=========================================================================== Digest of posts about Craig Anderton's Tube-sound Fuzz =========================================================================== In Craig Anderton's book titled "Electronic Projects for Musicans", he presents a schematic for a "Tube-sound Fuzz". This project is very simple to build, and very good sounding, and is an excellent beginner project, in terms of complexity and results. It is discussed on the net frequently enough to get its own FAQ. --------------------------------------------------------------------------- Newsgroups: alt.guitar From: META000 Subject: Re: Tube sound fuzz Organization: The University of New Brunswick Date: Thu, 28 Jan 1993 22:31:40 GMT I've built the Tube Sound Fuzz about 20 times now, and have the following advice to give about it: 1) Use UNbuffered 4049's (look for the suffix UBE) 2) Craig's design from GP '77 ( I think the one with Jim Messina on the cover) is much better than the EPFM one. It also runs off 9v. 3) The secret to getting the 4049's to sound like overdriven tubes is to overdrive them, NOT make them create the gainthemselves (as in the EPFM design). What I do is use 100k resistors and 220-510pf caps in the feedback loop of the invertor sections, and instead of using the pot in the feedback loop of the first inverter, I stick a single op-amp gain stage ahead of the 4049 and plunk a 10k pot in between the output of the gain stage and the input of the 4049. Other than that, I use the EPFM design as is. 4) Several advantages stem from this arrangement: a) the pot lets you pad down the input in case the device is being fed a very high level signal; the original design does not permit this, b) you can more easily create subtler levels of distortion, c) have an extra stage allows one to shape the tone even more (see below), d) it just plain sounds better. 5) I strongly recommend selecting capacitor values that will let you roll off the high end at around 4-6khz for EACH stage. This may sound drastic, but the rolloff is only -6db per octave when you use the feedback cap as a filter, so the effect isn't that dramatic. Cascading the section as lowpass filters keeps the high end grit from accumulating, and reduces the noise levels even further. The resulting circuit competes favourably in noise levels with the best floor boxes. You'll also find that by cascading the 3 stages as lowpas filters, you get kind of a speaker simulator effect, and will find that considerably LESS post fuzz EQ is required. You'll be able to set the amp for a crisp rhythm sound, stomp on the switch and get "brownomatic" without being blown away by the screeching high end. 6) If you stick a bypass cap between the input and output lugs of the 10k attenuator pot, you get a "bright switch" effect, that, at low drive settings, creates a kind of Rickenbacker simulator, or a poor man's Aphex, depending on how youy set it up, and whether you use larger or smaller feedback cap values. 7) I recommend setting the gain of the first stage at about 20 or so. This should give you enough drive to get thoseMOSFET's in the 4049's working hard and distorting sweetly, while still enabling you to easily trim back the signal to get subtler distortion. 8) If you want to REALLY hop this thing up, use a dual opamp, and use the second op-amp as a tunable lowpass filter tacked on after the last 4049 section. In these instances, I use 220pf feedback caps in the invertor sections to keep in the high end, and tune it out with the filter. Between the ability to feed the 4049's with lower level signals, the bright function, and the tunable post-fuzz filter (I seem to recall it sweeping from about 12k to 300hz), you can get anything from super bright hypertwang to very dark growl. EXTREMELY flexible. 9) I might note that the Electro-Harmonix "Hot Tubes" also used a 4049 as its' distortion device. I took a look at the photocopy I have of the pc board and parts layout, and traced a schematic from it today. Interesting circuit. It uses 3 of the 4049 sections, with increasing values of feedback resistors on subsequent stages, and a very bizarre op-amp circuit (set up like a comparator, or differentiator, or some non-standard arrangement) just prior to the first 4049 section. I seem to recall there was atone control on the thing, but my parts layout only shows the drive and output volume controls. Not sure where the tone control went, however the output of the last 4049 went straight to the output control, so I don't imagine there was any kind of sophisticated filter. Mark Hammer --------------------------------------------------------------------------- From: harmon@hepxvt.ps.uci.edu (matt harmon) Subject: Tube Sound Fuzz Modifications Summary: modified my tube sound fuzz Newsgroups: alt.guitar Date: 3 Feb 93 07:08:05 GMT Hey there folks. I was the one who built the TSF and complained about "flub" (too much bass response) and the sensitivity of the output level to the intensity of the effect. Well I considered re-working the whole circuit, but decided instead just to screw around with resistor values until I got the sound I wanted. This last bit is the reason anyone might want to build this thing. Here's what I changed and what it affected: 1) Input resistor changed from 100K to 10K. Increases "saturation" and reduces bass response. I could have changed the input cap, but resistors are easier to screw around with. 2) Eliminated 10Meg "lead" feedback loop. This way the intensity can be continuously varied along with the output level. 3) Made the feedback loop a 1M linear pot in parallel with a 1M res with both of those in series with a 10K. This gave me the most widely varied sounds. Min feedback R is 10K (barely noticeable crunch - makes my JC120 sound like it has tubes in it), and the max R is 501K (nice singing leads - fully saturated tone). 4) Installed the obligitory DPDT switch to bring the effect in and out. This required modifying the output level section because otherwise low settings of the OL affect volume of bypassed signal. I added a 1-10K resistor between the output lead and the OL pot. You too might enjoy playing with this circuit! Especially if you are very fussy about the tone of your distortion unit. Imagine what you could do ( and the headache) if you were to thoughtfully use pots for the critical resistor values (input, f/b#1, f/b#2, output)! Well it's late and I'm kinda burnt . . . . Matt --------------------------------------------------------------------------- From rg@futserv.austin.ibm.com Fri Sep 17 10:45:09 1993 Newsgroups: alt.guitar From: rg@futserv.austin.ibm.com (R.G. Keen) Subject: Re: Anderton's Tube Sound Fuzz Proj. Date: Fri, 17 Sep 1993 14:13:30 GMT Reply-To: ...futserv.austin.ibm.com!rg Organization: IBM Coporation - Advanced Workstations and Systems. Yeah, I've built it. It sounds good. Mark Hammer, who is temporarily off the net, has built several in different configurations, and had a couple of additional suggestions for me. It seems that the CD4049 is happier clipping than making gain, so he suggests using an op amp for the initial gain stage to drive the second stage into clipping. Also, he prefers to follow the clipping stage with an active lowpass filter to cut out some of the highs. I suspect that transplanting the cabinet simulation filters from Anderton's Tube Preamp article in Guitar Player would be a dandy addition, too. A variation on this design is to use the CD 4007 dual complementary pair plus inverter to make a composite gain stage that has two pullup PMOS devices and three pull down NMOS devices to get a more assymmetrical linear region. The unused gates all have their inputs tied solid either high or low, doesn't matter, and their outputs open. R.G. --------------------------------------------------------------------------- From rg@futserv.austin.ibm.com Tue Oct 19 11:19:58 1993 Newsgroups: alt.guitar From: rg@futserv.austin.ibm.com (R.G. Keen) Subject: Fuzz Face, fuzz box whats good? Date: Tue, 19 Oct 1993 14:25:04 GMT Reply-To: ...futserv.austin.ibm.com!rg Organization: IBM Coporation - Advanced Workstations and Systems. In article , tjs@eecs.umich.edu (tim stanley) writes: > Yeah - FYI, this is alledgedly the original version of the circuit > that Jimi Hendrix used and popularized. Another even easier Anderton > circuit (IMHO) is his tube-sound fuzz from his Electronic Projects for > Musicians book. Easy and good sounding (as has been said many times > by many folks in this group). > > R.G., have you ever built that Fuzz Face circuit? How do you like it? Actually, I've built them both, and they are both very good. The tube sound fuzz in the plain vanilla form is pretty decent, but it gets even better if you follow Mark Hammer's (Mark, when will you get another account?) advice and follow it up with a multipole lowpass filter. To my ear, this very close to hollow-state. Very good blues sounds here. The clipper can be followed by another stage or two of the inverter, since there are at least four unused inverters in the IC, and create a very intense sustainey sound, although the noise performance suffers in the following stages, as you would expect. The Fuzz Face is more of a hard edged, high distortion box, although it does have a somewhat unique sound. When I got my Fuzz Face working, the tone was very reminiscent of - no surprise! - Hendrix. The Fuzz Face has a couple of surprises for such a simple circuit. Unlike most two transistor fuzzes, it does have a degree of touch sensitivity due to the circuit configuration, a single transistor voltage feedback stage. This circuit has the property that it has very mushy saturation but hard cutoff clipping. The clipping is asymmetrical, and I keep thinking I hear a subtle octave overtone at some settings of the distortion control. The Fuzz Face could use some followup filtering, too. To my mind, the two effects are for different uses. If one is good with one's hands, both could conceivably go in the same box, since the circuits are really trivial. I keep meaning to extract the post-clipping filters from Anderton's article on the Stack-in-a-box tube preamp to use as a separate followup to things like these distortion boxes. That ought to be generally useful in taming the wild distortion box. Someone - Don Tillman or David Morning perhaps - noted that the speaker simulation in either the RED BOX or the SANSAMP (CRS) was a two- or four-pole lowpass simulating the response of guitar speakers. That would be a useful follower to a distorter, too. R.G. ---------------------------------------------------------------------------From Dstork@voyager.cris.com Fri Dec 16 10:04:12 1994 From: Dstork@voyager.cris.com (Dr.Distortion) Newsgroups: rec.music.makers.builders,sci.electronics,rec.music.makers.guitar Subject: Re: Tube Sound Fuzz - Craig Anderton Followup-To: rec.music.makers.builders,sci.electronics,rec.music.makers.guitar Date: 15 Dec 1994 21:34:13 -0500 Organization: Concentric Research Corporation NNTP-Posting-Host: voyager.cris.com X-Newsreader: TIN [version 1.2 PL1] Robert D. Herrick (herrick@sunchem.uucp) wrote: : You ought to able to sub, but the right chip is available from Radio : Shack for a big $2.50 or something. Not any more. RS stopped stocking the 4049 about a year ago. : This is a great-sounding circuit, but I had to customize it some to get a : more flexible tone circuitry. Plus, the Hi/Lo switch is pretty useless. : If you're interested in my new schematic, you can email and I'll snail it : to you. One reason the 4049 fuzz sounds good is because it's based on MOSFET circuitry. However, you can get MOSFET linear op-amps (like the RCA CA3260) that will give you the same effect. They're also simpler to work with because you can treat them as "regular" dual op-amps; the pinout is the same, and they'll work in the same kind of circuit. --Dr.Distortion