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Diode distortion

F

FrednBass

Feb 24, 2012
1,043
46
#1
Now, i've been wondering how that would sound in my bass.
I know many of you don't like that, but i heard that Jack Bruce did this to his bass, and i really like that fuzzed sound of his (yes, i know he also used Marshall stacks). it's just two diodes attached to the tone pot, so it would clip the signal.
Anyone that enjoys Cream and Jack Bruce have already tried that? Any sugestions?
 
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#2
If the idea appeals to you then try it. Search in this section and you will find other discussions of the notion that you may find useful. I'd suggest that you at least put a switch in to short out the diodes when you don't want them but then I play my bass totally clean so maybe I'm not the best person to ask!

Ken
 
#3
I've done it. I used two diodes (one in each direction) and felt that too much low frequency information was removed. I also tried it with one diode, and it was better (less fuzzy, more clean), but the end result was just not one that I felt was very usable. A little too "gimmicky" for me.
 
#4
khutch said:
If the idea appeals to you then try it. Search in this section and you will find other discussions of the notion that you may find useful. I'd suggest that you at least put a switch in to short out the diodes when you don't want them but then I play my bass totally clean so maybe I'm not the best person to ask!

Ken
Click to expand...

I plan to use a push/pull pot, so i can switch between the fuzz control and the tone control.

ctmullins said:
I've done it. I used two diodes (one in each direction) and felt that too much low frequency information was removed. I also tried it with one diode, and it was better (less fuzzy, more clean), but the end result was just not one that I felt was very usable. A little too "gimmicky" for me.
Click to expand...

I see... I want to keep the tone control, and i'm not going to use the fuzz efect all the time, so losing low frequencies ain't going to be a problem. I guess it will work.



Thanks for the feedback!
 
#6
khutch said:
If the idea appeals to you then try it. Search in this section and you will find other discussions of the notion that you may find useful. I'd suggest that you at least put a switch in to short out the diodes when you don't want them but then I play my bass totally clean so maybe I'm not the best person to ask!

Ken
Click to expand...

I would wire the switch to disconnect the diodes when you don't want them in the circuit. Shorting them out will cause the pot to vary output impedance, and that's not a good thing.
darius8 said:
Stew-Mac sells a capacitor called a "black ice" that could replace the existing cap.
STEWMAC.COM : Black Ice Overdrive
Click to expand...

That's not a capacitor. For the love of God, don't waste $27.50 on that! All that box is is a couple of diodes. Buy yourself a handful of different diodes spec'd for a low forward voltage drop and fast switching speed, and experiment. Diodes should not cost more than 50 cents a piece, or so.
 
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#7
very cool has anyone tried it on a p or a j bass... I mean diodes not the black ice. I hear jerry only uses the black ice. His bass tone sucks thats enough to keep me away from it. I am very interested in the diodes instead of the tone cap. I think ill get a 2 way on switch one will be the tone cap the other will be a certain number of diodes for fuzz. it will be a fun experiment.
 
#8
line6man said:
I would wire the switch to disconnect the diodes when you don't want them in the circuit. Shorting them out will cause the pot to vary output impedance, and that's not a good thing.
Click to expand...

It depends on how you wire them. If you were to wire them in series with the tone cap (as for some reason I assumed he was) then you would want to short them out when not using them. If you want to switch between them and the tone cap then I agree with you.

Ken
 
#9
line6man said:
That's not a capacitor. For the love of God, don't waste $27.50 on that! All that box is is a couple of diodes. Buy yourself a handful of different diodes spec'd for a low forward voltage drop and fast switching speed, and experiment. Diodes should not cost more than 50 cents a piece, or so.
Click to expand...

No kidding! I bought ten Schotky diodes from the 'Bay for like two bucks. I only used two of them. PM me your mailing address and you can have the rest!
 
#11
Sorry, that offer was for the OP - I'm quite sure you, being the electronics guru that you are, have more than enough of everything, line6man. ;)
 
#12
I recently found this little mod while reading up on Mr. Bruce. I have been a fan of the over-driven sound that John Wetton had on the last UK tour(1979). I dislike using pedals and this seams like an inexpensive mod to do. Can anyone that has done this please explain in detail how they did this as I don't have an electrical background.
 
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#13
krdavis32 said:
I recently found this little mod while reading up on Mr. Bruce. I have been a fan of the over-driven sound that John Wetton had on the last UK tour(1979). I dislike using pedals and this seams like an inexpensive mod to do. Can anyone that has done this please explain in detail how they did this as I don't have an electrical background.
Click to expand...

It's usually two diodes in inverse parallel, placed in series with a pot, with the whole thing parallel to the signal. In other words, a tone control with diodes instead of a capacitor.
 
#15
grenadilla said:
Maybe you could put diodes one just one pickup {bridge} and keep the other pickup clean=sounding?? Jack Bruce had some half-blown speakers in his 4x12 cabinets plus amp distortion. He seems to get a clean sound on the Cream reunion DVD.
Click to expand...

That would not work without buffering or series resistance to isolate the signal paths, since the diodes run parallel to the output.
 
#16
The only way that could be done without a buffer or a series resistance (line6man, you meant in the way the 62 Jazz Bass VTVT layout works, right?) would be using dual outputs and a two-channel amp head or two actual amp heads. Then each pickup can have its own tone control, be it a high-cut or a diode distortion.
 
#17
Hi there,

Just signed up here to hopefully follow up with information line6man posted.

In a reply saying the following: "It's usually two diodes in inverse parallel, placed in series with a pot, with the whole thing parallel to the signal. In other words, a tone control with diodes instead of a capacitor."

I'm confused with the statement "in series with a pot", as opposed to "tone control with diodes instead of a capacitor", which essentially a cap to ground inline with the tone pot.

I've tried simply substituting the diodes in place of the cap, and where it does introduce a farty distortion when the tone pot is all the way down, it also drops the level to practically nothing. Am I missing something here?

Thanks in advance for any help you can offer!
 
#18
Peter Hodgson said:
I've tried simply substituting the diodes in place of the cap, and where it does introduce a farty distortion when the tone pot is all the way down, it also drops the level to practically nothing. Am I missing something here?
Click to expand...

No. As it is a passive circuit it can only subtract from the output, not boost anything. The farty distortion is the diodes clipping; they are effectively shaving off the peaks and troughs of your output and dumping this to ground. This results in a lower output.

A simple trick might be to remove one diode so that only one hald of the signal (peaks or troughs) are chopped.
 
#19
That is a disadvantage to the circuit. It drops the output. I have an Epi EB-3 and installed a passive distortion on the bridge pickup only instaead of the tone cap. Works ok and keeps the Model 1 in the neck clean. Well, as clean as a mudbucker, even a good one, gets.

You could try Guitar Fetish or one of the places that sells an onboard distortion. Basically a pedal that mounts in the bass. Never used one. Just a thought.
 

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