From mzait–(at)–ol.com Fri Feb 7 10:31:05 CST 1997
Article: 37595 of alt.guitar.amps
Path: geraldo.cc.utexas.edu!cs.utexas.edu!www.nntp.primenet.com!nntp.primenet.com!news.maxwell.syr.edu!insync!uunet!in2.uu.net!152.163.170.17!newstf01.news.aol.com!audrey01.news.aol.com!not-for-mail
From: mzait–(at)–ol.com (MZaite)
Newsgroups: alt.guitar.amps
Subject: Re: Harp amp mods
Date: 7 Feb 1997 01:34:01 GMT
Organization: AOL http://www.aol.com
Lines: 17
Message-ID: <19970207013301.UAA0106--(at)--adder01.news.aol.com>
References: <32fa1022.6318966--(at)--ews.orst.edu>
NNTP-Posting-Host: ladder01.news.aol.com
X-Admin: new–(at)–ol.com

If you are using a Fender Blackface or Silver as your test bed, try one
with a 2
output tube set-up.
1) replace the 1M on the 1st input jack with a 5M resistor.
2) replace that channels 100K plate resistor with a 470K
3) replace the 1.5K cathode res. with a 2.7K, and leave the 25/25 bipass
cap in place.
4) decouple the stage with a .047 uF.
5) decrease slope res. from 100K to 56K
6) replace the Phase Inverter 12AT7 with a 12AX7.
7) If it has a tube rectifier, try a big bottle 5U4
here comes the BIG one install 6V6′s to replace the 6L6′s, and install
a dropping res. of high wattage to lower the screen voltage, say 500 ohm
10 watt.
9) set the bias to 27mA / tube .
10) plug in and give it a blow.
Later DR.Z