SR Technology is a relatively young company. At just under 11 years old, they have managed to compile an impressive catalogue of products including PA systems, power amplifiers, speaker systems and mixers, not to mention dedicated combo amplifiers. The two people behind SR Technology’s designs are engineers Sergio Menchinelli and Ferdinando Canale. Both were previously responsible for designing products for companies such as Marconi, SGS, Texas Instruments and Meyer Sound – all hugely respected names in audio.
   
SR Technology’s Jam 150 is a multi-channel amplifier that is largely designed for the performing multi-instrumentalist, acoustic musician who needs an amp that caters for more than one input channel. In the case of the Jam 150, it has six channels, two of which are stereo. SR Technology call this amp ‘A Compact Audio System’ suitable for amplifying just about anything including vocals, electric guitar, acoustic guitar and keyboards, as well as providing a separate stereo CD (or similar device) playback input.
   
Unfortunately, in researching for this review, a combination of mix-ups and inaccuracies resulted in numerous unresolved technical issues, which almost led to a very gloomy review. However, having now been supplied with the correct information, the future for the Jam 150 looks a little brighter.

Construction
The immediate appearance of the Jam 150 is good, displaying more than a little Italian aesthetic - its initial appearance could be mistaken for a large hi-fi speaker. It appears to be very well made, comprising of a chunky, ported plywood constructed cabinet containing both an 8” bi-amped woofer and hi-frequency compression tweeter.
For those of you who may be unfamiliar with these terms, bi-amp means (in this configuration) that the tweeter and driver have separate power amplifiers. The 8” woofer is powered by a 120 watt amplifier, while the tweeter is powered by its own separate 30watt amp - thus giving a better and smoother tonal response.
   
The speakers are given adequate protection by a strong metal grille, and the overall appearance is that of a sturdy and well-designed product. On the top of the amp, all the controls are neatly arranged in a recessed control panel, protecting them from the rigours of road life. The Jam 150 stands proudly at 45cm high, which considering its power rating is pretty compact.
   
Coming in at a relatively light 16kg, the amp has two recessed handles for comfortable lifting. A handle on the top would help with loading, but would maybe spoil its appearance.

Features
With a total of six channels, this amp offers the user plenty of options with the type of signal that can be connected. Channel 1 and 2 are both microphone inputs that are also suitable for low-level acoustic pickup instruments. Inputs 3 and 4 have a clever design feature allowing both matched stereo signals, or two independent signals to be amplified. This works fine providing the instruments used have suitable dedicated volume controls to allow independent control of level over and above the stereo channel volume pot.
All channels have a separate volume control and active tone controls comprising hi, mid and low frequency with cut and boost of 15db. Each channel has an independent effect send to the internal effect device, which is courtesy of Alesis. This comprises a very simple device with four pre-selections, one delay and three reverb settings. Selection is made via a simple non-latched button that cycles through the four settings.
   
Master controls include volume, effects return level and master effects send and stereo return loop. Outputs are catered for with a Left and Right phono record out, and a mono XLR line out to feed external amplifiers or mixers. The amp is also fitted with a handy switch to allow earth drop for the removal of mains hum.
   
The absence of an additional speaker output is of concern. It would be great to add further speakers for use on stage, which I find strange considering SR Technology make matching speaker cabinets. The amp is available in three types of finish - marquette wood or lacquered black to suit passive and the more gruelling of working environments.

Sound
I plugged various instruments in the Jam 150, ranging from keyboards to bass, and both electric and acoustic guitar. The sound produced by the Jam 150 could be described as deep and clear, having a good tone. The 8” driver produces some very rich bass tones, while the addition of the active bi-amped compression tweeter produced very good overall results. However, the overall output level seemed to be quite low, particularly with electric and acoustic guitar.
   
When playing acoustic guitar, I found the low frequency control had to be cut to its full -15db setting in order to keep the bass frequencies under control. As a result of this, I feel strongly that the addition of a hi-pass filter or more comprehensive equalisation on some of the channels would not go amiss for anybody who uses this for acoustic guitar.
   
I also noticed that when the amp was running at a reasonable level the top end seemed to compress. Maybe this is some kind of limiter that is protecting the tweeter, but at higher volume settings the effect was rather undesirable.

Conclusion
The sound quality produced by the Jam 150 was of a very high quality indeed. However, the output seemed low, and even at full volume it was not producing the kind of grunt I know some people would expect from a 150watt amp. The absence of an additional speaker output restricts the ‘power’ potential of this essentially good amp.
  
I feel this amp would be a very useful addition to a studio where simple and clean amplification is needed. However I do question how it would perform on a stage where sheer grunt and power is required. The built-in effects, although limited, sound fine and with the master FX loop allows expansion to your FX armoury.
  
Despite the overall build quality being very high, some of the input screws on the control panel were loose. Not what you want to discover on your first gig!
   
Despite the Jam 150 making my acoustic sound pretty good, I don’t see the amp as a dedicated acoustic amplifier. With the absence of comprehensive equalisers, in some instances one may struggle to control rouge frequencies. However, if you need a hi-quality sound reproduction amplifier for your studio or stage performances, with multiple inputs, the Jam 150 will be just the amp for you. It’s capable of making almost all instruments sound great and where it loses out on sheer volume the tone produced is sweet.