Amp Techs/ Modders Help ! Hughes & Kettner Triamp Mods

[jonathant83]

i have two hughes and kettner mk2 triamp heads. One used all the time, the other is my rig back up, which never gets used. i am looking for some mods to help out on the gain stage of Amp 2B, it just sounds to muddy and not clear at all. i can help clear it up to a usable level, but since it has shared eq with 2A, 2A becomes basically unusable. So i basically have to decide when i am playing which channel would get used the most and suit eq to that. it would be nice if each A/B had its own eq. I have played both the mk1 and the mk2 amps ( and whille the mk2s are better then the mk1s ) are still not up too the task. if any one can help out with any tricks or mods that can help out this amp, it be would be great. I am handy with a solidering iron and have no problem being able to change resistors and jump cuircuits and such . basicly want some input from guys that have opened one of these up before. thanks jon

 

[MississippiMetal]

I've been inside the MK1 many times, actually disassembled the entire amp, and I can tell you that "handy with a soldering iron" doesn't cut it with these amps. Even experienced technicians avoid working on a Triamp.

 

[jonathant83]

yes i understand, i had this thing apart before to basically go over everything ( i expected it to be like the old Marshall i had. ) But i didn't have to touch anything, solder wise. i have only been biasing for tube swaps. I have been reading and reading for ages. why did u happen to have ur's apart? mayor surgery ? The next for sure thing i need to do is change out my cracked up foot switch wiring that is coming/falling apart. thanks jon

 

[MississippiMetal]

Mine had a bad treble pot on channel 2.

 

[jonathant83]

i have been collecting some info for some whille here is what i gathered so far from previous posts in regards to the triamp. just wondering if anyone could go into details. the only other mods are done by the tone hunter in germany, and unless to start giging there its not worth it to get shipped just for mods. thanks jon


it can be revoiced, but will require a lot of tweaking

C2 to .68u
R2 to 2k7

bypass R31 or C19
R29 to 1k5
C20 to 1u

1u in parallel with R40

I'd also change R3 to 10k, C53 to 120p, C59 and C60 to 22n, R104 to 27k

SFW,

If you are referring to Crunch2 gain, all you have to do is replace r26 (220k) resistor with a 100k resistor. This will give you a healthy bit more gain and hardly effect the overall tone of the channel. If you want to do any voicing work to this channel beyond just this gain addition, let me know. There are many different places in this channel where you can fatten or tighten up the overall tone. After briefly reading through the schematics for the amp, I see it's a very modern and well engineered machine. They put alot of effort into creating their tone.

MississppiMetal, as just said, deoxit may do the job, but from my experience, it's just best to replace em outright. Just cut the damned pot up and pull it out in pieces. Them clean up the solder holes and install a new one. I'm sure the pot is nothing special. Look at Mouser.com and see if Alpha has a pot that will replace it. Otherwise just mount a pot to the chassis if it will fit and run flying leads into the pcb. If you rotate the pot 180 degrees and get the leads out of the way, this may fit. Try it out. You can email me a photo of the area and I'll look at what will match up for you.

 

[MississippiMetal]

Yeah that's from a very old thread. And we're talking about the MK1 there. I'm not sure what changes were made to the MKII, but im sure the PCB designations are not the same.

 

[jonathant83]

umm i see, maybe its time to open her up and take some snap shoots. would that help out at all? I have played both mk1 and of course i have logged some time with my mkII amps. they sound very very close. No dought that there would be differences in the two revisions. Like how some early mkI triamps had no tube fuses (1995-1997), and how the later ones did (1997+) then they did the swap to el34 to help with mid range.

 

[MississippiMetal]

Snapshots would certainly help, although not paint a very clear picture of the circuit.

 

[jonathant83]

ok, ill be taking it apart the next few days. ( i have my music room in a mess right now) I was thinking if id be able to put in a set of eq pots for the 2nd gain stage of amp 2 aka (2B). I really think its the fact that they shear the eq that makes 2b sound too bassy. Maybe be nice to add a tight button like 1A has for 2B to really scoop out the bass and tighten it up. I think this may start to get interesting...

 

[MississippiMetal]

2B is likely too bassy simply because it either adds an extra gain stage or swaps out a larger bypass cap. In either case there is probably wiggle room to tame the boominess. I'm not sure how you would manage to fit a second tonestack in there. That would require not only finding real estate for the knobs but also cutting traces and rerouting relay functions.