heh no, just isp problems... the schematic is pretty much verbatim to the DC coupled gain stage one on the sezkeres project page... I scaled the crap outta the caps as stated, but that's it. I left out the output cap drain resistor, it actually thumps LESS without it. (but I'd unplug the headphones before turning on/off, or use a switch like I did - just because)
Also I'm rethinking the sealed box... I need to emulate a hot summer day and measure the temp again... I'm gonna sit it next to the radiator for a bit, 6" away it's 105f. I think I may need to attach the heatsinks to the lid with countersunk panheads. If that's not enough I'll take them off the protoboard and mount them directly to the rear ala TimH's version.
The schematic for the meters... no need, it's easy. take a dual opamp, wire some diodes to the inputs so when you turn the main volume pot down it doesn't decrease the signal, then either mathmatically calculate the diode drop and the boost needed to make 1.228V = 0.775V to come up with your gain setting, or do like I did just wire it for Gx11 and use input pots... feed it a 0dB test tone off a test CD, measuring the line level... turn the trimpots until it's calibrated.. this way you don't need to rectify the signal either. It's all just for looks anyway, there's nothing going out from here. :)
Someone explain the bias thing to me, please. My skills are pretty much nerbie and I'm lost in how, without the resistor divider, to control the stupid thing.
posted 02-03-2001 01:58 PM CST (US) 
