Pro Audio Design Forum

I tried that first. Unfortunately, there's too much temperature drift. Dielectric isolation makes great transistors but the insulating "tubs" they sit in insulate thermally as well as electrically. Thus the Vos, tends to have more drift than a monolithic matched pair would typically have. ...

Roger - I think the buffered class-A might have some merit in non-transformer coupled applications where long cable lengths and lots of capacitance are anticipated. I agree though that it's hard to improve on the 1646 connected directly to a transformer. To get the output impedance really low for th...

There's alot to be said for galvanic isolation.

My Toro has a Briggs and Stratton. It's just a push mower with the self-paced self-propelled feature. We have about 1/3rd of an acre where we live now and it's not a difficult mow. At the new place, which is about 1-1/4 acres, most of it is wooded. The mowable yard is about the same. I don't think I...

I wonder if the ethanol in gas is trashing stuff Yes, it eats up rubber in chainsaws. My mowers don't get enough of a rest for it to happen but I've had stored gas in a chainsaw eat up rubber in less than a year. They say stabilizers help and I do use them now but on the chainsaws I just drain them...

David Birt (ex BBC) had the speaker & amp in a DC bridge to compensate for this on the fly. I've followed David's work on audio interfaces and did a fair amount of work adapting his line reciver to the 1570 mic preamp. Small world. http://www.proaudiodesignforum.com/forum/php/viewtopic.php?f=6&...

Just prior to remodeling the "atomic ranch" , the incandescent light bulb was issued a delayed death sentence by an act of Congress. Updated 4/25 added Cree CR6. I love the way incandescents look, they're cheap, easily dimmed and - when needed - warm a room. Based on what I've read, the 1...

Once again I am shocked... Low distortion transformers seem counter productive for all the folks who use them solely to add coloration. Yeah, well. I suppose one could put a knob on the negative impedance and label it "color." Crusty, you readin' this? There is a lot to be said for a dab ...

Thanks for the link. I saved it. I think Audio Precision got a patent on something similar as well which they used in the original System One. It is now expired. I may have a copy of that somewhere... Hofer, "Low-Distortion Transformer-Coupled CIrcuit," US Patent 4614914. http://www.proaud...

Yes Q19 is a mpsA06 a higher current and higher voltage part than the 3904 but still only a to-92 so it is important that this device is turned on hard (saturated switch) and turned off hard. This hard on/off is accomplished by the 47k from the raw unregulated. The snap off hysteresis occurs becaus...