AC/DC & POWERSTATION KIT BUILD THREAD

Support for JLM Audio Kits

Moderator: Joe Malone

User avatar
cromwell
Posts: 5
Joined: Wed Nov 18, 2015 11:20 pm

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby cromwell » Sat Nov 21, 2015 1:25 am

Joe,

I forgot to mention that I would like to have:
48V Phantom
+24V for the Micpres (2 x EZ1290)
+/-18V for two LED VU meter just 4 LEDs each

What transformer would you suggest?

Thanks

Eric
Everything has an end but a sausage has two...

horizonsound
Posts: 2
Joined: Fri Jan 30, 2015 7:15 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby horizonsound » Sun Dec 06, 2015 7:17 pm

Hi Joe,

For the last year I've been working on an 8 channel mic pre with AD/DA capability. It's basically an Amek Angela / M1000 mic pre front end, with a AD8000 back end.
The voltages required are +/-17v, 5v and 48v. I'm using a Powerstation and a 2x18v 50VA supply.
The concern is the 5v, and having to turn it down from 18v. It generates a LOT of heat at the V2+ heatsink.
In the AD8000, they have a +/-18v power supply with a separate 5v winding, which I cannot find anywhere. Thus I went for the Powerstation & 2x18v Toro.
Is the heat shedding typical when turning down to 5v, or would you think I've over speced the transformer... 50VA

Cheers,
Anthony,

User avatar
Joe Malone
Site Admin
Posts: 1572
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Mon Dec 07, 2015 6:29 pm

horizonsound wrote:Hi Joe,

For the last year I've been working on an 8 channel mic pre with AD/DA capability. It's basically an Amek Angela / M1000 mic pre front end, with a AD8000 back end.
The voltages required are +/-17v, 5v and 48v. I'm using a Powerstation and a 2x18v 50VA supply.
The concern is the 5v, and having to turn it down from 18v. It generates a LOT of heat at the V2+ heatsink.
In the AD8000, they have a +/-18v power supply with a separate 5v winding, which I cannot find anywhere. Thus I went for the Powerstation & 2x18v Toro.
Is the heat shedding typical when turning down to 5v, or would you think I've over speced the transformer... 50VA

Cheers,
Anthony,


Yes the heat is normal when turning down this far as our calculator link below will show you
http://www.jlmaudio.com/ACDC%20Calculator.htm

The calculator will tell you if you heatsink is big enough to keep the regs cool enough.

But I can tell you small separate heatsinks will not be enough for the 5v.

Best to bolt all the regs to the side of the metal case with there insulating kits directly to the case or with a piece of L aluminium.

Once the 5v reg has enough heatsink it will be fine.
Joe :-)
JLM Audio
Capturing Audio without Injury

horizonsound
Posts: 2
Joined: Fri Jan 30, 2015 7:15 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby horizonsound » Mon Dec 07, 2015 8:06 pm

Thanks Joe.

To put it to the theory test, I measure 37.7ohms over GND to +5v when the psu is removed.
5v / 37.7ohms is 0.133A, which requires massive heat dissipation.
17v rails measure about 660k, therefore about 1A.
Could have used a 30VA transformer.

My theory could be wrong. It's about time I learned it though.
You do not have the required permissions to view the files attached to this post.

User avatar
Joe Malone
Site Admin
Posts: 1572
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Mon Dec 07, 2015 8:38 pm

horizonsound wrote:Thanks Joe.

To put it to the theory test, I measure 37.7ohms over GND to +5v when the psu is removed.
5v / 37.7ohms is 0.133A, which requires massive heat dissipation.
17v rails measure about 660k, therefore about 1A.
Could have used a 30VA transformer.

My theory could be wrong. It's about time I learned it though.


This test is with no semiconductors actually turned on. So the current draw will be a lot higher than the ohms would suggest.

Also not sure how 17v / 660k = 1A?

Easiest way is to put 1 ohm in series with each rail and measure the voltage drop across the 1ohm as then I = V
Joe :-)

JLM Audio

Capturing Audio without Injury

whoops
Posts: 7
Joined: Sat Feb 13, 2016 2:04 pm

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby whoops » Tue Feb 23, 2016 12:19 pm

Hi Joe,
just built this the 3 rail PSU.
What a nice designed PSU, love it.

I would like to ask you some technical questions,
what is reason for the 10ohm resistor and 0.1uf caps that are on the board that connect 0V on the PSU to Case ground?
Is this some kind of filter?

Also, I needed 1,5 amps so I soldered the 4 extra diodes under the pcb, why are these extra resistors needed?
LM317 and LM337 can both supply 1,5amps, so wheres the limitation of 1 Amp? is at the 1N4007 diodes themselves?

if thats the situation why did you choose to design this PSU with the 1N4007 diodes instead of using an 1,5amp rated Bridge Rectifier?

User avatar
Joe Malone
Site Admin
Posts: 1572
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Tue Feb 23, 2016 12:35 pm

whoops wrote:Hi Joe,
just built this the 3 rail PSU.
What a nice designed PSU, love it.

Cool 8)

I would like to ask you some technical questions,
what is reason for the 10ohm resistor and 0.1uf caps that are on the board that connect 0V on the PSU to Case ground?
Is this some kind of filter?

It is used to stop ground loops happening. Isolates the chassis ground from the audio ground by 10R with 0.1uF across it so no RF gets in as well.

Also, I needed 1,5 amps so I soldered the 4 extra diodes under the pcb, why are these extra resistors needed?
LM317 and LM337 can both supply 1,5amps, so wheres the limitation of 1 Amp? is at the 1N4007 diodes themselves?

if thats the situation why did you choose to design this PSU with the 1N4007 diodes instead of using an 1,5amp rated Bridge Rectifier?


I don't know what extra resistors you mean or do you mean diodes? 1N4007 are 1Amp diodes which is perfect for 99% of the power supply uses. They are needed on the PCB for other protection diodes roles so make perfect sense to use them for everything so there is less parts confusion when building the kit. Remember to get to 1.5A per rail you will need very good large heatsinking of the regulators.
Joe :-)

JLM Audio

Capturing Audio without Injury

agentile1990
Posts: 6
Joined: Wed Jul 04, 2012 1:59 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby agentile1990 » Wed Apr 13, 2016 1:32 pm

A happy customer about 3 years later. After reading my responses from building this a few years ago, I realized that I never properly thanked Joe for walking me through the mess I got myself into. Moral of the story - read the instructions and look at the pictures twice before mounting anything. I think the saga is around pg. 10-13 if you're interested.

I ended up building an 11 space rack, right now only 2 units using the +/-16v rails.

We ran into an issue mounting the 6A bridge and I had to use a 4A instead. My rough math:

Normal Powerstation: 1A shared
4A Bridge (somewhere between 1A and 3A?)
6A Bridge: 3A shared

If 500 series units are 130-140mA each (if following spec), that makes for 1.3 - 1.4A on a fully loaded 10 space rack.

I guess a simpler way to phrase the question would be - what is the maximum current draw when using a 4A Bridge?

Thanks Joe, I'm glad to see this forum STILL providing such a resource for audio enthusiasts across the globe. To the readers on the fence - if you're hesitant about getting your hands dirty, rest assured that this is a vibrant community of folks who were at some point just like yourself. Not only will you learn something and feel good about it after - you're helping support others alongside and behind you.

whoops
Posts: 7
Joined: Sat Feb 13, 2016 2:04 pm

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby whoops » Thu Apr 14, 2016 4:17 am

Joe Malone wrote:
Also, I needed 1,5 amps so I soldered the 4 extra diodes under the pcb, why are these extra resistors needed?
LM317 and LM337 can both supply 1,5amps, so wheres the limitation of 1 Amp? is at the 1N4007 diodes themselves?

if thats the situation why did you choose to design this PSU with the 1N4007 diodes instead of using an 1,5amp rated Bridge Rectifier?


I don't know what extra resistors you mean or do you mean diodes? 1N4007 are 1Amp diodes which is perfect for 99% of the power supply uses. They are needed on the PCB for other protection diodes roles so make perfect sense to use them for everything so there is less parts confusion when building the kit. Remember to get to 1.5A per rail you will need very good large heatsinking of the regulators.


Yes, it was a type I meant Diodes.

What I meant to ask is if the Regulators are able to provide 1.5amps (if properlly heatsinked) then the 1Amp limitation is from the 1N4007 bridge rectifier diodes themselves, is that correct?

So the 4 extra 1N4007 Diodes are needed in order to solve the limitation of the BR 1N4007 diodes already used?

If I use 4 diferent diodes for the Bridge Rectifier that were rated higher than 1.5 amps instead of the 1N4007 could I skip the 4 extra diodes under the board?

thank you so much

User avatar
Joe Malone
Site Admin
Posts: 1572
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Thu Apr 14, 2016 9:20 am

whoops wrote:
Joe Malone wrote:
Also, I needed 1,5 amps so I soldered the 4 extra diodes under the pcb, why are these extra resistors needed?
LM317 and LM337 can both supply 1,5amps, so wheres the limitation of 1 Amp? is at the 1N4007 diodes themselves?

if thats the situation why did you choose to design this PSU with the 1N4007 diodes instead of using an 1,5amp rated Bridge Rectifier?


I don't know what extra resistors you mean or do you mean diodes? 1N4007 are 1Amp diodes which is perfect for 99% of the power supply uses. They are needed on the PCB for other protection diodes roles so make perfect sense to use them for everything so there is less parts confusion when building the kit. Remember to get to 1.5A per rail you will need very good large heatsinking of the regulators.


Yes, it was a type I meant Diodes.

What I meant to ask is if the Regulators are able to provide 1.5amps (if properlly heatsinked) then the 1Amp limitation is from the 1N4007 bridge rectifier diodes themselves, is that correct?

So the 4 extra 1N4007 Diodes are needed in order to solve the limitation of the BR 1N4007 diodes already used?

If I use 4 diferent diodes for the Bridge Rectifier that were rated higher than 1.5 amps instead of the 1N4007 could I skip the 4 extra diodes under the board?

thank you so much


Yes to all the above questions
Joe :-)

JLM Audio

Capturing Audio without Injury

whoops
Posts: 7
Joined: Sat Feb 13, 2016 2:04 pm

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby whoops » Thu Apr 14, 2016 10:45 am

Thank you so much Joe

User avatar
Joe Malone
Site Admin
Posts: 1572
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Sat Apr 16, 2016 7:42 am

agentile1990 wrote:A happy customer about 3 years later. After reading my responses from building this a few years ago, I realized that I never properly thanked Joe for walking me through the mess I got myself into. Moral of the story - read the instructions and look at the pictures twice before mounting anything. I think the saga is around pg. 10-13 if you're interested.

I ended up building an 11 space rack, right now only 2 units using the +/-16v rails.

We ran into an issue mounting the 6A bridge and I had to use a 4A instead. My rough math:

Normal Powerstation: 1A shared
4A Bridge (somewhere between 1A and 3A?)
6A Bridge: 3A shared

If 500 series units are 130-140mA each (if following spec), that makes for 1.3 - 1.4A on a fully loaded 10 space rack.

I guess a simpler way to phrase the question would be - what is the maximum current draw when using a 4A Bridge?

Thanks Joe, I'm glad to see this forum STILL providing such a resource for audio enthusiasts across the globe. To the readers on the fence - if you're hesitant about getting your hands dirty, rest assured that this is a vibrant community of folks who were at some point just like yourself. Not only will you learn something and feel good about it after - you're helping support others alongside and behind you.


:-) 8)

When using a 4A Bridge max current for total positive rails is 4A and same for negative rails. So 4A is fine to get maximum out of the power supply since each regulator max is 1.5A.
Joe :-)

JLM Audio

Capturing Audio without Injury

agentile1990
Posts: 6
Joined: Wed Jul 04, 2012 1:59 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby agentile1990 » Mon Apr 18, 2016 2:31 pm

Joe Malone wrote:each regulator max is 1.5A.


Once again - Joe to the rescue.
So essentially what you're saying here is that with the 4A or 6A Bridge, the limiting factor becomes the current capacity of the regulators?

User avatar
Joe Malone
Site Admin
Posts: 1572
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby Joe Malone » Mon Apr 18, 2016 2:59 pm

agentile1990 wrote:
Joe Malone wrote:each regulator max is 1.5A.


Once again - Joe to the rescue.
So essentially what you're saying here is that with the 4A or 6A Bridge, the limiting factor becomes the current capacity of the regulators?


Yes correct
Joe :-)

JLM Audio

Capturing Audio without Injury

amontesano
Posts: 2
Joined: Fri Nov 07, 2014 9:28 am

Re: AC/DC & POWERSTATION KIT BUILD THREAD

Postby amontesano » Mon Aug 01, 2016 10:40 pm

Hello everyone,

I've finished my AC/DC psu kit and I'm reading correct voltage on each rail (burnt it in for about 45 mins, measuring each rail). I then went to check continuity between the voltage regs and the psu chassis and noticed a short between the lM337 and the chassis...according to the information on the build, I shouldn't read continuity between any of the regs?

This is the second time I've powered up the psu, the first time, the 1W resistor burnt up, which was then replaced, and was never an issue after that.

Is this detrimental to the psu? Or can it operate normally like this? Like I mentioned before, the rails measured perfect, so I'm unclear as to how I should proceed. Any help would be greatly appreciated.

Thanks!

Return to “JLM Audio Kits”

Who is online

Users browsing this forum: No registered users and 5 guests