Search found 2066 matches

by Joe Malone
Tue Feb 20, 2024 11:05 am
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 25456

Re: MAC Rack kit Build Thread from October 2023 with slow attack led

Yes trimpot spot is correct across makeup pot. This is very seperate from the link area of the circuit. Did the link switch work before? Do you have a photo of the link pcb? Yes the link switch used to work just fine only a slight difference between the two -5db readings on the meters when engaged....
by Joe Malone
Mon Feb 19, 2024 7:50 pm
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 25456

Re: MAC Rack kit Build Thread from October 2023 with slow attack led

Ok never seen this before and the trimmer if done correctly will not affect this. Check the mac link pcb has the 10 pin headers and cables the correct way around and no shorts to 0v. With link switched on unplug one ribbon cable from the link pcb at a time to see if both comps come back to -5dB wit...
by Joe Malone
Mon Feb 19, 2024 10:58 am
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 25456

Re: MAC Rack kit Build Thread from October 2023 with slow attack led

Ok, I just got done adding the trimmer pot to balance the two output pots. It wound up being 98.6K and I got the outputs VAC to be equal now when you switch on the VU meter. Thanks so much. I have done the calibration again and made some slight tweaks to adjustments trimmers but now have something ...
by Joe Malone
Mon Feb 19, 2024 10:51 am
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 376
Views: 865151

Re: BA BA2 BA4 BAD Dual99v Build Thread

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...
by Joe Malone
Mon Feb 19, 2024 10:41 am
Forum: JLM Audio Kits
Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Replies: 107
Views: 182898

Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X

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...
by Joe Malone
Mon Feb 19, 2024 9:32 am
Forum: JLM Audio Kits
Topic: JLM99*MB Kit documentation
Replies: 26
Views: 56579

Re: JLM99*MB Kit documentation

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...
by Joe Malone
Thu Feb 08, 2024 7:50 pm
Forum: JLM Audio Kits
Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Replies: 107
Views: 182898

Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X

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
by Joe Malone
Wed Feb 07, 2024 4:18 pm
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 25456

Re: MAC Rack kit Build Thread from October 2023 with slow attack led

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
by Joe Malone
Wed Feb 07, 2024 3:14 pm
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 25456

Re: MAC Rack kit Build Thread from October 2023 with slow attack led

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...
by Joe Malone
Wed Feb 07, 2024 2:37 pm
Forum: JLM Audio Kits
Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Replies: 107
Views: 182898

Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X

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 :shock:
Short on the PCB or the pot?
by Joe Malone
Wed Feb 07, 2024 1:41 pm
Forum: JLM Audio Kits
Topic: FREQ500 KIT Build Thread
Replies: 17
Views: 38994

Re: FREQ500 KIT Build Thread

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...
by Joe Malone
Tue Feb 06, 2024 7:32 am
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 25456

Re: MAC Rack kit Build Thread from October 2023 with slow attack led

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...
by Joe Malone
Mon Feb 05, 2024 9:11 pm
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 25456

Re: MAC Rack kit Build Thread from October 2023 with slow attack led

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...
by Joe Malone
Mon Feb 05, 2024 2:06 pm
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 25456

Re: MAC Rack kit Build Thread from October 2023 with slow attack led

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...
by Joe Malone
Mon Feb 05, 2024 9:46 am
Forum: JLM Audio Kits
Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Replies: 107
Views: 182898

Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X

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 ...