Search found 2051 matches

by Joe Malone
Mon Mar 04, 2024 11:36 am
Forum: JLM Audio Kits
Topic: KRAFTWERK Power Supply BUILD THREAD
Replies: 33
Views: 101902

Re: KRAFTWERK Power Supply BUILD THREAD

Thanks, Joe, that's super. Can I just double check one more thing: from my 51X racks, I should wire the rack 'chassis' ground directly to the star point in the PSU case, is that correct, rather than the PCB audio 0v starpoint? Just wire your mains ground to the power supply chassis and onto the 51X...
by Joe Malone
Sun Mar 03, 2024 12:35 pm
Forum: JLM Audio Kits
Topic: KRAFTWERK Power Supply BUILD THREAD
Replies: 33
Views: 101902

Re: KRAFTWERK Power Supply BUILD THREAD

hi Joe - a quick question about Kraftwerk grounding, I'm just trying to make sure I understand why there are two 0V points on those Phoenix output connectors. Audio ground is connected to chassis ground via 10ohm resistor in series with 0.1uF cap, right?, and I thought that's the only way that audi...
by Joe Malone
Tue Feb 27, 2024 2:34 pm
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 21521

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

Ok 98.8k in parallel with 831k = 88.3k. So you can try a 1Meg pot. Since pots are +/20% it will not guarantee the pots will be at the same point in the turn of the pot due to the log curve mismatch but can help. Once you balance the ac volts at these 2 points you will need to redo the makeup balanc...
by Joe Malone
Mon Feb 26, 2024 6:39 pm
Forum: JLM Audio Kits
Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Replies: 104
Views: 165958

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

paulnajar wrote:
Mon Feb 26, 2024 3:03 pm
Total success!

Thank you Joe.

Amazing support. Loving the sound of this thing so far:-) Will most likely build another one before too long

Kind regards

Paul Najar
Cool Paul. Great to hear you got it working and are liking the sound :-)
by Joe Malone
Mon Feb 26, 2024 6:36 pm
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 21521

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

Ok here are the measurements CH A had .316 vac and 98.8k ohms with pcb cables unplugged. Ch B had .307 vac and 88.3k ohms with pcb cables unplugged. Settings are, y cable with 1.23vac at inputs. 1.3 ratio, VU, and flat. Ok 98.8k in parallel with 831k = 88.3k. So you can try a 1Meg pot. Since pots a...
by Joe Malone
Mon Feb 26, 2024 12:10 pm
Forum: JLM Audio Kits
Topic: Scorpion Tube power Supply Build Thread
Replies: 34
Views: 28911

Re: Scorpion Tube power Supply Build Thread

There is no filament connected with those previous voltage measurements. The filament is set to 6V right now. These are the original tubes to the preamp. The 48V seems fine. Haven’t put a load on it though The schematic for the mic pre you put up showed 12v filament as the 2 tubes are wired in seri...
by Joe Malone
Mon Feb 26, 2024 11:59 am
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 21521

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

Cool. With Y cable and thresholds CCW measure the voltage across the outside threshold pot tags again. If one is higher voltage a resistor can be added to bring it down to match the lower voltage side and then the makeup trim will need to be redone. This can sometimes balance the threshold pot mid ...
by Joe Malone
Mon Feb 26, 2024 11:50 am
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 374
Views: 824621

Re: BA BA2 BA4 BAD Dual99v Build Thread

My voltage was running a bit high. 47.5 volts in and 24.75 out or so on all 4 pres', So I dialed the volts back to about 46.5 in and around 24.33 out and that was enough to get the power supply out of hiccup mode. now all 4 preamps are running smoothly and sounding great! I was going to use them on...
by Joe Malone
Mon Feb 26, 2024 9:43 am
Forum: JLM Audio Kits
Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Replies: 104
Views: 165958

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

Hi Again Joe, apologies for all my bungling! So I decided to put the compressor back together after soldering the dip 8 pins I had missed on the side chain board. Good news is the meter appears to be working well now. the Sidechain NE5322A pin voltages all match the NE5322A on BIO500 board now as i...
by Joe Malone
Fri Feb 23, 2024 5:53 pm
Forum: JLM Audio Kits
Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Replies: 104
Views: 165958

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

You have to measure the 1.23v between pin 2 and pin 3 of the output XLR as that is the balanced out. Otherwise the output transformer is floating and you will just get random meausrements OK as stated previously closest to 1.23vac I can get is 1.224vac. I send this 1Khz sine to FC500A input. In VU ...
by Joe Malone
Fri Feb 23, 2024 10:55 am
Forum: JLM Audio Kits
Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Replies: 104
Views: 165958

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

OK main thing below is to test if the meter coil is intact. See below I had another good go at all the toggle switch points with the solder iron. Cool Input to JLM Eleven rack measured the 1Khz sine wave at 1.228 volts With rack power off or on and 500A connected via edge connector I measure 1.224 ...
by Joe Malone
Thu Feb 22, 2024 10:29 am
Forum: JLM Audio Kits
Topic: Scorpion Tube power Supply Build Thread
Replies: 34
Views: 28911

Re: Scorpion Tube power Supply Build Thread

I only have one preamp connected. With nothing connected to the PSU I have 306VDC unregulated and the regulated supply jumps up to 296VDC. Both HV1 and HV2 have the same issue, when the Filament is connected they won't go higher than ~256VDC Ok that is a bit low. Does it go to 320v with no filament...
by Joe Malone
Thu Feb 22, 2024 10:15 am
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 21521

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

I found the culprit, not sure how this got checked on or if it is set this way by default in REW but I went back to not using the Y cable and then I unchecked this and the link switch works perfectly. Such a stupid waste of time trying to troubleshoot a problem that really wasn’t there. IMG_6982.jp...
by Joe Malone
Tue Feb 20, 2024 3:07 pm
Forum: JLM Audio Kits
Topic: Scorpion Tube power Supply Build Thread
Replies: 34
Views: 28911

Re: Scorpion Tube power Supply Build Thread

I’ve got the scorpion up and running now with it bolted to a 1/4” bar of aluminum. The heater voltage seems solid, but I’ve got HV2 cranked as high as it will go, and under load it stops at 256V. I’ve got 266V unregulated at the power resistor and 116VAC at the outlet (USA). Does this seem correct ...
by Joe Malone
Tue Feb 20, 2024 2:11 pm
Forum: JLM Audio Kits
Topic: MAC Rack kit Build Thread from October 2023 with slow attack led
Replies: 39
Views: 21521

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

OK that looks ok. The clue will be what ac volts you are getting at pin 6 on each IDC 10 pin header on the mac link pcb when separate and when linked measured to 0v while -5dB GR is on each channel. Make sure the switch and threshold settings on both comps are the same. Ok, So just and FYI that I w...