BA500 Mic Pre Amp BUILD THREAD 500/51X

Support for JLM Audio Kits

Moderator: Joe Malone

grimmstar
Posts: 7
Joined: Fri Jan 11, 2013 1:26 am

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

Postby grimmstar » Mon Jan 14, 2013 12:12 pm

Hi Joe,

Thanks so much for our help. I actually soldered the two terminals on each board for each module like you first instructed, and everything works great!
They sound fantastic even though I just did a quick check with my voice and an SM57.
Can't wait to start tracking with them this week!!! I also can't wait to order more kits. Your pres, opamps, etc. sound awesome. I love the variable impedance. It should be standard on all preamps. Makes an already great pre even more versatile.
I'll send pics. There's no doubt i'll having nothing but compliments on the sound. That gives me 6 channels of JLM goodness. I don't plan on stopping there!

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

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

Postby Joe Malone » Mon Jan 14, 2013 8:08 pm

grimmstar wrote:Hi Joe,

Thanks so much for our help. I actually soldered the two terminals on each board for each module like you first instructed, and everything works great!
They sound fantastic even though I just did a quick check with my voice and an SM57.
Can't wait to start tracking with them this week!!! I also can't wait to order more kits. Your pres, opamps, etc. sound awesome. I love the variable impedance. It should be standard on all preamps. Makes an already great pre even more versatile.
I'll send pics. There's no doubt i'll having nothing but compliments on the sound. That gives me 6 channels of JLM goodness. I don't plan on stopping there!


Great to hear you got them going so easily and that you like the tone of them :D 8)

Please do add some pictures and feel free to spread the word. Thanks :)
Joe :-)
JLM Audio
Capturing Audio without Injury

grimmstar
Posts: 7
Joined: Fri Jan 11, 2013 1:26 am

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

Postby grimmstar » Wed Jan 16, 2013 12:36 am

Hi Joe,

You're welcome. But it's the truth. You're gear sounds fantastic. Whatever voodoo you have going on in there, it works. I got to try them on guitar yesterday, and today drums, which honestly these pres absolutely excel at as far as I'm concerned. Don't get me wrong, they sound superb on EVERYTHING, but they really have a snap and impact with the kit. Plus, more air on top then alot of other pres I've used, and I've used alot of the usual big name suspects.
I grabbed my BA4 used off eBay in 2009, for a steal averaging about $250 a channel, and I loved them from the first use. A friend who also does builds and his own designs, had been raving about JLM cause he built some BAs and Dual99s, and did shootouts with other pres and API clones he made, and although it was done more with guitars than anything else, the JLMs were his winners for I think all but one comparison. So trusting his opinion, I had been checking out the website, and then saw the eBay listing and scooped the BA4 up. That was the only listing for JLM equipment I ever saw, and that was 3.5 years ago.
What's interesting to me is that I still check there for JLM gear, and it's never there. Why? Well, because it's so good, no one is selling it. The sound-for-the-money ratio is astronomical. Now having built the kits, I can't wait to add more!
Question, when are those new products coming out? The SUMO, TG4, etc. I'm drooling for the TG500 this year- would the TG4 be available in kit form?
Thanks!

JacobM
Posts: 1
Joined: Thu Apr 18, 2013 6:29 pm

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

Postby JacobM » Tue Apr 23, 2013 6:29 pm

Hi guys.
I've recently put together a Mono kit Version 2, I believe it was the Red Transformer Training Version.
I'm thinking about getting one or two of the BA500s to put together for my Lunchbox.
How much more difficult is this compared to the Mono pre? I didn't have any trouble with my first build, I think it took me five or six hours, and worked first try.
I'm guessing this won't be much more difficult to build, maybe it'll just take a bit more time.
Any thoughts?
Cheers.

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

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

Postby Joe Malone » Tue Apr 23, 2013 9:40 pm

JacobM wrote:Hi guys.
I've recently put together a Mono kit Version 2, I believe it was the Red Transformer Training Version.
I'm thinking about getting one or two of the BA500s to put together for my Lunchbox.
How much more difficult is this compared to the Mono pre? I didn't have any trouble with my first build, I think it took me five or six hours, and worked first try.
I'm guessing this won't be much more difficult to build, maybe it'll just take a bit more time.
Any thoughts?
Cheers.


HI Jacob
Yes since you have done the Mono kit you should have no trouble with the BA500 with the step by step build thread here.

We also give full email support and if you get totally stuck we offer a fix it service for all kits as well.
Joe :-)

JLM Audio

Capturing Audio without Injury

friesdan
Posts: 13
Joined: Mon Jul 22, 2013 1:38 am

Need Help!

Postby friesdan » Mon Jul 22, 2013 6:28 pm

Hey Joe,

So I've just completed my build and I have essentially the same issue as "grimmstar" above. The pre lights up, 48V led lights up when the switch is switched downwards (is that an Australian thing or did I wire it wrong?) - the meter lights up - but no sound is passed, and the meter doesn't move. Double checked the lunchbox slot and another pre worked fine. The one difference is that I DO have a DI installed. Maybe I need to make a dummy header and test without my DI wired in? Maybe I mis-interpreted "NP" when installing the caps on the DI board? - I took it to mean the caps weren't polarized, and didn't see any + or - indication on the board. Tested the DI as well, and got no signal.
Anything I can test?
Many thanks,
Dan

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

Re: Need Help!

Postby Joe Malone » Mon Jul 22, 2013 8:59 pm

friesdan wrote:Hey Joe,

So I've just completed my build and I have essentially the same issue as "grimmstar" above. The pre lights up, 48V led lights up when the switch is switched downwards (is that an Australian thing or did I wire it wrong?) - the meter lights up - but no sound is passed, and the meter doesn't move. Double checked the lunchbox slot and another pre worked fine. The one difference is that I DO have a DI installed. Maybe I need to make a dummy header and test without my DI wired in? Maybe I mis-interpreted "NP" when installing the caps on the DI board? - I took it to mean the caps weren't polarized, and didn't see any + or - indication on the board. Tested the DI as well, and got no signal.
Anything I can test?
Many thanks,
Dan


HI Dan
The FETDI when plugged in to the ribbon cable with nothing plugged into the jack should just loop the audio if soldered correctly (doesn't use any of the circuitry of the DI this way).

The caps in the DI kit are NON polar and can go in either way around (they do have a negative strip on the plastic wrap but this can be ignored.)

Do you here the hiss on the output of the BA500 go up when the gain is turned up?

Are all the 10 pin IDC headers on the PCB fitted the correct way around?

Send me a couple of photos of of the PCBs with the opamp removed to my email so I can check it for errors for you.
Joe :-)

JLM Audio

Capturing Audio without Injury

friesdan
Posts: 13
Joined: Mon Jul 22, 2013 1:38 am

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

Postby friesdan » Tue Jul 23, 2013 4:00 am

will do thanks Joe

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

BA500 Transformer and wiring tests

Postby Joe Malone » Tue Jul 23, 2013 11:24 am

friesdan wrote:will do thanks Joe


HI Daniel
PCBs photos looks ok form the top.

Plug all ribbon cables back in and leave main opamp out and the BA500 unpowered out on the bench and with ohmmeter measure the below points so we can find the hole in the audio path. We will be starting from the output working to the input.

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

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

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)?

You should read 900R to 1k (JLM14) or 1.2k to 1.4k (OEP/VTX) across R25 1MEG on the BA500 PCB with impedance set high?

You should read 25R to 30R (JLM14) or 15R to 24R (OEP/VTX) between the edge connector pin 8 and pin 10 with the pad switched off (pin 1 starts closest to the JLM Logo next to output transformer)?

Please answers these questions here as they will help others. If you get a different reading let me know the value you get.
Joe :-)

JLM Audio

Capturing Audio without Injury

friesdan
Posts: 13
Joined: Mon Jul 22, 2013 1:38 am

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

Postby friesdan » Tue Jul 23, 2013 2:38 pm

Hey Joe, I saw you email first. Reposting the relevant bits here for the benefit of others.

Values were ok until:
You should read 450R to 500R (JLM14) or 1.2k to 1.4k (OEP/VTX) across R25 1MEG
on the BA500 PCB?
No, I'm getting 447R here. I've got the JLM14.

You should read 25R to 30R (JLM14) or 15R to 24R (OEP/VTX) between the edge
connector pin 8 and pin 10 with the pad switched off (pin 1 starts closest
to the JLM Logo next to output transformer)?

No,
13.62K with the pad in both positions.

Thanks Dan

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

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

Postby Joe Malone » Tue Jul 23, 2013 3:07 pm

friesdan wrote:Hey Joe, I saw you email first. Reposting the relevant bits here for the benefit of others.

Values were ok until:
You should read 450R to 500R (JLM14) or 1.2k to 1.4k (OEP/VTX) across R25 1MEG
on the BA500 PCB?
No, I'm getting 447R here. I've got the JLM14.

Sorry yes that is correct JLM14 should have read 450 to 500R (EDITED previous post to be correct)

You should read 25R to 30R (JLM14) or 15R to 24R (OEP/VTX) between the edge
connector pin 8 and pin 10 with the pad switched off (pin 1 starts closest
to the JLM Logo next to output transformer)?

No,
13.62K with the pad in both positions

Ok that is just the 2 x 6.8k phantom resistors in series so we are making it via the ribbon to the Go Between 500 PCB but not to the input of the JLM14. Need to check the transformer colored wires are soldered into the correct solder pads. Send me a photo of the top and bottom of the GO Between PCB to check over and we should have you going soon.
Joe :-)

JLM Audio

Capturing Audio without Injury

friesdan
Posts: 13
Joined: Mon Jul 22, 2013 1:38 am

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

Postby friesdan » Tue Jul 23, 2013 4:53 pm

image.jpg
image.jpg
yes, I'm trying to avoid what's likely inevitable- digging around again for my metric socket set and pulling this apart. It's just so pretty as is. Thanks for your help Joe.
You do not have the required permissions to view the files attached to this post.

friesdan
Posts: 13
Joined: Mon Jul 22, 2013 1:38 am

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

Postby friesdan » Tue Jul 30, 2013 3:53 pm

JOE - Thanks for all you help via email, the detailed pics, and perseverance over 5 days to get to the bottom of the issue. I'm surprised you have patience for a newb like me who puts you through it for a lifted pad/soldering mistake. Lesson learned on my part, time generously dedicated on yours.
The pre sounds great so far, I'm excited to get to know it better. I'll be buying more of your gear with the intention of leaving your time for you next time.

Thanks for being such a stand up guy.

Dan

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

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

Postby Joe Malone » Tue Jul 30, 2013 5:26 pm

friesdan wrote:JOE - Thanks for all you help via email, the detailed pics, and perseverance over 5 days to get to the bottom of the issue. I'm surprised you have patience for a newb like me who puts you through it for a lifted pad/soldering mistake. Lesson learned on my part, time generously dedicated on yours.
The pre sounds great so far, I'm excited to get to know it better. I'll be buying more of your gear with the intention of leaving your time for you next time.

Thanks for being such a stand up guy.

Dan


Thanks. Great it was something so simple in the end. Enjoy :D 8)
Joe :-)

JLM Audio

Capturing Audio without Injury

drew571
Posts: 2
Joined: Wed Mar 26, 2014 12:19 pm

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

Postby drew571 » Sun Jun 01, 2014 9:01 pm

Hi Joe and forum members,

I'm seriously thinking about building a couple of these kits. Almost done with a pair of LA500's and I'd like to add these to them.

Couple questions on the options while ordering.

What's the difference between the JLM14 and the OEP input transformer?

Any preferences?

Also, what are the differences between the op amps. I noticed there are quite a few to choose from.

Thanks!

Andrew

Return to “JLM Audio Kits”

Who is online

Users browsing this forum: No registered users and 5 guests