LA500A opto comp leveling amp BUILD THREAD 500/51X

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

Postby Mattso » Sun Apr 16, 2017 1:33 pm

Hi Joe,

This post is simply to say thanks for such a great product. I've built several kits from other companies in the past, and LA500A was by far the most straight-forward, with clear instructions and photos. I had a bit of a test calibrating it but that was down to my own misunderstanding of the guide. At the end of the day, this unit sounds awesome! Now I''m gearing up to build a second one to run in linked stereo or single mono, so you'll be hearing from me soon!
Cheers,
Mattso

mill8333
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Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Postby mill8333 » Tue Apr 18, 2017 2:22 pm

Hey, is there a schematic for the LA500POTv3 PCB?

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

Postby Joe Malone » Wed Apr 26, 2017 11:56 am

kante1603 wrote:Hello Joe,

don't know if this has been covered,but do you by accident have some numbers for attack and release times in both "normal" and slow attack modes for us?

Thank you in advance,

best regards,

Udo.


HI Udo
Sorry had missed this. It is to hard to explain the constantly moving attack and release times. And the slow attack also varies with ratio and opto moving times. Other than to say they work better than any normal preset attack and release ever :-)
Joe :-)
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Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Postby Joe Malone » Wed Apr 26, 2017 11:58 am

Mattso wrote:Hi Joe,

This post is simply to say thanks for such a great product. I've built several kits from other companies in the past, and LA500A was by far the most straight-forward, with clear instructions and photos. I had a bit of a test calibrating it but that was down to my own misunderstanding of the guide. At the end of the day, this unit sounds awesome! Now I''m gearing up to build a second one to run in linked stereo or single mono, so you'll be hearing from me soon!
Cheers,
Mattso


HI MAttso
Sorry I had missed this post. Thanks for the great review and comments :-)

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 

https://www.facebook.com/jlmaudio1

Thanks Again
Joe :-)

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

Postby Joe Malone » Wed Apr 26, 2017 11:58 am

mill8333 wrote:Hey, is there a schematic for the LA500POTv3 PCB?


LA500POTv4 schematic here
Joe :-)

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kante1603
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Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Postby kante1603 » Wed Apr 26, 2017 7:17 pm

Joe Malone wrote:HI Udo
Sorry had missed this. It is to hard to explain the constantly moving attack and release times. And the slow attack also varies with ratio and opto moving times. Other than to say they work better than any normal preset attack and release ever :-)


Thank you Joe,that's what I expected.I was asked by a friend and was unable to give an answer.
Anyway your answer in the last sentence is the best by far :D

Cheers,

Udo,

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

Postby hasbeen » Wed Jul 26, 2017 4:03 am

greenote wrote:Okay, sorry I refer that was as the Mac.
Had to de-solder the meter to remove PCB and get shots of the board.
I've attached photos and will send the voltages from the op amp on the LA500SC PCB after re-assemby.
IMG_5285.JPG
IMG_5286.JPG


This photo shows the opto leads have been soldered in to the "extra" holes that do not match the ones shown in the build photos.

The build info reads: "NEW LA500SCv3 PCB has extra MAC part that is cut off along white line with sidecutter when used in LA500A
and some extra holes under U1 & U2 optos which are not used for now"

Are those "extra holes" acceptable and the same as using the holes in the build instructions ?
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Re: LA500A opto comp leveling amp BUILD THREAD 500/51X

Postby Joe Malone » Wed Jul 26, 2017 7:39 am

hasbeen wrote:
greenote wrote:Okay, sorry I refer that was as the Mac.
Had to de-solder the meter to remove PCB and get shots of the board.
I've attached photos and will send the voltages from the op amp on the LA500SC PCB after re-assemby.
IMG_5285.JPG
IMG_5286.JPG


This photo shows the opto leads have been soldered in to the "extra" holes that do not match the ones shown in the build photos.

The build info reads: "NEW LA500SCv3 PCB has extra MAC part that is cut off along white line with sidecutter when used in LA500A
and some extra holes under U1 & U2 optos which are not used for now"

Are those "extra holes" acceptable and the same as using the holes in the build instructions ?


Yes if the opto sits the same way the 4 closer holes are fine to use.

Your photo is to small to see if they are in correct and it looks like both 10R protection resistor are burnt?
Joe :-)

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

Postby hasbeen » Wed Jul 26, 2017 11:10 am

Joe Malone wrote:
hasbeen wrote:
greenote wrote:Okay, sorry I refer that was as the Mac.
Had to de-solder the meter to remove PCB and get shots of the board.
I've attached photos and will send the voltages from the op amp on the LA500SC PCB after re-assemby.
IMG_5285.JPG
IMG_5286.JPG


This photo shows the opto leads have been soldered in to the "extra" holes that do not match the ones shown in the build photos.

The build info reads: "NEW LA500SCv3 PCB has extra MAC part that is cut off along white line with sidecutter when used in LA500A
and some extra holes under U1 & U2 optos which are not used for now"

Are those "extra holes" acceptable and the same as using the holes in the build instructions ?


Yes if the opto sits the same way the 4 closer holes are fine to use.

Your photo is to small to see if they are in correct and it looks like both 10R protection resistor are burnt?



I pulled the photo from an earlier post which I quoted in my post from 'greenote" His pic is the one I was referring to.

I could not find any number to indicate which post is which in this forum.

Why haven't the build instructions been updated to inform the builder that it is okay to use the other holes? Am I missing another set of instructions somewhere? I just finished my pair today.
Last edited by hasbeen on Wed Jul 26, 2017 11:35 am, edited 1 time in total.

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

Postby hasbeen » Wed Jul 26, 2017 11:16 am

Can you clarify what exactly all the jumpers are for in the builds?

Also confirm that there is no need to calibrate as a stereo pair if I ordered 2 units as a pair. I received the specially marked optos and installed as indicated.

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

Postby Joe Malone » Wed Jul 26, 2017 1:28 pm

hasbeen wrote:
Why haven't the build instructions been updated to inform the builder that it is okay to use the other holes? Am I missing another set of instructions somewhere? I just finished my pair today.


The holes are not for the kit but will work. They are for our built production LA500A modules so we can plug optos in with the dip sockets we use.

Can you clarify what exactly all the jumpers are for in the builds?

GND LIFT jumper on old BIO/LA500 main pcb. Not used on new BIO500v2 as all 500 racks now have this pin permanently to 0v GND so jumper is redundant. If PCB has GND lift jumper pins then fit jumper.

Link jumper on BIO/LA500 main PCB needs to be fitted for stereo link to work. Not needed on new BIO500v2 as PCB has link track under pcb but fitting pins and jumper will not cause any problems.

Balance / Stereo Match jumper fit to BAL side and align both comps and check when linked the GR meters do not deflect more than +/-1dB. If meters are not in range check calibration and optos are in the correct place as with the match stereo pairs of optos +/-1dB should be easy to do. If you want to do better than +/-1dB then read how to use the Stereo match jumper on the comp that shows higher gain reduction. But usually Stereo match will never be needed now with how tight we match the optos.
Joe :-)

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

Postby hasbeen » Thu Jul 27, 2017 11:08 am

Joe Malone wrote:
hasbeen wrote:
Why haven't the build instructions been updated to inform the builder that it is okay to use the other holes? Am I missing another set of instructions somewhere? I just finished my pair today.


The holes are not for the kit but will work. They are for our built production LA500A modules so we can plug optos in with the dip sockets we use.

Can you clarify what exactly all the jumpers are for in the builds?

GND LIFT jumper on old BIO/LA500 main pcb. Not used on new BIO500v2 as all 500 racks now have this pin permanently to 0v GND so jumper is redundant. If PCB has GND lift jumper pins then fit jumper.

Link jumper on BIO/LA500 main PCB needs to be fitted for stereo link to work. Not needed on new BIO500v2 as PCB has link track under pcb but fitting pins and jumper will not cause any problems.

Balance / Stereo Match jumper fit to BAL side and align both comps and check when linked the GR meters do not deflect more than +/-1dB. If meters are not in range check calibration and optos are in the correct place as with the match stereo pairs of optos +/-1dB should be easy to do. If you want to do better than +/-1dB then read how to use the Stereo match jumper on the comp that shows higher gain reduction. But usually Stereo match will never be needed now with how tight we match the optos.


I have what seems to be LA500SCv3. Is that an even later release than the BIO500v2?

Ot maybe I am looking at the wrong label. The other bag BIO PCB label reads: BIO500 and is batch number1603161.

So what do I need to do to use as a stereo pair?

Last question. If the jumpers are not necessarily needed why are they still part of kit?

BTW, thanks for your help and quick responses to my questions!

These compressors are so stunningly good looking and way too cool for school.

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

Postby Joe Malone » Thu Jul 27, 2017 12:07 pm

hasbeen wrote:I have what seems to be LA500SCv3. Is that an even later release than the BIO500v2?


NO each pcb type has its own version Ver number. Ver 1 is not shown on pcb name only v2 onwards.

The 3 pcbs in a LA500A are

BIO500 main in and out audio pcb
LA500SC comp sidechain pcb
LA500POT pot and led pcb

Or maybe I am looking at the wrong label. The other bag BIO PCB label reads: BIO500 and is batch number 1603161.

You should have BIO500 v1 so need to fit gold pins and jumpers. If ver 2 it will have BIO500v2 name on it.

So what do I need to do to use as a stereo pair?

Link Edge connector pin 6 between the 2 slots of your 500 rack. Depends on rack type if link is done already by zero ohm resistor or switch etc.
Set both comps to same settings and pull both makeup pots out to link comps.

Last question. If the jumpers are not necessarily needed why are they still part of kit?

Future kits as the sync with the new pcbs will have the extra parts removed if not used by any other product.

BTW, thanks for your help and quick responses to my questions!

These compressors are so stunningly good looking and way too cool for school.


Cool :-) They should also sound better than they look :-)
Joe :-)

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

Postby hasbeen » Fri Jul 28, 2017 6:45 am

The transformer in one of my pair seems to be too fat to fit comfortably in a rack with other modules. The other unit seems fine. Has this been a problem?


BTW I sent you a PM on another matter. Thanks

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

Postby Joe Malone » Fri Jul 28, 2017 7:06 am

hasbeen wrote:The transformer in one of my pair seems to be too fat to fit comfortably in a rack with other modules. The other unit seems fine. Has this been a problem?


BTW I sent you a PM on another matter. Thanks


The transformer with bracket take the full width of the 500 space so has to be set level when bolting in with the two rear bolts. Pressing on the middle of the yellow winding while bolting in will make sure the white plastic bobbin will press against the stainless steel bracket evenly. If the centre of yellow winding is bulging slightly outwards it will compact down as the module to the right is slide in and pushed towards it when bolted in. This gives the transformer good support especially when travelling. Always fit all modules to rack from left to right.
Joe :-)

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