JLM AUDIO

Perfect! Thanks Joe

Paul

I am starting to experiment with some piezo strip pickups, which need to be loaded with about 10Mohm or higher.

1) how would I modify the input impedance on the FET DI?
2) could this be made switchable?

Sorry if I'm missing the obvious. Can the BAN run with phantom power and no output transformer? The product page says the kit runs on a single 48V power rail, but does this also supply the phantom? Is there anything else I need other than a BAN, my choice of output op-amp, a 48V SMPS and maybe a va...

Joe Malone wrote:The DC trim is best done after the unit has been on for 30 minutes or more with the lid sitting on it so the unit is at it normal running temp.

Cheers Joe. That's what I ended up doing.

Paul

Thanks for fuse info, Joe. I have finally built my 4 BANs and have power tested and performed alignment. As mentioned previously, I am using the BD681 and a 39V zener, which gives about 38.6V at the base of the BD681 and about a volt less at the emitter. I'm setting 1/2V at TP3 at about 18.8V. I fou...

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Joe, What would be recommended fuse rating for 4 channels of BAN, using 2 x LME49860 per channel, powered with a JLM +48V smps. I will use the on-board Darlington regulator with a 39V Zener. Specs for the LME49860: quiescent current at +/- 18V 10.2ma, at +/- 22V 10.5ma, maximum 13ma. output current ...

Just what I wanted to hear! Cheers Joe!

Paul

Joe, I am considering using a power station to provide + / - 15V DC (max 200ma each), and +5V DC (200ma max) to power up a AD converter evaluation board. With a 15 - 0 - 15 transformer (I plugged in 18V in the calculator) the heatsink calculations are: 15V rails - about 45 C/W each, 5V - about 23 C/...

Joe Malone wrote:No changes needed. Just make sure the 48v reg is well heatsinked.

The AC/DC kit uses 2 x 1000uF 50v caps in series to make a 500uF 100v cap for the unreg voltage going to the 48v reg. So 80v unreg the tripler makes is fine.

Cheers Joe. That's what I thought. Paul

Thanks Joe. If I do use the tripler, are any component changes needed - eg higher voltage caps or anything?

Joe, I have a 20-0-20VAC transformer for a Powerstation, as I want +/-18VDC and +/-20VDC rails as well as +48VDC.

Not sure whether to use the Double or Triple strap for +48VDC?

Cheers, Paul

Easy one. With all resistors 1% there are 2 gain stages so 4 resistors all with 1% tolerance so +/-4% error. We do find that 1% resistors are mostly within +/-0.5% range so general error is usually only +/-2%. Easiest way to minimize channel error when building a matched pair is to use a multimeter...

Joe, I have 24-position switches, and I'm thinking of implementing 2dB gain steps.

Assuming 1% resistors, how well matched would gains be between channels?

Thanks! Paul