My New Favorite, The Chickenhead

Jovi Bon Kenobi

Jovi Bon Kenobi

Well-known member
Sweet baby Jesus this pedal sounds incredible! I couldn't even wait to label it to share my excitement. I haven't even biased it yet! I built it stock with no alterations. The hard to find 5nF cap was from Smallbear. The NPN germanium CV7112 was from reverb. The HFE is 88 and the leakage is zero! It's dead quiet except for a wee bit of crackling when turning the boost knob. I don't mind. If you haven't built a Germanium treble booster I can't recommend this enough. The boost knob is sort of like a volume and gain rolled into one. The other knob is "range" and boosts certain frequencies and can add the most creamy and warm bass or perfectly musical treble I've ever heard from a pedal. There is not a bad setting at either end of each knob. It's my new favorite sounding pedal I've ever built.

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Very nice build. The size of the knobs is equaled only by the size of C2. ?
Nice touch with the colored insulation on the transistor leads.
Let us know how tweaking the bias changes the tone.

I've got one of these in the works, with a PNP Ge tranny.
 
whgfive said:
What are your steps for adding the insulated wires to your transistors? Any tips? Love your builds. :)
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Thanks! That is just 3 pieces of 24AWG hook-up wire insulation. I just pull the wire out and used the insulation only. Once the wire is pulled out I just line em up and square off the ends with a craft knife so they're all the same size. Then I wiggle them onto the pins of the Ge transistor and plug it into the transistor socket. Actually, on any pedal that you have a "bias" trimpot, like the one here, it would be a smart idea to make the insulation for the "collector" pin a few mm shorter so you have an exposed section to test from. This allows you to use your DMM to probe the collector to measure and bias it in circuit.
 
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I've built a few of these on vero and can attest to their wonderfulness. Absolutely my favourite booster. I always build 'em NPN and have used AC127 and MP38s with excellent results. I've even built some with a 2N2222A and a cap on the output to lose some of the highs to make it sound more Ge. It actually works really well! And you can obviously make it slightly brighter sounding than a Ge pedal if you want and with less noise.

The best thing about this booster is that you can bump up the lows to fatten up a Strat or drop it down a bit to get that classic Beano kinda sound with a Les Paul. It sounds so authentic. I share your enthusiasm.
 
HamishR said:
I've built a few of these on vero and can attest to their wonderfulness. Absolutely my favourite booster. I always build 'em NPN and have used AC127 and MP38s with excellent results. I've even built some with a 2N2222A and a cap on the output to lose some of the highs to make it sound more Ge. It actually works really well! And you can obviously make it slightly brighter sounding than a Ge pedal if you want and with less noise.

The best thing about this booster is that you can bump up the lows to fatten up a Strat or drop it down a bit to get that classic Beano kinda sound with a Les Paul. It sounds so authentic. I share your enthusiasm.
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Yeah I just love it. I'm quite shocked it's not noisier. I was thinking with the Ge it would be but it's so quiet. These military OC140's (CV7112) all have zero leakage. The guy I bought them from said David from D*A*M used to buy them from him and asked for 80-90 HFE when doing so...so I requested the same.
Nostradoomus helped me and said that the 5nf cap that's in this circuit is the one that controls the general tone of the range knob so it's not a bad idea to play around with that value. If you look at the new PedalPCB "Rangefinder" pedal you'll see that that cap is the one on the rotary switch, selecting different values. I couldn't be happier with the NOS 5nf from Smallbear. I think it's just perfect. I would suggest to socket it, but some of these NOS caps have really thick leads that wouldn't fit in the socket holes so take that into consideration. 5nf or even 4.7nf is just lovely.
 
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I find 4n7 is close enough - and you can obviously get closer to 5nF with the range pot anyway I guess. I really love it with the range knob at around 10.00 with a Gibson. Still has that classic honk but also a bit more grunt than a stock Rangemaster. I am tempted to build one with a Sozo 4n7 cap to see if I can hear a difference but I doubt I could!
 
The CV 7112 is a British military spec oc140 so yeah, but any NPN germanium with low leakage and HFE gains around 80-90 hfe would work. Socket it so you can a/b. Smallbear has a good selection.
 
roll those dice and place that ebay order.... I've had good luck overall ordering some transistors from ebay, but have been disappointed with counterfeits a couple of times.
 
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