Consignment Items (Amps and
Guitar Amp Modifications and
Fender Tube Amp Modifications
Also see the section below about general mods for most amps.
Modifications for Princeton Reverb (blackface and silverface)
Correct the bias circuit so that the output tubes no longer
overheat. Overheating tubes can cause damage to the tube sockets, circuit
board and premature failure of the tubes. This is normally done when
output tubes are replaced. $25 for fixed resistor. An adjustable
resistor can be installed as part of the BillM mod (see below) or individually
for about $80.
Correct factory problem with wiring that causes ultrasonic
oscillation, bad tone and premature tube failure. (This is not a problem
on every Blues Jr. We can scope the output to see if your amps is in need
of this mod.) **$20
Replace both plastic output tube sockets with more durable ceramic
Install and 2 position power switch so you can have a
standby function without modification to the chassis or board. **$30
On the green board versions (older production), Fender installed a
linear taper bass pot and an audio taper treble pot. This caused the bass
control to be too touchy in the low numbers and the treble control to not do
much until it reached the high numbers. We can update both pots to cream
board (later production) specs. **$25 A good time to do this is
during the BillM mod (below)
Modifications for Blues Deluxe, Blues DeVille, Hot Rod Deluxe
and Hot Rod Deville
We've developed our own modifications for the Hot Rod amps that will
improve the tone and controllability of the amp. Here is what you
1) The clean channel will have a somewhat more classic-type tone with a little less
gain. The bass will be slightly reduced and bass frequencies will be a bit tighter
clean channel volume control will not be so touchy in the low numbers so you'll
have a bit more adjustability at lower volume.
2) When playing the overdrive channel, the Master Volume control will be more evenly adjustable instead of being so
touchy in the low numbers.
3) The shrill treble tone of the overdrive channel will be slightly
reduced for a smoother sound.
4) Ghost notes that are normally heard when playing single-note leads at
high volume will be greatly reduced and the low strings will sound a bit tighter
Cost - $135 for Hot Rod Deluxe and $145 for Hot
*** NOTE - a substantial portion of the price of these mods is the
disassembly of the amp, removal and re-installation of the main PC board.
If your board is being removed for other work, the price of these mods will be
lowered by about $65.
They're all rated at 75 watts each and carry
at least a 5 year
warranty so you won't have to worry about trashing them no matter how loud you
play. Other 10" speakers are also available. Mixing two or more
speaker models is another option.
Triode/Pentode Switch (1/2 power switch)- This allows to you
reduce your output power level to about 1/2 of normal. This usually means
a reduction of around 20% in output volume. There is also a slight reduction in treble. $85
Install metal Switchcraft input jacks. These are much
more rugged than the plastic ones installed in the American-made Deluxes and
Cost is $95. If we already have the board out for other repairs or mods, we
upgrade the jacks for $35.
The Mexican versions (Reissues) of these amps have
upgraded plastic jacks that don't typically break.
These have have large power resistors
mounted on the PC board that tend to overhead and cause damage to the
solder connections and copper traces on the back of the board. This
is a very common problem on these amps and causes problems with channel
switching and other issues. We can remove these resistors and
replace them with super high quality chassis-mounted resistors. This
will remove the head from the board and eliminate the possibility of ever
having problems in this area. About $50
There are also several Fender factory reliability mods for
the early versions of these amps (especially Blues Deluxe). We can do these as well. We'll
have to look at your amp to see if these have already been done.
The 4 X 10 version of the Deville had under-rated speakers
from the factory and we've seen many bad ones. For a bright crisp vintage
style tone at a good price, consider having us install a set of WGS G10C or
G10C/S speakers. For a deeper, warmer, and louder
tone, try the Eminence Ragin
Cajun speakers. For a similar effect but with a bit more midrange, try
the Eminence Ramrod.
Modifications for Deluxe Reverb
Remove the treble boosting capacitor on the reverb channel for a warmer tone.
This is a popular mod on the re-issues but rarely needed on the vintage ones. **$10
Install a solid state rectifier and 6L6 output tubes. This will give
you a bit more clean headroom and volume. We have to make sure your power
supply capacitors are in good shape before doing this mod. In fact, I
recommend adding changing some of the filter caps to higher values for this mod. Price varies
depending on the tubes you choose.
Modifications for most silverface models
Modifications for most models with reverb and tremolo
- Wire for reverb and tremolo on both channels - **$30
Modifications for most models without reverb
We can add spring reverb to your
Fender Deluxe, Bandmaster, Concert or Showman. You'll have to give up the
vibrato function and the "Normal" channel that you probably never use anyway.
The new reverb circuit will feature dwell, bass and treble controls. Cost is
around $245 to $295 depending on whether you want it to be footswitchable or
not. Note: there is not enough room in the head cabinets to add the tank
without excess humming so if you want this added to a head model you'll have to find a bigger cabinet or mount the tank
outboard of the head cabinet. There is no problem adding the tank in combo
models. Not available for Champs, Broncos and Princetons.
Modifications for Custom Viobrolux Reverb
- These amps don't have a negative feedback circuit. That means
they have excessive background hiss and limited clean headroom. We
can add a standard Fender feedback loop for about $80.
Modifications for all Blackface amps
- Install a grounded AC cord and correct the out of date AC wiring so that
the amp will be safer and much less likely to cause nasty electrical shocks.
Marshall Tube Amp Modifications
Do you find the Crunch and Lead channels in your
Marshall JCM2000 to be too bright and piercing? We can tame the treble
without affecting the clean channel. Cost is about $80.
Treble taming mods are available for many other
Marshall models as well including JVM models.
Convert from 6550 or 5881 to EL34 output tubes.
(or visa versa).
Mercury Magnetics Transformer upgrade and/or
the addition of a choke. This mainly applies to newer models. The
addition of the choke and upgraded output transformer will provide slightly
stronger bass response and improved note defination when the amp is played at
high volume. Little improvement will be noticed at lower volume settings.
Also see below.
Jet City Amp Modifications
JCA-22H - We offer a substantial upgrade for this model.
It includes an additional "Crunch" channel, voiced a bit different from the
stock "Crunch" channel. The new channel will be slightly more scooped in the
midrange and will have it's own gain and master volume pot. We include
a new footswitch for accessing the new channel. The footswitch has 2
buttons. One button switches between the lead channel and the crunch
channels. The second button switches between the original crunch channel and
the new crunch channel. Also, we make the lead channel slightly fatter
sounding. Finally, we add a depth control on the rear panel so that you may
dial in a more beefy bottom end for the amp overall. The cost is $495
JCA-50H and JCA-22H - SLO mod, Clean Scoop mod, Clean Tone
mod, Depth Control mods are available.
Ampeg SVT VR Standby Power Modification
SVT-VR amp has a protection circuit that will not allow the amp to go from
standby mode to play mode unless the AC line voltage is above 110 - 115 volts.
There is a modification floating around the internet that defeats the standby
relay circuit to resolve this problem. Although the mod works, it disables
the turn-on delay circuit and protection against loss of the low voltage power
supply. Our mod leaves the protection and delay circuit intact while
lowering the low AC limit to 95 volts, thus allowing you to still use the amp in
venues where the power is a little low and still maintaining the other useful
parts of the protection circuit. (Using the amp with power below 95
volts is not a great idea anyway!) The price of the mod is about $100.
Yamaha T-50 and T-100 Mods
General Modifications for Most Tube Amps
These and other modifications may be available
depending on amp make and model.