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Full-Drive II questions

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5/7/2000 6:30 AM

Full-Drive II questions

just picked up a FD II in mint shape w/ M. Fuller directions sheets....
1) fuller's directions say old-type zinc-carbon batteries will sound better than alkaline, which sound harsh. i believe it, but anyone actually done the comparison? what did you hear?
2) my FD II has the mid-range hump but i hear there is an FM (flat mids) option. anyone compared the regular FD II with the FM version? what did you hear?
i play old fender amps mostly and like their tones fine--got the pedal as an experiment, and to see if i could get more varieties of OD. am i right in thinking the FM version would be truer to the orig. tones of the amps?
thanks, bill m.

5/7/2000 3:53 PM

One thing to remember is that the fulldrive is a variant of the tube screamer and like all tube screamer clones, is going to have that mid hump as you call it. The Fulldrive does have extra bottom added in as well but the mids are still there. Are you comfortable with modding it? Changing a few caps could extend the highs as well and may get you more where you want to be.
Personally the mid hump is what I like about tube screamer clones.
jason

5/8/2000 6:57 AM
bill m.	still looking for comparitive answers re batteries and FM vs. regular units.... thanks!!! bill

5/8/2000 2:35 PM

Most if not all of the battery differences(some effects are very voltage sensitive the WR2 is fun to change the voltage on for one) go away if you use a good 100uf or greater electro to bypass the battery. If you don't use the bypass cap and the battery has a high internal Z you can get sag and/or osc. (this can be a good thing) problem is that when a battery starts to die and cool thing start happening the time is short with all that fun. the trick is to sim the voltage, sag(internal Z)with a PS. This is why alot of my petals have bias controls.

5/8/2000 3:48 PM
JJ	Re: Full-Drive II questions >fuller's directions say old-type zinc-carbon batteries will >sound better than alkaline, which sound harsh. with op-amps? B.S., B.S. -JJ

5/8/2000 6:13 PM

op amps and batterys are not BS. In high gain circuits opamps take on different tones, most were not made for audio and high gain circuits. The carbon zinc batterys are cheap and the connections between the 6 cells are not as well made as the more expensive batterys(twist a C Z battery in you hands when someone is using an effect) the C Z's are part of the circuit and not just a plain low Z (stiff)voltage source. The changing voltage with current draw can shift the bias points of the active devices in an effect and sometimes change the sound, not magic but science to my ear starts about 8.2 volts with carbon zinc to about 7.5v under 7.5 volts the internal Z goes way up. I often cut open devices to SEE what is different.

5/9/2000 3:24 PM

Original post said: "fuller's directions say old-type zinc-carbon batteries will sound better than alkaline, which sound harsh."

There is no mention of nearly dead batteries there, and even if there were, contemporary carbon-zinc batteries that are available in the US are as sturdy and well made as alkalines.

Maybe you can induce a difference with power supply that allows the output impedance and voltage to be varied but it would be so very minor that a tiny twist of the tone or gain knob would wipe out the difference (especially in opamp based circuits).

I'm totally against propagating voodoo-hoodoo in audio electronics, so take my advice, plop an alkaline in the box and jam on. No one will notice.

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