AMT Electronics SS-20 3 Channel Tube Guitar Preamp

Features overview

The Features of SS-20:

– High-grade high-voltage feed of triodes.
– Complete elimination of operational amplifiers traditionally used in hybrid preamps for sound amplification and processing.
– Application of special semi-conductor amplifiers modeling triode-based harmonics and providing signal amplitude necessary for high-grade valve operation.

In order to achieve the full opening of input valve cascades working in the “hottest” conditions the giant amplitude of one hundred and more volts is necessary. The dynamic properties characteristic to valve – based preamps are implemented in SS-20 due to the elimination of signal limiting OA (feed level of 20-25V) in the part of preliminary amplification and using special cascades capable of reaching 250V amplitude with non-linearity similar to 12AX7 triode. Thus, we managed to achieve full dynamic characteristics of guitar signal without usual hybrid “squeeze” as well as assign special sound character to SS-20.

Special attention was also paid to clean channel – in this section we also followed the way of preserving the dynamics of guitar signal with simultaneous formation of soft “nonlinearity” inherent in the cascades on vacuum triodes. It also allowed us to escape both the “squeeze” and “refinement” peculiar to many clean-channels of hybrid devices.

The Architecture of SS-20:

– Two high-grade channels CLEAN and DRIVE with the possibility of Drive-channel operation in two basic modes: moderate sensitivity (CRUNCH) and high sensitivity (LEAD).
– Effects Loop Send and Return.
– Operation via both direct unaltered signal for guitar amplifiers heads, combos, and speakers (OUTPUT jack) as well as speaker cabinet compensated output for mixing consoles, computers, or other recording devices.

The basis of the inner preamp structure is the principle of maximum use of amplification and nonlinear transformation of the valve part of the device. Thus, the semi-conductor part of the hybrid practically does not participate in the sound limitation (except for the use of preamp in LEAD mode at Gain LEAD level of higher than 7) and the entire spectrum is formed by the valve preamp part. In the preamp stage the quantity of semi-conductor cascades is not used in the sound processing, and in the absence of jacks in SEND and RETURN the signal is forwarded to OUTPUT through compensating circuits directly from the output triode cascade. Therefore it is advised to use high quality minimum length cables for connecting the preamp input with guitar.

The SS-20 uses the original cabinet emulator, however, ONLY in direct out mode! It models the amplitude-frequency characteristics of guitar amplification systems for the most accurate reproduction and ease of recording direct. Secondly, it simulates own nonlinearity of dynamic head peculiar to instrumental loudspeakers, that in its turn colors the output signal with short-range harmonics making it live and closer to real. Our unique speaker emulator circuitry supplements the signal with 2nd and 3rd harmonic with smooth increase in their level at signal level growth (it actually is similar to instrumental head in the closed cabinet), not found on other manufacturers pedals.

Technical Information:

Power: External Adaptor AC 120V-240V 12V DC 1.25A
Tubes: 1 x 12AX7 – 12.6V (6.3V)
Anode Voltage: DC 290V

Outputs/Inputs

Amplifier Output – for Combo Connection
Mixer Output – for Mixer/Recorder Connection
Effects Loop Send and Return
Input In

Footswitches

Left F Switch – DRIVE effect on/off
Right F Switch – DISTORTION effect on/off