the voltage clamp in the regulator can come in and fry the pots but you will usually see smoke if this happens.

Have you got the center tap of the transformer secondary winding going to the 0v on the left side of the AC/DC which is terminal closest to the front pcb edge? Not the center terminal.

Make sure the 120R resistors are the correct value with a meter and that the pots go from 0R to 5k with the AC/DC off and a ohmmeter?

Are the 2 x LM317 and LM337 in the correct places?

Was it one of our full kits or just a PCB?

I'm using the doubler - I think this is correct?
Cheers

Strapping to D is correct.

As always when no sure or stuck with a problem send large clear in focus macro on photo's to my email of the top and bottom of the pcb and wiring with a short to the point explanation of the problem and I should be able to get you going.
Joe :-)
JLM Audio
Capturing Audio without Injury

Spendor
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Joined: Thu Sep 03, 2009 11:37 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Spendor » Mon Sep 07, 2009 5:35 pm

Thank you very much for your reply. I had some 10k trimmers so I used them. Before I put them in I wound them all down to 2.5 k thinking that would be fine - well it probably would have been if I had measured them correctly! In circuit they were all reading 7.5 k so I messed up there. I have wound them all back and the 48V rail is looking good as is the positive - unfortunately the negative voltage is still stuck on 40V with the trimmer not doing anything. I checked the 120R and it seems OK - could I have a dodgy LM337 or perhaps a short somewhere?
Once again, thanks for pointing me in the right direction!

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Mon Sep 07, 2009 7:19 pm

- unfortunately the negative voltage is still stuck on 40V with the trimmer not doing anything. I checked the 120R and it seems OK - could I have a dodgy LM337 or perhaps a short somewhere?
Once again, thanks for pointing me in the right direction!


I presume you mean stuck at -40v. The LM337 pinout does have the in and out pins next to each other so would be good to check they are not shorted together which would do this but if the pot is wound fully down the 120R will smoke and so will the pot if this is the case. All pots need to be wound anti clockwise to pull any rail closer to 0v if the pots are put in the way shown in our photos. If the pots are put in with the trim screw at the other end the direction is reversed.
Joe :-)

JLM Audio

Capturing Audio without Injury

Spendor
Posts: 5
Joined: Thu Sep 03, 2009 11:37 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Spendor » Tue Sep 08, 2009 8:45 am

Ahh yes I meant -40V. Trimmer orientation is correct and reading 2.5k so I replaced the LM337 and it is now all working 100%. Now to try out this mic preamp...... Thanks once again for your invaluable help.

Yoons
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Joined: Sun Feb 14, 2010 9:32 pm

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Yoons » Tue Mar 16, 2010 8:30 pm

Hi every body!

I would like to use Elna capacitor but they are too big to fit on the pcb. Can I use 10µF/35V to replace 10µF/63V? I need only +/-15V!
For 48V I used 10µF/63V.

Thanks in advance.

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Wed Mar 17, 2010 11:15 pm

Yoons wrote:Hi every body!

I would like to use Elna capacitor but they are too big to fit on the pcb. Can I use 10µF/35V to replace 10µF/63V? I need only +/-15V!
For 48V I used 10µF/63V.

Thanks in advance.


If the transformer is less than 22vac - 0v - 22vac then the unreg volts should be less than 35v unreg so yes you could use 10uF 35v for the +/-V rails.

But using the elna will make no difference to our standard low esr high temp ones.

If you want ot improve the power supply performance slightly use 10uF 35v tant bead caps
Joe :-)

JLM Audio

Capturing Audio without Injury

Yoons
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Yoons » Thu Mar 18, 2010 7:00 am

Thanks for this answer.
The transformer (R) is 15Vac/0V/15Vac and the unreg voltage is 24V so there must be no problems.

Sorry but my english is not fantastic (I'm french), do you speak of tantalum capacitor?
You would use them as replacement for 10µF only or for 1000µF too?
Can you tell me a little more? I am not a great electronician and I have red somewhere to avoid them for audio applications because they are too noisy...

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Sun Mar 21, 2010 8:30 am

Thanks for this answer.
The transformer (R) is 15Vac/0V/15Vac and the unreg voltage is 24V so there must be no problems.

Sorry but my english is not fantastic (I'm french), do you speak of tantalum capacitor?

Yes

You would use them as replacement for 10µF only or for 1000µF too?

Only the 10uF caps

Can you tell me a little more?

Tantalum caps are the best due to there super low ESR and leakage.

I am not a great electronician and I have red somewhere to avoid them for audio applications because they are too noisy...

Tantalums are not noisy at all but they need a polarizing voltage for audio use or they will cause THD and you never want to run them at there voltage limit as they do fail sometimes going dead short. So try to use a voltage rating like 35v for you 24v unreg.

---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

NEW JLM Transformer VA, Heatsink C/W rating and 1000uF voltage rating calculator for AC/DC & PowerStation kit at the link below
http://www.jlmaudio.com/ACDC%20Calculator.htm
(Hold down shift and click on link to open in new window)
Joe :-)

JLM Audio

Capturing Audio without Injury

Yoons
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Joined: Sun Feb 14, 2010 9:32 pm

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Yoons » Mon Mar 22, 2010 6:38 am

Thanks to have taken time to answer. :wink:

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