JLM AUDIO

Howdy, I'm building a single BA with JLM14 transformer, LME49860 opamp, fet DI, and VU buffer+meter. Ok remember the fit the #BD681 and a #zener of 39v 400mW so you do not blow up the LME49860 which can only do +/-22v max. (If you mention the LME49860 when you ordered in the comments box the guys w...

I have te ACDC 3 rail kit. I was wondering if i could mod it in a way to take the negative rail and make it into another positive rail that i can bring down to 12V. Besides changing the LM337, would I have to reverse anything else? (can this be done on this board?) Cannot be done without cutting th...

Hello and happy new year to all! this is my first post. I bought some "smart" kits from JLM, nice work! I have one question please: Can i use one VU Buffer kit for 2 VU meters? If you want to show the same mono signal in 2 different places with the same type of VU meters you can run 2 meters in par...

HI Yes just back from my Xmas trip away to a land of no internet or mobile phones. Very strange and very quiet :-) I see you got it worked out fine and your module looks fantastic I must say. The transformer 2 x 12vac secondary just needed to be wired in series to get the high enough voltage for the...

sorry for hijacking, but Joe would it be possible that you put the PDF's for the Baby Animal circuit diagram back online, the PDF's on the following links are not showing up (Safari webbrowser on Macintosh): http://www.jlmaudio.com/Baby%20Animal%20Mic%20Pre%20PCB%20Full%20Circuit.pdf http://www.jlm...

Hi Joe, I have built some of your PSUs before,but now I have a problem with an AC/DC.The negative rail is not working. I use a small 2 x 18v(2x290mA) torroid.center tapped reading fine about 21 Volts AC each side. I did the mod. with the 2 wire links and doubbler to "d" to achive +12v DC on V2. Bot...

Hi Joe and fellows... i forgot to say thanks, i finished my pres sometime ago, but right now theres a few problems again... 1. One of my oep 262a3 + 99 has very low gain, i dunno where to check, maybe is something about the op amp but i dont find the probelm 2.One DI box worked , and now the unit s...

Ok... a bit of an unusual question. Can I use this as a full or half-wave rectifier, buffer/gain for the front end of a LED VU meter? Would I just take the outputs from the meter output into the LED VU meter (either based on a typical LM339 or LM3916 circuit)? Thanks. CC The rectifying circuit on t...

I couldn't get the whistles to show up on the scope well enough to see a voltage or frequency. I have bought new boards and rebuilt the BANs using some new parts and some retrieved from the old boards and all works fine now! I used low temp lead/tin/silver solder and socketed the input transistors ...

I want to use the dingo kit to implement a Revox B77 1/4" machine as a tape delay into my PT rig. Is it possible to insert a feedback circuit into the dingo kit? Has anyone done something like this before? -Pittsburgh Yes easy one to do with just a 5k or 10k linear pot across the dingo unbalance in...

Hello, I am new to DIY, and am building an AC/DC kit. I am getting no DCV out of the supply at all. I have 22VAC going in, but am not sure the best way to trouble shoot this. I have confirmed all resitor values, and locations, and all components are in the proper locations. I cannot see any bad sol...

tdog wrote:hi

is it possible to drop the +48v rail to 12v?

Thanks, tom

Yes easy one. Link over C1 and C2 positions and link center pad to D.
Works the same on AC/DC or Powerstation. See photo below.

Actually I suspect the audible whistles and the steady supersonic oscillation may be unrelated. Both channels are subjectively similar to listen to with whistles at some gain settings, but the frequency I can see on the scope goes away at higher gains on one preamp but is much the same regardless o...

little izzi wrote:That sounds great, I may buy the VUPPMGR40 led meter for it, can the led's be changed for blue ones? bearing in mind the blue led's need a higher voltage I believe?

The VUPPMGR40 needs the special tricolor led bars which are not available in blue as far as I know.

Hi Joe, thanks for your reply, I have a very good but now very distant understanding of electronics, so didn't know about the leds not needing the buffer, so that is a real bonus for me! However I've since modified my needs, I am going to need the meter to be switchable between input and output and...