From Dstor–(at)–oyager.cris.com Tue Nov 22 13:16:36 CST 1994
Article: 28664 of alt.guitar
Path: geraldo.cc.utexas.edu!cs.utexas.edu!howland.reston.ans.net!news.sprintlink.net!deathstar.cris.com!voyager.cris.com!not-for-mail
From: Dstor–(at)–oyager.cris.com (Dr.Distortion)
Newsgroups: rec.music.makers.guitar,alt.guitar
Subject: Re: Vibro King == no feedback loop?
Followup-To: rec.music.makers.guitar,alt.guitar
Date: 17 Nov 1994 19:27:26 -0500
Organization: Concentric Research Corporation
Lines: 32
Distribution: world
Message-ID: <3agsde$32--(at)--oyager.cris.com>
References: <3a80pl$22--(at)--rnews.intel.com>
NNTP-Posting-Host: voyager.cris.com
X-Newsreader: TIN [version 1.2 PL1]
Xref: geraldo.cc.utexas.edu rec.music.makers.guitar:32903 alt.guitar:28664
David Covell – MPG DA (dcovel–(at)–rc702.intel.com) wrote:
: I persuaded the salesman to let me look at the schematic and was suprised to
: see no sign of negative feedback. Either I’m blind or Fender’s using the lack
: of feedback to increase warmth and open up the low end.
You’re right. I have the schematic, and there’s no -FB loop.
: Unfortunately I didn’t have time to locate the fat switch implementation; with
: the huge transformers and the lack of feedback it wouldn’t surprise me if the
: fat switch, when engaged, is actually the amp’s normal voice, and that turning
: the switch off just switches in a cap to roll off some bass.
Good guess, but that’s not it. The fat switch puts a 22uF bypass cap
across the first stage cathode resistor, which increases the gain at
low frequencies. It’s an old trick that’s been used in other amps,
usually labeled as a “bass shift” or some such (a la Boogie).
: At any rate, I really liked the amp; I wouldn’t say it sounds any better than
: a good vintage Fender but it certainly has more depth to the low end. Now if I
: could just get my Showman to sound that way I’d be content (for a while, at
You can get a lot more bass out of your Showman by replacing the
coupling cap to the phase inverter (typically .001uF) with a .01uF
cap.
________________________________________________
_ | _ _ | _
/ ==|== / ==|==
| ——–|–//////////–|——– |
-|——– | ///DOCTOR//// | ——–|-
_|~~~|_/ ///DISTORTION/// _|~~~|_/
~~~| /////////// |~~~
—–*STAUDCO*—*New York*–*dstor–(at)–ris.com*—
