Audio i2e

JESS20 Guitar amplifier
"Solid-State", 20W, Compressor, Reverb, active EQ, Output Transformer

Manual (PDF)

Quickstart (PDF)



JESS is not a tube amp !
JESS is not a digital modeller that provides hundreds of sounds !

The philosophy of
JESS can perhaps be summarized as follows:
One channel, pre-amp gain adjustable to light crunch, master volume to overdrive the
output, a little bit of EQ, compressor and reverb, no frills, everything else about pedals.
No soulless digital high-gain modeling of countless tube
amplifiers, pure analog circuit technology.
No operational amplifiers in the signal path, no power amp IC, only discrete semiconductors.
But also no boutique ramblings of hand-soldered point-to-point wiring, NOS tubes, rushing carbon press resistors or orange voodoo capacitors.
Output transformer, pure rock'n'roll, or jazz, or whatever, the player and the guitar set the tone,
JESS supports.

And a very important part of the philosophy:
Developed and produced in good old Germany, with fair pay for all involved and with respect for the people and the environment.

Or more technical:
JESS is a 20W solid-state guitar amplifier.
JESS tries to create a new, independent sound, which always puts the features of the connected instrument in the foreground.
Practically, field effect transistors (FETs) are used with JFETs in the pre
amp and MOSFETs in the power amp.
There is no operational amplifier in the signal path
! Virtually every stage of the amp adds overtones that give the amp its musical character.
The MOSFETs of the power amplifier works on an output transformer,
what on the one hand optimizes the matching to different loads, on the other hand, of course, also has a certain share of the sound of the amplifier, especially when overdriven.
JESS offers a switchable compressor in the input and an effects section with reverb or phaser / flanger.
The logical control of the various switching functions, the control of the compressor, the generation of the phasing / flanging and the "intelligent" bias control of the output stage are handled by a microprocessor.
The EQ unit works actively, so it can both attenuate and amplify different frequency ranges.
JESS can generate 20 honest, analogue watts or switch back to about 5 watts. A "bedroom" unit provides output below 1 watt at full dynamics and for practicing at home.
In order to avoid having to connect a box for practicing,
JESS has a built-in monitoring loudspeaker which, controlled by the "bedroom" unit, makes even the quietest practicing possible.

Frequently asked questions about JESS

Technical data

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