LA500A opto comp leveling amp BUILD THREAD 500/51X

Support for JLM Audio Kits

Moderator: Joe Malone

User avatar
Joe Malone
Site Admin
Posts: 2070
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

G-Sun wrote:Great compressor.

Tried to write a review myself,
but on missing star-rating the review was deleted..

A second forum-meta: Using first post as manual is maybe not a good idea.
Makes loading posts a pita.

Thank you very much Joe!
Great to hear you like the comp :-)

Sorry yes part of killing off the hundreds for spambot reviews a day was to make zero star rating posts which all spam ones are auto delete as it was taking to much time each day to clear them out. Any rating from 1 to 5 will work.

Yes we are looking at a whole new way of redoing the step by step build threads as the photo load is not fun.

Please if you have a comments and/or photos of your JLM Audio gear in your rack please put them up on our facebook page at the link below or send them to us by email as we work completely by word of mouth with no paid advertising. Feel free to add your website link and other details if you like 
Joe :-)
JLM Audio
Capturing Audio without Injury

G-Sun
Posts: 39
Joined: Mon Dec 12, 2011 3:48 am
Location: Norway
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by G-Sun »

Joe Malone wrote:Please if you have a comments and/or photos of your JLM Audio gear in your rack please put them up on our facebook page at the link below or send them to us by email as we work completely by word of mouth with no paid advertising. Feel free to add your website link and other details if you like 
Of course Joe!
I believe you've designed a high-end compressor in the LA500,
and for a very budget-friendly price. Cleaver mechanics, good manual and easy build.
My hat of to you :)

If I could change one thing about the LA500,
then that would be fast attack switch instead of slow attack switch:)
Second, would be slow release switch :D

But man, this is very good as it is.
www.g-sun.no/en/

kante1603
Posts: 86
Joined: Wed Jan 20, 2010 6:12 pm

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by kante1603 »

Joe Malone wrote: HI Udo
Thanks for the great review here and on our web site :-)

Yes we have just found the latest batch of 10000 blue leds (which are supposed to the be the same ones we always get) are different. They need total 240k = 2 x 120k.

Remove one 470k and place it under the pcb across the other 470k and link where the 470k was to get 235k with existing kits and the correct brightness blue leds.

All new kits from December 2015 will now have 2 x 120k instead of the 2 x 470k. Sorry for the stuff up.
Thank you Joe,will do so tomorrow,

best,

Udo.

User avatar
Joe Malone
Site Admin
Posts: 2070
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

G-Sun wrote:
Joe Malone wrote:Please if you have a comments and/or photos of your JLM Audio gear in your rack please put them up on our facebook page at the link below or send them to us by email as we work completely by word of mouth with no paid advertising. Feel free to add your website link and other details if you like 
Of course Joe!
I believe you've designed a high-end compressor in the LA500,
and for a very budget-friendly price. Cleaver mechanics, good manual and easy build.
My hat of to you :)

If I could change one thing about the LA500,
then that would be fast attack switch instead of slow attack switch:)
Second, would be slow release switch :D

But man, this is very good as it is.
Cool thanks for the great review. :-)

Yes hard to make the opto cell faster unfortunately. Longer release is also hard without killing the variable release that makes optos so great ;-)

If you need fast and longer release then you need our FC500A (FET comp) or our new DC500 (Diode Bridge comp) coming early in the new year.
Joe :-)
JLM Audio
Capturing Audio without Injury

G-Sun
Posts: 39
Joined: Mon Dec 12, 2011 3:48 am
Location: Norway
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by G-Sun »

Joe Malone wrote: Yes hard to make the opto cell faster unfortunately. Longer release is also hard without killing the variable release that makes optos so great ;-)
Understandable
If you need fast and longer release then you need our FC500A (FET comp) or our new DC500 (Diode Bridge comp) coming early in the new year.
Nice. Will the DC500 be kit?
What's the features?
www.g-sun.no/en/

User avatar
Joe Malone
Site Admin
Posts: 2070
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

G-Sun wrote:
Joe Malone wrote: Yes hard to make the opto cell faster unfortunately. Longer release is also hard without killing the variable release that makes optos so great ;-)
Understandable
If you need fast and longer release then you need our FC500A (FET comp) or our new DC500 (Diode Bridge comp) coming early in the new year.
Nice. Will the DC500 be kit?
What's the features?
DC500 looks identical to FC500 and has same control set. Just internally completely different comp and sound :-)
Joe :-)
JLM Audio
Capturing Audio without Injury

G-Sun
Posts: 39
Joined: Mon Dec 12, 2011 3:48 am
Location: Norway
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by G-Sun »

Joe Malone wrote:
G-Sun wrote: DC500 looks identical to FC500 and has same control set. Just internally completely different comp and sound :-)
Mm.. that's very interesting. At least if kit.
Ratio min?
Soft knee?
Auto-release?
www.g-sun.no/en/

User avatar
Joe Malone
Site Admin
Posts: 2070
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

G-Sun wrote:
Joe Malone wrote:
G-Sun wrote: DC500 looks identical to FC500 and has same control set. Just internally completely different comp and sound :-)
Mm.. that's very interesting. At least if kit.
Ratio min?
Soft knee?
Auto-release?
Not kit at least to start with. Ratio min? 2:1, Soft Knee? kind off, Auto Release? yes.
Joe :-)
JLM Audio
Capturing Audio without Injury

G-Sun
Posts: 39
Joined: Mon Dec 12, 2011 3:48 am
Location: Norway
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by G-Sun »

Joe Malone wrote:Not kit at least to start with. Ratio min? 2:1, Soft Knee? kind off, Auto Release? yes.
Ok, cool. Will be looking forward to see and hear the unit :)
www.g-sun.no/en/

nenett
Posts: 15
Joined: Fri Dec 11, 2015 3:43 pm

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by nenett »

Hi all, I recently purchased a LA500A opto comp kit. I managed to finish it a couple of days ago. I tried calibrating the unit, but am having some issues with it. When I plug it in the meter goes all the way to the right (+4). I checked that the voltage on the output is 1.23 V. Had to do some adjusting of the signal generator etc. to get there. I can not get the meter to change at all. adjusting the trim pot following the instruction for calibrating the VU meter does not change anything. The indicator just seems to be glued to the right side. I went over the PCB again and double checked that everything is soldered properly the right way around. I saw that the OPA2604AP opamp was the wrong way around and have managed to fix that (i.e. turn it around), but the meter is still not budging from the right side. :( Do you have any ideas, what the reason might be? Thank you in advance for your assistance.

User avatar
Joe Malone
Site Admin
Posts: 2070
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

nenett wrote:Hi all, I recently purchased a LA500A opto comp kit. I managed to finish it a couple of days ago. I tried calibrating the unit, but am having some issues with it. When I plug it in the meter goes all the way to the right (+4). I checked that the voltage on the output is 1.23 V. Had to do some adjusting of the signal generator etc. to get there. I can not get the meter to change at all. adjusting the trim pot following the instruction for calibrating the VU meter does not change anything. The indicator just seems to be glued to the right side. I went over the PCB again and double checked that everything is soldered properly the right way around. I saw that the OPA2604AP opamp was the wrong way around and have managed to fix that (i.e. turn it around), but the meter is still not budging from the right side. :( Do you have any ideas, what the reason might be? Thank you in advance for your assistance.
Plugging a opamp in backwards and powering up will usually kill the opamp or burn one or both the 10R resistors in the same PCB as it.

Check the 2 x 10R carbon resistors still measure 10R each and change the OPA2604AP for a new one should have you going.

Does the meter light up when switching to VU or GR? If not the comp will never switch the bypass relay so will stay in permanent bypass.
Joe :-)
JLM Audio
Capturing Audio without Injury

nenett
Posts: 15
Joined: Fri Dec 11, 2015 3:43 pm

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by nenett »

Joe Malone wrote:
nenett wrote:Hi all, I recently purchased a LA500A opto comp kit. I managed to finish it a couple of days ago. I tried calibrating the unit, but am having some issues with it. When I plug it in the meter goes all the way to the right (+4). I checked that the voltage on the output is 1.23 V. Had to do some adjusting of the signal generator etc. to get there. I can not get the meter to change at all. adjusting the trim pot following the instruction for calibrating the VU meter does not change anything. The indicator just seems to be glued to the right side. I went over the PCB again and double checked that everything is soldered properly the right way around. I saw that the OPA2604AP opamp was the wrong way around and have managed to fix that (i.e. turn it around), but the meter is still not budging from the right side. :( Do you have any ideas, what the reason might be? Thank you in advance for your assistance.
Plugging a opamp in backwards and powering up will usually kill the opamp or burn one or both the 10R resistors in the same PCB as it.

Check the 2 x 10R carbon resistors still measure 10R each and change the OPA2604AP for a new one should have you going.

Does the meter light up when switching to VU or GR? If not the comp will never switch the bypass relay so will stay in permanent bypass.
Hi Joe. Thanks for the reply. The meter does light up when switching to VU or GR. I checked the resistors and they still measure 10R as before. i'll try and find a new OPA2604AP and change that and then take it from there. Thanks for your help. I'll keep you posted.

Damir

User avatar
Joe Malone
Site Admin
Posts: 2070
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

nenett wrote:
Joe Malone wrote:
nenett wrote:Hi all, I recently purchased a LA500A opto comp kit. I managed to finish it a couple of days ago. I tried calibrating the unit, but am having some issues with it. When I plug it in the meter goes all the way to the right (+4). I checked that the voltage on the output is 1.23 V. Had to do some adjusting of the signal generator etc. to get there. I can not get the meter to change at all. adjusting the trim pot following the instruction for calibrating the VU meter does not change anything. The indicator just seems to be glued to the right side. I went over the PCB again and double checked that everything is soldered properly the right way around. I saw that the OPA2604AP opamp was the wrong way around and have managed to fix that (i.e. turn it around), but the meter is still not budging from the right side. :( Do you have any ideas, what the reason might be? Thank you in advance for your assistance.
Plugging a opamp in backwards and powering up will usually kill the opamp or burn one or both the 10R resistors in the same PCB as it.

Check the 2 x 10R carbon resistors still measure 10R each and change the OPA2604AP for a new one should have you going.

Does the meter light up when switching to VU or GR? If not the comp will never switch the bypass relay so will stay in permanent bypass.
Hi Joe. Thanks for the reply. The meter does light up when switching to VU or GR. I checked the resistors and they still measure 10R as before. i'll try and find a new OPA2604AP and change that and then take it from there. Thanks for your help. I'll keep you posted.

Damir
You can swap the OPA2604AP from the LA500 PCB and LA500SC PCB to see if the comp behaves differently which will narrow down if it is the opamp or not. Like your comp should pass audio and have makeup gain at the moment and swapping the opamps may stop the audio from working in GR or VU but stop the meter from pinning to the right. Which would show that OPA2604AP is dead.

If you are still having problems send me some well lite in focus photos of the top and bottom of the PCB's to check over.
Joe :-)
JLM Audio
Capturing Audio without Injury

nenett
Posts: 15
Joined: Fri Dec 11, 2015 3:43 pm

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by nenett »

Plugging a opamp in backwards and powering up will usually kill the opamp or burn one or both the 10R resistors in the same PCB as it.

Check the 2 x 10R carbon resistors still measure 10R each and change the OPA2604AP for a new one should have you going.

Does the meter light up when switching to VU or GR? If not the comp will never switch the bypass relay so will stay in permanent bypass.[/quote]

Hi Joe. Thanks for the reply. The meter does light up when switching to VU or GR. I checked the resistors and they still measure 10R as before. i'll try and find a new OPA2604AP and change that and then take it from there. Thanks for your help. I'll keep you posted.

Damir[/quote]

You can swap the OPA2604AP from the LA500 PCB and LA500SC PCB to see if the comp behaves differently which will narrow down if it is the opamp or not. Like your comp should pass audio and have makeup gain at the moment and swapping the opamps may stop the audio from working in GR or VU but stop the meter from pinning to the right. Which would show that OPA2604AP is dead.

If you are still having problems send me some well lite in focus photos of the top and bottom of the PCB's to check over.[/quote]

Hi, Joe. i have replaced the OPA2604AP with a completely new one. I ran the power and audio signal through it. The light comes on when I turn the switches to GR or VU on the meter, but it still is pinned to the right. ran some audio signal through it and it comes out unaffected. turning the makeup and threshold pots does not do anything to it. I am including some photos, so you see the PCBs the way they have been built. I can only attach three photos here. Can I send them to your email instead? what's the email?

Damir
You do not have the required permissions to view the files attached to this post.

User avatar
Joe Malone
Site Admin
Posts: 2070
Joined: Wed Jan 24, 2007 11:35 pm
Location: Brisbane, Australia
Contact:

Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Post by Joe Malone »

nenett wrote:Plugging a opamp in backwards and powering up will usually kill the opamp or burn one or both the 10R resistors in the same PCB as it.

Check the 2 x 10R carbon resistors still measure 10R each and change the OPA2604AP for a new one should have you going.

Does the meter light up when switching to VU or GR? If not the comp will never switch the bypass relay so will stay in permanent bypass.
Hi Joe. Thanks for the reply. The meter does light up when switching to VU or GR. I checked the resistors and they still measure 10R as before. i'll try and find a new OPA2604AP and change that and then take it from there. Thanks for your help. I'll keep you posted.

Damir[/quote]

You can swap the OPA2604AP from the LA500 PCB and LA500SC PCB to see if the comp behaves differently which will narrow down if it is the opamp or not. Like your comp should pass audio and have makeup gain at the moment and swapping the opamps may stop the audio from working in GR or VU but stop the meter from pinning to the right. Which would show that OPA2604AP is dead.

If you are still having problems send me some well lite in focus photos of the top and bottom of the PCB's to check over.[/quote]

Hi, Joe. i have replaced the OPA2604AP with a completely new one. I ran the power and audio signal through it. The light comes on when I turn the switches to GR or VU on the meter, but it still is pinned to the right. ran some audio signal through it and it comes out unaffected. turning the makeup and threshold pots does not do anything to it. I am including some photos, so you see the PCBs the way they have been built. I can only attach three photos here. Can I send them to your email instead? what's the email?

Damir[/quote]

More photos and answer all questions below.

I need a photo of the underside of the LA500SC PCB and top and bottom of the POT PCB. Always best to send a fully built photo first.

Sounds like the bypass circuit is not working. Which is only the VU/GR switch 1k8 resistor and relay but this travels on the ribbon cable.

Does the meter pin to the right in both VU and GR?
Is the meter back to -20 fully left when VU/GR is off?
Have you got the ribbons plugged in correct positions?
Check you have +16v at pin 8 of the OPA2604AP measured from 0v?
Check you have -16v at pin 4 of the OPA2604AP measured from 0v?
Joe :-)
JLM Audio
Capturing Audio without Injury

Post Reply