AC/DC & POWERSTATION KIT BUILD THREAD

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Joe Malone
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

micdaddy wrote:Hello,

I have here a JLM powerstation. I'm using V1 V2 and 48V.
ok
C1 and C2 on the powerstation went puffy on me only after having it burnt in and working properly for >24hours.
C1 and C2 are the pump charge caps for the 48v rail. They will only puff up if the power secondary transformer AC voltage is to high or there is a dead short on the 48v rail or the doubler/tripler jumper is set wrong. What power transformer are you using and what is its output voltages? What have you got the tripler/doubler strap set to? IS this a full JLM powerstation kit of parts with our 1000uF 50v caps?
The condition of which they went puffy, I was firing up 4x 1290 preamps from V1, and using 48V from the powerstation to supply 4x gobetweens.
Ok that is fine if there are no shorts in the build.
3 of the 4 gobetweens phantom LED lit on first power up, 1 lit only momentarily and then went dead. All 4 channels did measure proper phantom voltage that was available at the powerstation terminal, including the channel with the now dead LED.
Are the leds soldered directly across the top two legs of the 48v toggle switch with long leg closest to the edge of the PCB?
I'm now experiencing hum on any channel that has phantom engaged. The 3 LEDS that initially lit up are all still working properly, phantom is still available on all channels, but I seem to have pissed off the powerstation as C1 and C2 are puffy.
Do you get zero ohms between all audio 0v and GO between 0v points and XLR pins 1's? Are the in and out XLR wired mirror image of each other?
My question would the dead LED gobetween suggest a fault that would cause the caps to bulge, i.e. a possible short, or too much current draw? They appear to still be functioning as there is still phantom voltage at the powerstation terminals, though clearly they have been worked over and need to be replaced. Before I go puffing out more capacitors I'd like to wrap my head around root cause.
Answer above questions and I should be able to get you sorted and send any photo's of your wiring and powerstation PCB top and bottom to my email address.
Are these filter/reservoir caps for the 48V section or what exactly are C1 C2 doing? Is there a schematic I missed for the powerstation? Thanks

Ben
Powerstation Schematic is in the first post of this thread with the full build and setup instructions. If you have trouble downloading the PDF's read the first thread on the kit forum.
Joe :-)
JLM Audio
Capturing Audio without Injury

micdaddy
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by micdaddy »

Thanks for the prompt attention Joe!
C1 and C2 are the pump charge caps for the 48v rail. They will only puff up if the power secondary transformer AC voltage is to high or there is a dead short on the 48v rail or the doubler/tripler jumper is set wrong. What power transformer are you using and what is its output voltages? What have you got the tripler/doubler strap set to? IS this a full JLM powerstation kit of parts with our 1000uF 50v caps?
-Ok, starting to make sense. The transformer I'm using is an Avel-Lindberg toroid 115V 2x primary 12V 2x secondaries. I have the secondaries wired in series which is coming in around 28.1V~.
This is a complete JLM powerstation, using the 6A rectifier, omitting D1-D4, C8, C9, C10, both LM337 and neg side parts. I have a jumper between the pads of C10.

:oops: well this is embarrassing, I have completely neglected to install a jumper in either doubler/tripler section. Seeing now I need to install a jumper from the center pad to doubler. (this also explains why I'm only able to dial in the available 31.5V for the 48V rail :roll: )

edit: needed it to be on tripler, doubler only gets me around 36V at the input leg of the LM317. Learning as I go.
Ok that is fine if there are no shorts in the build.
After seeing the one LED go, I'm not so sure I don't have a short at that specific gobetween, or perhaps I flipped the legs and reverse biased the LED causing it to go out. I will need to investigate this further.
Are the leds soldered directly across the top two legs of the 48v toggle switch with long leg closest to the edge of the PCB?
Yes, I tried to solder them exactly how the diagram shows on the JLM shop website.
Do you get zero ohms between all audio 0v and GO between 0v points and XLR pins 1's? Are the in and out XLR wired mirror image of each other?
I will determine this after a more extensive investigation.
Answer above questions and I should be able to get you sorted and send any photo's of your wiring and powerstation PCB top and bottom to my email address.
I will snap some photos as I go.
Powerstation Schematic is in the first post of this thread with the full build and setup instructions. If you have trouble downloading the PDF's read the first thread on the kit forum.
Yes, I had a blank page open but wouldn't load a schematic... I'll look around on kit forum, thanks! edit: I was able to download the schematic, thanks!!

micdaddy
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by micdaddy »

Hi Joe,

I've since replaced C1 and C2 pump charge caps.

Installed jumper to voltage tripler, and dialed in +48V

Everything is working as it should, thank you again Sir for your kits and for your support, it is very much appreciated!! :wink:

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

micdaddy wrote:Hi Joe,

I've since replaced C1 and C2 pump charge caps.

Installed jumper to voltage tripler, and dialed in +48V

Everything is working as it should, thank you again Sir for your kits and for your support, it is very much appreciated!! :wink:
Cool good to hear you got it going 8) . Thanks for your kind words :D
Joe :-)
JLM Audio
Capturing Audio without Injury

monkeyt
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by monkeyt »

So, I'm just putting a PowerStation together and I'm looking to get some +/- 32v rails and I'm wondering what size of transformer to get.

http://www.mouser.com/catalog/catalogUSD/643/2549.pdf

From that, I'm thinking one of these two would work, or do I need something bigger?

553-VPT30-1670 VPT30-1670 50 30.0V CT @ 1.67A 15.0V @ 3.34A
553-VPT36-1390 VPT36-1390 50 36.0V CT @ 1.39A 18V @ 2.78A

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

monkeyt wrote:So, I'm just putting a PowerStation together and I'm looking to get some +/- 32v rails and I'm wondering what size of transformer to get.

http://www.mouser.com/catalog/catalogUSD/643/2549.pdf

From that, I'm thinking one of these two would work, or do I need something bigger?

553-VPT30-1670 VPT30-1670 50 30.0V CT @ 1.67A 15.0V @ 3.34A
553-VPT36-1390 VPT36-1390 50 36.0V CT @ 1.39A 18V @ 2.78A
This transformer 553-VPT30-1670 VPT30-1670 50 30.0V CT @ 1.67A 15.0V @ 3.34A wired as 1 x 30VAC into 0v and one AC in on the powerstation will give you +/-32v easy.

Best would be a 2 x 28vac or 2 x 30vac.

As for size do not know what you are planning to run from the powerstation?

Or what current you think you will need?
Joe :-)
JLM Audio
Capturing Audio without Injury

kante1603
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by kante1603 »

Joe Malone wrote:
As for size do not know what you are planning to run from the powerstation?

Or what current you think you will need?
Hi,

best way to find out is using Joe´s calculator:

http://www.jlmaudio.com/ACDC%20Calculator.htm

You can fool around with the voltages and currents there.
The needed watts in VA for your transformer and the heatsink (if needed) are calculated on the bottom left of the page.
I use it all the time-great tool!
Tipp:When filling in values with decimals use point (".") not comma (",").

Cheers,

Udo.

janczmok
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by janczmok »

i am stuck with a problem, which you might be able to sort out with me:

Feed:

- Primary Feed is 220V
- Secondary Feed 2 x 25V Toriod (Farnell MC-146-030-125)
- wired as chassis gnd, orange, yellow, black, red

My aim:

- 48V for Phantom Mic
- V+/V- 18V for 2 DDA Channel Rackings

My problem:

- 48V could be correctly set.
- V+ and V- are "stuck" around 36.1 V -- the trims only have "little" effect on this.

Any idea what could be wrong ? I double checked PCB for soldering faults, every part
seems to be correct.

Thanks for looking into!

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

HI Jan
I answered this in your email this morning. See below
- Primary Feed is 220V
- Secondary Feed 2 x 25V Toriod (Farnell MC-146-030-125)
- wired as chassis gnd, orange, yellow, black, red
[Joe] Ok nothing from the transformer should go to the chassis gnd.
What colours go to each AC in?
What colours go to the 0v on the transformer side of the AC/DC?
Is it a version 4 AC/DC with the extra terminals?
What AC volts do you measure across each winding of the transformer?
Can you send me a link to the transformer so I can check the colour code?
Does the 10R resistor still measure 10R?
My aim:

- 48V for Phantom Mic
- V+/V- 18V for 2 DDA Channel Rackings
[Joe] OK that should work fine with that transformer with the doubler strap fitted to the front of the PCB
My problem:

- 48V could be correctly set.
- V+ and V- are "stuck" around 36.1 V -- the trims only have "little" effect on this.
[Joe]36v sound about correct for the full voltage sitting at the reg input. But the voltages should have been about 22v at power up if everything is correct as the trim pots come set to half way?
Any idea what could be wrong ? I double checked PCB for soldering faults, every part seems to be correct.
[Joe] I am thinking the transformer wiring since you mention it was wired to the chassis which it shouldn't be. If you have a photo of the top and bottom of the PCB and the transformer wiring it would help. If you find a wiring problem and have turned down the trim pots to very low make sure you set them back to roughly half way as explained on the AC/DC build thread on the JLM forum.
Joe :-)
JLM Audio
Capturing Audio without Injury

janczmok
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by janczmok »

See attachments. Will answer questions in separate post:
IMG_8453.jpg
IMG_8454.jpg
The transformer datasheet URL: http://www.farnell.com/datasheets/85993.pdf
You do not have the required permissions to view the files attached to this post.

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

janczmok wrote:See attachments. Will answer questions in separate post:

The transformer datasheet URL: http://www.farnell.com/datasheets/85993.pdf
Transformer is wired correct. But from the first photo looks likes you have the negative LM337 reg in the middle position instead of the LM317 that should be there and LM317 in the third position where the LM337 should be. I cannot see the numbers but the metal tabs are different shaped on our LM337 and LM317. Make sure you reset the trim pots to middle position 2k5 before powering up again after swapping the regs over. Not sure if the regs will be ok or not. If you wound the trim pots down fully they may be damaged as mentioned on the AC/DC kit build thread but check them with a meter as they are probably ok if no smoke escaped form them :D
Joe :-)
JLM Audio
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janczmok
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by janczmok »

Hi Joe,

AC/DC Kit now working fine. What was the issue ? One: One of the AC feeds was reversed (probably minor, but still) and fixed. And you were right on the 317/337 combo. Wonder why i haven't seen that before :oops:

48V, +/- 18V now provided steady :-) thanks for the excellent help.

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

janczmok wrote:Hi Joe,

AC/DC Kit now working fine. What was the issue ? One: One of the AC feeds was reversed (probably minor, but still) and fixed.
No you had this correct the first time as I said in the last email. It is always the 2 winding ends in the middle of the diagram that go to 0v to form a center tap.
The transformer 0v VSec is a bad way to show phase in the winding and should be ignored.
The way you have it changed it to now will work but you will only get half wave rectification instead of the better and smoother full wave rectification.

Image

And you were right on the 317/337 combo. Wonder why i haven't seen that before :oops:

48V, +/- 18V now provided steady :-) thanks for the excellent help.
Cool that would have been the only problem and it is good everything survived the reg reversal.
Joe :-)
JLM Audio
Capturing Audio without Injury

janczmok
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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by janczmok »

Thanks for pointing that out. Will (again) fix the wiring.
Last question: HUM elimination. I am having a substantial portion of humming on the channels when i touch the chassis.
I tried different points of grounding, but which way is the correct one?
I assume Chassis should go to Chassis GND, same as the 3rd (yellow/green) 220V wire (FI secureswitch).
Anything else to connect to Chassis GND, and how to separate Audio GND from Chassis GND ?

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Re: AC/DC & POWERSTATION KIT BUILD THREAD

Post by Joe Malone »

janczmok wrote:Thanks for pointing that out. Will (again) fix the wiring.
Last question: HUM elimination. I am having a substantial portion of humming on the channels when i touch the chassis.
I tried different points of grounding, but which way is the correct one?
I assume Chassis should go to Chassis GND, same as the 3rd (yellow/green) 220V wire (FI secureswitch).
Anything else to connect to Chassis GND, and how to separate Audio GND from Chassis GND ?
The mains lead ground wire must go straight to a bolt on the chassis and then from that bolt to the CASE terminal or any of the 4 bolt holes on the AC/DC kit. So if the AC/DC is bolted to the case by the PCB bolts no extra wire is needed. The AC/DC provides a 10ohm in parellel with 0.1uF isolator between mains and audio ground to stop grouund loops. So all audio ground/0v need to come from the 0v terminals on the DC side.

BEWARE most powdercoated cases need the paint removed under the screws that hold all the case parts together to get all the panels to be connected to mains ground. This will often show up as hum when you touch the front panel as it is still floating and not connected to the panel with the mains ground bolt. Always a good idea to check with a ohmmeter that all panels of the case are 0ohm between each other.

But most of hum problems we see are power transformers in the same box as audio transformers. So the hum is direct injected into the audio transformer and the audio circuit.
Joe :-)
JLM Audio
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