Please note
: you may find that some pre amp tubes, whether newly manufactured, used, or even
n.o.s., may be too
"
microphonic
"
for the first gain stage
(V1)
of a Komet
amplifier. A
microphonic preamp tube is a condition in which a tube will absorb mechanical vibration and
amplify it into the audible range. In this scenario, a tube can
"
feed-back
"
, or give off a loud,
high pitched squealing noise.
Feed-back can occur intermittently, even without an instrument plugged into the input of the
amp. This does not mean that the tube
(
s
)
are completely unusable. One possible solution you can
experiment with is moving the microphonic tube to the
V2
phase inverter socket where
microphonics are not as noticeable. The microphonic
12AX7
may be quieter in the
V2
position
as opposed to the
V1
position.
Please note
: a small amount of
"
hiss
"
is normal for high gain amplifiers. An excessive amount
of hiss, especially when the volume control of the amplifier is all the way down and with no
instrument plugged in the amplifier’s input, usually denotes a bad pre amp tube. Some n.o.s.
audio tube suppliers offer
"
select
"
or hand picked pre amp tubes, which are superior in all
aspects of quality, especially when it comes to being quiet and non-microphonic.
Please note
: your amplifier produces heat. Prolonged gigs, outdoor or non-climate controlled
venues, only multiply that factor. We suggest after extended play - that you allow for a
sufficient amount of time to pass - so as to let your amplifier cool down prior to moving or
loading. This will help protect and extend the lifespan of the audio tubes and internal
components from excessive vibration or damage.
Please pay close attention
when extracting and installing the power and pre amp tubes. The
pins must align perfectly into the tube’s socket. Bent tube pins, especially when forced into a
tube socket, can cause serious damage to an amplifier’s tube socket pin inserts. This results
99%
of the time with the tube socket needing replacement. To avoid this contingency, we
recommend that you purchase a miniature pinned, nine hole, pre amp tube pin straightener.
These can be found on line from many vintage tube retailers. This easy to use device guarantees
that your pre amp tube and EL84 power tube pins will be straight and aligned for socket
insertion.
Please note
:
Komet
Amplification’s limited lifetime warranty will not
cover damage
done to a tube socket’s insertion pins from forced or accidental mis-alignment / and or bent /
crimped insertion pins.
TUBE REPLACEMENT
A noticeable deterioration in your amplifier’s overall sound is an indication of an imminent tube
replacement. You may notice symptoms such as
"
muddy
"
or
"
saggy
"
power chords, a loss of
tightness or
"
punch
"
, a weak sounding treble and bass, and loss of certain sonic frequencies or
note "
bloom
"
. We suggest that you first start by replacing your power tubes. Pre amp tubes can
last a very long time, and do not necessarily need to be replaced as often as the power tubes.
However, we do recommend that you have both the pre amp and power tubes properly tested by
a technician between servicing.
Copyright 1999-2017, Komet
Amplification. Group, L.L.C. May not be reproduced in any form without express written consent from Komet
Amplification.
