Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: ALBATROS1234 on January 22, 2024, 09:33:09 pm
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So, I am building a National/Valco 1224 Tremotone. At first the amp sounded great but then I built the Trem and with that tube inserted it kind of seemed to bog down the preamp tube. I cathode biased that tube separately which helped some but it is too present. I basically built it like the schematic and this trem only has a speed control. I am just finding the tremolo a bit too overpowering, I have been looking at fender tremolos and such and experimenting to see if I can dial it back but this is my first build with Trem so I am ignorant regarding tweaking it. I tried to add an additional resistor with a decade box between the cathodes but it at certain lower values I hear little or no trem or it makes the faster speeds disappear and the slower is unchanged I assume it is acting like a RC filter. I tried to tap directly into the PI like on a 5E9 Tremolux since they both use a paraphase, using a fixed 220k resistor instead of a 250k pot and 100k to the wiper and I got squat, no trem. Is there a mod to make to whole thing have a less powerful effect/mix on the dry signal with this tremolo. I guess I could switch to a 6SL7 from the 6SF5 I am using and completely rebuild it like a tremolux but I would rather not. Any suggestions on how to make it more subtle it seems too choppy.
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You may get some ideas from the Marshall 18 watt amp...
https://el34world.com/charts/Schematics/files/Marshall/Marshall_18watt_schem.pdf
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It's the cheapest trem amp in the store (in 1957). It is what it is. You want it? Or you want to come back with another $47 and get the Fender?
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I really like the raw grit and harmonic content of this amp with its octal preamp tubes, I just would like to tone down the tremolo mix, there has to be a way. I will take a look at the 18 watt tremolo and see what I can do to make the trem less choppy. Thanks Sluckey.
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If you changed to a 6SL7, you could cop the trem circuit in an Ampeg J-12 Jet