ONSLOW SITE

CUSTOMIZATION
Marshall Mods
Fender Mods
Bluesman
Other Mods
Pedal Mods
MAGAZINE
TECH HELP LIBRARY
TUBE AMP FAQ
VINTAGE GALLERY
SEARCH
ABOUT RICK
CONTACT RICK




Fender Amp Customization



Fender Amplifier Mods

Add overdrive and channel-switching to a Silverface combo amp and you have an ideal gigging amp. With the increased value of vintage equipment today many of my mods to not add any holes to the amp chassis. My Bluesman Modwill give you all of this without any permanent


British Mod - Bassman Marshall Conversion


The Blackface and Silverface Bassman amps, with their hefty output transformers, are ideal candidates for a Marshall conversion. The Bass channel gets transformed into a complete Marshall preamp with Marshall EQ and the Normal guitar channel of the Bassman remains unchanged!

It is possible to obtain separate Volume, Treble, Mid,and Bass for each channel (Marshall and Fender) without having to drill any holes.

Options:

  • Foot-switchable channel switching (no holes)

  • Presence control

  • EL34 output tube conversion

  • Master volume

  • FX Loop

  • Resonance control

Fender Brown Tone


The Brownface Deluxe had a single tone control that sounded very different from the Treble and Bass controls used on the later Blackface and Siverface models. The sound is fatter and not "scooped out" in the mids. There is also quite a bit more output as well, similar to the gain boost setting on a mark 1 Mesa Boogie.

This mod adds a tone pot in place of the low input jack in one of the channels. If the amp has a brite switch it can be rewired to select between the two EQs, if not, a toggle switch needs to ba added

  • Select between Brownface and amps original EQ with one switch

  • Independent tone control for Brownface EQ

  • Great fat boost

  • Foot-switchable for live playing (additional option)

Reverb Hi/Lo


I can't remember ever using the reverb on/off switch on a Fender amp. So, I converted the standard on/off operation of the stock reverb foot switch into a high/low setting for the reverb effect. This way you can switch between a normal setting and a "surf" setting and finally get to use that foot switch for something useful.

No added holes and completely reversible

Power Tremolo Conversion


Fender used an opto-coupler design in most of their amps. This system was crude and inconsistent so some amps have better sounding tremolo than others. Conversion to power tremolo will improve the effect and does not require any additional tube


Power Tremolo

FX Insert


The FX Insert is a simple unbuffered FXLoop available only for Reverb model amps. It does not require any additional tubes nor holes to be drilled in your amp. It does not utilize any buffering or low impedance driver so is intended for high impedance effects with short cables

  • Low cost

  • No added tube or control

  • Completely reversible for resale value

FX Loop


A fully buffered FX Loop requires an additional 12ax7 preamp tube to be installed. Another option is to disable the tremolo circuit and use the the tremolo tube instead


Onslow FX Loop

Blackface Conversion


Any Silverface amp can be transformed to the earlier Blackface models. Depending on the model of amp this can make a significant difference to your sound. The TFL5000 series made in Santa Ana would particularly benefit from this conversion to the old AB763 circuit.

Fender Reverb Unit


Both modern reissue and vintage Fender Reverb Units (the separate stand-alone tube models) can benefit from this mod which greatly enhances the depth of the reverb effect. Now it is possible to get a bigger "surf" sound and bring these units closer to the classic Premier Reverb sound.

Princeton Driver Mod


The Deluxe (Reverb) amp has more gain and breaks up more smoothly than the Princeton (Reverb) because it has the same driver stage design that you find in larger amps such as the Super Reverb or Marshall JTM45 design. This driver utilizes 2 triodes that operate in a push-pull configuration and that clip symmetrically and uniformly as you push the amp into distortion. While acting as phase-inverter they also provide gain to the driver stage.

The Princeton, on the other hand, uses a single triode as phase-inverter and has no gain at all in the driver stage. The signal has less drive and does not break up in the same manner as you start pushing the amp. By upgrading the driver design you can get all of the great tone of the Deluxe in a smaller, lighter package.

This mod requires disabling of the tremolo effect in order to provide the extra triode required by the driver circuit but requires no extra holes and can be reversed back to original spec (including tremolo)

Class A Cathode Bias


Cathode Bising is available for many models of Fender amps


Cathode Biasing

 

Fender®, Marshall®, Ampeg®, Boogie®, Vox® and any other registered trademarks referred to on this page are the properties of their respective owners and are not affiliated in any way with Rick Onslow

©2001 - 2018 Rick Onslow
all rights reserved

 

--------