JTM312 problem

useppewind · 06-14-2009, 08:34 PM

Hi to the Marshaller!!!
I have an 8 years-old JTM30 series amp. The first 4 years used 8 times/month, the latter 4 years not used.
Always perfect sound, never had problem.
Now after 8 years: the clean sound is perfect, but the distorted sound is horrible, the gain at 100% seems to reach the old 50%, and it is unusable.
If I connect a boss ds2 pedal on the clean channel the sound is the same.
I tried to exchange the three preamps tubes but nothing.
Help me please.

Jesstaa · 06-16-2009, 08:31 AM

Did you try the power tubes? (It has power tubes, right?). They'll affect the tone lots.

useppewind · 06-22-2009, 06:23 PM

I have swapped the 2 powertubes: the distorted is slightly better, almost 70% the original max of the gain.

useppewind · 06-30-2009, 05:52 PM

I have replaced all the 2power tubes and the 3 preamp tubes with new ones, the sound is fairly better, there is more presence, but is still not at the 100% of the original distorted sound.

06-14-2009, 08:34 PM	#1 (permalink)
useppewind Junior Member Join Date: Jun 2009 Posts: 3	JTM312 problem Hi to the Marshaller!!! I have an 8 years-old JTM30 series amp. The first 4 years used 8 times/month, the latter 4 years not used. Always perfect sound, never had problem. Now after 8 years: the clean sound is perfect, but the distorted sound is horrible, the gain at 100% seems to reach the old 50%, and it is unusable. If I connect a boss ds2 pedal on the clean channel the sound is the same. I tried to exchange the three preamps tubes but nothing. Help me please.

06-16-2009, 08:31 AM	#2 (permalink)
Jesstaa Senior Member Join Date: Apr 2009 Location: Gippsland, Vic, Australia. Posts: 797	Re: JTM312 problem Did you try the power tubes? (It has power tubes, right?). They'll affect the tone lots. __________________ GEAR LIST Marshall JCM900 4100 (6L6) (1995) Marshall Valvestate 1965A cab (????) Cort VX-2V (2008) TUBES/SPEAKERS Power: Groove Tube 6L6GCB Phase Inverter: Sovtek 7025 Pre: V1 - N.O.S Mullard ECC83. V2 National 12AX7A Speakers: Celestion G10L-35 Marshall forever My tube amp & Real Music appreciation forum

06-22-2009, 06:23 PM	#3 (permalink)
useppewind Junior Member Join Date: Jun 2009 Posts: 3	Re: JTM312 problem I have swapped the 2 powertubes: the distorted is slightly better, almost 70% the original max of the gain.

06-30-2009, 05:52 PM	#4 (permalink)
useppewind Junior Member Join Date: Jun 2009 Posts: 3	Re: JTM312 problem I have replaced all the 2power tubes and the 3 preamp tubes with new ones, the sound is fairly better, there is more presence, but is still not at the 100% of the original distorted sound.

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