Search found 2078 matches
- Thu Apr 25, 2024 11:36 pm
- Forum: JLM Audio Kits
- Topic: Stereo VU meter kit BUILD THREAD
- Replies: 102
- Views: 310083
Re: Stereo VU meter kit BUILD THREAD
a -10db switch would probably be useful for me. Where would I fit that and what would it be comprised of? Have you got a circuit diagram? Cheers Phil We set the pcb trimpots to +14dBu = 0VU and then use a DPDT switch to switch a second pair of trimpots across the pcb ones and adjust them for +4dBu ...
- Sun Apr 21, 2024 9:11 am
- Forum: JLM Audio Kits
- Topic: FET DI QUESTIONS
- Replies: 38
- Views: 113353
Re: FET DI QUESTIONS
I’m going to build the fet di into its own dedicated 500 series module. Are there any changes i need to make to run it on the 16v standard rail? The FetDI circuit will work fine across the +/-16v but the pcb 0v will be at -16v so will have to have a look at how to isolate that and reference the 500...
- Sun Apr 21, 2024 9:06 am
- Forum: JLM Audio Kits
- Topic: Stereo VU meter kit BUILD THREAD
- Replies: 102
- Views: 310083
Re: Stereo VU meter kit BUILD THREAD
I've built the VU meter and it seems to be working fine. A few questions though: 1) I've attached a diagram of my interpretation of the PSU noise filter. Would you check I've understood correctly psuSchem.jpg 2) What does the end of this sentence mean: ' and a 470uF to 2200uF cap across the DC term...
- Wed Apr 17, 2024 7:27 am
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
You have the opamp facing the wrong way, so unplug and turn it 180 degrees
- Tue Apr 16, 2024 5:14 pm
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
- Tue Apr 16, 2024 7:35 am
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Probably the first in a series of stupid question from myself. 1) Do the J99 sockets get soldered into the board? I said on the instructions not to press them in and to use a piece of cardboard to hold them in, but now the J99 is inplace it seems a bit odd that is a bit loose. 2) I put the DIP8 soc...
- Mon Apr 15, 2024 8:36 pm
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Success!! Or so it appears. I've completed the meter calibration process, and everything worked as expected now. I will take it to the studio now to put it in my main rack for an audio test. Joe, for others reading this I'd like to run a theory by you. I tend to solder from the underside of the PCB...
- Mon Apr 08, 2024 10:49 pm
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
I was trying to put the opto back in, when I noticed the anode joint doesn't look good. It appears that the pad is gone. Perhaps it was already a bit loose earlier: IMG_4209.jpeg In the instructions you mention that SCv3 has extra/alternative holes for U1 and U2. I have SCv5. Are those the holes I ...
- Thu Apr 04, 2024 10:27 am
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
- Wed Apr 03, 2024 10:51 am
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
I've hooked the opto up to two multimeters, and the results are... Meas2.jpeg Meas1.jpeg The Fluke is measuring resistance on the bottom leads, the Brymen is in diode test mode. Notice that the red probe is connected to the left top pin, while the dot is next to the right top pin. This means that t...
- Sun Mar 31, 2024 9:24 am
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Ok, I think I found something. I’m spelling this out to avoid dummy mistakes. If I put the red lead of the DMM on the pin marked with the dot, and the black lead on the pin immediately next to it, I get an open-loop reading in diode test mode. If I switch the leads (black on dot, red on the pin nex...
- Fri Mar 29, 2024 8:16 am
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
Re: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
Hi Joe, Thanks for the quick response. I believe the U2 opto was oriented correctly, but since I wasn't 100% sure if I was seeing the dot or a smudge on the package, I popped it out with the desoldering gun. Here is what it looked like when U2 was still in: IMG_4148.jpeg Here's a top level view of ...
- Thu Mar 28, 2024 10:23 pm
- Forum: JLM Audio Kits
- Topic: LA500A opto comp MAY 2021 BUILD THREAD 500/51X
- Replies: 126
- Views: 425465
Re: Meter calibration issue
Hi Joe, I finished the LA500a, my first JLM build, and I really like the component layout, structure, and quality of the kit. The modular approach is really nice. The meter calibration process is giving me a bit of trouble, so I think I have a problem somewhere that I hope you can help me diagnose....
- Wed Mar 27, 2024 6:06 pm
- Forum: JLM Audio Kits
- Topic: GEQ500 kit BUILD THREAD
- Replies: 13
- Views: 45649
Re: GEQ500 kit BUILD THREAD
Heya Joe, Not sure if my post got confused with another partially, but I've got it sorted out now :) I had a bad solder joint that 8) was causing some trouble on the Control card. Just want to say I'm STOKED on the way these are sounding. Thank you for responding promptly. I am grateful! Much appre...
- Wed Mar 27, 2024 9:39 am
- Forum: JLM Audio Kits
- Topic: GEQ500 kit BUILD THREAD
- Replies: 13
- Views: 45649
Re: GEQ500 kit BUILD THREAD
Hi again Joe, Now that I've got my pair of GEQs all set up, one of them is working great but the other is having some prominent static when I engage the faders toward +. Thanks Ok, I would have never removed the socket no matter how melted as long as the metal sockets were not touching. Your bottom...