AMT StoneHead SH-100-4R - Guitar Head Amplifier (rack version)

INFORMATION

AMT's Artist Andrey Smirnov (U.D.O., DIRKSCHNEIDER) uses this guitar amplifier on studio and Live stages.
You can check the sound here:

AMT StoneHead SH-100R Guitar Amplifier is our third approach to gold standard

The recent history of modeling the valved cascades with semiconductor devices started for AMT some 10 years ago, when the science identified the main reasons for valved sound being precisely «valved» and the company started developing its first series of «Legend Amps» pedals.

LA-1. With the release in 2008 of the first Legend Amps series the guitarists got the opportunity to use compact pedals simulating overloads of preamplifiers - common amplifiers that are now a legend among the guitar players. The overloads are based on the cascades that use field-effect transistors with Schottky diodes for modeling the grid limits of triodes.

LA-2. Over the next few years, AMT engineers have been working on the modernization of the first series, taking into account the imperfect simulation of the first series. This work culminated in the launch of a second LA series in 2012. The list of modeled amps was significantly expanded, the company also applied a new and effective technology for getting the «triode» restrictions, further complicated the simulation and provided an opportunity to use LA as overdrive pedals connected to a clean amp channel. Yet despite the obvious successes, the quality of emulation in terms of full compliance with the originals left much to be desired, primarily due to restrictions on the supply voltage (remember, pedals are powered by + 9..12V voltage source). Increasing the supply voltage for cascades in SS-30 «Bulava» preamp and StoneHead-50 amplifier helped in many ways to get around these limitations by boosting the brightness and dynamic sound. The StoneHead SH-50 amplifier may be called the «crown jewel» of emulation technology, considering its implementation in the LA-2 series. It is no coincidence the device has been warmly received by the guitarists community and many musicians are happy to use this compact, lightweight and functional amplifier for rehearsals or in touring.

Apart from restrictions related to low voltage, imperfect LA-2 emulation is also due to the fact that this device emulates only the limit itself, not the triode character of currentvoltage characteristics inherent to vacuum triodes with, of course, a significant impact on the overall sound.

LA-3. The development in 2013 of 12AX7 solid-state analogues has created the basis for the emergence of solid-state preamps that almost completely copy the behavior of valved prototypes, enabling the development in 2014 of micro-triodes (the basis for LA-3 series), that is, the devices that by their current-voltage characteristics are miniature replicas of the vacuum triode parameters. Over 2014 company's engineers done a lot of work to bring the micro-triodes to virtually complete similarity to their vacuum prototypes (taking into account the scale), and in 2015 AMT began to develop its LA-3 line of products.

A few words about micro triodes

The new analog modeling technology of AMT Electronics is based on the use of microtriodes - scaled down copies of the electrical characteristics of real vacuum devices. You can take an image of the anode properties of a conventional «guitar» ESS83 (12AX7) device, compare with the picture below which shows the «anode» characteristics of AMT micro-triodes and see for yourself that their form is almost identical and differ only in scale.

They also behave identically during the processing of the guitar signal, ensuring signal match on level difference of different samples of same-type triodes.

When using micro-triodes, the vacuum-tube circuitry of the prototypes remains virtually unchanged, only power supply goes down K times, and the signals in micro-triode-based devices are simply K times reduced copies of these in the vacuum-tube prototypes, reproducing both all the subtleties of inter-cascade signal changes and the nuances of interaction between the cascades.

A little bit about the amplifier AMT StoneHead SH-100R

The firstborn of the third generation of emulation technologies implementations became inheritor of «StoneHead-50» - rack full 4-channel amplifier SH-100R. This amplifier is a concentration of the latest developments of the AMT Electronics in the field of solidstate emulation of processes occurring in the tube stages. Playing through this amp you can feel the very same «tube» kickback and feedback, - which is still slightly lacking in previous approaches to emulation, - you can feel the melodiousness of sharp attacks' handling, and catch yourself thinking that you want to overload these stages again and again to enjoy the richness and precision of the resulting sound.

SH-100R is a 100 W, 4-h channel guitar amplifier, made in the 1-rack case and designed for usage in studio and during concerts.

Architecture and features of guitar amplifier SH-100R

• Preamp section consists of four completely separate channels.
• Each amplifier channel has a separate equalizer, controls for sensitivity and output level.
• The amplifier has an effect loop with the possibility to turn it off.
• It is possible to work with specialized guitar cabinets (8 Ohm, 16 Ohm plugs), and directly with the mixing board or linear amplifier (through OUT CAB. S. outlet). There is a balanced XLR output and a separate headphone output.
• Power amplifier allows you to work on load of 8 or 16 Ohm. In both cases output power will be 100 W.
• Powering on the amplifier without a load does not lead to amplifier's failure - unlike with tube amps.

The first channel can operate in two modes: CLEAN and CRUNCH. CLEAN mode focuses on classic clean sound with graceful easy limitation in maximum sensitivity mode and crystal clearness and brightness in a zone of moderate values of sensitivity. CRUNCH mode has a broad range of sensitivity adjustments. This, in combination with flexibility of output tone control, allows to get any sound from a slightly loaded clean signal to significantly loaded dense and bright guitar sound through a channel in this mode. First channel is equipped with an additional VOICING regulator, widening the range of tone control.

Second channel is clear, unlike the first, and gives a much higher total amplification of guitar signal. The channel has classical sensitivity and level controls, equalizer with three regulators, switch between two modes which differ by a general level of sensitivity and the final tone. LOW mode gives a rounded sound perfectly suitable for many lighter music styles. HIGH mode has more vivid «modern» sound.

The third channel is the most universal. With the additional VOICING regulator the range obtained with the help of its overloads extends from classical English amps to heavy modern «Americans».

The fourth channel has the most aggressive sound. Channel is marked out by spectral and tonal balance, which allows to achieve bright flageolets and readability of fast passages. Two channel's modes allows you to choose more rich or more dry sound. The power amp section has two switchable volume adjusters for MASTER VOLUME, and also for PRESENCE and RESONANCE.