Search found 17 matches

by htm
Fri May 22, 2020 4:44 am
Forum: JLM Audio Kits
Topic: 1290 Build Thread
Replies: 82
Views: 124598

Re: 1290 Build Thread

Hi Joe. I got consistent readings with both channels, and it didn't make any sense. I tried different cables and even different inputs on my interface, but the difference was still there. It was driving me nuts until I checked the output jack, that had a loose "hot" connection. (I use jack i/o inste...
by htm
Mon May 18, 2020 7:43 pm
Forum: JLM Audio Kits
Topic: 1290 Build Thread
Replies: 82
Views: 124598

Re: 1290 Build Thread

Thank you for the advice Joe! I finished my 2x1290 and it works. However one channel seems about 10 dB quieter. I measured input and output connections resistances + to - and both to ground, and both channels are identical. So are the connections at the GoBetween Plus and the input and output transf...
by htm
Fri May 01, 2020 7:03 pm
Forum: JLM Audio Kits
Topic: 1290 Build Thread
Replies: 82
Views: 124598

Re: 1290 Build Thread

Hi Joe I just ordered my set of 1290 kits and I'm about to order Carnhill input TX. ... thanks, Hannu Wow! Three years have passed quickly! Finally I'm back to this project. I have VTB9045 input TX, but I'm not sure about the wiring. Here's the pdf for the Carnhill: http://www.audiomaintenance.com/...
by htm
Tue Apr 18, 2017 4:20 pm
Forum: JLM Audio Kits
Topic: 1290 Build Thread
Replies: 82
Views: 124598

Re: 1290 Build Thread

Hi Joe I just ordered my set of 1290 kits and I'm about to order Carnhill input TX. I'm guessing that the pinout doesn't allow me to stick the Mu-Metal can version ( http://www.audiomaintenance.com/acatalog/CA-18-VTB9045M_extended_info.html ) straight into the pcb, so I need to fix the TX to the cha...
by htm
Sat Apr 08, 2017 10:48 pm
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

Check 10R resistor is still 10R ? Voltage you get on either side of the 10R measured to 0v? Voltages at opamp pins measured to 0v? Voltages at +/-in measurted to 0v with phantom on and no mic plugged in? Ok, here goes 10R is 10R 47.3 on the opamp side of 10R and 47.5 on the other side opamp pins ar...
by htm
Fri Apr 07, 2017 6:04 am
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

Hi Joe I've been happily using my four BA's on drums and guitars for a good while, but I 've noticed that there's something going on with one of them. The gain on one is some 4 dB lower than others and it's not giving out the full 48V phantom power, only 15 or so volts comes out. I checked the wiri...
by htm
Fri Apr 07, 2017 6:04 am
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

Hi Joe I've been happily using my four BA's on drums and guitars for a good while, but I 've noticed that there's something going on with one of them. The gain on one is some 4 dB lower than others and it's not giving out the full 48V phantom power, only 15 or so volts comes out. I checked the wiri...
by htm
Sat Apr 01, 2017 5:30 am
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

Hi Joe I've been happily using my four BA's on drums and guitars for a good while, but I 've noticed that there's something going on with one of them. The gain on one is some 4 dB lower than others and it's not giving out the full 48V phantom power, only 15 or so volts comes out. I checked the wirin...
by htm
Thu Oct 16, 2014 4:16 am
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

Darn. I must have missed that. Seems that I have to get new ones.

Thank you so much for the quick answers.

- Hannu
by htm
Wed Oct 15, 2014 9:22 pm
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

It thought it was weird too, but I checked, and its 3,3 I took another one I had lying around an it reads: 8,5 + 8,5 /15,5 primary 80,5 + 80,5/2,3 secondary i changed the multimeter battery and the readings are the same +/- 2 ohm the earlier reads about the same with the new battery If you want to l...
by htm
Wed Oct 15, 2014 4:28 am
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

Ok. Here we go. I hade a spare one to test.

Primaries
1+2 is 12,2 ohm
2+3 is 12,2 ohm
1+3 is 19,2 ohm

Secondaries
1+2 is 83,5 ohm
2+3 is 83,5 ohm
1+3 is 3,3 ohm
by htm
Tue Oct 14, 2014 4:46 pm
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

The tx's are from an old AKG Tapco 6100 series mixer. No markings on them, and the manual doesn't say much. "Custom built high nickel alloy" "Microphone impedance matching 30 to 600 ohms" "Common mode rejection 105 db" I wired them the same way they were in the mixer. Three taps on each side. Primar...
by htm
Mon Oct 13, 2014 5:22 pm
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

Hi

I'm using 1:8 input transformer with JLM25HV. How much smaller could I go from 68R?

- Hannu
by htm
Sun Oct 12, 2014 10:16 pm
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

Hi! One more question about the BA. I got all of my four API-type BA:s finished and racked. They sound really good, especially on vocals (a little surprise there). I'm wondering about the gain range though. When using a tube condenser mic, that is plenty loud on other pres, I have to crank the gain ...
by htm
Mon Aug 18, 2014 6:29 pm
Forum: JLM Audio Kits
Topic: BA BA2 BA4 BAD Dual99v Build Thread
Replies: 335
Views: 382372

Re: BA BA2 BA4 BAD Dual99v Build Thread

Ok, thanks for the answer. There seems to have been a bad connection in the input wiring, and I have two BA:s working now. One thing puzzles me though. I'd be glad to get somebodys opinion on this. My vintage input transformers seem to have their primaries connected. So when I test with a beeper the...