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Fulldrive vs. TS differences (summary?)

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1/17/1998 11:23 AM

Fulldrive vs. TS differences (summary?)

Are the only differences between the TS-x and Fulldrive 2 as such?:

- boost mode switching in larger value pot to increase gain of 1st opamp stage
- different input/output transistors (result = ?)
- 22k resistor (instead of 51k) leading into drive control, 3.3k resistor (instead of 4.7k) to ground before clipping diodes (net result = less gain when drive on zero)
- 250k pot for drive control (result = less gain when drive control maxed)
- .33uf cap (instead of .22uf) to gnd from tone control
- different opamp

So, has anyone tried playing around with some of these alternate values? I'm finding that my TS-9 RI is still a little too crunchy even when the drive is at zero.

1/17/1998 12:14 PM

The .33uF cap is *not* a change. I have since verified that nothing in the tone control section was changed.

The differences are what you mentioned plus:

-The input capacitor is changed from .02uF to .01uF.

-The capacitor connect to the inverting input of the opamp(in series with the 3.3K) is also a .1uF.

-two different diodes. By the package shape and size I would say one is a shottky diode and the other is a small signal diode.

The input transistor is the same as the TS but the output transistor is Germanium. Why, I don't know but it is.

I've scanned in a schematic of the Clone I made and will be putting it on the webpage soon. The only difference between my schematic and the FullDrive 2 will be the diodes. I used an extra 1n34a in one side to really give it some assymetrical clipping.

If you want to reduced the crunchiness of your TS-9 change the 51K resistor feeding the Drive control to a 22K. I have some simulations that shows how much this cleans it up which I will also be putting on the Webpage, all I need is some time to do it. Right now I'm too busy building more clones for friends. Everyone I've shown it to wants one!

--john

1/17/1998 12:18 PM
John Greene	Whoops, typo!! -The input capacitor is changed from .02uF to .01uF. should be .1uF. The two .1uF changes only show up in Fulldrive 2's with serial numbers greater than 710 or so. These changes give the pedal much more bottom end. A friend said that the older FD2 works well with Gibson Humbuckers but the later model with the more bottom end works better on a Strat. --john

1/20/1998 1:15 AM

Hi John.

I like your FullClone a lot. I am going to build one and test it with my gear.

By the way, in RG's Technology of TS he says that one of the factor, that could determine the sound is the tybe of op-amp. In the TS and in your FC2 the schematics indicate the use of a dual op-amp, (what type?) I think i could be a nice experiment, to use single opamps instead, and find out how the tone/sound is affected.

How about a 741 as first Op-amp and TL071 as 2.nd op-amp ? Even the old 709 could be a nice try.
You could even use some heavyer current consuming op-amps. If it sounds good I am personally willing to quit the use of batteryes and use a pedal-board power supply instead!
---- Preben

1/20/1998 8:47 AM

Right now I have one of the new JRC4558Ds in there. I'm pretty sure it the same chip as the FullDrive 2.

When I ordered the parts I also ordered around 10 different opamps to try. I still have to get around to that chapter of the development.

I need to play with it the way it is for quite a while to really get my ear used to its sound so the differences will be more apparent.

Thanks for the comments.

--johng

1/18/1998 12:02 AM
John Greene	Apparently noone else has realized Steve only screwed up the frames version of the bbs. One too many '<'. Anyhoo, I stayed up late tonight to get some of the stuff I've been collecting on the webpage. It's probably full of typos and who knows what else but hey, I don't do this stuff too often. Y'all http://www.cyberverse.com/~johng/" TARGET="_top">take a look and send any comments. --johng

1/18/1998 2:49 AM
Steve Morrison	tboy takes a nap at the keyboard Uh... oops! I really fumble-fingered it that time. Not only did I eliminate access to the frames page with the extra '<', but I typoed the noframes URL to boot! My appologies to all, and to all a good (yawn) night... --Steve

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