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Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Fri Dec 18, 2015 1:03 pm
by Joe Malone
PaulQ wrote:Hi Joe
I put links between P+ to S+ and and one between P- to S-
The di is working but very distorted .The mtrs not moving .The pad is working
The mic is not working

You should read 12 to 15R between P- & P+ terminals next to the transformer ribbon header on the BA500 PCB =4.33

You should read 24R to 30R between S- & S+ terminals next to the transformer ribbon header on the BA500 PCB = 3.3

You should read 24R to 30R between the edge connector pin 2 and pin 4 (pin 1 starts closest to the JLM Logo next to output transformer) = 3.4

Thanks Paul


Those readings are only for when a output transformer is fitted. So don't mean anything if one is not fitted. Best to email me some photos of your build to look at so I can check it over for you.

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Wed Jan 11, 2017 4:15 am
by njallen
Joe, thanks for your attention to detail in these instructions!!

I finished the build with no trouble at all (and even had some fun putting it together :D ). Plugged it in and began testing with both mics and DI. BOTH are passing a signal to my interface but both are extremely quiet and a bit dry sounding. If I turn the BA500 gain all the way up and crank my interface to around 8/10 I will get reasonable levels, but that gets pretty noisy and still isn't really usable. I have ruled out a bad lunchbox/cables/mics etc.

I'm sure I misplaced something along the way but haven't been able to figure it out. Anybody have any thoughts on this?

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Wed Jan 11, 2017 9:36 am
by Joe Malone
njallen wrote:Joe, thanks for your attention to detail in these instructions!!

I finished the build with no trouble at all (and even had some fun putting it together :D ). Plugged it in and began testing with both mics and DI. BOTH are passing a signal to my interface but both are extremely quiet and a bit dry sounding. If I turn the BA500 gain all the way up and crank my interface to around 8/10 I will get reasonable levels, but that gets pretty noisy and still isn't really usable. I have ruled out a bad lunchbox/cables/mics etc.

I'm sure I misplaced something along the way but haven't been able to figure it out. Anybody have any thoughts on this?


Ok with the module unplugged from the rack what ohms do you get between the large solder pads marked +/-P? and +/-S?

Does the pre sound full range or no low end?

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Thu Jan 12, 2017 8:46 am
by njallen
Joe Malone wrote:
njallen wrote:Joe, thanks for your attention to detail in these instructions!!

I finished the build with no trouble at all (and even had some fun putting it together :D ). Plugged it in and began testing with both mics and DI. BOTH are passing a signal to my interface but both are extremely quiet and a bit dry sounding. If I turn the BA500 gain all the way up and crank my interface to around 8/10 I will get reasonable levels, but that gets pretty noisy and still isn't really usable. I have ruled out a bad lunchbox/cables/mics etc.

I'm sure I misplaced something along the way but haven't been able to figure it out. Anybody have any thoughts on this?


Ok with the module unplugged from the rack what ohms do you get between the large solder pads marked +/-P? and +/-S?

Does the pre sound full range or no low end?


Thanks for the speedy response! I am getting about 8 Ohms on +/- P and exactly 20 Ohms on +/- S. It seems to have enough low end... DI was tested with a bass and it sounded pretty normal. I've not been able to test specific frequencies just yet. Thanks!!

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Mon Jan 16, 2017 10:25 am
by Joe Malone
njallen wrote:
Joe Malone wrote:
njallen wrote:Joe, thanks for your attention to detail in these instructions!!

I finished the build with no trouble at all (and even had some fun putting it together :D ). Plugged it in and began testing with both mics and DI. BOTH are passing a signal to my interface but both are extremely quiet and a bit dry sounding. If I turn the BA500 gain all the way up and crank my interface to around 8/10 I will get reasonable levels, but that gets pretty noisy and still isn't really usable. I have ruled out a bad lunchbox/cables/mics etc.

I'm sure I misplaced something along the way but haven't been able to figure it out. Anybody have any thoughts on this?


Ok with the module unplugged from the rack what ohms do you get between the large solder pads marked +/-P? and +/-S?

Does the pre sound full range or no low end?


Thanks for the speedy response! I am getting about 8 Ohms on +/- P and exactly 20 Ohms on +/- S. It seems to have enough low end... DI was tested with a bass and it sounded pretty normal. I've not been able to test specific frequencies just yet. Thanks!!


Ok cool so the output transformer is fine. Best to email me a couple of photos of your wiring and pcbs all assembled as they are now so I can check it over.

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Mon Mar 26, 2018 2:52 pm
by rturnock
Hi Joe,

I've run the tests from page 1, and am getting a reading of 900 between edge connectors 8 and 10.
VU and Phantom Power light come on, but no signal. I don't have the DI module.

Any help much appreciated.

Thanks,

Rick.

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Tue Mar 27, 2018 5:14 pm
by Joe Malone
rturnock wrote:Hi Joe,

I've run the tests from page 1, and am getting a reading of 900 between edge connectors 8 and 10.
VU and Phantom Power light come on, but no signal. I don't have the DI module.

Any help much appreciated.

Thanks,

Rick.


If you do not have a DI do you have a dummy plug fitted on the third ribbon connector or the 2 solder links under the 10 pin header?

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Tue Mar 27, 2018 5:16 pm
by Joe Malone
Joe Malone wrote:
rturnock wrote:Hi Joe,

I've run the tests from page 1, and am getting a reading of 900 between edge connectors 8 and 10.
VU and Phantom Power light come on, but no signal. I don't have the DI module.

Any help much appreciated.

Thanks,

Rick.


If you do not have a DI do you have a dummy plug fitted on the third ribbon connector or the 2 solder links under the 10 pin header?

Otherwise there will be a hole in the input wiring

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Tue Mar 27, 2018 5:34 pm
by rturnock
Hi Joe,

Thanks for the reply, yes, I do have the dummy plug fitted.

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Tue Mar 27, 2018 5:47 pm
by Joe Malone
rturnock wrote:Hi Joe,

Thanks for the reply, yes, I do have the dummy plug fitted.


Ok email me some photos of your build so I can check it over and see if I can spot the problem

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Mon Dec 17, 2018 4:01 am
by Warbler
Hi!

Can you tell me how to wire the JLM1:4 to the go between board? The PCB is color coded for all the wires except the black.

Thanks,
Sean

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Mon Dec 17, 2018 9:37 am
by Joe Malone
Warbler wrote:Hi!

Can you tell me how to wire the JLM1:4 to the go between board? The PCB is color coded for all the wires except the black.

Thanks,
Sean


HI Sean black wire is not used. We cut it short and fold it back into the heatshrink tube at the bottom of the JLM14 or put a small piece of heatshrink over it. Other four wires go as marked on the pcb :-)

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Mon Dec 17, 2018 3:02 pm
by Warbler
Thanks. That’s what I thought. I have a very low gain issue. Wondering what I did wrong. I’ll have to do some diagnosis, and potentially get back to you. Thanks again.

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Mon Dec 17, 2018 3:06 pm
by Joe Malone
Warbler wrote:Thanks. That’s what I thought. I have a very low gain issue. Wondering what I did wrong. I’ll have to do some diagnosis, and potentially get back to you. Thanks again.


OK Make sure if no DI fitted that you have the dummy plug fitted to the 3 header on the cable otherwise there is hole a on the audio input.

Even with DI if dummy plug in kit best to try dummy plug instead of DI to see if that fixed the problem.

If in trouble as always put photos up here or email them to me to check over. Make sure photos are well lit and in focus.

Re: BA500 Mic Pre Amp BUILD THREAD 500/51X

Posted: Tue Dec 18, 2018 1:55 am
by Warbler
You are so helpful! I really appreciate that.

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