No New Owners?

Hi from Australia. New to the forum but had my GM36 for about 18 months.

Sadly I only play in an acoustic band so the amp has been gigged once in its life so far, hopefully that will change soon.

Run my amp with JJs in the pre and power sections using a Boss GT100 to switch it, an iPad mini to set it and a Marshall 2061cx cab where I have replaced the bottom celestion heritage with a V30. At home it sounds very trebly but recorded and from the one live gig it really cut through the mix.

The only thing I wish I could do was control the eq a little easier live (without the ipad connected) but the presence and resonance controls seem to do a good enough job of this.

Overall I am happy to have scaled back to this little head and a 212 as opposed to my old Framus half stack.

Welcome Matty_K! Hope you find a great electric gig to exercise your GM. As you can imagine, due to its weight and 4 uniquely voiced channels, it's a great gig amp. I noticed you responded to the guy trying to use a Boss to control the GM, good forum etiquette. I know a couple people on here like me are using a Line6 to do the same, so it's got be possible.

New GM36 owner here.  Received it about a week ago, along with the footswitch and 2x12 cab.  Unfortunately, my experience is not all positive.  

I have been enjoying the sounds of the GM36, so I decided to program a few settings and use it at a gig instead of my JVM210H/1936 rig.  Before we finished the first song, the amp went silent.  Nothing out of the cab.  nothing out of the red box.  I always take a Vox Tonelab as an emergency backup so I was able to limp through the rest of the show using the amp sims through the PA.  It was quite hot that night, and I was running the amp at 18W.  Got the amp home, to try and troubleshoot, but the amp fired up and acted normal (maybe it had stage fright!).  So i am suspecting a heat issue.

So it is being sent back, but I like the amp enough that I will patiently wait for the replacement.  

Has anyone else has any issues with their GM36?  I like this amp a lot for the short time that i have had it, but if it is going to have problems at gigs, I won't be able to keep it.  Here's hoping that I had a dud and the replacement does not have the same problem.

Ron

I suppose it`s my turn to chime in

I`m about 85% happy with my GM36. I got it for a few reasons and functionally, it`s perfect. It replaced a Carvin Legacy 3, and I have to be honest...it`s tone doesn`t even compare. The L3 sounded much better. With that said, over time I have gotten the GM to sound pleasing. The reason I opted for this over the Carvin was that the L3 was simply too damn loud. I rarely turned it up past about 4 at a gig and it was just a bear to record with, especially at home.

Also, being of the generation of guitarist that I am, I used a rack setup many years ago and enjoyed having all of my sounds basically one click away vs a tap dancing session on various pedals and channel switches. The GM delivers on every count in that department. I run a pretty streamlined rig, just the amp, a wah, and an Eventide H9. I use the Behringer FCB1010 (hey, it`s just about the most reliable piece they ever made) to run the whole show. Between the amp`s programming capabilities and the midi integration of it all being so easy, I get the amp to switch channels, have the right effects on (or off all together), and the H9 to be on the right preset with one button. So now I`ve got a group of clean sounds on one bank, crunch/rhythm sounds on another, lead tones on a third and my weird Satriani/Buckethead sounds on yet another.

For the most part, I love the amp. It`s tone is a tad brittle at times, but I hear this amp responds well to tube replacement so as soon as I feel like ordering gold pin preamp tubes I may have a differing opinion. The Legacy had a warm, living, organic tone to it that I really loved, then I bumped the bias a bit and it "browned out" beautifully. Another thing we can`t do with the GM36.

Oh, and over the years I have had every kind of experience possible with tube amps. They get hot. They`re supposed to. BUT: Heat is the enemy of any electronic circuit. And with the power soak active, this amp get plenty hot. While not "above what it is designed to handle", any amp can use a little help. I had made a fancy fan setup for my Legacy, but the GM36 doesn`t have room inside for that. I simply stuck a small desk fan behind the head and it keeps it plenty cool enough to never trigger thermal shutdown, even in this Texas heat.

I promise you the heat issue is overstated.  Yes, any reduction in heat is a good thing but just because this amp feels hot to the touch doesn't mean the temperatures are at anything like awkward levels.  Your hand is a very good warning device for telling you whether something is hot enough to harm you but is a very poor measure of general temperature.  What it tells you is very hot is way below the temperature that modern components are designed to run at.  Testing the temperatures in and on the amp with a genuine thermometer would be a very useful exercise!

The GM/TM will be no hotter inside than your average wooden cased valve amplifier which has a case built from some of the best insulating materials we could choose.  The GM has a metal case chosen deliberately to act as a heat transfer device to the outside.  The whole metallic structure is effectively acting as a heatsink.  The major heat producing components, the valves, are isolated in the upper compartment standing on insulating bases, and heat rises.

In the lower compartment the power soak is a non-issue.  For a start, while it is in use one pair of the output valves is not working.  At it's top dissipation, on the 1W setting, it is dissipating a theoretical absolute maximum of 17W and that is not considering music as a variable transient signal.  At the 5W setting it dissipates 13W max, and at both the 18W and 36W setting it isn't even in circuit.

The components used inside in all of the circuitry, including the solid state stuff, are the same as have been used in valve amps for many years.  They have ratings of thousands of hours life working at temperatures way above any found around them in the amp.  Choosing the probable worst example, electrolytic capacitors today's "bad boy" components, (the ones people feel the need to block replace every few years   ), have a design temperature at which their expected lifetimes are quoted.  The cheapest category is designed for constant working at 85degC with higher spec devices at 105degC.  Arrhenius' Law of Chemical Activity says that the working lifetime of a capacitor doubles for every 10 degree Celsius decrease in temperature you drop below that.  65degC will feel very very hot to your hand but means 4 times the quoted lifetime, (as it's 2 x 10degC it means 2 x 2 x the quoted lifetime).  And remember this is thousands of hours IN USE!  I've posted figures for this before to show how unlikely it is to be a problem.

And capacitors do not "dry out", that is a myth!  They can leak if subject to external physical damage in some way, or they can eventually use up their electrolyte in self repairing if subject to overwork dealing with overly high voltages or ripple currents which damages their molecular insulating membrane.  For the most part this means their capacitance slowly drops below tolerance after many many hours of use.  They are made to cope with the ambient temperatures they will meet in even extreme use without complaint.

It really really is an overstated problem but if you want to help to address it why not try this?  (It's already posted in the TM36 section but no self respecting GM owner would look in there.    )



It's made from a couple of pieces of scrap 18mm MDF I had lying around.  The two double fan units cost £0.99 each on ebay.  The top has locating recesses for the amp feet to stabilise it.  It has a few strips of soft sealing strip around the fan hole edge to ensure a seal around the base of the amp where the air is forced in.  On the back I mounted a tiny scrap of aluminium I made into a power socket plate and I just used a standard pedal DC type socket to match a 12V wall wart I had left over from a piece of computer kit.



Underneath there is a slot to locate and lock the base over the handle of the speaker so it is very stable.  The underside of the fans has a couple of pieces of dust grille just pinned over them to keep some of the dust out.  Stick on felt feet make it cute and cosy. When we are not playing it can be heard from close by just as a computer can, but it isn't intrusive in any way.

You can knock something like this together in a couple of hours from junk lying around your home or bought for almost pence on ebay.  If it is a worry to you give it a try.

My Grandmeister 36 head arrived today with the pedal FSM 432 MKII and the cab TM112 and WMI-1.
I plug it in and the sound was not so great, it was very bright, noisy and little thin.
I work in a musicstore (part time) and the service tech gave me some tubes (he´s a reel tube geek) and I put them in and voila it sounds GREAT!!! Varm not so bright and quiet.
The tubes he gave me was for the power JJ EL84 and the preamp tube was, position 1: NOS Telefunken 12AX7, position 2: NOS Mullard 12AX7 and position 3: NOS Philips made in Holland 12AX7.

It sound so good now   . I play most hardrock and metal.
I gone have this amp both in my studio and in my home for some song writing and practice.

I haven´t tried to hook up the WMI-1 yet. I will try that in the weekend.

bordonbert wrote:I promise you the heat issue is overstated.  Yes, any reduction in heat is a good thing but just because this amp feels hot to the touch doesn't mean the temperatures are at anything like awkward levels.  Your hand is a very good warning device for telling you whether something is hot enough to harm you but is a very poor measure of general temperature.  What it tells you is very hot is way below the temperature that modern components are designed to run at.  Testing the temperatures in and on the amp with a genuine thermometer would be a very useful exercise!

The GM/TM will be no hotter inside than your average wooden cased valve amplifier which has a case built from some of the best insulating materials we could choose.  The GM has a metal case chosen deliberately to act as a heat transfer device to the outside.  The whole metallic structure is effectively acting as a heatsink.  The major heat producing components, the valves, are isolated in the upper compartment standing on insulating bases, and heat rises.

In the lower compartment the power soak is a non-issue.  For a start, while it is in use one pair of the output valves is not working.  At it's top dissipation, on the 1W setting, it is dissipating a theoretical absolute maximum of 17W and that is not considering music as a variable transient signal.  At the 5W setting it dissipates 13W max, and at both the 18W and 36W setting it isn't even in circuit.

The components used inside in all of the circuitry, including the solid state stuff, are the same as have been used in valve amps for many years.  They have ratings of thousands of hours life working at temperatures way above any found around them in the amp.  Choosing the probable worst example, electrolytic capacitors today's "bad boy" components, (the ones people feel the need to block replace every few years   ), have a design temperature at which their expected lifetimes are quoted.  The cheapest category is designed for constant working at 85degC with higher spec devices at 105degC.  Arrhenius' Law of Chemical Activity says that the working lifetime of a capacitor doubles for every 10 degree Celsius decrease in temperature you drop below that.  65degC will feel very very hot to your hand but means 4 times the quoted lifetime, (as it's 2 x 10degC it means 2 x 2 x the quoted lifetime).  And remember this is thousands of hours IN USE!  I've posted figures for this before to show how unlikely it is to be a problem.

And capacitors do not "dry out", that is a myth!  They can leak if subject to external physical damage in some way, or they can eventually use up their electrolyte in self repairing if subject to overwork dealing with overly high voltages or ripple currents which damages their molecular insulating membrane.  For the most part this means their capacitance slowly drops below tolerance after many many hours of use.  They are made to cope with the ambient temperatures they will meet in even extreme use without complaint.

It really really is an overstated problem but if you want to help to address it why not try this?  (It's already posted in the TM36 section but no self respecting GM owner would look in there.    )



It's made from a couple of pieces of scrap 18mm MDF I had lying around.  The two double fan units cost £0.99 each on ebay.  The top has locating recesses for the amp feet to stabilise it.  It has a few strips of soft sealing strip around the fan hole edge to ensure a seal around the base of the amp where the air is forced in.  On the back I mounted a tiny scrap of aluminium I made into a power socket plate and I just used a standard pedal DC type socket to match a 12V wall wart I had left over from a piece of computer kit.



Underneath there is a slot to locate and lock the base over the handle of the speaker so it is very stable.  The underside of the fans has a couple of pieces of dust grille just pinned over them to keep some of the dust out.  Stick on felt feet make it cute and cosy.  When we are not playing it can be heard from close by just as a computer can, but it isn't intrusive in any way.

You can knock something like this together in a couple of hours from junk lying around your home or bought for almost pence on ebay.  If it is a worry to you give it a try.

That is a kewl setup you have there Bordonbert! Thanks for sharing the idea here.

Welcome aboard MetalAnimal!

Well, shipped my GM36 back to Sweetwater, and they turned around a new one in a day (I can't say enough about their customer service!). I've only had a short time to play around with it, but so far so good.

Hopefully, I'll be able to spend some time with it on the Labor day holiday, to try and make sure that everything is A-OK.

KY91C2 wrote:Well, shipped my GM36 back to Sweetwater, and they turned around a new one in a day (I can't say enough about their customer service!).  I've only had a short time to play around with it, but so far so good.

Hopefully, I'll be able to spend some time with it on the Labor day holiday, to try and make sure that everything is A-OK.

Best wishes with the replacement and please keep us posted. I'm particularly interested... I've owned my GM for about a year now but it has never left my home studio (band was on a bit of a hiatus for a little while)... but next month we have a show and the amp will finally see some live action. I've done my best to put it through its paces here at home and I've never experienced any issues at all (knocks on wood).

Good luck!

Sorry to hear about the return, but the Sweetwater guys have never let me down.

I got my GM36 in December 2014. I picked up the HK212 cabinet, but on the same day I was offered a
new Marshall 1960A custom shop cabinet at a decent price and bought that too. Happy with both,
although I don't haul the Marshall around. The HK cab is more convenient. Every time I haul even that
around though, I think about a good 1x12. I am 67. Backs are not forever.
Clarification; there are different versions of 1960A's it seems. Mine is a 1960A cabinet, 4x12 with Celestion G12T-75W's.
So yes, 300W, and sounds great with the H&K GM36. In the end however, all is subjective.

I had no idea this forum existed until today, and am happy to have stumbled upon it.
The GM36 is the best amp I have, great sound (metal played here mostly) and no back strain. There is a
lot to be said for that.
Sometimes I get the bug for the JVM410H matching head, but sanity has prevailed. So far.

I got the FSM432 at the same time, nice pedal, easy to use and easy to change if a mistake is made.
I use the SW app, as I suppose most do.
I own mainly ESP's and PRS's. They sound great through this amp. I will spare you all the details.

Do many of you (us) change the tubes out for better tone? I was happy with what I had, but now wonder
if I am undiscerning.  Would like to know, just was looking at the EH site. Ah well, sometimes ignorance
is bliss -ish, and sometimes it is not.

I've been gigging three times a month with the GM36. On Aug 22nd I did an outdoor gig with a generator. My power soak and HD500x wouldn't work, but the GM36 did. I did the whole gig with my SG,a tube screamer, and the GM36. Yup, this is a good amp

WhiskeyMike,I changed my tubes out for a browner tone. JJ's all the way around. Sounds great. I believe a have a 5751 in V1 to tame the gain a little. Please check the tube swapping thread on this site.

Thank you namklak, I will look for that thread.
Found it, very informative, and I corrected information deficiencies in my own post.

Hey guys

New user here - gm36 - my first h and k amp ! I have been playing a orange dark terror with an orange ppc212 open backed cabinet and as much as I love the sound , it's s one trick pony!

I was recently was told about the h and k gm36 head and immediately bought it! What a beautiful amp! I never knew there were valve Amps with these capabilities !

I was running a monstrous pedal board and since buying the gm36 I have sold three quarters of my pedals !! I'm a set and forget kind of guy so to have four amps in one, a built in noise gate and the capability to program and save true valve patches with varying levels of chorus, delay, phaser and tremolo is simply mind blowing!! Add to this the beauty of the fan mark three pedal and I'm the happiest I've ever been !

I'm loving it and I'm a happy bunny! Can't wait to turn it up I auditioned for a couple bands recently and even on 18 watt mode the volume knob was barely turned on.

This brand and amp are the music industries worst kept secret - why the hell are h and k screaming this amps capabilities from the proverbial roof tops?

Welcome, other new user! And I agree, GM 36 is a well-kept secret. I haven't seen many around, and my GM 36 never fails to generate interest.
I love mine. It's all I use any more.

Hi Mike

Yeah i'm not using much else these days! I had a HUGE pedalboard (17 pedals) which i have reduced to:

Wireless unit
Tuner
Wah
Volume pedal
Fuzz pedal (which in reality i don't need as this amp can generate lots of fuzz)
Power supply

To be fair i am so impressed with the amp that I may not even use a pedal board anymore as at my last audition i simply placed the wireless unit and tuner on top of my amp and used my guitar volume knob for volume increases.

I don't want any external colouration of this amps tone - its THAT good - never thought i would get to the point where i do not want to use pedals as I have been a pedal junky!

Howdy Grand Meisters!

Future new user checking in; got my gm36, fsm432, 112 cab and wmi-1 on the way from sweetwater - should be here Saturday if all goes well! Also have the Jerry Cantrell sig wah coming to put in front of that sexy blue box.

Appreciate all the knowledge I've gained from this forum so far, thank you's! Kind of bummed to hear many of you swapping out tubes right off the bat but I'll see how it goes. Got my cart filled up at the tube store with some JJ EL844 low power, maybe a JJ 5751 for v1, and some JJ ECC83 for v2 and v3 - just in case. Also a little disappointed about volume control via expression pedal issue but I have and old Ernie Ball volume pedal laying around that I'll try in the FX loop.

Really looking forward to playing around with this bad boy and getting it on with some hot tube action! I've been an Axe FX user for the last several years; really nice sounding and incredibly powerful kit (maybe it will make a nice processing unit in the FX loop of the gm36?). But I lack floor control and their MFC foot controller has been unavailable for months now. I want to get out of the bedroom and start gigging again so I needed to come up with a new plan. After exhaustive research and going down several Marshall and Orange rabbit holes with a slew of new stompboxes I ended up with the gm36 rig instead. Honestly I was not all that familiar with H&K so I'm glad my sweetwater guy turned me on to it. So many features and it really seems to cover all the bases on paper so far. Can't wait!

Anticipation....

Hi Steve

I have an orange dark terror (which ive held onto it) as a backup so i've come from a good amp. I have NOT swapped out the tubes as I find you can tame any potential "fizzyness" by playing with the gain, eq , presence and resonance.

I do not find the tubes too fizzy and in fact i like the sound! I will keep playing these tubes until they give in or until my ears tell me otherwise. Im a total tone freak (like the rest of you im sure!) but let your own ears judge it - can't see the point to buying a brand new amp and changing tubes before you have even played it!

Hi Conrad! Thanks for your input! The dark terror was definitely on my short list and I'm glad you're digging your gm36 as is!

Sorry my post was unclear - I meant that I only have some new tubes picked out just in case, I have not actually purchased them yet. I fully intend to put the stock tubes through their paces before even thinking about replacing them! In fact, I'm counting on loving the stock tubes since my bank account has taken a beating over this new rig haha!

steve_napp wrote:Howdy Grand Meisters!
...I have an old Ernie Ball volume pedal laying around that I'll try in the FX loop.  
.

Make sure it is the 25K model if you are putting it in the fx loop. If you have the more common 250K, it will act funny in the loop (been there done that, trial and error, live and learn, yadda yadda) The taper/sweep will be uneven.

The 25K VP wants to see a low impedance signal, which is what the amp's fx send puts out, as well as most buffered/active devices. The 250K VP wants to see a high impedance signal, such as a signal from a guitar with passive pickups.

I prefer a VP in the amp's loop because when I do volume swells I want the pedal to act like a master volume, not affecting the gain. A VP placed between the guitar and amp will affect gain, just like your gtr's volume knob.

Good luck!

Hi Gravy! Thanks for the heads up!

Your posts in another thread regarding volume control were incredibly helpful so I was already aware of the impedance and control placement considerations. I want to use my vp exactly as you do so I appreciate you sharing your knowledge and experience, big help! Not really sure what my old ernie ball vp is but I'm all too familiar with Murphy's law so I'd bet it's a 250k impedance one, doh! I was also looking perhaps at the Boss FV-500L if I end up needing a new one...

No problem Stevo!

I ended up settling on the Boss FV-500L after trying a couple different brands. I don't need the stereo capability but it seems most/all of the low impedance pedals have it.

Another friendly tip, don't expect to be able to use the tuner out on the VP if it's in the fx loop... (again, trial & error)... apparently the amp's pre-amp section adds a lot of harmonic content which confuses the tuner. So, my tuner is earlier in my signal chain.

I MAY replace the FV-500L with the smaller FV-30L, only because I'm trying to trim down my board.

Right on, Gravy, good tip on the tuner - thanks!

BTW Luckily I often don't even need a tuner at all - the evertune bridge really does a remarkable job holding tune for me. I live in SW FL and my ESP guitar often goes from 76 degrees under air out into our nice jungle-hot summer to play by the pool with no issues at all. Holds tune through the life of a set of strings, no matter how much I abuse it. I've heard many say you can't do bends or vibrato...that's bogus! I bend and vibrato all over the place - just takes a few extra seconds to set it up properly.

Hello Steve_napp, and welcome. I am new here as well. About the tube swapping; I read everything here, but at this point in time I am very happy with the as-delivered tubes. It might be a function of the music you play and the guitars you use; in other words, subjective. I am very happy as is. So give it a bit, see how it goes.