Guitar Amplifier Repairs & Modifications

We specialize in repair and modification of Fender silverface/blackface/brownface/tweed amps from the 1950's thru 1970's, Marshalls (1960s-1970s), Traynor, Gibson, Ampeg and Dynaco ST-70 amplifiers.

We respect  your vintage amp and will not drill any holes in it to make modifications (unless it's a basket case and you insist on it).

With 30 years of playing/gigging experience under my belt, I know what a properly functioning amp is supposed to sound like. Engineering/technical background is necessary, but playing experience is crucial in this field.

If you're not in the Washington DC area you can ship your amp chassis to me. Call or email for a price estimate and turnaround time.

Mike Kropotkin
Sterling, Virginia


Guitar Amplifier Repairs& Amplifier Modifications include but are not limited to:

Cap Jobs

Replacement of all electrolytic capacitors. These capacitors were generally not intended to last more than 10 years. Tone and power enhancement and hum reduction are the result of a cap job. If your amp has original or 15+ year old filter caps, it's time for a cap job. Serious problems can result from not replacing them.

Installation of a grounded, 3 pronged power cord

For your safety, all ungrounded power cords must be replaced with a grounded power cord. If you insist on keeping the original power cord installed, we cannot accept your amp for repair/modification.

Fender Silver face to Black Face conversion

Makes your silver face sound as good (or at least close) to a black face version. Increases gain, sustain, tone and in some cases converts a bias balance pot to a true bias pot.

Re-biasing of output tubes

This is required in all "fixed bias" amps when new power tubes are introduced.

Noise reduction

Get rid of those annoying "snaps, crackles and pops".

Tremolo Enhancement

Install a "Surf Bug" tremolo device which improves the depth of your tremolo and also improves the tone and response of your amp when the tremolo is switched off. Highly recommended.

Reduction of excessive treble

This is a fairly common problem in Fender amps. Removes piercing highs.

Mid Range Boost

Turns your bright switch or new volume control with a "Pull Switch" into a mid boost.

Pentode/Triode switch

Switchable power reduction allows your power tubes to be overdriven at lower volumes (more than half volume)

Cathode Bias

Configures your output stage like that of a Fender Tweed amp (or a Vox AC-30) for lower power, mellower highs, smooth distortion/compression at lower volume levels. Either hard-wired or switchable.

Half Power Modifications