Matrix GM50 review

yek

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Hi there,

This week I received the new GM50 mono power amp module from Matrix.
It's a module, designed to be added to a speaker cabinet, therefore converting a passive cab into an active one.
I think it's a brilliant idea.

I already own the GT800FX, and will also compare the GM50 to my Atomic 50/50.
I'm using a 1x12" cab with an EVM 12L Classic (200w, 8 Ohm).

Power and tone specs
The GM50 features the same output power specs as the GT800FX power amp by Matrix: 400 watt of Class AB mosfet power at 4 Ohm, 250w at 8 Ohm, 120w at 16 Ohm.
It's solid-state but shares characteristics with the GT800FX and the newer GT1000FX: designed to sound like a valve amp while still featuring flat EQ response.
No fancy controls, just on/off and gain.

Outside
- Small enough to fit most 1x12 and larger cabinets. Solid build quality.
- Input: XLR or 1/4".
- I'd prefer the speaker cable to be longer. I had to extend it for testing purposes. I also would prefer if it came with a 1/4" jack plug connected.
- The mounting plate supports mounting the unit with the controls at the outside of the cab. However, when fastening the unit to the inside of a cabinet, the mounting plate is of no use. It would be nice to be able to move the mounting plate to the other side of the unit.
- The fan is audible but certainly quieter than my GT800FX's fan. Also, the fan on my GT800FX rattles, while the GM50's just moves air.

Is it loud enough?
Yes, it is for me. Lots of headroom. Not as loud as the Atomic 50/50 but I have never maxed out that one or the GT800FX for that matter.

How does the GM50 compare to the tone through FR speakers?
I'm using Adams A7X monitors for FRFR. The Cab block in my presets has an OwnHammer EVM MixnMatch 10 IR (no mic), plus a Red Wirez MarkIIC IR (U87 at CapEdge 2"). These IRs together sound very close to my real cab "in the room".

When comparing tones through my studio monitors to the GM50, things sound very close. The GM50 has about the same amount of bass and treble as the FR tone. And it's immediately clear I went the "real cab and power amp" route some time ago, at least when it comes to LIVE tones. The GM50 and EVM cab emphasize punch, attack, dynamics and 3D, compared to the sound through the (also terrific) Adams monitors.

How does it compare to the GT800FX?
TBH, there's not a world of difference. I'd be happy with either, and I'd not upgrade my GT800FX to the GM50 or GT1000FX, based on tone alone.
But as reported by others, the GM50 does sound more open, less gritty and more direct.

How does it compare to the Atomic 50/50?
I compared the GT800 to the 50/50 earlier, read this. I concluded that the Atomic 50/50 has more output power, sounds a bit more round, less gritty and slightly more natural with depth. Also, it is brighter, even with Presence at zero. When playing the same presets through a Matrix amp after dialing them in for the Atomic, I need to increase the top end. Of course, you can discuss whether the Matrix is too dark or the Atomic too bright ....
The GM50 improvements do narrow the gap with the Atomic valve amp. I'd be happy to play either of them at a gig.
The Atomic is also more expensive here in Europe, much much heavier and as a valve amp requires more care / maintenance than the Matrix offerings.
So, it all comes to what YOU think it important. I love my 50/50, but the weight factor does matter.

Conclusion? The GM50: highly recommended when you need an easy way to transform your passive cab into an active one!

I'm contemplating buying the GM50 to add it to my 1x12. I'm always playing mono, it'll make my rig lighter and smaller and I can sell the GT800FX.
But I need an easy way to mount the GM50 to the inside of my 1x12 cab. I'm bad at working with tools. Open for suggestions ... :)

P.S. Just to be clear: I received the GM50 for review purposes. I'm not paid in any way for this.
 
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But I need an easy way to mount the GM50 to the inside of my 1x12 cab. I'm bad at working with tools. Open for suggestions ... :)

Thanks for the review Yek... As to mounting the GM-50 to the inside of your cab I would say Heavy duty Velcro or hook loop tape. Specifically this stuff, it sticks to just about anything ;).
 
Thanks for the review Yek... As to mounting the GM-50 to the inside of your cab I would say Heavy duty Velcro or hook loop tape. Specifically this stuff, it sticks to just about anything ;).

Thanks for the tip. The rear surface of the GM50 is probably large enough to cover it with Velcro and hold on.
 
If you supply them with the correct dimensions of the GM50 you could also ask your cab manufacturer (TT?) to make you a new back board with the hole pre bevelled, cut out and finished in the same covering as your original cab - will be a lot handier to connect to and also swap back to passive if you want. Only requisites on your part should be a screwdriver and a lack of colour blindness for hooking up the terminal wires to the speaker :)

(Actually - now I think of it, the rear screws were probably hand drilled - so you might have to use a blank rear and drill new ones to suit)
 
I ended up buying the GM50. :) It's in my 1x12" with an EVM 12L and I'm having a blast with it.
Did 3 rehearsals with it already. Lots of of output power on tap but also sounding great at low volume level.
Everything from super clean to high-gain.
And loving the fact that my rig is much more compact and portable now. Went from a 5u to 3u rack case.
Together with firmware 6 and the MFC update, this is one killer rig!
 
I ended up buying the GM50. :) It's in my 1x12" with an EVM 12L and I'm having a blast with it.
Did 3 rehearsals with it already. Lots of of output power on tap but also sounding great at low volume level.
Everything from super clean to high-gain.
And loving the fact that my rig is much more compact and portable now. Went from a 5u to 3u rack case.
Together with firmware 6 and the MFC update, this is one killer rig!

You mean to say you went to rehearsal and let your band mates hear V6 pre-launch? Are they not in danger of Dojo coming for them with a baseball bat and a gagging order (rolled up sock and gaffa tape)?
 
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How did you end up mounting it and wiring it? Do you still have the option to use the cab "normal"? Meaning are there 2 inputs(the original and the GM one)

Could you post a pic? I am thinking of adding one the my Port City OS 1x12 but still want the option to use the cab with my Mesa mini-recto from time to time.
 
Sorry to be resurrecting this ancient thread, but do you think that Velcro-ing a GM50 to the outside of a 1 X 12 cab would be viable too, yek?
I'd probably dismount it when traveling with it in the trunk.
I'm not doing gigs that require me to take gear on a plane, etc.

I'm thinking of of going this route because if I have a powered guitar cab, I can see me using one of the Fractal floor units like the new FM3 for an exceptionally simple rig.

One of my issues with the Axe-II, which I love, is that it's usually too much of a schlep to take my rack (even though it's just 4U) plus a cab plus the MFC to the low key jazz gigs I tend to do.
If everything except the power amp and cab was on the floor then I'd just have to deal with the floor unit and the powered cab and then I could use my Fractal gear on a more regular basis.

I don't feel like taking a saw to any of my cabs at the moment in order to permanently mount a GM50.
And I think that Velcro-ing it to the inside of a cab might be a drag sometimes for setup/tear-down/etc.

Also...
If anybody from Matrix is reading this....
Is the GM50 circuitry more similar to the GT800 or the GT1000, or neither?
I had a GT800 briefly and did not like it at all compared to the GT1000 I also own.
Maybe I had a bad unit.
Most other folks don't hear much of a difference.
But I returned the GT800 right after getting it.
 
I’ve been thinking similarly lately. An FM3 and 1 or 2 active cabs is such an easy setup!
I’d be interested in the cab selection you decide!
I’ve got a 45 year old 15” JBL in a box I like, but I also like stereo and light and active too. Just can’t figure it out yet...I’ve also got a matching set of 1964 Altec 605 15” duplex speakers too but they are all heavy!
 
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