Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: imgumby001 on February 12, 2023, 05:56:06 am
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Hello all,
Post recap, three prong and output Jack mod, my 1484 has no sound. My voltages are low compared to what’s on my schematic, but there are only a couple values listed on the copy I have. If anyone has a more detailed list of voltages, or any ideas it would be greatly appreciated!
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More pics…
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Hello all,
Post recap, three prong and output Jack mod, my 1484 has no sound. My voltages are low compared to what’s on my schematic, but there are only a couple values listed on the copy I have. If anyone has a more detailed list of voltages, or any ideas it would be greatly appreciated!
Did it have sound before you fixed it?
https://el34world.com/charts/Schematics/files/Silvertone/Silvertone1484.pdf
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output Jack mod
What does that mean? Did the amp work ok before you started working on it? If so, you should go back and look carefully at each thing you did. Hopefully you documented what you had before you started.
Photos show some jacks not connected to anything? Repairs that are potential grounding spots, etc.
If you went from sound to no sound, chances are you grounded something that was not supposed to be grounded, or you did not ground something that is supposed to be grounded.
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Yes, the amp 100% functioned, even the reverb. It had flubby bass, but was nice and loud. I was worried about my output Jack, but have looked through a bunch of threads where it was added, and mine looks like everything else I’ve seen. As far as grounds, the only one I did as a matter of purpose was ground the caps that replaced the can using the ground that was attached to the can lug, thinking that was what made sense. I’ve traced all my steps a few times now and am not locating the issue at any of those spots. I’m not saying I didn’t make a mistake, but if I did I haven’t found it.
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Ok, I did find my biggest mistake so far. Jack WAS wired wrong. My old eyes failed me again. Have sound now, but she’s noisy. Had a microphonic tube in V2, so it’s been swapped, but really didn’t help the noise. Gonna check everything over again and see what else I missed. Voltages are still way too low. Channel 2 not working or the reverb, so not sure how I screwed that up yet. Thanks again for y’all’s time.
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Glad you got sound now. You might want to swap all tubes - they can be noisy without being microphonic. And check all paths to ground with a meter.
I think there are multiple troubleshooting threads on this model - probably covers helpful ground.
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Yes sir!! Thanks so much. I feel like I’ve read 40 hours of threads on this bad girl, and that’s just the ones on this site!!! Found multiple loose socket pins, a few resistors too far out of spec to be useable, and changed some wire routing. Everything is working now. The reverb pot will probably need to be replaced as it has a dead spot early in the sweep, but it sounds as good as a silvertone reverb can. The tremolo will probably be left alone, even though I feel changing some values in that part of the circuit would make it more useable. She’s still a bit noisy, haven’t completely got that issue wrangled. I was thinking of trying some self grounding input jacks may help, or even trying a trick I saw uncle Doug do where he shields jacks by enclosing them in a metal “box”. I’d have to revisit his video on that first for sure.
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I have a 1484 that is discussed in this forum
I added one shunted input jack on channel two left most input and the noise was gone.
You can see what I did at www.stillampd.com under amp restoration (site is down currently)
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Thanks boss! I’ll definitely check that out!!!
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check out reply #33 and up for the shunted jack story, link below
https://el34world.com/Forum/index.php?topic=26406.msg288878#msg288878
BTW - the 1484 is my bestie. And the reverb was repaired and sounds great too.
sorry for stillamp'd.com being down. Maybe another few days. We self host and server is being replaced
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check out reply #33 and up for the shunted jack story, link below
https://el34world.com/Forum/index.php?topic=26406.msg288878#msg288878
BTW - the 1484 is my bestie. And the reverb was repaired and sounds great too.
sorry for stillamp'd.com being down. Maybe another few days. We self host and server is being replaced
I’m actually really, really enjoying this amp!!! Despite it being noisy I really love the tone!! It’s surprising to me how really “rocky” it is. I was imagining a more super twin-ish sound and response, but it’s super not!!!