From selkir–(at)–elsci.arc.nasa.gov Wed Jan 10 11:09:08 CST 1996
Article: 5062 of rec.audio.tubes
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From: selkir–(at)–elsci.arc.nasa.gov (Rennie Selkirk)
Newsgroups: rec.audio.tubes
Subject: Fender coupling cap values
Date: 9 Jan 1996 20:31:35 GMT
Organization: NASA-Ames Research Center
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I have noticed in comparing the schematics of this and the two other
“first-generation” piggyback blackface non-Bassman amps (i.e. the
Tremolux, Bandmaster and Showman) to their comparable combos (the
Vibrolux and Vibrolux Reverb amps, the Pro Reverb and Twin Reverb,
respectively), that Leo & co. chose 500 pf caps to couple the preamp
to the phase inverter on the piggybacks and 1000 pf (.001 uf) for
the combos. (Compare for example the AB763 Tremolux to the AB763
Vibrolux. They’re identical except for this cap and the size of the
phase inverter ground resistor which is 100 ohms for the 4-ohm load
Tremolux and 47 ohms for the 8-ohm load Vibrolux combo.)
Any guesses on the design rationale for this? Mine would be that the
Leo & co. thought that the smaller cap would offset ‘flabbiness’ due
to the increased bass response of the closed-back cabs relative to the
open-back combos.
I have tried both cap sizes in my Tremolux. It’s my impression that
the differences aren’t that great. The bottom end is decidedly flabby
in both cases, forcing me to back off on the bass more than I’d like
in many situations. I think I hear another effect of the smaller cap,
however, and that is to reduce the dynamics of the amp. The sound is
tighter and little less mushy with the smaller cap, but some of the
sparkle seems to go with it. A smaller hole to push the music through
so to speak.
Anybody care to comment on this or the issue of coupling cap sizes in
general?
Thanks,
Rennie
From edmund_liste–(at)–indlink.bc.ca Wed Jan 10 11:09:16 CST 1996
Article: 5063 of rec.audio.tubes
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From: edmund_liste–(at)–indlink.bc.ca (EAL)
Newsgroups: rec.audio.tubes
Subject: Anyone know what happened to MagnaQuest?
Date: Tue, 09 Jan 1996 22:16:27 GMT
Organization: MIND LINK! – British Columbia, Canada
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Tried phoning them for the past 3 weeks…
Regards,
Ed.
