previous: bobCT Gil,Re your stateme... -- 8/10/1999 6:56 PM

Re: Replacing trim pots with fixed resistors?

8/10/1999 7:12 PM

Gil Ayan

Re: Replacing trim pots with fixed resistors? quote: "     The Dumble schematic we all seem to be working from has a Lead Master as well as the trim pots. Where the trim pots brought out ot the panel on later Dumbles or were/are they always left inside? I was under the impression the the trim pots allowed the amp to be "fine-tuned" to suit a particular player's preferences and than left alone. I agree with Steve that bringing them to the panel, whether front or back, would allow you to "tweak on the fly" and would have its advantages. My idea has been to use the same pots that Fender uses as Hum Balance controls...the ones that have the slotted, recessed shafts...as trim pots and mount them on the back panel. In that way they would be readily accessible but out of the way and once you fine-tuned the amp to your personal taste you wouldn't have to worry about bumping a knob and changing the setting by accident.         Bob     "         Well, unless I'm mistaken, you are all working from a schematic which shows a 100KL trimpot at the input of the overdrive, and another trimpot at the output of the overdrive. The latter became a front panel control labeled many things over the years, at times it was called ratio.         Now, when I contacted Dumble to have him build me an amp in 1995 (which I didn't go for for financial reasons), his literature indicated that the OD Special had an "internal trigger control" for the overdrive -- which we can assume is the first 100K trimpot -- and a "internal HF taper." This means, to me, that there was a high frequency taper control, namely a treble gate in there, that allowed you to set the overall brightness of the lead channel.         Nowm those would be two controls that could be tailored to the user's preference. However, when Line 6 was modeling Dumbles, I got an email from George Van Wagner (I believe that is the gentleman's name) who mentioned the Dumble thay had modeled had a midrange control before the OD and a Treble and Bass before the OD. I asked if this would be the infamous Skyline mod, and he say quite possibly NOT. The reason being that later Dumbles they had seen (and they didn't like the sound as much) had the whole tone stack postioned after the overdrive control.         AS you can see, none of this information is reflected in the schematics currently on the Internet. Furthermore, the K&M amps -- which just hit the market and are asid to be "Dumble Killers" -- have "internal tone controls" which allow you to adjust the character of the overdirve. Som it would seem that there may be many trimpots in the later Dumbles, however, I have no further information on that.         Maybe after people start buying the K&Ms and posting their schematics (he he!) we will all know more about the myterious, ever evolving, Dumble design.         Gil

 

Replies:

Jim S. I've never heard of K&M before. Ho... -- 8/10/1999 8:12 PM BWilliamson q{Maybe after people start buying t... -- 8/13/1999 10:38 AM