No New Owners?

I'm a new owner and I am just getting to grips with it I think that its going to be a fair while till I have set it up to my liking. But hopefully it will be a pleasurable experience. The GM certainly has more program-ability than my Marshall JVM 410C.

WhiskeyMike wrote: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.

can you please compare the two amps, jvm vs grandmeister....since you own them both then your opinion is precious...

Anther NOOB here. I've had my GM36 and HK112 for about 5 months. Still learning and enjoying. To my ears tone has improved as the 112 "loosened" up. Loving it! Thinking about another 112 with a different speaker. We will see... Play on!

new owner.

von haulshoven wrote:new owner.

Welcome! How do you like it so far? What's the rest of your rig (spkr cab, guitars)?

Many of us here have done our best to post about our respective learning curves with the GM, so with any luck you're able to sift thru our jabberings and find some useful info

Let us know how you're making out!

all new gear seems to be good the first days :-)
have a TM 112 H&K cabinet and the footswitch.
wish the amp had stereo out to connect a second cabinet. (for the delay/chorus/phaser fx)
I play strat.


I make rock/boogy/doom and yes completely different electronic music / ambient as well.

Hi Von Haulshoven, welcome to the forum.  (My apologies for the poor joke but I almost said 'Allo 'Allo! Older UK members will understand that.) You're right, there is always that honeymoon period with new gear before you start getting fussy about the little things where everything is wonderful.  Let's hiope that lasts a long time for you and that some of the advice posted here by other users is of use when the worm eventually gets into your brain.

Re your stereo out, there is a really simple and satisfying answer to this one as long as your pedals have stereo out!

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It is interesting to look at pictures of Jeff Lynne's ELO concert in Hyde Park recently.  You can see how Milton McDonald solves it.  He just has two GMs, clever man.  After all, the only thing better than having a GM is having 2 GMs!

I'd love to hear some of the Doom Ambient Boogy Rock you talked about.  

Actually he has two Tubemeister 36's. I always have one with me in case my Grandmeister gives me problems. I don't do the stereo thing, although my cab would support it.

You're absolutely right Bishop. I have a TM too so I should have spotted that from the channel lights. What price a TM + a GM for some unusual sounds then?

Hi all.  I'm new here.   Just got my GM today with the TM 2x12 cab and the 432 foot pedal.  Initial playing was fantastic.  Just digging into a nice rich clean tone reminded me of why I love playing through a tube amp.  I knew the head was smaller than a full size but was pleasantly surprised when it arrived and was even smaller than I thought it would be...perfect for gigging.  First sounds with the onboard effects were perfect for me.  One of my goals with this rig was to have very little to hook up to it so the built-in effects were a big selling point, in addition to the tone.  Programming seems straightforward but planning on interfacing an iPad for a little more info/ease of reviewing the patches and maybe for use live eventually.  

Like most of us, I've been through a never ending buy and sell pattern of guitars and amps and finally getting back to a basic and smaller setup after so many versions of stacks and then the Line 6 Dream Rig which took me into some decent tones and flexibility but not close enough and too complicated/involved to program for my tastes (and needs).  I don't really need too many different sounds.  I'm so looking forward to playing my first gig with this rig in about 2 weeks!

Before buying it it, I watched several videos online with some playing/reviews but the one that captured my interest and basically sold me on this head was the NAMM show video featuring Dennis Sheperd.... ...his tones and the clarity clean or dirty was amazing.  Today, I verified for my ears that it is the real deal.

Welcome apenny!

Hi Apenney, good to have you aboard. you're right, that's a great review vid. I get so fed up with seeing reviews on YouTube where the player turns on, whacks the volume and gain up and starts hammering out metal riffs. It seems like the only thing they value in an amp is it's ability to drive out ultra high gain shredding tones. I'm still learning how to vary the controls to come up with much more varied tones than that. Your vid touches on that too. Seeing him show the GM's ability to fire out killer clean tones with its own effects is great. Developing the ability to keep the gain down is a great asset which I'm just getting the hang of. Thanks for the link.

Make sure to pop in from time to time and let others know about how you're getting on with the GM. You may just be able to point some of the rest of us at something new.

New owner here. About a month in and I'm loving it. I'm still on the honeymoon and haven't even begun tweaking any settings. Still just exploring the presets. I do find it a tad bright, but that will get taken care of when I run my EQ through the FX loop. The only gripe I have so far is that when I power up it doesn't show the channel and patch number the amp is currently as left from the last power down.

I'm running this into a closed back cabinet I made, loaded with a Celestian V30 (I think). I haven't opened it in a while and I don't remember what I had in it last. I have a Marshall 4x10 with Celestions that I will try once I rewired the input jack.

I've also run the Redox directly into my Macbook through an Apogee Jam. It runs a little hot but workable. I've only processed it through a reverb plugin via Logic, but so far it's the best direct input I've ever used. Having the touch and dynamics of an all tube amp as a direct input has been elusive for me for many years, and no simulation I've ever tried came close. This is awesome.

AngryBudha wrote:It runs a little hot but workable.

Welcome aboard!

The Red Box output is Line Level (hot), and I'll bet your interface is expecting Mic Level which is a much lower signal level. I ran into this problem with my Presonus interface, it only has Mic Level inputs (some interfaces have both, but mine does not). My solution is to attenuate the signal, it might take a good -40dB to tame it enough. I still struggle with trying to "warm up" the signal, as it sounds a bit cold/sterile to me. Some folks use an IRF (impulse response) to add some "mic ambience" to the signal. The Red Box is only simulating a cabinet, not "a miked cabinet in a room", and so maybe that is the missing link?

hi all

i'm using the redbox direct into my emu1212m sound card, or into one of my matrix poweramp (used for my axe fxII).
In both case it sounds really good. I used my loadbox Koch lb120 too, direct from the speaker out of the GM36, and use some IR from OwnHammer or Two notes with cab+mic. Sound great too, but in fact I prefer to use the redbox directly (simpler), as I found the tone to be really good, on the modern side.
i have to say that I made some mods on the tubes (see other thread) and I have a nice creamy tone now.

Thanks gravydb. What have you used for attenuation? I can't say I'm displeased with what I'm getting right now through the Apogee, but I don't know how long it will hold up. I'll have to take a few measurements and do a little research to see if it can withstand what the Redbox is throwing at it.

Stop me if I get more tech than you want ABud......

H&K GM36 Manual: wrote:Heads Up: The amp’s Master knob settings and the selected Power Soak mode directly affect the signal level: Stepping up to 36 watts from 18 watts changes the Red Box Out level as it does the Speaker Out level.  Stepping down from 18 watts to 5 watts, 1 watt and Speaker Off (for silent recording) does not change the level! So you can step up from 18 watts to 36 watts on the fly (via preset change), for example, to boost the volume for leads when playing live. The level of the signal sent to the Red Box Out (and to the mixing console) will be bumped up accordingly. The signal level of the 18 W, 5 W, 1 W and Speaker Off modes remains the same for a very good reason: That way you can choose the right Speaker Out level for the rehearsal room, home practicing and silent recording without having to adjust Master knob settings.

So it's 18W/5W/1W to get the lowest Redbox signal but no difference between the 3.  That means Redboxwise everything will be set up as though it was the 18W setting selected even with 1W.

According to the H&K specs the Redbox nominal level out is -10dBV at 3W. -10dBV is 0.32V RMS and 0.9V p-p.  It's going to be pretty dynamic though as it specifies that it can go up to +3dBV which is 1.4V RMS or 4V p-p.  The Jam lists no input level that I can find, only "guitar" which could mean anything.  If it's powered from the USB port then you have only 5V DC on tap so it's pretty limited in headroom.  I'd be tempted to make up a resistive attenuator starting with about 10:1 and see how it goes from there.  You have 40dB of gain at hand in the Jam so being a little restrictive shouldn't be an issue.  The Redbox is 1360ohms output impedance so anything fairly well above that would be fine, about 10k:1K should be a good guess.

If the Jam has been designed properly, and I would be surprised if it hasn't, the Redbox output level even as it stands shouldn't damage anything at it's input though I'd keep the volume down until you can drop it.  (Hope someone sanity checks this for me just to keep us on the straight and narrow.)

This is the attenuator I use: http://www.ebay.com/itm/Balanced-Line-to-Mic-level-converter-attenuator-pad-XLR-/200810579560?hash=item2ec13e4668:m:m-gJ4ydZ1EkckQTMpids_Nw

There are other inline attenuators out there, the ones that look like a metal tube, with selectable attenuation 10dB-20dB-30dB etc. Some have fixed attenuation too. Shure and Hosa and Audio-Technica are a couple brands that come to mind. I tried one of those and I didn't care for that type of design, it was too klunky. I much prefer the simpler one on ebay.

There are a couple of things I'm not sure about with those attenuators Gravy.  Are they "Balanced Line" to "Balanced Mic", or are they "Unbalanced Line" to "Balanced Mic"?  In other words, is the line input balanced or not?  When he says that the impedance to each of the pins 2 and 3 on the XLR is unequal he is right but I'm not sure at which end he means.  In fact I don't see any mention of impedance in that listing.  What he says about phase issues could be right from my experience but I'd like to know what sort of loading he is anticipating and whether that is taken into account with the -40dB figure.  Do you have any idea what the impedances involved are?  It just says that it takes a "line level" signal down to a "mic level".  We are driving it from the balanced 1360R output impedance of the Redbox on the amp not the 600R of a standard balanced output.  It should fit in with that of course.

At the end of the day the only answer is do they sound ok and I would guess that's a hearty yes, but we must be a bit wary of how super scientific we think the design is, it's only a few resistors after all but the values could be important to properly match what you are using them for.

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This is a pic of a commercial unit I blagged to show what we might have.  Just imagine the right hand socket was another XLR connected to pins 8, 7 and 1.  It really should have the centre of the 12R resistor connected to ground to be truly balanced.  You can see that from pin 2 to pin 3 of the line input there is about 600R, (300R to ground on each pin if the ground was there making it balanced impedance), which is a standard configuration.  If that is how he has set up the attenuators then that is lower than our Redbox output impedance which isn't the best setup.  He also mentions that he found you couldn't use the commercial attenuators in either direction.  With that configuration why not?  it is symmetrical both across the sockets and in both directions in the line.  I don't think he can have the same values, and if not, what does he have?

Can you solder? If you put the first two resistors into the Input XLR and the rest in the output XLR that is a piece of cake to make up!  And here is a little site, H-Pad Calculator, where you can get the accurate values to match your particular setup.


EDIT: I'm sufficiently geeky and intrigued enough with this topic to ask the seller of those attenuators about his impedances. If he gets back to me I'll let you know what I find.

Hi bordonbert! I'm always glad you chime in on these threads with your technical knowledge I don't understand all of it (my fault not yours) but nonetheless it's fascinating and interesting.

All I can say is that the -40dB ebay attenuator works and sounds fine. I've played lots of shows with it (mostly with my prior TM18) and it just works, I never gave it any 'technical' thought. I don't use it when the mixer is capable of accepting Line Level but in the instances where there were only Mic inputs it was a life saver.

I suppose we could contact the seller (as he makes the units himself) and ask some tech questions? Because now I'm curious, I'd be happy to do that.

That's in hand Gravy, the question has been sent and I'm waiting for him to come back.  I hope I'm not sowing paranoia with all of the tech mumbo jumbo?  As I said and you confirmed, if it sounds good to you and what you want then it's fine.  (Even those damned 12AT7s are liked by some people! )  It's just with these technical issues it's always best to start yourself from the position of knowing as much as you can about their background.  That way the BS sniffer is keenly honed, plus, those musical myths that haunt my wee wee hours lose some of their hold on you.

And not understanding something is fine, being ignorant is not the same as being stupid.  I'm ignorant of most of the craft of running a farm but I don't think that makes me stupid, (at least not now I've seen a few farmers).  The trick is to pick up what you can of anything that interests you.  (For example, my knowledge of farming is improving every day.    <- That's a pig.  That's a cat ->  . That's the ghost of last night's pie ->   .  And that's cider! ->    )

I'll keep you up to date with any replies.

Ok, it's 150R and 15150R.  He didn't say which was which!  That gives us some easy to work out values that he has used, (you could use the calculator link I posted).

Unfortunately we are not going to get a really good match either way around, though it probably doesn't mean too much in this case, it's not power transfer we are interested in but voltage and we only need to preserve the fidelity and the symmetry takes care of that pretty much.  If the 15150R (15.15k) is on the input then we are driving a higher impedance in the XLR from the Redbox which is the good way around, and a higher impedance in the Jam from the 150R output in the XLR.  It screws with the accuracy of the attenuation kicking it off the -40dB, but that shouldn't be a problem as long as there is enough there for your purposes.

The most important thing is that the mismatches are symmetrical +ve and -ve which his ebay post says he has taken care of.  Noisewise we still have symmetrical levels on both lines at equal impedances which will cancel each other out.  And the cable is much too short to have to worry about cable capacitance effects which are again symmetrical!

It would have been nicer to an anal engineer to have a more customised impedance match to the Redbox and the standard input but, I declare you to have done a "good thing" Gravy!  

I dig this forum already! I'm a SW engineer, so the while EE discussion isn't foreign to me it's not my main bag. I'll take just about any technical discussion though and learn something from it.

I imagine I can cobble together an attenuator from parts laying around my office. Enough electrical components to build something that simple, and enough electrical engineers to run the circuit by.

And finally, kudos to the Newcastle Brown Ale reference bordonbert. I've got family up in Sunderland and I've been to the brewery. My dad loves it, but says it's not the same as it was 35 years ago. Now my friends in the UK say it just causes trouble, LOL! Good old Newci Brown.

The attenuator should be very easy to set up if you use the link I posted to the calculator.  Make sure to use the H-Pad version to keep your balanced configuration.  Perfect matching of the 1360R and 600R impedances is not absolutely critical as long as you don't need a very accurate attenuation factor, but balance between the two legs absolutely is for noise.  And also split the connecting resistance in the branch of the H into two equal parts and ground the mid point.  It isn't truly balanced without that.

Haha!  Another engineer, great! I have a thing about industry myths and someone else who may push a logical approach will be welcome. It's a small world AB, I'm actually from Hebburn/Jarrow on Tyneside, near enough to be family!  For my sins I've been a lifelong Sunderland football club supporter and this year is plain sh*t!  That doesn't make me popular in some places around Newcastle which is nearer.

A warning about Newcy Brown, it's not known as "Lunatic's Broth" up North for nothing.  It's an amazing drink if you imbibe it very rarely, and Newcastle Amber Ale is less well known but just as good.  It rots the brain like nothing else can if you drink it regularly.  It's a chemical brewed in the bottle beer!  Lovely flayour but it causes the "Brown Ale Shakes".  I used to work in bars as a teenager and when you saw a guy walking towards you with rheumy eyes and his hands and knees trembling you just opened the bottle for him before he even got there. It was always rumoured that Cherry Knowles Asylum in Sunderland had a special ward for drying out Brown Ale drinkers. Happy days!

The reference is a typical Steve Marriott lyric from "Thirty Days In The Hole".  Humble Pie, best little rock and roll band in the world!

I ordered one of those line attenuators a couple of months ago. Nine days later he hadn`t shipped it nor contacted me about it so I cancelled my order. Sucks, too. Looks like a great piece.