Fender Brownface 6G7a question

[JohnJankowski]

I recently completed a 6g7a Brownface Bandmaster clone. It works perfectly but i have a question for others more experienced with the 5 triode harmonic tremolo.

The tremolo on my amp does not really start until the intensity knob is at about 5. It works great after. Is this typical?

I dont look at this as a problem. Just a quirk, so to speak. If the originals worked like this, fine. If not, well that’s ok too.

Anyway, is this typical of that model or no? What is typical regarding where the tremolo kicks in with the intensity control?

[maxkracht]

Are you using a reverse audio pot for the intensity?

[JohnJankowski]

Yes. 3meg RA.

[johnnyreece]

I don’t know this particular trem, but some require a strong tube to oscillate properly. Have you done any tube rolling?

[maxkracht]

The original was 10M. Weber sells them for the revibe, not sure if anyone else makes something better. https://www.tedweber.com/wp106ra/. Could also play with adding resistors to get a better usable range.

[JohnJankowski]

Actually, it is a 10m RA. The 3m is speed control

[maxkracht]

I don't think it should be subtle early in the rotation. Might be worth subbing in a new tube like johnnyreece suggested or double checking your wiring if it bugs you.

[JohnJankowski]

Thanks. The “new tube” suggestion is easy enough to do. Actually, I don’t consider this a problem as much as a quirk. It works great otherwise. Finest tremolo effect I’ve ever heard.

I’ll leave it as is for now. I plan to build another, but with these issues in mind. I’ll experiment on that unit.

The near hypnotic effect of this tremolo design is worth the effort.

[Stevem]

I don't know if you have ever heard it, but the tremolo on a Vibrochamp has great depth also .
Change out the caps to slow it down more and pop in as strong tube and your in love!

[maxkracht]

It's also possible you got a pot with an odd taper. I've only messed with one original 6g7 and my revibe, so not a great sample size of harmonic trems, but both had noticeable tremolo on 1 or 2. Might be worth checking out Sluckey's revibe project if you are planning to build another. He has nicely drawn plans and some useful mods. https://sluckeyamps.com/revibe/revibe.htm

[JohnJankowski]

It's also possible you got a pot with an odd taper. I've only messed with one original 6g7 and my revibe, so not a great sample size of harmonic trems, but both had noticeable tremolo on 1 or 2. Might be worth checking out Sluckey's revibe project if you are planning to build another. He has nicely drawn plans and some useful mods. https://sluckeyamps.com/revibe/revibe.htm

I’ve actually built a ReVibe. It and Sluckey’s seem to be based on the 4 triode design. Some of those mods might help this build. Thanks for the suggestion.

[maxkracht]

Since the 5 triode version with the lfo buffer should have a slightly deeper tremolo, I would assume it would also have more tremolo on lower settings if everything is working correctly.