Fratus Amplification repairs tube amps and other audio gear.

Tube Amp Repair and More in Houston

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New! Modules that help you build your amp or preamp project faster.

Modules are designed so that the parts are accessible from the back of the board. That way you can tweak the values to your heart's content.
The Modules then solder onto the back of a standard 9-pin tube socket and works with 12AX7, 12AT7, 12AU7, ECC81, ECC82, ECC83, ECC803, 7025, and their equivalents.

2-stage Preamp module

This PCB module can be configured as either:
1. Two individual self-biased gain stages
2. One self-biased gain stage and one voltage follower stage
There are separate B+ power and ground for each triode section.

Phase inverter PCB module

The phase inverter module is a long-tailed pair design used in many of today's and yesterday's vintage models.
It has connections for negative feedback and a presence control.

By "stage," I mean an amplifying stage in an amplifier. I added one preamp stage board to a "British" amp with wonderful results, using the filament voltage of the amp and the B+ of the amp to power it.
Each of these modules is a complete stage as found in many popular tube amp designs. The component values are left up to the builder, but each PCB comes with a component placement diagram and schematic so you can tailor them to your application. The Preamp Module has a ground plane on one side to reduce interference to a minimum.

These modules need filament and high voltage from some source. If you don't build them into existing amplifiers, you need to provide a power supply that provides filament (6.3VAC) and B+ of up to 300VDC maximum, down to maybe 24VDC or so. How low B+ can be depends on the preamp tube used.
To build a preamp stage, all you need is one assembled preamp module (which contains two preamp stages).
To build a single-ended speaker-output amplifier, you need is one assembled preamp module, and one assembled output tube module.
To build a push-pull output amplifier, you need one or more assembled preamp modules, an assembled phase inverter module, and two assembled tube output modules.

Here's one I built up from the PCB to a usable level by assembling the module, building a power supply, and assembling a control panel.
view of built-up preamp assembly
Shipping is $7.50 to anywhere in the USA. We'll have to figure out the postage if you are somewhere else.
Call Mike at
9AM-6PM, Monday-Friday.

Article: Tube Kits for Guitar Amps
Copyright 2012

Here are a few things I've found while looking around. By no means is this list complete.
Making a guitar amp from a kit is pretty involved. I would start first by assembling a stompbox or pedal kit. If it works and stays working then MAYBE you are ready. But a whole amp is a complex job.
You might first try a single-ended amp, as they are MUCH easier to make.

CeriaTone has an impressive selection of amp models, some of which are clones of popular British and American designs, and some of their own designs that look impressive. They come in kit form and semi-kit forms. they will even ship the kit minus the tubes and transformers to save shipping, since they are in Malaysia. Whew! Long way away, but there's plenty of technical help available around the world.

Antique Electronics has the MOD101 and the MOD102 kits. They are interesting head-only configurations.
The MOD101 is a 60W Push-Pull model that offers 32 variations of construction to achieve the sound you want. Comes with two 6L6's, two EL34's, one 12AX7 and one 12AT7. The MOD102 is a 5W Single-Ended Class-A amp with an EL84 and a 12AX7.

Weber Amp Kits has a mind-boggling variety of amp designs. Some are clones and some are original designs. Combos and heads are both available.
Youtube video Weber Amp

Tube Depot sells kits modelled after the Fender Tweed, Fender Blackface Deluxe, Fender Bassman and Marshall JTM 45.

Mission Amps offers two starting models of all tube guitar amps, the Aurora and the Aurora Reverb, that are configurable to suit your tastes. The Aurora is available in 10, 18, or 28 watt models, and the Aurora Reverb comes in 25, 35, or 50 watt models.

Torres Engineering features a line of amplifier kits include the 3 watt Boogie Mite, the British Invasion Matchless Killer amps, and a Tweed Deluxe on Steroids.

The Doberman Music Products website works AX84. Find the building information on AX84 and buy your parts from Doberman.

STF-Electronics has the Combo Super Champ and the Champ Head. Worth a look-see.

DIY Tube Guitar Amp is a great source for parts, tubes, kits, stompboxes, etc. Really, really informative.

Not a true "amp kit" like what I started with, but still, its a small amp for headphone practice, as well as a kit.

These were real popular a short while back... and an interesting concept. Choose your own box. I want one in a Whitman Chocolates Sampler box!

And There are bread-board amps in the old style available. They even come with the wooden board to mount them on!
Look for them in the 8 Watt Mono and Stereo forms. Find them at AES Kits.

If you want an experienced amp-builder to build your amp for you, give me a call or drop me an email. I'll charge according to how much time the project takes.
And, of course, if what you built yourself is not working, call me and we'll see what can be done.

Call me, my name and phone number graphic (after 9AM, please).

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Be safe! Observe published safety rules about measuring high voltages, which CAN absolutely kill you or at least ruin your day.


Its nice to have books, just like anything else. The thing that I have learned is that first you need to understand electronics, that is, learn how electrons behave and how to tame them. Then you have to learn the skills and practices that make it safe and effective to work on stuff in general. Then you need to learn about the particular type of product that you are interested in.
I found lots of good books on Alibris: Alibris
See how much a custom amp will cost with Amp Cost Estimator. I hadn't thought of it before, but I can also make your amp a kit or semi-kit. We can discuss that if you email me. (If that link does not work for you, use as the address, subject "AmpKit".)

Select the features you want and hit the button, and get an immediate estimate according to the features you have chosen.
If you include your email address or phone number, I can send you a detailed description and an invoice for a down payment to start work on your amp.
But nothing will happen if you don't send me a payment, so don't worry that you might accidentally order something.

My main site is
Join the search for tone at
Need parts? I'll help you find them. Use my Amp Parts link.
Its a page that helps you select parts you might have trouble finding. I don't make anything off of it, but it doesn't take long to answer, so I do it for free. You CAN drop some change in the TIP JAR. Thanks, if you do.

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A word about our sponsors: I buy a lot of stuff from Parts Express. I've never received any bad parts or junk. Try them out at the link nearer the bottom of the page.
I recently added Vann's. Check them out.
My friend Cathy does wonderful costume work for your act, and sets for shows... See Cathy's Theatrical Costumes for any purpose. - Pro Audio Equipment - Vintage Tube Amplifier Schematics - AmpsLab - Amp Info and Schematics
The Carvin Museum - Technical Documents
GeoFeX Circuits - Audio Electronics Page - Schematics, Circuit Diagrams Sharing & Download -- fx projects
Analogguru Schematics
Vintage German modules (Neumann, Siemens, TAB, IRT, Lawo, ANT, Eckmiller, Adis, Monitora and Telefunken modules and Braunbuch scans)
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A guide to replacement guitar amp speakers from Loudspeakers Plus is here.
(Look for the small links just under the title that lead to separate Eminence and Jensen replacement charts, too.)
There are lots of schematic and technical information links on my Technical Links and Ads Page.
Choosing Speaker Wattage and Ohms to maximize Sound Output and minimize burnt speakers and amps! A techish article from Antique Electronics and!
Speakers and Power Explained
Off-page article: How to repair circuit board problems, by billm. I use these methods as well. Good dude.
PetMeds: Best Selling Flea & Tick Products
Auto Parts Warehouse: Top Selling Part Names
Equal Exchange, Inc: Fair Trade gifts, Inc. All Valentine's Day Baskets
Vintage Tube Amp Repair Experienced vintage amp repair.

Tube Amp Debug Page R.G. Keen. This page is designed to lead you through debugging a problem with a tube-type guitar amp.
Prowess Amplifiers has a large collection of guitar amp schematics. - Building your own Tube Guitar Amp - Troubleshooting Tube Guitar Amps Amp Stuff - Tube Amp Schematics - Fender Schematics
Schematic Heaven. Where All Good Amp & Effect Designs Await Resurrection... (down right now, might come back up!) Use Prowess Amplifiers
TDSL Schematic Links
Poland site - Amp and Stomp Box Schematics Google-Translated English Version
The Free Information Society - Audio Electronic Circuit Schematics
Mesa Boogie Schematics
Electroconducive DIY Audio - Schematics - Index of /new/schem - The Site for Electronics, Microcontroller, Tubes, Forum, PCB, Circuits, Onlineshop - Electronic Circuits - Electronic circuits - Electronic Circuits

Great amp-building video from Tube Depot! If this is too much work, I'll build your kit for you. Priced according to difficulty. Vast array of references, resources, nearly everything! Electronics Hobbyist Web Site GREAT Links! Don't pass this one by! Electronic references, circuits, data, repair info.

Schematic Sources and Other Electronic Information Links:

Got to my Ad and Tech Links Page!
Large collection of tested sites with actual useful data!
Entire site Copyrighted - don't snag! Leave email with suggestions or requests at: (If that link does not work for you, use as the address, subject "AmpKit".
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