Hi guys, great forum, already learning lotsa stuff.
Just purchased a second hand GM40, have dreamed about a GM for quite a few years....ever since the 36 came out.
I have to say I have seen every single YT demo of the GM40, at least twice.... for the past 3 years before pulling the trigger... great sound, features, and it seemed quite fit and flexible for what I play, Floyd, U2, 80's metal (yeah... I'm 51....50 lol). I can equally say I have been really disappointed by the sound I'm hearing in person, harsh, fizzy, thin, boxy, cold and sterile... a high gain tone that sounds like a bad solid state distortion of 30 years ago...in fact the shock had me almost resell it immediately... but I took a breath.... I will give it a second chance.
Fortunately I have definitely found all I needed to know on the tube swapping thread, thanks to all of you.
I guess power JJs and a 5751-5751-83s combo might do it for me.
Now, I have an issue/failure that I believe tube-related, hopefully someone here has a clue.
After playing for a couple of hours just on the clean channel, there was a massive drop in volume, I mean easily 80%.... the crunch channel is affected , say by 50%, lead and ultra are as loud as ever. I would imagine it might be a preamp tube assigned to the clean/crunch channels that just failed? I took all tubes out and put them back in, they all seem to glow normal, no klonking sound when I tap them, so.... I'm hoping it's just the one tube that decided to go south.... I messaged the HK team on FB, they were very nice but didn't seem to have an answer.
Oh, and for the record I'm playing through a beauty of a Panama 1x12 cab with an aged V30, and despite the speaker influence, I can say I have played it with a 5w class A Baroni Lab head and it sounds sweet, not Fender-ish of course (also EL84s) but warm and clean, so I can't blame the cab ( and that doesn't explain the loss of the clean channel anyway).
*UPDATE*
I've run a few tests:
*Took a 12ax7 from my other head and swapped for each of the preamp tubes in the GM one at a time, and checking for some difference every time. Nothing.
*Swapped the outside EL84 pair to the inside. Nothing.
*Took an (the) EL84 from my other head and swapped for each of the power tubes in the GM one at a time, and checking for some difference every time. Nothing.
The clean channel is basically dead... I have to put the master AND the gain at 10 to even hear anything...
Meanwhile the crunch channel is now a pristine clean, and I have to put the gain way up and use a humbucker for it to start crunching...
From limited experience but common sense this would seem to me like a preamp gain problem, so tube failure, but replacing one at a time didn't do anything I suppose the only way to be sure would be to change the whole set... but buying a complete set of tubes for an amp that may be faulty sucks the big one. Damn, really not a good start.
btw I also find the lead and ultra channels extremely loud on 1W setting.... but I suppose that is normal.... " yessss yesss..metalll... hehe hehehe hehe"
Any clues much appreciated. Thx in advance.
Just purchased a second hand GM40, have dreamed about a GM for quite a few years....ever since the 36 came out.
I have to say I have seen every single YT demo of the GM40, at least twice.... for the past 3 years before pulling the trigger... great sound, features, and it seemed quite fit and flexible for what I play, Floyd, U2, 80's metal (yeah... I'm 51....50 lol). I can equally say I have been really disappointed by the sound I'm hearing in person, harsh, fizzy, thin, boxy, cold and sterile... a high gain tone that sounds like a bad solid state distortion of 30 years ago...in fact the shock had me almost resell it immediately... but I took a breath.... I will give it a second chance.
Fortunately I have definitely found all I needed to know on the tube swapping thread, thanks to all of you.
I guess power JJs and a 5751-5751-83s combo might do it for me.
Now, I have an issue/failure that I believe tube-related, hopefully someone here has a clue.
After playing for a couple of hours just on the clean channel, there was a massive drop in volume, I mean easily 80%.... the crunch channel is affected , say by 50%, lead and ultra are as loud as ever. I would imagine it might be a preamp tube assigned to the clean/crunch channels that just failed? I took all tubes out and put them back in, they all seem to glow normal, no klonking sound when I tap them, so.... I'm hoping it's just the one tube that decided to go south.... I messaged the HK team on FB, they were very nice but didn't seem to have an answer.
Oh, and for the record I'm playing through a beauty of a Panama 1x12 cab with an aged V30, and despite the speaker influence, I can say I have played it with a 5w class A Baroni Lab head and it sounds sweet, not Fender-ish of course (also EL84s) but warm and clean, so I can't blame the cab ( and that doesn't explain the loss of the clean channel anyway).
*UPDATE*
I've run a few tests:
*Took a 12ax7 from my other head and swapped for each of the preamp tubes in the GM one at a time, and checking for some difference every time. Nothing.
*Swapped the outside EL84 pair to the inside. Nothing.
*Took an (the) EL84 from my other head and swapped for each of the power tubes in the GM one at a time, and checking for some difference every time. Nothing.
The clean channel is basically dead... I have to put the master AND the gain at 10 to even hear anything...
Meanwhile the crunch channel is now a pristine clean, and I have to put the gain way up and use a humbucker for it to start crunching...
From limited experience but common sense this would seem to me like a preamp gain problem, so tube failure, but replacing one at a time didn't do anything I suppose the only way to be sure would be to change the whole set... but buying a complete set of tubes for an amp that may be faulty sucks the big one. Damn, really not a good start.
btw I also find the lead and ultra channels extremely loud on 1W setting.... but I suppose that is normal.... " yessss yesss..metalll... hehe hehehe hehe"
Any clues much appreciated. Thx in advance.