I recently built a JTM 45 for a friend and everything seems ok, but the amp doesn't clean up well untill the volume is at 2, and when it is distorting the high end is very harsh, while at the same time the bass is a bit muddy.
I've tweaked the circuit to clean up the bass but the harsh highs are really getting on my nerves. And I'd like to get more clean headroom.
I think it may be the speaker, I'm using a BBQ silver bell speaker and its just got a really flabby low end.
Any suggestions for circuit tweaks or speakers would be appriciated.
fizzy and farty JTM 45
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yeahyeah
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Deadwood
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I have a Ceriatone 45 and it's fantastic. I have 2 W**** 12's, both 50w ceramic, one's a blue dog, the other's a silver bell. Through these speakers the 45 is dull and lifeless. Through two Celestion G12T-75's the amp is pristine. I use the treble input, vol on 8/10, bass off, presence middle and treble at 3 oclock. The guitar volume knob set at 7 gives a beautiful clean ballsy tone, go to 10 and it's just a bit more balls. Fantastic amp. I'm only using JJ pre tubes but it sounds great.
You could try swapping the OT primaries, I've made 4 of Niks amps and the OT primaries can be around the wrong way, it's a toss of a coin so says Nik ol buddy. Otherwise it does sound like there's something not right, check all your wiring and grounds and soldering, just check it all out, you probably already have done so but there's not much that will go wrong if it's assembled right.
Also the bass on all of my Ceriatone amps is set full off. See if you can plug that thing into a Celestion of sorts, I bet it livens up in the true JTM45 tradition. Good luck.
You could try swapping the OT primaries, I've made 4 of Niks amps and the OT primaries can be around the wrong way, it's a toss of a coin so says Nik ol buddy. Otherwise it does sound like there's something not right, check all your wiring and grounds and soldering, just check it all out, you probably already have done so but there's not much that will go wrong if it's assembled right.
Also the bass on all of my Ceriatone amps is set full off. See if you can plug that thing into a Celestion of sorts, I bet it livens up in the true JTM45 tradition. Good luck.
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PCollen
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If the OT primary wires to the tube plates are wrond, you will have a LOT more indication than fizzy tone and early distortion. The POSITIVE feedback will just drive you wild building from a murmur to a crescendo without ANY signal input. I had the OT primary wires backwards in my 6M45, I've been through it...Deadwood wrote:You could try swapping the OT primaries, I've made 4 of Niks amps and the OT primaries can be around the wrong way, it's a toss of a coin so says Nik ol buddy. Otherwise it does sound like there's something not right, check all your wiring and grounds and soldering, just check it all out, you probably already have done so but there's not much that will go wrong if it's assembled right.
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