Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: octa on March 28, 2023, 01:05:02 pm
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Hi
I built standalone harmonic tremolo a couple of days ago, and it is working, no problems. Very silent in regard to noise, very low background thump almost none. DC heaters. Oscillator is strong, depth is good, but I wish for that phasing-wobbling effect to be more pronounced. Would that be possible? For now it sounds just like ordinary tremolo, with just a hint of "harmonic"...
Mybe my PSU is to low (260Vdc) for this to come to life?
Schematic included with mods that I already introduced, thanks to Sluckey's revibe mods.
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Mybe my PSU is to low (260Vdc) for this to come to life?
That could be.
How does your unit sound compared to the demos?
https://el34world.com/Misc/Music/files/ReVibeTest1.mp3
https://el34world.com/Misc/Music/files/ReVibeTest2.mp3
Try to tune out the reverb if you can.
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How does your unit sound compared to the demos?
https://el34world.com/Misc/Music/files/ReVibeTest1.mp3
https://el34world.com/Misc/Music/files/ReVibeTest2.mp3
Try to tune out the reverb if you can.
Very similar, but far less of that " harmonic" thing, like I have about 20% of "harmonic" and 100% of tremolo compared to the demo. Tremolo got a bit stronger (more depth) with your mods, thank you.
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The harmonic tremolo is just ONE effect. You can't separate harmonic from tremolo. I think what you want is more strength. Higher B+ "may" get you there. My B+ is considerably higher than yours. If that won't do it for you, I don't know what will.
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I just realized that you used the later circuit based on the 6G4-A which is quite different from Hoffman's circuit that is based on the 6G4. That may explain the differences.
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I built standalone harmonic tremolo ... but I wish for that phasing-wobbling effect to be more pronounced. ...
I just realized that you used the later circuit based on the 6G4-A which is quite different from Hoffman's circuit that is based on the 6G4. That may explain the differences.
And owners of brown face Fender amps also report that the two versions of the harmonic trem circuit sound different. However, I don't remember which one is supposed to be more phasey.
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+1 on the higher supply voltage! That is usually the ticket for a stronger effect.
FWIW on my recent build (6G11 Vibrolux-ish) it was easier and a shorter wire to feed the tremolo from the preamp node (290 DCV). But the tremolo wasn't as strong as I like, so I tried to supply it from the screens node (405 DCV) and bingo! STRONG tremolo.
I think you can also try a higher value intensity pot though...I remember this as a fix in the past too, but I might be wrong :icon_biggrin:
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His INT pot is already 10M! This circuit is very different from your 6G11.
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His INT pot is already 10M! This circuit is very different from your 6G11.
Ok I understand…
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I just ordered new power transformer.
Any consensus on what circuit sounds more phasy, 2 tube or newer 2,1/2 tube? I can quickly rebuild this to 2 tube version.
Like this tremolo very much:
Since this amp is 1963 I assumed the 2.1/2 tube circuit to be what I want.
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Try changing the 10nF cap that goes to ground after the 220k resistor to 4.7nF.
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This might help you decide what to change
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This might help you decide what to change
Great! Thank you very much! Once I get my new power transformer I'll return to it.
In the mean time, any consensus on what circuit sounds more phasey? 4 triode or 5 triode?
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In the mean time, any consensus on what circuit sounds more phasey? 4 triode or 5 triode?
No idea. I've only heard the 4 triode circuit.