MAINTENANCE
WARNING: If you aren't familiar with the innards of tube guitar amps, DO NOT OPEN THE
G-1000. It is a VERY complex amp, more so than any other guitar amp you've ever seen. The
tubes are difficult to access, so changing them requires cabinet disassembly. Sorry about
that.
BE CAREFUL removing the chassis from the wooden cabinet.
There are two sets of cords
going to the reverb tanks, which are attached to the rear of the cabinet front panel. Pull the
chassis partway out, reach in and unplug the reverb tanks, then remove the chassis fully.
The tubes have their heaters run on 5 volt regulated DC power. This will insure a maximal
lifetime. They should last for many years, so why are you worried about replacing them
already?
All of the tube types used are no longer made, except for 6CG7s. Fear not. All these tubes are
VERY commonly available in great quantities in NOS form, and not available from your friendly
guitar dealer. Try Antique Electronic Supply (
www.tubesandmore.com
) or
Radio Electric Supply (
www.vacuumtubes.net
).
The 6BK5 output tubes are being run conservatively, and should last some years. You DO
NOT need matched pairs, as they are in a self-balancing and self-biasing circuit. There are no
bias adjustments. Sadly, there are no other tube types that will work here, so DO NOT try to
“tube roll” different types.
The overdrive tubes in the HAPPY channel can be almost any sharp-cutoff pentode. 6AU6s or
6AK5s will work fine. There are a lot of pentodes that will work here. I can't list them all, for
lack of space. Check with us if you want to “tube roll” here.
The tubes in the overdrive of the ANGRY channel are remote-cutoff pentodes. You can also
use sharp-cutoff pentodes for a different sound. The 6BN6 tube can NOT be replaced with any
other type.
Keep the same types in the reverb section. The HAPPY amp-input tube can be a 6AU7 or a
7AU7 (the difference in heater voltages will have very little effect on sound or gain).
DO NOT try 12AX7s anywhere in this amplifier. They won't work. DO NOT listen to guitar amp
“tech gurus”. They know very little, and have never seen this circuit before. Check with us
BEFORE YOU DO SOMETHING STUPID. Thank you.
The plate-circuit fuses should NOT blow. If they do, there is probably a shorted 6BK5 tube, or
a shorted filter capacitor. Check with us if new 6BK5s don't fix the problem.
If an amp channel stops working or you smell melting plastic, the amp has overheated. DO
NOT TAKE CHANCES. Turn the damn thing off IMMEDIATELY and let it cool for a few hours.
Then, and ONLY then, can you have a technician look at it.
“Retarded Animal Babies” Cartoons ©2007 David C. Lovelace, all right reserved. Thanx man!
Check out Dave's horrendously offensive animations at umop.com
(text is copyright 2008 Metasonix. All rights reserved. It is a violation of federal law to reproduce, reuse or duplicate this publication without the express written permission of
Metasonix or its assigned representative.) (Oh, you want to FIX it? You say you want a SCHEMATIC?? Oh, that's PRICELESS.
Contact us at METASONIX. PMB 109, 881 11tth Street, Lakeport CA 95453, (707) 263-5343, [email protected]. We'll arrange for repair, while refusing to give you a
schematic. The circuit of this bastard thing is so embarrassing, we didn't write it down anyway.)
