Are JTM45s mushy?

guit_lar

Member
Messages
305
Particularly at higher settings of the volume knob. Say with KT66s. I've read some things that seem to say this. But Angus' (if indeed what he has used) sounds nice and crisp, even with that Gibson guitar...
 

RocksOff

Member
Messages
7,459
Alot of it is that SG. My Bon Scott era AC/DC tribute act uses JTMs. They sound great, and can be very crispy. You just have to dial that bass down.
 

Miles

Member
Messages
3,966
I second keeping the bass down. Those vintage amps with big bottles get muddy when you ride the bass up. Keep the mids up, presence up, treble to taste and bass down. Power tube saturation can often get farty/muddy easily. You've got to cater your eq to your cooking tubes.
 

guit_lar

Member
Messages
305
Thanks for the replies.
Follow-up question: what speakers (2 X 12) for that crisp defined sound, minimize flubby bass, get some nice high-mids...
 

JosephN0624

Member
Messages
456
I have a Jackson Ampworks Union Jack....not a JTM but uses KT66s and definitely has that sort of vibe. I've got it dialed in perfectly though pretty much by doing what Miles says. I picked up one of their 112 cabs as well with a Celestion Gold in it also...and it made a world of difference....crystal clear.
 

wildshoetwt

Member
Messages
831
keep the bass down, go with a 2x12 of very highly rated speakers or a 4x12 to avoid speaker breakup which can get very mushy with celestions, especially very broken-in celestions


worst thing you can do is turn the bass up past 9 oh clock, use a rosewood fretboard, and a 2x12 of broken in celestions that are rated just high enough to be used with the amp, string gauge and tension also plays a part here, and you want to make sure to tailor that bass to your playstyle, if you play mostly on the neck pickup and want to keep the bass tight on the bass channel, you will have to dial the bass off almost, whereas you can get away with more on the bridge where theres more string tension to keep things tight
 

RocksOff

Member
Messages
7,459
I disagree with wild's post, but to each his own.
I use 5881s in my JTMs, and old Celestion Greenbacks. My are plenty crisp, but I keep that bass turned WAY down... like 8 o'clock. Mine especially love humbuckers (low winds, if possible) and rosewood fretboards. A semi hollow or LP sounds glorious.
As mentioned above, turn the presence and the mids up, bass down, put the treble where it sounds best. Use the 'brilliant' channel', top input. Also, don't jumper the channels if you want it super crisp.
Keep this in mind... it's never going to be JMP crisp. That's partially due to the JTMs using tube rectification. And the key to great JTM sounds is keep the gain lower than you think it should be. When you dig in, it will give up the goods.
 

riffmeister

Member
Messages
16,607
A lower gain preamp tube helps reduce mush when the volume is up. In addition to everything else that has been mentioned.
 

Mattbedrock

Gold Supporting Member
Messages
4,750
With my JTM45, I usually use a 2x12 cab with Jensen C12K's in it. They're 100 watt rated and quite bright. They don't mush out at all. I do Y cord the channels but use more of the bright than normal channel. I also have a Tung Sol 12Ax7 in the V1 position that is a little lower gain than some of my other preamp tubes.
 

Roe

Member
Messages
7,929
45s are a littly myshy yes, but it depends on voltages, tubes, filtering, rectifier and even pots
 

Hand of Doom

Member
Messages
4,484
3 or lower in safe mode or everything dimed and ride the vol on your guitar. You are in for a BIG surprise if you try the later.
 

Nickcha

Gold Supporting Member
Messages
697
I've played '65 and '66 JTM45s (never tried the earlier ones). If they're healthy, I wouldn't describe them as mushy. In fact, a couple of them I've played were fairly sharp and crisp, and had a nice hard edge. I agree with the assessment above, that they do best not turned all the way up. And I also agree that they're not going to sound quite like a JMP, but that's the beauty of them, isn't it. Even the JTM45/100s have that sweetness and happy bounce in the low end.

Whether Alnicos or H30 ceramics, is a matter of taste. That Alnicos for sharpness and the H30s for warmth/sweetness, IMO.
 

t.hendrix

Member
Messages
1,900
They seemed to fuzzy on the top end ,but that's what kt 66 tubes sound like.plus with a tube rectofier there a little looser sounding,not mushy.
 

908SSP

Member
Messages
5,801
I run the bass no higher than 2. The treble and mids on 10 and the volume between 9 and 10. A 4x12 even for low volume playing with my attenuator. Using good tubes helps and the right speakers helps too. I use old JTM45s or good clones. The reissues just never seemed to be that good they have tiny transformers running lower voltage.
 

RussB

low rent hobbyist
Messages
11,170
45s are a littly myshy yes, but it depends on voltages, tubes, filtering, rectifier and even pots
This.


Don't be afraid to turn the bass down...way down, even all the way off


Greenbacks sound killer with a JTM 45
 

jiml

Gold Supporting Member
Messages
10,941
Surprised to find out that JMP's are a lot "mushier" than the 45's I have owned/played through..
 

Nickcha

Gold Supporting Member
Messages
697
I run the bass no higher than 2. The treble and mids on 10 and the volume between 9 and 10. A 4x12 even for low volume playing with my attenuator. Using good tubes helps and the right speakers helps too. I use old JTM45s or good clones. The reissues just never seemed to be that good they have tiny transformers running lower voltage.


I apologize in advance for departing from the topic, but, Alex, do you use a regulator to give your old JTMs 110v, or are you running off wall current (122-125+volts)? I have one of your attenuators - love it - and just wondered about the strain on the mains running present wall currents. I'd like to use the Alex with my '67 JMP50 and run the amp up a bit.

Thanks
Nick
 

Nico.

Member
Messages
348
I played a Bluesbreaker combo reissue with KT-66's. Hated it! YES it was mushy even with the bass on 0. Dreadful amp, I might not have played the good old ones, if there is such a thing...
 

908SSP

Member
Messages
5,801
Hi Nick
I forgot that I always use a Variac with the voltage at 100 to 110. That might make a difference. I do it to protect the amp.
 




Trending Topics

Top