I make amplifiers for guitar or harmonica … Small, like my workbench !
Available as separate head … One can also order a combo, with a 10 or 12′ speaker.
The layout and the equipment are to be composed “custom” according to your project.
Transistor realizations feature a real power of 10 to 25W on 8 ohms.
They use a 60s germanium technology, which denies the bad reputation of transistors…
It brings especially a natural compression and a progressive transition to overdrive which have little to envy tubes, with a price also compressed!
I also realize high quality tube models, custom 5, 10 or 15W, with vintage or high-end components where it’s audible.
In both cases my aim is to offer amplifiers intended for home use or small concert venues, without technical weakness, and with a sound that will please the instruments.
GeAmps,
my special germanium amps
I use a proven assembly from the 60s / 70s, recognized as an excellent mix of solidity and sound quality … It was then found as well in HiFi equipment as in sound equipment (sound system at Woodstock …).
The original production technology was germanium. The sound was smooth, but it required to sort carefully the components. Seeking easier industrial solutions, western countries abandoned germanium transistors after 1969. On the contrary, they were kept in the USSR, and perfected until the 90s. This is where my stocks come from: components to military standards, so highly reliable … And always excellent from a sonic point of view.
10W amp board using Soviet transistors (personal prototype).
Welcome properties in instrument amplification …
The germanium transistors provide compression of the global signal and in the treble, as well as a progressive entry in saturation. This lets compare them to the operation of tube circuits, and differentiates them from silicon transistors, which are more faithful and constant, but generally quite dull.
Sonic expressivity is my priority
The bad reputation of solid-state guitar amplifiers comes from that since the 70s, they have been confined to the production of low-end equipment, with circuits that are weak in power (which do not hold up) and in technology (with preamps more simplistic than the least of the pedals.
Contrary to popular belief, there were very good transistor amps at the end of the 60s: Remember the Vox Defiant and Superbass amps used by the Beatles in 1966-67, the first Santana records, American combos made in the 70s by Randall or Kustom (the original brand, not its current Asian ghost) …
Conversely, some tube amps do not necessarily have the quality they promise, if only because their output transformers are pitiful…
In any technology, you need what you need!
GeAmp10W amp
Its output circuit is called “quasi-complementary” and realized with Russian germanium transistors from the 70s and 80s. These military components are severely sorted, which optimizes the simplest circuits, without unnecessary accessories.
This is a typical amp for home. It is upgradeable on demand to 15W / 8ohms. This is advantageous for working with loudspeakers whose output is a little lower than the current average, like the small 10 inch Greenback by Celestion.
GeAmp15W type amplifier board in progress …
In the background, an original Accutronics reverb tank – option requested by the customer.
15W combo during assembly. The head seen above is in 2-unit Rack format.
It will be fitted with an HP Celestion Greenback 10 “, with an original Fender Oxblood canvas.
GeAmp25W amp
The same quasi-complementary assembly is here carried out in hybrid Silicium + Germanium in order to support a higher supply voltage.
Germanium is still used in the main amplifier stage and in the power transistors, which preserves the effects of compression and the grit in overdrive.
Silicon ensures the fidelity of the input circuit and the driving of the output stage.
Finaly : a surprising 25W amplifier, which has nothing to fear from its competitors.
GeAmp25W 3/4 rack amp head (330x88x180mm)
The Louisiana drawing of the facade was decided in conjunction with the client.
The preamp is derived from my SweetGerm stompbox, with an external effects loop requested by the customer …
Choosing a preamp…
The choice takes in the circuits of my pedals that are best suited to this role…
First option: a SweetGerm type preamp
Suitable for 1/2 and 3/4 body “hot” guitars, with humbuckers and P90s …
As well as acoustic instruments: guitars, double basses, and others.
Very bright with single coil pickups, friendly with the bass strings of the Telecaster.
Second option: a CurvyMama type preamp
Gives some thigh to sharp instruments: Fender type guitar, all single pickups.
Special version for the harmonica, enhancing the warmth and grain of the instrument.
Germanium overdrive circuit, with a special grit…
Custom preamps on request
Classic bass / medium / treble guitar tone stack, used by the big brands.
Ampeg-style passive or active Baxandall circuits for bass and acoustics.
Additional functions can be added:
Adjustable gain, custom presets, solo booster …
Integration of a low voltage tube final stage, like in my LowVoltTube pedal.
Accutronics spring reverb, LittleW saturable analog echo, external effects loop …
My tube amps
Here is a true custom way: models are designed following the customer’s personal order.
Always for material questions — the size of my workbench — I can only make small heads or combos, from 5 to 15W …
They will be designed and developed based on the wishes of the customer, who will decide what can be saved and what should be generously considered. My role as designer is then to offer him a coherent whole, responding to his wishes and respecting the rules of the art.
An example of realization, produced in spring 2021.
This is the project of a 15W head based on the original AC15 Vox from the 60s, but completed with additional circuits: solo booster, effects loop with tone control, speaker attenuator, and a line output with speaker simulator.
Old-fashioned production, except for the general mixing card which will be a PCB.
High-end Mercury Magnetics output transformer.
Tube head after the AC15 Vox, sixties version, currently being assembled and tested …
The general circuit board is not yet installed.
Detail of the main card. NOS components from the 50s to the 70s.
Electrochemical capacitors are contemporary because more reliable at the same price.
The link capacitors at the critical points are Russian military paper in oil models.
At your service ! Tell me your desires…
Guitar Poppa.
