JLM AUDIO

I just realised that I had the impedance pot attached across #10K instead of RLoad. Doh! :lol: I've fixed that now and retested voltages again. Most voltages are ok except: #BD681 : 43.5v Bottom Right 470uF : 44.3v (looking from above) Bottom Left 470uF : 21.8v XFMR Yellow : 21.8v XFMR Blue : 21.8v...

baadc0de wrote:Thanks for the heads up. I can get the TI TL072ACP, I understand that's ok and within spec.

The regulators, as I see, will get me to +- 15V. Can I let IC3 work on +- 24V or must I always regulate that down?

Thanks

TL072 can only run on +/-18v max. So +/-15v is the ideal.

http://www.jensen-transformers.com/as/as083.pdf I see this "original schematic" says to use AD706 and seems to be using 15k as the resistor after the opamp. Maybe I could use OPA2604AP with +- 24V rails, the same as the discrete opamps will be using, so there should be no need for additional regula...

Hi, I'm putting together a 99*MB PCB (not a kit). I have a Haufe input transformer that is a LL*38 equivalent. I would like to use the board with two 990-style opamps in 2520 footprint without an output transformer (but balanced). As far as I understand, I want the DC servo option. That brings me t...

Hi Joe, I’ve just built my first BA and am having a few issues with it, hoping someone here can help me out. I am getting signal through to my DIGI 002 line input, however the signal is extremely low. (BTW this is my first DIY project so apologies in advance if I’ve done something stoopid!) :oops: ...

Hi, I have a 200ma 48v DC unregulated wall wart, that actually measures 61volts. Give or take a bit depending on mains supply variation I guess. Would that be ok as is, or would you recommend regulating it to 48v? Is there any problem with what I am guessing is a diode bridge and a couple of caps i...

Samples of new metal work for LA500 opto comp and BA500 mic pre 500/51X modules finally arrived. Stainless steel bracket is universal for BA500 and LA500 having all holes punched for both modules and has holes for standard API output transformers as well a JLM111DC. These will be available as full a...

Hi Joe- Just an update- issues with the 1st channel seem to have been related to a faulty input jack. I've replaced this and all seems ok on that channel now, fingers crossed. Explains why replacing other parts wasn't helping! Still yet to solve the 2nd channel, but I'll keep trying. Just to elimin...

Thanks for pointing that out. Will (again) fix the wiring. Last question: HUM elimination. I am having a substantial portion of humming on the channels when i touch the chassis. I tried different points of grounding, but which way is the correct one? I assume Chassis should go to Chassis GND, same ...

Hi Joe, AC/DC Kit now working fine. What was the issue ? One: One of the AC feeds was reversed (probably minor, but still) and fixed. No you had this correct the first time as I said in the last email. It is always the 2 winding ends in the middle of the diagram that go to 0v to form a center tap. ...

See attachments. Will answer questions in separate post: The transformer datasheet URL: http://www.farnell.com/datasheets/85993.pdf Transformer is wired correct. But from the first photo looks likes you have the negative LM337 reg in the middle position instead of the LM317 that should be there and...

HI Jan I answered this in your email this morning. See below - Primary Feed is 220V - Secondary Feed 2 x 25V Toriod (Farnell MC-146-030-125) - wired as chassis gnd, orange, yellow, black, red [Joe] Ok nothing from the transformer should go to the chassis gnd. What colours go to each AC in? What colo...

That is going to be one nice lookimg 500 module

Hi Joe -another quick question: Because I'm going for a vintage look on my REDD 47 build, I would prefer to use lamps instead of LEDs on the front panel to indicate phantom power. I'm going to power it using the 6.3vac tap on the Hammond PT. My first thought was to use a 3pdt toggle switch for the ...

JLM VUPPM Meter used in D'Anca Product