JLM AUDIO

Hi folks, got a question about the 111dc circuit boards, do any of the resisters need to be fitted? I built a BA4 with jlm 14 inputs 99v opamps and 111dc output transformers. with the 48v 25 watt power supply. They are all working but I'm getting a pulsing from the power supply. The leds get dimmer...

Hi Joe, I've just built my LA500A. Great build, great design but sadly I have a couple of issues. What's working? Both coloured LED's, meter LED, makeup gain, hardwire bypass. No smoke What's not working? Don't appear/ hear to be getting any gain reduction. no movement on the meter regardless of sw...

Hi Joe. This circuit JLM99 works in a +/-16v? I sent you a email about Go Between Plus. Thanks, Luís The JLM99*MB pcb runs the JLM99v on whatever power rails you send in which used to be +/-24vdc and then makes +/-15v rails for the dc servo ic. You could just run in +/-16v power in and link over th...

Alex1990 wrote: ↑

Wed Feb 07, 2024 7:11 pm

Actually - I am getting 2 x 20k measurements on the front lugs so maybe pot is fine after all? But can’t understand where issue would be on PCB. Perhaps it’s easier and quicker to get a new pot PCB at this point.

OK email me so we can workout the pot kit or parts you need

saxmonster wrote: ↑

Wed Feb 07, 2024 3:44 pm

Thanks Joe,
Once I get them equal should I drop the output of my daw so that I get 1.23vac on both opto outputs so I can zero out the meter when I recalibrate?

Yes

Hi Joe, I have started to work with figuring out what exact resistor size I would need. I have not made any changes or soldered anything yet. In doing that I decided to setup my Apogee duet interface to use for the REW Signal generator because both outputs are equal on that. With that said I sent 1...

Alex1990 wrote: ↑

Wed Feb 07, 2024 8:34 am

Ok so there still appears to be a short - in addition to this I had to cut a couple legs to get it out so not exactly workable. My desoldering is getting better but this was a tricky one

Short on the PCB or the pot?

Hello Joe, I just completed my first of two Audio Path PCBs. Per the build guide, I went to test it, inserted the two jumpers, connected it to an extender...and when I powered on my rack, the two 4R7 resistors instantly fried. Any troubleshooting tips? Best to post here or send me photos of the top...

Thanks again for all you help Joe. You can add a resistor across channel B makeup pot outside pads to balance the outputs exactly. Somewhere between 240k and 330k should balance it perfectly at the minimum makeup setting. When you have it balanced adjust the interface so both MAC outputs are 1.23va...

Check with VU/OFF/GR in off that you have identical output levels ? Y/N I have both channels of the opto receiving 1.23 VAC and the outputs of the opto are the same but they have dropped to 1.197 VAC. This is hard relay bypass so the level difference is your interface sagging slightly under the loa...

Sorry but I am still confused on the inside / outside part. Before I pull these boards out because I can’t reach the front six soldering points cause they are covered by the case lip. Can I measure from the back 6 solder pads on each pot? Are these part of the switch or the potentiometer? I have ci...

Okay so terribly slow with this over new year but I sourced some pot cleaner and the problem has remained unfortunately! OK as I mentioned up the page. Can you get the pot of the pot PCB ok without damaging it? Otherwise you will need another pot kit. Ok managed to get make-up gain pot off the PCB ...

If the voltages don't match turn off the comp and leave off for a while and measure the outside pins of the threshold and makeup pots still fully CCW. (Like left threshold 95.76k and right threshold 102.54k and left makeup 9.33k and right makeup 11.11k. be as accurate as you meter shows) Which ones...

Does anyone know how I can get the two channels a little bit closer in measurements. It seems that I have to throw a lot more signal at channel B than A by looking at the Volts AC. VAC. Almost .5 DB extra on the fader coming out of my DAW to get 1.23 VAC on the B Channel. Is it the output pots that...

Hi Joe I have built the amp I got from your shop last Monday morning and it is going very well. Thanks for all your help. I believe there is a 'mod' I can do "With no volume control fitted the +/-vol pins can be used to do EQ like low end extension by adding a resistor and capacitor" What resistor ...