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Sick Marshall Studio 15...

4/19/2003 12:17 AM
Deltablues	Sick Marshall Studio 15... I've never worked on a PCB amp before and I need some recommendations on a sick Marshall Studio 15... Symptoms: 1. With all the knobs dialed up to 10, it's not as loud as my vibrochamp and it's still completely clean sounding, (no breakup even though the gain is set to 10). 2. I'm hearing radio stations through the amp when it's turned up. (This doesn't happen on any of my Fender amps in the same location on the same outlet). 3. The previous owner "claimed" that it worked fine for him before he shipped it to me. What I've tried: 1. Changed out the original Sovtek 12AX7's for a couple old Nationals, which significantly raised the volume, but only to the level described above (think clean champ tone with volume on 6). 2. Changed out the 6v6's, but this made no perceptible difference. 3. Tried plugging headphones into the headphone jack and unplugging the speaker. This sounded just like it did when I was playing through the speaker, so I think this eliminates the speaker and associated wiring as the potential culprit. 4. Plugged the speaker into the headphone jack (I was told that this would allow attenuated operation), but when I do this I get no perceptible sound out of the amp at all. Any idea's on where the problem might be? Barring that, does anyone know a good tech that works on Marshalls? Also, would an authorized Marshall Repair facility be likely to work on a discontinued amp that's this old?

4/19/2003 12:17 AM

Deltablues

Sick Marshall Studio 15...

I've never worked on a PCB amp before and I need some recommendations on a sick Marshall Studio 15...

Symptoms:

1. With all the knobs dialed up to 10, it's not as loud as my vibrochamp and it's still completely clean sounding, (no breakup even though the gain is set to 10).

2. I'm hearing radio stations through the amp when it's turned up. (This doesn't happen on any of my Fender amps in the same location on the same outlet).

3. The previous owner "claimed" that it worked fine for him before he shipped it to me.

What I've tried:

1. Changed out the original Sovtek 12AX7's for a couple old Nationals, which significantly raised the volume, but only to the level described above (think clean champ tone with volume on 6).

2. Changed out the 6v6's, but this made no perceptible difference.

3. Tried plugging headphones into the headphone jack and unplugging the speaker. This sounded just like it did when I was playing through the speaker, so I think this eliminates the speaker and associated wiring as the potential culprit.

4. Plugged the speaker into the headphone jack (I was told that this would allow attenuated operation), but when I do this I get no perceptible sound out of the amp at all.

Any idea's on where the problem might be? Barring that, does anyone know a good tech that works on Marshalls? Also, would an authorized Marshall Repair facility be likely to work on a discontinued amp that's this old?

Replies:

Deltablues Oh... It's also fairly noisy when ... -- 4/19/2003 12:20 AM