View Full Version : Your input needed: Excelsior Tremolo Depth Mod

10-17-2013, 02:53 PM
I'm trying out some ideas for an adjustable depth control for the tremolo on the Excelsior. I put up a quick and dirty YouTube video and would appreciate some feedback from you Exy players (or just people with an opinion. :) )

My "manifesto" for Excelsior mods is that anything in the top chassis has to be a top-of-board mod. It's just too much trouble to remove the board, and there's the danger of breaking something. So this control is currently two wires that attach to component leads on the board.

It has the stock depth and no adjustability in pull-up position and starts its adjustable range in the down position with somewhat more depth than stock. It goes up to full-cut, throbby intensity, with a nice bias-modulated "swoosh."

Please give it a listen and tell me if you think it's useful and if this is how you envision the control working. Clicking on the pic takes you to my tremolo page. I don't think I can embed YouTube links here.

http://billmaudio.com/wp/wp-content/uploads/2013/10/excelsior-tremolo-depth.jpg (http://billmaudio.com/wp/?page_id=1532)

10-17-2013, 03:54 PM
Nice job!
I think it's a very worthwhile mod. I test-drove one of these amps when they first came out, and was pleasantly surprised at the sound-per-dollar.

BTW that speaker change to the Eminence is pretty convincing as well.

10-17-2013, 06:49 PM
Sounds great, much better depth but I would also like to hear it turned to slower speed than stock.

10-17-2013, 07:49 PM
I never turned the speed down less than halfway in the the video, but with the extended speed range, it's pretty slow--about 2.5Hz. Nice and pulse-y
Slower than stock Excelsior.

10-17-2013, 07:56 PM
Nice work Bill! Much improved over the stock tremelo.

10-17-2013, 08:04 PM
Bill, how soon will you have this tremolo mod available for sale?

Also, how much of a diffference does bypassing the sag resistors make in the clean headroom? How about offering a sag resistors in/out switch?

10-17-2013, 08:16 PM
I got a suggestion to make it a two-range control, from stock to middling and from where it starts now to pulse-y. I need to try that; it's a good idea.

I've got another project that will eat up the next week or so, but I should have time to develop it further after that. Producing it as a mod is not a big deal; I might have to order some resistors and knobs, but I have about 600 of the switched pots in stock. ;)

The sag resistors don't make much difference in clean headroom; they're mostly there to sag and provide some transient distortion. I have to re-look at the best way to bypass them; the connections are underneath the resistors, so it may be hard to make a reliable connection. They're in the high voltage line, so you don't want things coming adrift. I do have a good supply of Carling DPDT switches, though.