Palmer Macht 402

I've been using this amp for a few days now and I'm very impressed with it. I had looked at purchasing the Harley Benton GPA-400 but decide on this one as it has a lot more features included and seems to be of a better quality. Palmer is part of the Adam Hall group. Compared to the Harley Benton GPA-400, it has more output options for a start: 2 x Speakon and 3 x 6.3mm (1/4") jacks. Inputs: 2 x balanced 1/4" TRS and 2 x balanced XLR line inputs for channels A and B. It also has very good built-in circuit protection: over-voltage; overheating; short-circuit; soft-start and DC. Switching power supply. Operating voltage is switchable: 230v or 115v, AC. Always check the voltage setting before turning a device on for the first time. I once had a power supply blow-up because the voltage switch was supplied with the switch in the wrong position: 110v instead of 240v. I didn't check before switching it on - bang! An expensive mistake, one very dead power supply. It has more output power modes than the Harley Benton GPA-400, as well: 2 x 200w@4ohms; 2 x 100w@8ohms; 2 x 50w@16ohms. In bridge mode: 1 x 400w@8ohms; 1 x 200w@16ohms (mono).

FRONT CONTROLS:
On/off; volume; treble and bass controls (sometimes call resonance and presence). Rumble filters: low frequency lock at 40Hz for channels A and B which are independent of each other.

FRONT LEDS:
Power, signal, clip, protect, Output Mode: bridge/parallel).

REAR CONTROLS:
Ground lift: eliminate ground loop hum. Clip limiter: output set to maximum possible level. Output mode: bridge, stereo or parallel. Adjustable input sensitivity: Hi (-10 dbu/240 mv); Mid (-2 dbu/610 mv) and Low (+4 dbu/1.23 v).

CLASS-D AMPLIFIER
This is a class-D amplifier, and therefore, is very efficient. The theoretical power efficiency of a class-D amplifier is 100%! But, real-world power MOSFETs are not ideal switches, but practical efficiencies well over 90% are common. If you don't know the difference, by contrast, linear AB-class amplifiers are always operated with both current flowing through and voltage standing across the power devices. An ideal class-B amplifier has a theoretical maximum efficiency of 78%. Class A amplifiers (purely linear, with the devices always "on") have a theoretical maximum efficiency of 50% and some versions have efficiencies below 20%. The power consumption of this amp at full power is 820 watts. It also weighs in at 3.8kg which is very good.

I have connected my rack version of the brilliant Kemper Profiler Amplifier (KPA) to the Palmer Macht 402. The amp then powers two Line 6 DT25, 1x12 extension cabinets. The cabs are designed by Reinhold Bogner and use 12" custom Celestion G12H-90, 8 ohm speakers. They sound great and have lots of bass because of the close-back design. It's my dream set-up at the moment, until something else comes out ;-) It's loud and it's got more than enough oomph, 200 watts to be precise! And, it all comes in full glorious stereo, so modulation and delay effects sound fantastic.

CONCLUSION
Overall, I'm very happy with this amp and for the price it a bargain. It looks and feels like a quality unit, it's got no valves so I hope it's (very) reliable, I can't tell yet as I haven't had it that long, but it comes with a 3-year Thomann guarantee, highly recommended.

I bought this stereo amp to replace my all tube Peavey Classic 50/50 amp. The tube power amp is four times heavier (26.5 pounds - 12 kilos) and takes 2U spaces. Plus it needs re-tubing and occasional service as all tube amps do. I paired my Macht 402 with the Digitech GSP1101 rack processor which I have been using for about 10 years now. I was worried about two things: first that the 402 will not have enough volume and second that it wouldn't sound as good as Peavey. I was wrong :) I use two Carvin Legacy 2x12 cabs 8 Ohm each, with Celestion Vintage 30s, and the Macht 402 amp has plenty of power on tap even in stereo mode. It's definitely loud enough to play live with a loud drummer. As far as the sound goes it's as close to the Peavey as it gets: clear and worm, but punchy. The EQ controls are very effective and I was able to dial the sound that I was used to within minutes. The Macht 402 is loaded with features and very solidly built even though it's made in China like pretty much everything else these days :(

Bought this to put in a 2U rack, along with my Digitech GSP1101, as a live back-up or my Kemper, just in case.
I use the Kemper with a Yamaha DXR10 powered monitor, but wanted the option of using it with a guitar cab (mine is the unpowered Kemper "toaster") and this new Palmer amp fitted the bill perfectly: small, light, powerful. Oh, and a great price!
It seems very well made - a solid feel and quality, notched controls. It's very light, which is important to me, and super-quiet in operation (the cooling fans are silent).
Sound-wise, it seems great - it works well with both the Kemper and the Digitech - with a pleasing warmth to the sound and a very useful 2-band EQ on each channel, to tailor the sound on-the-fly. I have gigged it and there is more than enough volume on tap for any backline requirement.
I particularly like the auto stand-by feature, too.
I don't think there's a better guitar-dedicated power amp at anything close to this price.

I use this to match my KEMPER, It only has 1U space. But it burst out with enough power to deal with all CABs, I output a signal from Kemper monitor without CAB simulation to 402.In this way, I can deal with the situation where all the venues have different AMPs, just one 412 CAB, no longer need to go into the AMP return to monitor my KEMPER sound.It's very functional, it has the usual presence, resonance, dual channel input and output, low cut, 400W 8Ω in bridge mode, etc. for a guitar power stage, and even a SPEAKON output, I think there is a chance to me Need to try to connect PA speakers directly, including some humanized protection measures, 115V/230V, soft start, overload protection, clipping indicator, this is the best power amplifier I have ever used

So either was this or HB GPA.
I got this and what can I say. It`s a really great unit.
I use it with GSP1101 and 70/80 Blackstar cab. It works like magic. I mainly use Bridge mode with only volume without Lows and highs beacons of the cab. If you have let`s say a Marshall or Engl preamp then the Lows and Highs can be useful. If you have a unit like GPS then you just turn those off, because if you switch a lot of those preamp sims. You ruin the sound.
Quality is great. I use this for over a year and I didn't`t find any faulty on it. Sound is the same as the first day I got it out of the box. It has wide area of use with all features that are provided with this unit.I really like the auto stand by mode, I jump all around and some times I forget to turn it off so that's a + for me(can be turned off on the back).
Overall a great unit that will not let you down.