Laser-printed panels and other topics

Magnus Danielson e93_mda at drum.it.kth.se
Tue Oct 22 01:56:19 CEST 1996


>      Hi DIY,

Hi Gene!

[Interesting panel makeing idea left out here]

>      Next topic: tube amps! Does anybody know where to get replacements for 
>      those old multi-value high-voltage paper electrolytics? Man I went to 
>      a half-dozen places this weekend, and I found some, but certainly no 
>      direct replacement and maybe a "close enough" or two but I need to 
>      measure the power supply voltages because the cap voltages available 
>      are not quite the same as the original. I'm looking for some 525 VDC 
>      30-20-20-20 quad paper 'lytics for a couple Dynaco Mark III's. 475 VCD 
>      is the max apparently. Actually I'd prefer some more modern 'lytics, 
>      I'm thinking Spragues or Mallorys.... I'll cruise the catalogs but in 
>      the mean time - anybody got any ideers?

Eh, well yes. You happend to catch my memory on something... so I digged into
my latest "Elektronikkatalogen" (Nr 4 95/96) from Ericsson Electronic Services
(fancy name... for selling components, there's no respect these days for 
calling
stuff by it's real name). In there I found what I suspect migth be what you are
looking for, 500VDC cap's from RIFA migth be what you are looking for except
for the fact that they are available in 100, 470, 1000 and 3300 uF and you 
can't
acuse them to be cheap. However, these things are being demoed with full
operating voltage (230 VAC) and being drilled... they burn a little around the
hole and changes value a little but will not burn up... just keep working :)

>      Speaking of tube amps, here's another project story - I needed a combo 
>      amp for the garage, so I could use it as a monitor amp for projects on 
>      the workbench (besides it's good to have a guitar amp lying around 
>      anyway). I had an old Magnatone solid-state with two twelves in it, 
>      but it had a pretty bad hum and if you were standing on the garage 
>      floor in bare feet and touched the input cable ground, you could feel 
>      a pretty hefty AC potential course through your body. I could tell by 
>      the feel of it, like when I would squeeze harder on the cable jack, 
>      that there was plenty of amperage to spare and it would give me all I 
>      could take from it if I'd only walk over to a puddle of water. Well 
>      needless to say I don't take that kind of crap from lowly electronic 
>      stuff so I proceeded to gut the thing after verifying that this 
>      behavior was "per design". As I was doing this I started to eyeball an 
>      extra old Fender PA head sitting in the corner - it looked like a 
>      perfect fit to the top of the speaker case. Sure enough, it was. So I 
>      grafted it to the top, and ran a couple speaker wires down to the 
>      speakers. Next a little trip to the local guitar junk shop, and two 
>      12AX7's and a reverb tank later I had a pretty cool 140 watt combo 
>      amp. As soon as I powered it up I tried the ol' finger-on-the-cable 
>      hum test to see if it was alive, and I practically got sterilized by 
>      the blast. Ha ha, bet the neighbors got a kick outta that. Okay so I'm 
>      drifting from synth-related topics - well amplification has its use in 
>      synthesis, doesn't it?

Well, you synthesized a blatt, didn't you... you've got it all basically, a
tounch sensitive 1 key keyboard, an voltage controllable amplifier (the amp...
voltage control - power/no power), a resonator (speaker assembly).

>      Anyway busy week on the workbench, I just wanted to tell someone about 
>      it.

I know that feeling, it seems you had a fun week :)

Be a bit more carefull with turning the volume up the next time.... and mind
your ears...

Magnus




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