Trace Elliot GP7 SM 150 Watt Head Review

[DGBass]

I've had a few of these pass through my hands in recent years and found them to be very capable and underrated amplifier heads. The Trace Elliot GP7 SM 150 heads were almost an entry level TE amp head of the late 90's /early 2000's and typically came in an enclosed metal case which was fitted in a wooden sleeve covered in green carpet covering. The RAH heads could be rack mounted ( assuming you had purchased a set of TE rack ears ) but in my experience most of these amps came in the green carpet covered wooden sleeve. The amps were fairly straight forward design with either a Mosfet power board or a Bi-Polar power amp board ( The Bi-Polar Bear) and were fan cooled. Output was 150W RMS, 300 Watt peak. The input stage was a standard 7 band graphic with pre-shape buttons and a graphic output knob and an EQ balance knob. A DI option complemented these features and an effect send/return and  line out completed the front panel options. On the rear panel was two speaker jacks and a tuner out. In use the amp has a fairly characteristic Trace Elliot tone using the pre-shape. Using the graphic EQ in conjunction with pre-shape 1 gives a fairly wide option for tones and its not difficult to get a useable tone for almost any musical style. 

In use these amps are very versatile/toneful and their output will more than cope with rehearsals and small gigs even with a good 8 ohm cab. With a good quality 4 ohm cab they can be very loud and remain stable for an all night gig lasting several hours. I haven't experienced any issues with cutting out or overheating with prolonged high output usage of these amplifiers. 

Pro's

Trace Elliot classic pre-shape sound

Quality pre-amp tone shaping abilities

150 old school Watts is deceptively loud

cheap to purchase used 

easy to repair/maintain

Good build quality

Great amp for punk/metal tones

Cons

fairly heavy for a 150W amp head

rack mounting options limited as TE rack ears unobtainable these days

cooling fan can be noisy as tend to run very fast

Watch out for crackly/noisy examples.  There is an issue with some builds that don't have a locking washer on the power amp ground post(mounting screw can shake free after years of service and cause noise/crackles).

 

For the amp aficionados and techies, there are a couple of simple mods for these amps that can improve their usability. Changing R21( GP7SM 150/300 schematic) on the pre-amp from 10K ohms to 4.7k ohms transforms the input sensitivity and overall volume responsiveness of the unit and makes a huge difference to how these amps perform. The same mod was carried over to early Clive Button designed Ashdown MAG amps to also increase the pre-amp sensitivity and overall amp performance. For examples with a very noisy and fast cooling fan, you can mod this by fitting a series resistor on the fan positive to drop the fan voltage( usually a high 16v rail). In my experience, a 5 Watt 82 ohm or 5 Watt 100 ohm resistor will reduce the fan speed without adversely affecting cooling ability. Thermal cutout on these amps is designed as 100C so you really need to be thrashing them to death to cause a cut out. Always consult your amp tech before applying any mods*

Overall, nowadays these are great budget amps that we're still built up to a spec and not down to a cost. The sound and performance from them is still valid today and I'd give a good example 8.5/10 -  in my humble opinion.