RnFR- Panzer Fuzz

RnFR · Post by **RnFR** » 17 Jul 2009, 23:51

hey dudes.

i figured that everybody has some GT308s lying around right? so i thought i'd build a fuzz around them! enter the Panzer Fuzz!
so, considering that the 308s are nice and relatively gainy for soviet germs, i figured i'd build up a super high gainer. this one is great for chunky metal and doomy grind. it's got plenty of bite and should satisfy any metal craving you might have. it consists of three 308s feedback biased with controls for gain, hi drive, lo drive, tone and volume. the lo drive is basically running up the gain through a 47uF cap in stage 2, and the hi drive does the same through a 100uH inductor in stage 3. there is some fancy hi and lo pass filtering to smooth things out, some feedback to reign it in a bit, and a little tone control that i modified from one of mr. orman's designs. rolling the gain back gives a great crunch as well. the pcb isn't verified as of yet, but eagle says it's good.
i'll try and get some crappilly recorded clips soon to show off the chunk.
hope you guys dig it- it's a beast!

culturejam · Post by **culturejam** » 18 Jul 2009, 01:52

Cool.

RnFR · Post by **RnFR** » 18 Jul 2009, 09:26

i did a full write up breaking down the schematic here-

http://circuitworkshop.com/forum/index.php?topic=33.0

here's the gist of it-

i'll try to go through the circuit piece by piece-
the input cap(.033) was chosen to roll off just the bottom end of the input signal, there will be plenty more of that to come. the first stage is a basic booster using feedback biasing(1M resistor), and a .47 uF bypass cap for more gain throughout the full frequency range of the guitar. the emitter resistor(1K) was chosen to limit the amount of output from the first stage, and the 470pF cap rolls off some highs and stabilizes any oscillations that might happen.. next we have the gain pot(500K) and a 2K2 resistor setting the minimum amount gain available. the .01/220K combo allows highs to pass easier than lows trimming some of the fat off of the boosted signal. stage 2 is biased the same, as is stage 3. i find this technique of biasing easy and simple, allowing for fewer components as well. the .047uF cap rolls some high end off of this stage. the lo drive pot is a 10k pot going through a 47uF cap to ground. this isn't really just low end getting boosted per se, more of a full range gain control for this stage, but with the lows rolled off by the .o47 cap it definitely has some of that feel to it. the 100K/.1uF combo are doing negative feedback duty, reducing the overall gain a bit, as well as taming some noise and adding stability. next, the .0047 cap is more low pass filtering, and the .068 is hi pass,interstage coupling, and DC blocking. stage 3 also has some more high end filtering grom the .0022 cap to the 9V rail, and the bias values have been tweaked by ear a little. the hi drive pot is a 1K connected to ground through a 100uH inductor. turning this up adds a decent amount of sizzle to the sound. the 680/.1uF to ground were added to round out the frequency response of this stage a bit. the tone control is a tweaked version of jack orman's swtc2. i changed some values and added the .0033 and .01 cap to ground. the final .001 cap is rolling off a bit more of the very top end. finally the volume control has a 2K2 resistor to ground to limit it's lowest value. the mosfet and 1M resistor are there for reverse polarity protection, and the 100uF cap is for power filtering.

soulsonic · Post by **soulsonic** » 18 Jul 2009, 10:13

It definitely looks intense. Ja, I'm gonna have to try this one out since I'm working on an obscure evil metal album right now.

RnFR · Post by **RnFR** » 22 Jul 2009, 13:21

update-

lo drive works better with a 25K pot. will edit schematic and layout when i get a chance.

also- 10uF cap on layout should be 47uF.

devastator · Post by **devastator** » 27 Aug 2009, 19:51

Have you made soundclips ?

If we use NPN transistor some values must be tweaked I guess ?

RnFR · Post by **RnFR** » 27 Aug 2009, 20:09

devastator wrote:Have you made soundclips ?

If we use NPN transistor some values must be tweaked I guess ?

no soundclips yet- been very busy, but just got a board ready to etch etched so it shouldn't be too long. regarding NPN, the normal things go into play- switch polarized caps etc. also, you'll have to get a PNP MOSFET if you still want to use the polarity protection. i guess you could just jumper that stuff, or better yet, just don't drill out those parts on the PCB.

something i just found out last night-

the PCB is 10% too small using the dimensions listed. so print to the dimensions on the PCB, then increase the size by 10%.[/color]

i put a note on the attachment. you could probably fit it on the PCB as listed, it would just be tight.

RnFR · Post by **RnFR** » 08 Oct 2009, 09:48

the PCB layout is now verified!

this circuit works well if you want a scooped metal fuzz out a fender amp, or a bit of a thicker fuzz on darker amps. the multiple drive controls have the most affect with a bright amp. also change the gain control to 100KB.

devastator · Post by **devastator** » 30 Sep 2010, 16:11

any feedback about this "panzer fuzz" ?

someone built one ?

RnFR · Post by **RnFR** » 02 Oct 2010, 03:07

i like it.

the tone control is rather nice. kind of a "variable loudness" control. it increases bass and treble as you turn it up.

SpencerPedals · Post by **SpencerPedals** » 02 Oct 2010, 13:15

Sound clip!

RnFR · Post by **RnFR** » 03 Oct 2010, 02:14

i'll try, but don't hold your breath. it's not with me right now, and my computer setup isn't what it used to be. breadboards, brothers, breadboards!

i'm actually working on something else right now that is much higher gain that i will hopefully be able to show sometime in the future. it's a hybrid MOSFET/Ge design. kinda muffish, but with it's own flavor for sure.

devastator · Post by **devastator** » 10 Oct 2010, 16:37

RnFR wrote:the PCB layout is now verified!

this circuit works well if you want a scooped metal fuzz out a fender amp, or a bit of a thicker fuzz on darker amps. the multiple drive controls have the most affect with a bright amp. also change the gain control to 100KB.

Can we have other sound than "midscoop" (I'm not really fan of that kind of fuzz to be honnest, I like when that's fat and "punchy") ?

(yes , i'd like to breadboard your little beast but I haven't the ge transistor and the inductors. But I'll have some maybe, soon)

you gave me a similair idea , a fat fuzz with mids controlled by inductor , looks really nice.

RnFR · Post by **RnFR** » 22 Oct 2010, 03:02

well, it's not that scooped really. we probably have similar tastes. mid-scooped for me is nothing like a metal zone.

this thing was meant to have a slightly scooped metal sound on a super clean, bright, fender amp- like a twin. on anything else, it'll sound dark! if you look at the schem, there is an assload of LPFing going on, you could probably reduce it a bit. i've got a few others in this section, and some new ones on the way. i'll post them when i get a chance. btw- the inductor isn't absolutely necessary.