Slow Boost

[Krinor]

I have a special liking for boosters and in my incredible Effect Building Noob-ness I have conceived an idea which I'd like to pursue:

I'd like to build a treble booster which distorts slowly. Sort of like a slow gear effect but with subtle distortion being "faded" in. The cicuit must not raise the volume. It should just crack up little by little at the end of notes when I let them ring. How could this be done ?

[Isaiah]

Slow Gear clone into some sort of drive/fuzz with Gain and Level pots?
Just a guess.

[Krinor]

Yeah... But the Slow Gear fades in the signal. This cicuit should fade in the effect. 

[Mark Hammer]

Uh-huh.  And if the faded-in signal exceeds some clipping threshold along the way, then the distortion fades in along with the level.

Another approach is to use the AMS-100 voltage-controlled distortion modules in DEVICE (issue 4, I think; http://hammer.ampage.org), and feed them with a triggered ramp-up envelope generator.

[Isaiah]

Yeah... But the Slow Gear fades in the signal. This cicuit should fade in the effect. 

Ah, I see.
Sorry, I misunderstood your question.

[Krinor]

Uh-huh.  And if the faded-in signal exceeds some clipping threshold along the way, then the distortion fades in along with the level.

Another approach is to use the AMS-100 voltage-controlled distortion modules in DEVICE (issue 4, I think; http://hammer.ampage.org), and feed them with a triggered ramp-up envelope generator.

Er... Is this actualy a kind of complicated cicuit to build ? Has it not already been done ? I was hoping for a layout here 
Care to elaborate further ? I really want to make this thing.

[ambulancevoice]

probably the easiest method of doing this i could think of is by housing the booster in a wah pedal with the boost (or gain, which ever distorts the signal) knob controlled by the foot pedal, so a manual effect like the one you described can be done
im not sure how to do this automatically...

[Krinor]

I was thinking maybe some part of a compressor cicuit could be modified to do the trick ? In my recent experience with the Orange Squeezer I noticed that it amplifies the signal when a note is sustained.
Okay, maybe I could live with a subtle increase in volume too if keeping it down while adding more grit is a problem. Any further ideas ?

[Barcode80]

build a slowgear/fuzz combo in a box and build in a blend which would allow you to evenly mix the clean and other signal. then when you hit a note, it plays, and a distorted double of it fades in.

[Processaurus]

The slow gear isn't that slow, the longest swell seems to be less than 1/2 a second, it sounded like the original poster was after something that happens after a few seconds of sustaining a note.  I haven't seen a diy equivalent, but the toadworks enveloop pedals does an envelope controlled crossfade between two inputs.  I bet a boss NS-2 noise suppressor could be modded to do the same with the extra unused voltage controlled attenuator and an inverted version of the gate control voltage, and some tweaks to the sensitivity.  There isn't an official project like that around here, I think its something you'd need to polish your mad scientist skills for.

[Krinor]

build a slowgear/fuzz combo in a box and build in a blend which would allow you to evenly mix the clean and other signal. then when you hit a note, it plays, and a distorted double of it fades in.

Ah, this sounds interesting. And I guess the slow gear might be modded to become even slower. But doubling the signal might also produce a doubling effect?

There isn't an official project like that around here, I think its something you'd need to polish your mad scientist skills for.

Ha,ha yeah I guess so... Thanks for the other hints as well. And I thought this would be a "come here son and I'll show you" sort of thing.

[RickL]

Doesn't the Gretch Controfuzz kind of do that? Clean and dirty signals are present at the same time but the clean signal overwelms the dirty signal until the clean fades out, then you hear only the dirty.

[Meanderthal]

Doesn't the Gretch Controfuzz kind of do that? Clean and dirty signals are present at the same time but the clean signal overwelms the dirty signal until the clean fades out, then you hear only the dirty.

Not really- the distortion is always lurking in the background and never gets louder on its own, but, strangely, as you turn down the volume knob on your guitar, the clean vanishes leaving only the distortion.  Well, I guess you sorta said the same thing... only about the note decay .

It's about as close to what's being sought as you can get for a DIY with easy layout, but I really like Mark's idea about voltage controlled distortion. That has the potential to do EXACTLY what ya want, and much much more. Bit complex, would take a bit(maybe quite a bit) of tweaking, but a voltage controlled distortion with a decent envelope generator/follower might be a very interesting beast.

[MikeH]

You could acheive this simply (sort of) by building the ROG splitter blender and using one side clean mix and a distortion/OD in the other channel, with a volume pedal inline too.  Or just have the mix controlled by a foot pedal.  Then you can play a chord with the mix set to clean, and slowly fade in the disortion.

[Arn C.]

How about an Autowah circuit(minus the wah sound), that swells up along with a booster circuit and when it gets to the "top", it restarts instead of going back down.   "Thinking out loud"


Peace!
Arn C.

[Mark Hammer]

Here's an idea, following up on Rick's insightful mentioning of the Controfuzz, and Arn's musings about envelope control.

The Gretsch Controfuzz "works" by having a clever mix of heavily fuzzed signal and clean signal.  The two signals are mixed in opposite phase (differential mode) such that one cancels aspects of the other.  Because the heavily clipped signal lasts longer than the clean one, and because the clean signal essentially cancels the fundamental of the distorted one, the fuzz appears to creep in over time.  Not perfectly, though, as was pointed out.

Here's where we get tricky.

The gain of the non-inverting fuzz section ( http://www.freeinfosociety.com/electronics/schematics/audio/gretschcontrofuzz7798.pdf ) is set by a 220k feedback resistor and 100R ground-leg resistor.  You don't want to tamper with the 100R resistor, since the low-end rolloff is set by the 100R and 10ufr cap in concert.  But what if you could monkey with the 220k feedback resistor?

If one had an optoisolator fed by an envelope detector, you could place the LDR half in parallel with the feedback resistor (whose value might need to be increased a bit).  When you strummed, the parallel feedback resistance of the LDR and fixed resistor would drop and reduce the gain and clipping of that stage.  As the string decayed, and the LDR returned to its "off" state, the feedback resistance would gradually increase, and the clipping would start to intensify.  The extent to which the fuzzed sound would become apparent with time would depend on both how you set the fuzz level pot (and you might need to reduce the 220k series resistor to 100k or so), and the sensitivity and recovery time of the envelope follower and LDR.

Again, because you always have the clean signal present, the note itself doesn't fade in, just the fuzzed version of it.  In some respects, this is the "improved" version of the Controfuzz concept.

[Krinor]

I like the Controfuzz concept, but what I'm after is a subtle boost. Not fuzz. And being a tricky Eruopean bastard I might not be satisfied with a duplication of the signal allthough we are in a very interesting territory here...

How about making a booster with a kind of master volume where the gain automaticaly increases while the master volume drops. Thus leveling the volume out even though more gain is heard. And then to make it return to "normal" after a preset periode of time. Could this be linked and automated in some sort of way ? I think both a compressor and an envelope filter has some of the features needed ?