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Thanks to Autofive I now have this to play with Early 70's "wau-wau fuzz" pedal. Also sold as an Ibanez wau fuzz, from what I can find out they were built by the usual matsuoka/fugi-gen combination and more or less a cheaper copy of slightly earlier fuzz/wah units. When I tried it out, the fuzz worked (if you can call it "working"... think like a musical buzz-saw) but the wah didn't. There was a sort of ghost wah noise, but certainly not right. Both switches are noisy, but working.. except if you try to get fuzz and wah together you get nothing. Firstly, the best page anywhere on how a wah works and what you can do to them is here, I already used the info there to make this breadboarded wah circuit with audio transformer as inductor, I've been looking for a suitable box to build one into... So, the new pedal. Trawled the internet for info, found a PCB diagram and a schematic (fuzz section only) here and set about checking and mapping the wiring before I did anything to it. First sketches of the wiring and a stab at the wah circuit.. Some seriously crappy soldering in here - I'm not the first to try and fix this one. Got to grips with the wah circuit now - it is a little strange compared to "classic" vox/dunlop wah, but basically standard. While I was fixing the soldering I changed the two 0.22uF capacitors (because I had some new ones, and they are hard to test) Tried it out - it wahs! just not very well. It sounds bassy and naff, the sweep is short and close to the end of the pedal travel and there is a large signal drop when you try to use it, also still no wah and fuzz together, but it works well enough to know that the inductor and the pedal potentiometer are good (these are the really important bits) More later. I have a few mods to make to it (clever folk will be able to guess based on the differences between this wah and the diagrams in the R G Keen article )
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To get a standard A40 this low, you'd have to dig a hole to put it in
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awoo
Posted a lot
Posts: 1,506
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May 23, 2011 10:57:19 GMT
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looks awesome! surely that things worth a few $$$
my experience of fuzz/wah pedals has been they sound good on individual wah or fuzz but together they sound rubbish
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dungbug
Posted a lot
'Ooligan!
Posts: 2,852
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May 23, 2011 12:20:06 GMT
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****Waits for youtube vid of 'Hendrixescque' action**** Good work chap.
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Past: 13 VW Beetles from 1967 - 1974 Bay Window Campers (1973 & 1974) Mini's (1992 Cooper lookalike & 1984 '25 Anniversary) MK2 Polo Coupe S (1984 & 1986) MK2 Polo Breadvan (1981 & 1984) MK4 Escort (1989) MK2 Granada Based Hearse (seriously) Fiat Uno 60S (1986) Punto 60S (1998) Cinq (1997) 1998 Yamaha YZF600R Thundercat 2003 Ford KA
Current: 2004 Ford Focus (barely alive)
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May 23, 2011 14:42:50 GMT
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Oh i approve very much of this. The topic is cooly named as well I'd love to do something like this, how much did the pedal set you back dare i ask?
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May 23, 2011 15:10:07 GMT
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Birthday present from autofive I'm 40 today.
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To get a standard A40 this low, you'd have to dig a hole to put it in
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May 23, 2011 17:38:42 GMT
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Ah nice one! i wish you a happy birthday Hope your having a decent day
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May 23, 2011 19:17:18 GMT
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fookin frilliant!!! *goes to dig out nuggets trash collections*
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May 23, 2011 22:20:54 GMT
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More messing with it this evening, the cutting out was down to the fuzz select switch which is broken. The top is coming away from the base allowing the contacts to float, so for now I've bypassed it entirely and hardwired the input to the wah selector instead because it's the wah bit I need to fix. Anyway, although it stopped the cutting out and crackling (and boosted the gain quite a bit too) the wah effect was still far to bassy and so subtle it was hard to tell if it was doing anything at all, so I got the multimeter out again. Remember I said the wah pot was working? I was wrong. Yes, it has 100k across the track but the wiper is reading between 1.5 and 10 meg from either end in a seemingly random pattern. So that's where the sound went! Out with it then. I don't think it's original either, the pictures in the link show a single gang pot where this is a dual gang with only one connected (like it's been robbed out of an old stereo amplifier, for example) and in with the 100k log pot from my breadboard experiment. The cog fits the shaft with a rollpin, so I had to drill a 2mm hole for it. Quick test, we now have a very compressed wah (more like a quack) at the bottom of the stroke (pedal up) but it is certainly improving. I swapped the ends round on the pot (it's logarithmic - most of the resistance is at one end and tapers to the other) and suddenly it's 1971 again ;D Big, fat rolling wah, harmonics everywhere! I'm seriously impressed at the moment. This thing has a sound that would make a dunlop cry-baby run away to its mommy! Problem is, it's too late to do Hendrix impressions through an amp (for video) because I don't want to share his early demise. Tomorrow will have to do.
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To get a standard A40 this low, you'd have to dig a hole to put it in
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May 24, 2011 10:38:59 GMT
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oo nice man! good luck with it, if i was logged on wich unfortunatly yesterday i didnt come on the computer, i would have wished u one then, but happy birthday for yesterday pal! nice guitar too, ive got a normal acustic guitar, and an electric , I'm not sure if youve heard of them, but back in the 70s Roy Butterfield out of the Tom robinson band, Played with a 'Stratocaster squire Fender' And few years back, i went to my grandads friends house, who had this Exact guitar he used back then,no replica or curse word like that, this is the one HE himself touched and played and lucky me i got it For Free! Must be worth something ey? anyone have any idea what it would be worth?
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May 24, 2011 13:05:57 GMT
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dandandan, that sounds interesting if a little odd! A free guitar is always worth more than you paid for it First, the guitarist from the Tom Robinson band was called Danny Kustow (and I can't find any evidence to support a Roy Butterfield ever being in the band) Second, valuing the guitar is going to be hard just from 'Stratocaster squire Fender' because Fender used the Squire name for budget USA guitars in the late 70's (but didn't badge any as stratocasters), and also Squier as a brand name (with "by Fender" in smaller script) on japanese built guitars from about '83 until '91, then on korean/chinese built guitars to the present day. A Fender Esquire is also an early 50's telecaster with no neck pickup. This is mine, 1991 MIJ (made in japan) Squier Stratocaster. Post up a picture of your headstock and I'm pretty sure I can tell you exactly what it is. PS, "Stratocaster Fender" is like saying "Robin Reliant..."
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To get a standard A40 this low, you'd have to dig a hole to put it in
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chevazon
Posted a lot
1939 Chevrolet 2 door coupe, `67 `Zon estate, `87 Ragtop Cavalier, 4 x 800 Drifters,(!) 1500 Drifter
Posts: 2,259
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May 24, 2011 13:39:55 GMT
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Wye isn`t that A5 a nice chap. Andy - looks a good project (again). It reminded me that I had this - Bought it when I was 15 yrs so it is now 37 yrs old and may even be as old as you ! (Happy Belated Birthday) Also Strats aren`t always what they appear to be -
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May 24, 2011 14:10:17 GMT
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Wow, a colorsound! I haven't seen one of them in ages. Does it work? I can tell that strat is a fake just from the headstock shot Real 58-62 strats have a one piece neck, that has a separate fingerboard.
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To get a standard A40 this low, you'd have to dig a hole to put it in
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chevazon
Posted a lot
1939 Chevrolet 2 door coupe, `67 `Zon estate, `87 Ragtop Cavalier, 4 x 800 Drifters,(!) 1500 Drifter
Posts: 2,259
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May 24, 2011 14:41:29 GMT
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Pedal is Ok and good for that "Shaft" sound. ;D "Strat" is a bitsa but I believe it is mostly Fender, Mex etc.
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May 24, 2011 21:10:18 GMT
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Here's the pedal with only the wah side working, and my old marshall guv'nor overdrive (everything set to 11) doing the dirt. I found a replacement footswitch (at maplin, £5) so I fitted it and did another video demoing the full range of sounds from the pedal in standard condition. It's uploading now....
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To get a standard A40 this low, you'd have to dig a hole to put it in
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May 24, 2011 22:17:28 GMT
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I'm going to have to do something with that fuzz but this what the pedal should sound like in working non-messed with condition.
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To get a standard A40 this low, you'd have to dig a hole to put it in
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May 25, 2011 16:01:53 GMT
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I've been having a bit of a think about the fuzz section - mainly the differences between it and the marshall pedal (I found a schematic here) Now from what I can see (and please correct me if I'm wrong), we have (from left to right) a FET first stage which is probably just to isolate the input impedence from the rest of the circuit, then a class A input amplifier (with a gain control) , a class B push-pull stage, then the tone shaping, then another class A output level stage (with a level control). The interesting bit is the two Ge diodes in the tone stage, the basic idea of the circuit is to boost the signal into the diodes, which then clip off the tops and bottoms of the wave before the remainder is amplified again at the output level stage. The "tone" switch is just a big capacitor as a frequency cut. Now, the marshall circuit. This is an op-amp implementation of the same principle, the only notable differences are that the tone circuit is more sophisticated (passive capacitor/resistor network, Low, mid and high pots) and the two diodes are now 3mm red LEDs. The tone section is irrelevent - I tend to run it will all pots to max, but I think the LEDs are the key to the tonal difference. Reason being *I THINK* is that the Ge diodes have a flat response and chop the waveform pretty much square leading to the brassy fuzz noise where the LEDs have a softer cutoff that mimics an overdriven amp stage a bit better. Anyway, I'm going to test my theory by sticking a couple of red LEDs into the fuzz circuit and having a listen.
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To get a standard A40 this low, you'd have to dig a hole to put it in
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May 25, 2011 17:22:49 GMT
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Looks like you're about right. That first FET stage does have some gain, being a Common source amplifier. The next stage is operating as a phase splitter to drive the differential pair, but will have som gain. The differential pair is probably run in Class A (to do with the conduction angles rather than how many transistors - I could sit here and analyse it but, erm, I can't be bothered...). Why a diff pair? Probably to do with the current drive capabilities being equal in both directions.
Ge diodes have a lower on-stage voltage drop (0.3V) than Silicon diodes (0.7V), and LEDs tend to be higher still (1.2-3.3V). Not sure if the amp stages will have anough gain to get enough clipping at LED voltages - but it's worth a go, and can't do any harm.
It's possible that the capacitors and resistors around the diodes will have a bigger effect than the diodes themselves - I'd expect a smaller capacitor (like the 220n in the Marshall circuit), and a higher resistance (1k) to cause (a) faster drop-off with clipping but perhaps mroe imporantly (b) a fater rise-time afterwards. It might be worth replacing that 10uF electrolytic between the differential pair and the diodes with something smaller.
HTH, James
EDIT - NB, changing that capacitor value might well alter the tone control response.
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Last Edit: May 25, 2011 17:24:29 GMT by jrevillug
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May 25, 2011 17:42:51 GMT
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Yeah, I see what you mean about the capacitors... I noticed that the wah circuit is also full of 10uF electrolytics where you would expect lower value poly caps, and I was wondering how much is down to bulk buying and how much to do with optimal values.
Seeing as I have plenty of components I'll probably do some swapping this evening.
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To get a standard A40 this low, you'd have to dig a hole to put it in
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May 26, 2011 22:24:58 GMT
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Results of this evening's play - First, I tried 2 red LEDs in place of the diodes. This made a large difference, and yes there is plenty of gain available to make them clip. Too much in fact, so you have to keep the input level down but it's a much warmer sound. Next I took James' advice and substituted the 10uF capacitor for a 220nF one. Again, it softened the tone and added warmth. Next in goes a 1k resistor in series with the capacitor which reduced the output gain and stopped the amp from clipping all the time. So far so good! It's still a fuzzbox, but a nicer sounding one. Wah and fuzz still sounds lousy, but I noticed that the marshall pedal sounds best used after the wah, but the wau wau fuzz is wired for fuzz first, then wah. So I swapped them round (and made both switches true bypass as well) which improved it a bit. I'm still not sold on the fuzzy wah though, it's like the fuzz obliterates most of the frequencys that the wah works and kind of cancels it out. So I played with the wah a bit too... I changed the input capacitor from 10uF to 0.01uF and the resistor from 100k to 68k (these values are used by most wah pedals) and it too sounds a bit better. Next, I added a resistor (33k) across the inductor - this is missing from this circuit but present in a "classic" wah, and according to RG Keen is important for "sharpness" of the filter response. It made everything sound quaky and naff, so I took it back out again. Noisy testing will be done at the garage again, but it sounds nice through a headphone amp.
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To get a standard A40 this low, you'd have to dig a hole to put it in
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May 26, 2011 22:40:27 GMT
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The problem (i find) with most stuff nowadays, is that its trying to mimic all the old stuff, in a much cheaper way, which means if you want the real think you have to fork out a fortine.
If i wasnt so terrible with schematics i'd build myself a vox grey way and a coloursound fuzz of some description (germanium, of course).
I'm just poor and rubbish at diy pedals, otherwise i would!
Nice work on this, though.
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