In Reply to: Re: yeehaw, no smoke came out posted by Wayne Parham on September 05, 2002 at 21:24:07:
but not gold ones. I was torn between "tweak first" and wanting to hear Phil's unit "as-designed". Didn't even increase the size of a single p/s cap :) Why I bothered with wiring the dual voltage (120/240) switch I can't say. Input/output jack wiring could be shortened a few inches probably (left them the 8 inches specified-too long!). I thought "heat shrink" tubing was for sissies...but it did make for a much more professional looking finished interior (where no one can see it but me!).
The oem lm353's OPAMPS are kind of dated now, and the OPA2134's will go in their place soon, for an improvement in the s/n ratio already speced at better than 110dB, response dc to 100kHz,+/-0.2dB. Seems transparent, like can't tell it's there, just the music is a bit smoother, bass more solid. No real concrete listening tests or measurements yet, I want to play and relax with it in the system for a while.
I've been shelving these altec HF drivers at -12dB for a long while...per the XM9 dial calibrations (?), about -14dB sounds like a better overall tonal balance...I don't think any added HF compensation is needed at the moment.
This was a fun project, but man are some of those parts small...try reading the numbers on a 1n4148 diode...that's why the "helping hands" thingy came with a magnifing glass I guess. I think this is why older guys like tube gear...then they can see the resistor color codes without their glasses. Samwife keeps whining, "when will I fix the MC-240 tube amp"...some people are never happy :(
it's only been down about a year, I'll get to it sooner or later :)
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