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Mosfet Booster Pedal Synthetic Tubes Custom Amps by Custom-Designed Pedals Modified Echo Pedal Fratus-Amplification Fixit Supply Store

The HushPuppy is back!

The HushPuppy is a plug-in module that replaces your output tubes and reduces the power substantially, allowing you to overdrive the output stage at a much lower room volume.
No modifications are needed to your amplifier, other than removing one or more output tubes and replacing with the HushPuppy. It does not matter if your amp is Single-ended (Fender Champ, for example), Class-A (Vox AC-30 and many others), or Fixed-bias [which includes adjustable bias]. The HushPuppy creates its own environment within itself. But don't mix Class-A original tubes and the HushPuppy. The Vox AC-30 has its tube cathodes in parallel, and if you pull one tube, the rest draw more current to make up for it. Always check before purchasing if you are unsure of how your amp is biased. Eventually I will provide a table for this.
As an output tube, the HushPuppy can use quite a few standard preamp tubes that you probably already have: 12AX7, ECC83, ECC803, 7025, 5751, 12AT7, 12AU7, 12AV7 ...and more variations of pin-compatible tubes. There is a long list.

So, how does it sound? Expect a change in tone, but not a bad change. It is more capable of high and mid-range sound than huge chunky lows, since the surface area for carrying current is so much lower, but that is not always a bad thing.
The first one I installed on a Hot Rod DeVille had the owner saying, "Finally, I can play my guitar at home!"
I have built several amps with the HushPuppy technology built in, and they all sounded good.

Hush Puppy Module

Noisy EF86 replacement!

The well-known EF86 tube is notoriously microphonic. If you have a Vox or another amp that uses the EF86 tube for vintage sound, take a look at this. Its hard to find a current production or even an Old Stock tube that is not microphonic. I have a solution for that. My new EF86 Tube Converter will plug into the EF86 socket and allow a quieter 6AU6 tube to be used.
I plan on selling them with the replacement tube included and installed in the module. In preliminary sound checks, it sounds the same as the EF86, but with no microphonics. The first units are now available. Call for pricing.
If you are thinking of a new amp, look at my Custom Amps page to get an idea of what a custom amp from me could cost. New formula on 4/15/2015! (Closer to reality, I think.)

The Mosfet Booster from

If what you need is more gain, but you are happy with your tone, then this is for you. Made in the USA!
$165 - Sold directly from this website!
This pedal is really different. I scoured the world through the internet, and found that almost all the "mosfet boost" and "clean boost" pedals have in the reviews and fine print phrases like, "overdrives nicely when you turn it up", "adds shimmer and sparkle", "enhances", "fattens up your tone", and so on. If that is what you are looking for, then this is not your kind of pedal.

This pedal is a studio-quality preamp, designed like a tube preamp stage. Consequently, it does not favor one frequency over another, and it does not change your tone.

This is a new design, designed after a lot of study and contemplation. It has its roots in classic tube preamp designs.

Gain: Adjustable Amplification levels of zero (no signal output) to nearly +20dB.
Noise: TBD, but imperceptible.
Distortion TBD exactly, but very low.
Power: 9 volt standard battery or DC Power Jack 2.1mm, Center Negative (Stomp Box Standard).
Power draw: 4mA Maximum, Operating or Quiescent.
Input: High impedance, at least 330K Ohms via 1/4 inch Mono Jack.
Input Level: 4 Volts P-P Maximum.
Output: Adjustable level, with a low impedance of about 10K. 1/4 inch Mono Jack.
Output Level: 4 Volts P-P Maximum.
Power Switching: Power comes on when you insert a Mono 1/4 inch plug into the input jack.
Indicators: The LED on unit shows when the effect is switched into the signal path.
Signal switching: True Bypass Push-On/Push-Off via Footswitch.

Mike Fratus, at

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The Synthetic Tube Module

Synthetic Tubes

Now you can have the tube sound but without the tube problems!

You will not believe how good these sound... In normal amp preamp positions, they sound every bit as good as the best NOS tubes!
This module is designed for use in the normal Class-A stages of most first tube preamp stages. If there is any doubt as to whether they will work in your application, please call with your amp's make and model number and I will look it up.
This will not work for the Phase Inverter or Cathode Follower in most amps, as it requires more current capability. I have another Synthetic Tube Module for that usage in the testing stage. It will be released for production soon.

New Models Available!

You can buy them online right here. Just chose which model(s) you want:


Please Donate to the Red Cross!

From the Past: My Custom Amp Projects

R.R. Special Guitar Amplifier

Custom 45 Watt all-tube guitar amp built by Custom 45 Watt all-tube guitar amp built by
- This amp is an all-tube, one-input design, with two internal channels. The Normal channel is used all the time and can be run clean or dirty, depending on your settings. The Overdrive channel is mixed with the Normal channel via the Mix control, into the Master Volume control.
- This amplifier design uses two separate output devices: 6L6's or my "Hush Puppy" outputs, so that the output power is selectable as either 45 Watts or 4 Watts. It can be switched on the fly, during play in fact.
- The Effects Loop Output is buffered and the level is adjustable. The Effects Loop Input goes right to the Master Volume Control input.
- The power supply is selectable for either a solid state diode or a tube rectifier. The Diode give more power, but the Tube gives more personality, and the amp responds more to your playing.
- There is a Feedback control that controls negative feedback. Turn it down, and the amp can get real dirty. Turn it up, and the amp becomes very clean.
- The Ultralinear switch cuts in the Ultralinear windings on the output transformer, creating even more linearity.
- Bias for the 6L6's is switchable to self-bias (Class A-like), or adjustable bias. Bias is adjustable from the front panel, and is limited to extremes of Cold and Hot. The Hot setting would break up sooner.
- The Harmonic switch purposely unbalances the Phase Inverter to create harmonics.
- The cabinet is built from Bubinga, an exotic red wood from Western Africa and Cameroon. Sometimes called "African Rosewood," it is not related to rosewood at all. But it is incredibly beautiful.

The Mr. J. Guitar Amplifier

Custom Hendrix-voiced 40 Watt all-tube guitar amp built by Custom Hendrix-inspired 40 Watt all-tube guitar amp built by
The goal with this design was a Hendrix-like sound with plenty of gain and overdrive distortion. Power is from two 6V6's, with switchable Hush Puppies to reduce power. A spring reverb added a nice dimension, and external effects loop makes it expandable.
Mr. J. is now up North somewhere.
See how much an amp might cost with Amp Cost Estimator.
Pick the features you want on my Custom Amp Worksheet. Get an immediate response with a detailed price breakdown.

I can then send you a detailed description and an invoice for a down payment to start work on your amp.

Or, of course, call Mike at
my name and phone number graphic
9AM-6PM, Monday-Friday.

Custom Rack-Mount Amp

Here's a 50W EL34-based rack-mount power amp that is a kind of hybrid of 2 popular amps. It fits in a 2U slot. Full-range sound with ability to overdrive nicely. Check out how much a new custom amp from would cost you.

Amp-on-a-board Project

This Amp on a board needs no soldering to assemble.
This was an experiment that I might sell as a product - an amp built with terminal strips and screw-terminal sockets.
It can be assembled with nothing but a screwdriver! It would make a good kit to go along with a tube amp course.

50-Watt Clean

Here is a clip of Les Connally noodling around with an even more recent amp, a 50 Watt 6L6 Clean amp, designed like the 50W rack-mount amp. (Any clipping is from my recorder, not the amp itself.)
, or listen to the MP3 Clip Here!.

Other Projects

The demo for this Box was done by Michael Anthony Shanks. A really great-sounding and informative YouTube video.

Excuse the appearance... This is the most-recent pre-production model.
It has a 3-position distortion level control, a tone control, and an output level control. The latest model has 4 levels and a Fuzz switch for those who want lots of fuzz. Plus, always True Bypass and operation on standard 9V battery or standard stomp box power supply.
, or listen to the MP3 Clip Here!.
This is the most-recent pre-production model. I think this is going to be the final design.
It has a 3-position distortion level control, a tone control, and an output level control. Plus, True Bypass and operation on battery or standard stompbox power supply.

A Custom Stompbox

This particular custom stompbox is a combination of Treble boost/cut with Bass boost/cut. Nice range of control. Overall Gain Knob. True bypass. Sounds great!

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