First impressions on the GMD40

Hi guys,

Picked up mine yesterday, alongk with the FSM Mk III MIDI board. Thought about a small pedalboard I can carry to rehearsals and small shows, so along came Korg PitchBlack Poly (tuner) and a CAE MC404 wah. Probably wii go with a Line 6 M5 tu use as a compressor, but will make this decision later on.

On the GMD40: oh, boy, it's light and small. I know dimensions were online since the GM36 came out, but to see it in person is a whole different thing. Looks awesome (I'd prefer red LED lighting, but no biggie), and the bag is a really nice touch. As another user noted, too bad the pouch isn't big enough for the FSM and cables, but that's what boards are made for.

Setting it up is really easy, took me about 5 minutes to unbox all gear, light it up, and hit Standy... and now the fun & games begin. Just tried the presets (the amp will need a lot of time for me to set it as I want it, and I'll need to program sets for different guitars), and they are, well, kind of meh. Really liked about six of them, and they may be the basis for developing my own presets. Overall the really show the potential of the amp, but most are a bit bright for my tastes (and I'm playing through a Line 6 DT Extension cab, loaded with a Celestion G12H-90), but a little fiddling shows I may be able to dial it out. The amp is quite responsive, gainier sounds clean up nicely using the guitar's volume pot, but doesn't quite sing into feedback, something I quite enjoy. Once again, it'll come down to dialing it in.

Really liked the way the channels are voiced, enough for all my needs. The boost is again something I must explore, but doesn't really sound like there's a lot of "tubescreaming". Well, maybe some effects will get me there.

On to the effects and noise gate; effects sound allright, but not vintage at all. Since the design of this amp is surely geared towards modern sounds, they fitthe bill nicely, just not something to write home about. Will probably go with a Line6 M Series effects processor, all depending on how my onboards effects programs turn out.

The noise gate isn't really what I expected. Most presets don't have it active, so gainier sounds tend to have a bit of noise, but when activated, they do get noise free-- until you play a note, and there's a background hiss I'm not used to when using other brand noise gates, even on clean settings, and using a Giblson Les Paul Traditional loaded with Classic '57+ pickups.

To sum it up, this is not a "plug and play" amp. Definitely needs a lot of time to dial it in, and I'm sure I will not be underwhelmed by the results I'll get in a few weeks' time. Nevertheless, I really like the warmth the sounds translate (even though it's a modern soundng amp, I didn't find it harsh or sterile, so maybe a few vintage-y tones may be lurking in there).

Now, an Android app would be the icing on the cake, since programming it with the knobs isn't the quickest way to create presets! (Do yo hear me, H&K? )

Is this what you mean Syn? H&K GM40D iPad App

Syn666... My first impressions were very similar. I've had mine for about a month now and here are some observations.
1- Replace the tubes. I dropped in a set of JJ (the high gain option) and wow, just wow. The gain is so much clearer and the overall EQ response is more balanced.
2- Like most tube amps, the tubes respond best when they are being pushed. So for home use I find I am playing it at 5 watts so I can keep the master around noon (the channel volumes range from 9ish to 11 ish to maintain unity across presets).
3- I agree with you on the boost, noise gate and effects. So I put my ISP Decimator, Wampler Ego, EHX East River Drive and Soul Food out front with an M5 in the loop. Magic. I haven't messed with the MIDI on the M5 yet.
4- I had two cabinets to try out - Line 6 DT25 and Mesa Boogie Ported Compact cab with a C90. The Mesa responds much better without that brightness. But I do find the amp to be bright in general. The presence control helps the most with that.

With a few pedals out front, this amp can cover just about the entire sonic spectrum of guitar tones.

bordonbert wrote:Is this what you mean Syn?  H&K GM40D iPad App

Bordonbert, since I'm not an Apple user (for my own reasons, I prefer Android), an alternative should be very handy... I know the Fredo is waiting for his own GMD40 to start the conversion of software at least for Windows, so as long as a Win solution comes around, I'l be happy. Until then, know fiddling galore...

Papa_moz , last night I started playing with the clean channel, and it's very usable. So far I'll keep the amp stock, until I "diagnose" what it won't do, according to my needs. And I completely agree with you when it comes to the effect the Presence control has on how it sounds through the DT25 speaker, it does a good job on tmaing the brightness. I was considering buying the TM212 later on, but I really doubt the Vintage 30s to be a good match for this amp...

So far, I think the best way to use the EQ is along with Presence and Resonance controls, since they really seem to complement each other, kinda like filling in each other's gaps. Without using the Boost, I was able to set the amp from sparkly clean to pushed clean without any issues. Even without pushing volume (I'm still trying it using 40W, and I live in an apartment), the sounds, using Duncan Stacks on a Strat-based guitar, were quite warm. I will later on find out how things sound using other power settings. On the clean settings, a very musical natural compression comes through, making me think whether I'll be using an outboard compressor as I did before.

Tried to mess around a bit with the crunch channel and some effects, and it's immediately apparent that this little box does a lot of gain, and does it well. I even managed to get some convinced lead-like tones on the crunch channel with the boost on using a bridge Duncan Hot Rails, some delay and reverb.

My main gripes are definitely with the noise gate and with the effects. The gate silences the guitar completely if not strummed, dependending on how you set it, but even using stack pickups, when the guitar is played some noise is always coming through, even on clean settings, will definitely look elsewhere for a noise gate...

Now the effects: I tried some classic 50's/60's sounds using the clean channel, tremolo, and a bit of reverb. The tremolo minimum speed is way too high for my tastes, so until I explore the effects section, I look around for an alternate route for effects.

But all in all, I'm really liking this little creature. It's a handful, but it pays in great sound!

Papa-moz, may I ask you if you can try the M5 before the clean channel, to see how the compressors sound through it? I'm mainly focused on the transparency of the compressors, really not looking to add gain per se... Thanks in advance!

Sorry Syn, I completely missed the "Android" and read it as "Apple". For that alone I should be taken out and shot! (I'm not one of the "iGhly iMpressed" either!)

Musically we are as different as can be but I'm with you on the V30s, I would never touch them with my TM36 or GM36. The combination is far too shrill and harsh at the top end for me.

I would really suggest you get into the Power Soak options early on in your explorations, they can be crucial. You will get no output valve saturation at all with the amp on 40W and the Volume set low for home use. That way you are reliant on the preamp for all of your distortion. Even with 20W and only a single pair of output valves in circuit it improves. You can get the Volume up to drive those EL84s hard then lose some of the output to keep the sound level down, to my ears the whole sound of the amp is enriched if you do that. Mind you, that "preamp only distortion" could be the sound you like for your Metallica but I'd at least explore it now to rule out the PS as a useful factor in your sound.

Not sure about your Noise Gate problem, it's an oddity. The GM36 gate is not like a gate pedal, it has no active circuitry which passes the signal through it. It's just an electronic switch controlled by the signal level which is either plain on or off. When there is no detectable signal the microcontroller section tells it to mute the amp and it just pulls a signal line to ground, it doesn't actually pass the signal through itself in any way. It's also late in the signal chain where signals are highest so any noise it could contribute would be minimal by comparison. When it's open any noise which gets through while you play is unlikely to be the fault of the gate, it's more than likely from the rest of the amp. Is it actually constant steady noise you have or just a kind of coarsening of the sound as the notes are played or they die away? People have reported that type of issue before.

bordonbert wrote:I'm not one of the "iGhly iMpressed"

No worries, BordonBert, that line alone made my afternoon!

Yes, I know how valve amps work, I've had a few in the past, but with this one there are a lot of new features, so I'll be taking my time with it. Unfortunately, I got the amp last monday after work, so I really had little timw with it, maybe around an hour up to today. Next weekend will delve into it deeper, specially into the power soak options, but I also have a CAE MC404 wah in the box waiting for me to try it out on the amp.

Concerning the noise gate, it's a constant small hissing noise going on in the background when note and chords are played, but your input on how this works on the GM makes total sense, since I'm used to noise gates in pedal and rack form, and the signal when playing is completely free of noise. So, I guess it's back to pedals.

It's not much of an issue, since building a board depended on whether the built-in effects work for me or not. So far, I'm leaning towards a board with probably 2 Line 6 M9's synced by MIDI, one straight to the input (for gate, compressors and overdrives) and other on the GMD40 effects loop (for modulation, reverb and delay), along with the MC404, a volume pedal anda a Korg Pitchblack Poly tuner.

Will keep you posted on my findings, but don't get me wrong, I'm really liking this amp for its sounds and portability. I'm sure spending time with it will render me amazed!

BTW, I'm really not into Metallica (well, maybe 30 years ago I was...)

The amp will mostly be used for hard rock / gothic rock / some post rock nonsense.

Syn666 wrote:

bordonbert wrote:I'm not one of the "iGhly iMpressed"

Concerning the noise gate, it's a constant small hissing noise going on in the background when note and chords are played, but your input on how this works on the GM makes total sense, since I'm used to noise gates in pedal and rack form, and the signal when playing is completely free of noise. So, I guess it's back to pedals.

I also noticed a relative high level of "hiss" when the noise gate was open and especially just before it was about to close, compared to my other rigs. However, in my case it was mainly due to me having the GM40 head to close to my computer since I was testing and programming my MIDI Foot Controller and what have you via my PC. I relocated the GM40 further away and it was a huge difference. I also primarily use humbuckers equipped guitars, which are a bit easier to deal with from a noise perspective.

Generally speaking noise gates are relatively dumb" meaning they simply close or open their "gate" at a given threshold - even though there are some more advanced NG´s like the ISP Decimator ProRack G (http://www.isptechnologies.com/portfolio/decimator-pro-g-rack/) - the best NG I´ve ever owned. Anyways ... any noise, whether it´s coming from the guitar, amp, RF etc will blend with the guitar signal and will be audible depending on it´s relationship to the guitar "volume", the threshold settings and how quickly the gate closes.


I figured the GM40 would have a "simplistic" Noise Gate but reading the manual:

"Outboard noise gates sandwiched between the guitar and amp or plugged into the FX loop can only measure the signal at one point. The Intelligent Dual Breakpoint (IDB™) technology gauges the signal at two points, directly at the Input jack and post preamp, but pre effects. The noise gate uses these two values to calculate the optimum response. What’s more, it does not cut off Reverb and Delay signals"

The above statement is promising since it indicates that it´s not purely a "one-point-at-the-input" tracking gate and designed properly based on my experience from my other rack based rig using the ISP mentioned above. I play a lot of start-and-stop metal type riffs and setting the NG of the GM40 at noon actually works really well for me - even at hi- to ridiculous gains - and I'm also used/spoiled with silent rigs. Hence I´d like to ask if you are evaluating the GM40´s Noise Gate in the same context as to your previous gear or setup - meaning same guitars, location, proximity to RF sources etc?

mlordin, yes, it's all in the same context as to my previous gear and setup - meaning same guitars, location, proximity to RF sources, etc.?

The GMD40's gate does it's job: when nothing is played, nothing comes through. Yes, when the gate open, along with the notes/chords being played, there's always a background hiss, not very high, but quite different from other noise gates I've used previously, where the sound of what's played came through pristine, even others that work on two points (input/preamp output).

I still have a lot to find out about this amp, and little time during work days to do it, so I hope next weekend I may shed a little light on what's going on.

By the way, on the GMD40 the built-in effects are all pre-loop, am I correct?

Built in effects being pre-loop would make sense but not sure - hopefully someone else knows...

Plan on running mine thru a Helix for the added Effects. Nice read and thanks!

The built-in effects are post loop, which I am grateful for. I have a volume pedal in the loop and I don't want the effect tails getting cutoff when I heel down! I have a GM36 btw but I'm sure the GM40's loop location is the same.

Well, if the effects are post loop on the GMD40, that may allow me to buy a Line 6 M13, which can have up to 4 effects simultaneously thatcan be set pre or post it's own FX loop, allowing to use it with the amp via 4CM.

That way I can have the M13's compressors and drives going in the front of the GMD40 preamp, have the M13's EQ and modulations after the GMD preamp, and then use the amps delay and reverb!

The M13 also has a pretty good noise gate that can be set globally (I had one a few years set in 4CM with a Marshall TSL, and it worked flawlessly), so that I can have up to seven effects at once ( gate included) plus the GMD40 preamps, and control different channels and effects by MIDI.

I will try to plug some effects in the GMD40 this weekend, to see whether the fx loop is pre or post the built-in effects.

Will keep you guys posted on this. BTW, thanks you all for your input, this is an awesome community, maybe H&K should promote this forum to official status?

Have to admit coming from a traditional amp set up I struggled at first and was convinced my gm40 was faulty.

Connected 4 cable method with a boss es-8 controlling midi selection of presets and which effects pedals were ON or OFF and where in the chain they sat, pre or post loop. This together with an eventide H9 which wasn't set to wet/dry AND second amp hooked input of the boss es-8 I was getting in a bit of a muddle.

Think my issue was I was selecting presets that sometimes had the effects loop on in one preset then off in another.

Think I got the logic sorted in my head eventually.

Syn666 wrote:BTW, thanks you all for your input, this is an awesome community, maybe H&K should promote this forum to official status?

That's a hats off to Hwystar who started the whole thing and looks after the tone of the place.  He's not around too much at the moment as he is busy with other life stuff but he's the real glue that holds this place together.

You are way to nice again BB! You post and I listen.

380+ members. Come on in H & K. Facebook is cool but all the guys in here are cooler!

I played guitar yesterday. First time in a month. My left hand almost fell off my wrist. The pain is way to much to bear. My pinky was sticking out in the air and I couldn't really bend it. Everything I have tried has failed. Well at least I can say that I "used" to be able to play guitar.

Thx for the kind words Bordon! You are a true gentlemen and scholar.

HwyStar my personal thanks for your efforts. As it grows this site will become invaluable I am sure.

Have you tried using open G tuning? Might not give you full access to the guitar but the chord shapes ala Keef Richards will still allow you to enjoy rocking out on the guitar.

Once again thank you and I hope h&k endorse it some day.

Thanks so much George! This place runs itself. Easy peasy.

Thanks for the open G tuning idea too! I will give that a try. Most of the time I am just playing ad-hoc scales against songs that are playing on Amazon prime. Every song is one-long-ass solo...

Nord/Clavia keyboards has had a user forum for years and has never been endorsed by Nord. They should participate so they can understand what their users want. I don't think they are here participating in this forum. At least to my knowledge and BB's knowledge. We would have gotten a PM from them by now if they were in here, silent trolling...

Speaking of silent trolling, yes it would be nice if this forum had "likes for posts". I don't think this free forum supports it. Oh well.

Thanks again J200George!

HwyStar, I wish you a full recovery, and hope that it's nothing serious. Also, thanks for all your work concerning this forum!

Tried the GMD40 at reheasal last saturday, at full power, using a Marshall MG 4x12. Not the best cab, I know, but it's what available at the rehearsal place. I really loved the sound, considering I used a bank to which I copied 4 of the factory presets.

Only effect apart the built-in ones were a CAE MC404 wah, and a Korg Pitchblack Poly tuner.

Well, it does amazingly at note separation. Really liked the presets at high volume, it's truly the most musical amp I've played. Notes ring out clearly (I had the noise gate activated, set at noon), no choking from the noise gate, and the background noise I mentioned earlier at bedroom volumes didn't seem to come through.

Realy enjoyed the clean and high gain sounds I was using, although the high gain sounds seemed too mushy for my liking, a tad bassy and scooped. Still have to dial in my own presets, but programming this amp without an Android or Windows app (my main gripoe with H&K concerning the release of the GMD40) will be a pain in the a$$. Time consuming, and even comparing with the factory preset list, will not be easy the gauge the amount of variation to a factory preset sound, even with the "store" ligh blinking as a reference point. Hope H&K sends Fredo a GMD40 to help with the software development, something that may even help boost the sales of this amp. As a matter of fact, the amp sounded so good that the studio guys and guitarist from the band reheasing next door to our pace asked what amo I using, some took it for a quick spin and were floored by the sounds and portability, but all said the same: "No app for Android or PC?"

The effects seemed alright, although I don't find them to be " studio quality". They get the job done if you're pressed with time and don't want the hassle of carrying and setting up a separate pedalboard, but developing my own sound I do find them lacking. Didn't have the chance over the weekend to try outboard effects with the amp, but I still wonder what gear I'll be adding the the amp. I own a Line6 POD HD 500 I'll try using 4CM, but since it's not true bypass I've wondered if a Line 6 M13 or even two M9's will do it for me. Line6 Helix or Fractal FX-8 are the obvious candidates for a professional multieffects pedalboard, but I really ca't justify their cost right now.

The cheapest way for the effects I need wound be tu use two M9's linked by MIDI and by audio.

1st M9 Midi Out===> 2nd M9 Midi In===>2nd M9 Midi Out===>GMD40 Midi In

This way, if I want to select a new patch, the 1st M9 would change (by MIDI) the patch on the 2nd M9 and also change channels on the amp head. I still don't know if I'd need a MIDI Trhu box in order to try this.

Also the ideia is to have different effects routed differently on each M9, like this chain:

Guitar===>:1st M9 (Compressor / Drives / EQ)===> GMD40 IN===>GMD40 FX Loop Send===>2nd M9 (Modulation / Delay /Reverb===>GMD40 FX Loop Return

I'd use a different effect in each type for different amp channel (For instance, a Blue Comp and a Fuzz on clean, with tremolo, analog delay and spring reverb in the amp loop, and the change amp channel, to have a Vetta Juice, a Screamer on Ultra amp channel, with flanger, digital delay and hall reverb in the amp loop).

Will still investigate more. But this little box is really blowing me away.

Thanks for the kind words Syn666! I'll get it sorted out one of these days.

I'm glad to hear you are digging your GMD40! I agree; that if H & K came out with an amp that had studio quality effects the rest would all fall into place nicely for a small band amp setup. Light, durable, sounds good and at 97dB it is hard to really hear if the effects are not studio quality. It's when you are at band practice or are doing recording that the effects can kind of let you down. At least that is my feelings about the GM36 effects.

I could never have been that accurate in so few words HwyStar. I'm with you on that. It's only the loud dingy bar and sweaty club atmosphere I'm interested in and I've always found they're fine for that. Of course others may be recording where it could be more important.

HwyStar wrote:Thanks so much George!  This place runs itself. Easy peasy.

Thanks for the open G tuning idea too! I will give that a try. Most of the time I am just playing ad-hoc scales against songs that are playing on Amazon prime. Every song is one-long-ass solo...

Nord/Clavia keyboards has had a user forum for years and has never been endorsed by Nord. They should participate so they can understand what their users want. I don't think they are here participating in this forum. At least to my knowledge and BB's knowledge. We would have gotten a PM from them by now if they were in here, silent trolling...

Speaking of silent trolling, yes it would be nice if this forum had "likes for posts". I don't think this free forum supports it. Oh well.

Thanks again J200George!

H&K is very well aware of the forum, but I'm not sure how much or often that they read them. I'm not endorsed by them, but I frequently talk to the FB crew who are over in Germany. I mentioned this forum to them. They told me they were aware. I didn't ask why they don't participate.

Again, thanks for running this forum!

Back for more notes on the little big box.

Last night I tried my Line6 POD HD 500 with the GMD40 using 4CM. Didn't notice any signal loss or degradation, but I was using the 5W PS setting, so I'l try it again using 20W and full power over the weekend.

The only thing I found strange is that pressing the FX Loop button on the head, and getting it to light up, seems to cut off the FX Loop! I had no amp sims running on the POD, , the FX Loop light on the GMD40 deactivated (which, according to the manual, would have the FX Loop off), as well as all the built-in effects off, yet all the POD's effects were going through as they were supposed to (both going pre and post preamp). If I changed channels on the head, the different preamps were sounding correct (tried some of POD compression pre GMD40, and with the POD's tremolo, delay and reverb going after the GMD preamps).

So, is the manual wrong? To me, it seems that lighting the GMD40's FX Loop button (which, according to the manual, would activate it) is really DE-activating it, and that the FX Loop wound always be on, unless you pressed the button on the head...

Could be an oddity with the GM40D but my GM36 dsoesn't behave like that. Button press, light on, effects in play for me.

Guys, call me dumb. I hás the connection on the 4CM all wrong. Loop now works fine, light on and it's active. Did a LittleBigPlanet noodling with both, using different channels and effects Chainsaw, and now I'm completely floored by this amp. Cleans are pristine, and with different modulations, delays and reverbs it sounds divine. Pushed cleans sound awesome too.

With compression and overdrives in front of the lead and ultra sounds, with and without the Boost, the high gain channels are rich, powerful and warm. EQ, presence and resonance controla seem to come alive, and I'm finding my own sounds. Using both the POD and the amp's gate really keeps everything noiseless.

Now, I still have to delve into MIDI so I can handle channel switching and the amp's presente along with the POD, and I'm all set to play shows. Will keep the FSM, wah and tuner o have a smaller board for rehearsals, maybe adding a L6 M5 for compression, as I planned earlier.

Awesome sound and integration with my other gear, and light as a feather? My dreams have come true!

Excellent. It's good it's ticking all the boxes for you. Didn't like to say anything but the 4CM was the obvious area to look. And it isn't really dumb to set things up wrongly, we've all done it! (Well I know I have.)