Mosrite - Fuzzrite [schematic]

[Masuto]

Here's a perf layout I did for the GE fuzzrite..

[ Image ]

verified

Hi erm... Could you make it complete for us newbies here and give us a complete layout with switch connections, input and output jack layout, pots and all?
Cheers!

[Masuto]

I wonder if Robbie Krieger (spelling?), the Doors guitarist, used one of these for the lead break on the studio recording of the song "When The Music's Over"?....

It has been told by their engineer, Bruce Botnick, that it was done overloading the tube preamp of their console.
shake it out:
http://www.soundonsound.com/sos/dec03/a ... tracks.htm

[mictester]

Hi erm... Could you make it complete for us newbies here and give us a complete layout with switch connections, input and output jack layout, pots and all?
Cheers!

OK. Here's my layout for the same circuit - it's a little different because all the resistors are lying down and I've used modern values. This layout has been built several times, and the results are pretty consistent (within the tolerances of the transistors themselves!).

Enjoy!

[lowbrow]

A lot of what I've read on gain advice for the Ge Fuzzrite simply doesn't match my own personal real world experience with the transistors they used. The RCA 2N2613 from that era nearly always measure well over 120 hfe (corrected) and 2N408's typically average around high 80's low 90's. Now, I will admit my sample on the 2613 is only about a dozen, and from different dates of manufacture, but my data on the 408 is pretty solid as I've tested hundereds of these from a couple different years of manufacture. I personally shoot for something closer to 150hfe in Q1 and something 90ish in Q2.

[mictester]

A lot of what I've read on gain advice for the Ge Fuzzrite simply doesn't match my own personal real world experience with the transistors they used. The RCA 2N2613 from that era nearly always measure well over 120 hfe (corrected) and 2N408's typically average around high 80's low 90's. Now, I will admit my sample on the 2613 is only about a dozen, and from different dates of manufacture, but my data on the 408 is pretty solid as I've tested hundereds of these from a couple different years of manufacture. I personally shoot for something closer to 150hfe in Q1 and something 90ish in Q2.

I've got two of them here. They're built with OC72s. The first one has 110 and 80 for the Hfe of Q1 and Q2 respectively. The second one has Hfe of 135 and 89. They sound pretty much identical, except the lower Hfe one hisses a bit less.

[modman]

I built a couple more of these nasty germanium things tonight, and slightly improved my layout. It's slightly smaller and rather neater, and it makes a great beginner's project. I've also changed the colour of the soldered connections to make them show more clearly. I changed the wire colours too, to remind everyone that this is a positive ground circuit. The only thing to beware of when soldering this thing together is to connect the transistors last and take great care not to overheat them. A heat shunt is a good idea!

If you have NPN germanium transistors, you can use them - just reverse the electrolytic capacitor polarity and connect the battery the other way 'round. This will make for a negative ground effect, like most modern pedals.

I didn't include an LED indicator. The circuit draws around 1mA, and even the most efficient LED would draw much more than that - it seems silly to waste battery power, especially when it's really obvious when this little beast is switched on!

Fuzzrite.png

Fuzzrite_tracks.png

Enjoy.

Mods: Can the earlier version of the layout be removed, please?

[skumberg]

A lot of what I've read on gain advice for the Ge Fuzzrite simply doesn't match my own personal real world experience with the transistors they used. The RCA 2N2613 from that era nearly always measure well over 120 hfe (corrected) and 2N408's typically average around high 80's low 90's. Now, I will admit my sample on the 2613 is only about a dozen, and from different dates of manufacture, but my data on the 408 is pretty solid as I've tested hundereds of these from a couple different years of manufacture. I personally shoot for something closer to 150hfe in Q1 and something 90ish in Q2.

Thanks for the info on the transistors. Could you please share some leakage on them transistors or collector voltages with them in circuit? I have tried some different transistors and depending on leakage and gain I have 0.2-4V on q1 and 0.3-1V on q2. I'm trying to get some spirit in the sky tones. That is clean with light picking on G string and heavy distortion with heavy picking on A string.

[Masuto]

Thanks for the assistance but in the end i stuck with the tagboard version, Silicon trannies.
Sounds solidly 60es and garagey.. think The Harbinger Complex's I Think Im Down type fuzz.
I decided to build it w/si because i found out the germanium version was soon replaced by the silicon.
the si is its trademark sound we all know and love.
anyway, thanks to you all.

[lowbrow]

Thanks for the info on the transistors. Could you please share some leakage on them transistors or collector voltages with them in circuit? I have tried some different transistors and depending on leakage and gain I have 0.2-4V on q1 and 0.3-1V on q2. I'm trying to get some spirit in the sky tones. That is clean with light picking on G string and heavy distortion with heavy picking on A string.

Just saw this, sorry for the delay. I have no measurements from a original germanium Fuzzrite to share (would be nice to know), but I've built a number of them and here's the info on my latest, which sounds just like it should. Hope to have a sound clip next week.

Q1 is a RCA SK3003, one from a batch of these I stumbled on that spec out almost exactly like 2N2613s. Gain 222, leakage 142 µA
Q2 is a RCA 2N408 gain 97, leakage 226µA

Q1E and Q2E are zero
Q1B is 51.1mV
Q2B is 92.2mV
Q1C is 0.390V
Q2C is 4.74V

I was under the impression the Norman Greenbaum fuzz was a one-off custom build someone did for him and not a Fuzzrite, BTW....is that wrong?

[agoldoor]

I have read over and over that Spirit in the Sky is a Jordan Bosstone... but that could be apocryphal. But whenever someone asks what a Jordan Bosstone song example is, they point to Spirit in the Sky... so you might want to check that out skumberg.

[lowbrow]

It occurred to me I fell back into a bad habit...dropping the negative sign on those voltages I listed. Sorry about that, consider them implied....negative source, positive ground.

[skumberg]

Thanks for the voltage and transistor specs. That is lower leakage than I thought. Most of my Ge trannys have higher leakage than that, though I have a few 2n404 that is similar to the 2n2613 spec.

I was under the impression the Norman Greenbaum fuzz was a one-off custom build someone did for him and not a Fuzzrite, BTW....is that wrong?

This is what I've read as well. I did a Ge Fuzzrite on breadboard and around that time listened to "Spirit in the sky". Of the fuzz circuits I have tried this one seemed to sound closest to the SITS riff. So whenever I bring out my Ge fuzzrite breadboard I try some mods(changing trannys caps and bias) and play spirit in the sky. Hopefully I will get it even closer since I like that sound and behavior.

The reasoning I'm using is that the guy who built the fuzz for Norman could have looked at what other pedals was popular at the time and built something similar. So I'm just guessing here.

[lowbrow]

The SK3003 happened to be a bit lower leakage than your average 2N2613. The 2N408 was pretty average.

[tabbycat]

Here's a vero layout I did with on board pots - Unverified as of yet.
Fits into a 1590B no problem.

hey ho and away we go...

thanks to scruffie for the vero layout for this. has anyone made it or can anyone verify it?
i've only made one pedal before, so am a bit of a lego-amateur and not up to much trouble-shooting on my own.

thank you.

[tabbycat]

hmmm above quote of scruffie's vero fuzzrite post dropped the image. it's on page one of this thread halfway down

[tabbycat]

He was thorough, and thoroughly unwise…

I have just been through everything I can find on this site regarding transistor options and substitutions for the silicon version of this fuzz (will build germanium once I can get silicon to work).

Basically I’m hoping to go into breadboard land for the first time this weekend.
This is a fuzz I wanted to build anyway, but I thought I could also use it as an intro into experimentation by building it into a breadboard and then swapping transistors and bits in and out and thinking about how that effects the sound. I can’t do books, the words start swimming and brain goes stiff. So hands-on learning through experimentation is my thing. it’s how I learned to play guitar anyway.

So... the following suggestions for transistors came from the freestompers credited:

Theehman = The original transistors were TZ82 (impossible to find now) or PN2222A.

Keto = 2n3904 best

Thaxt = Anyone who is doing some mods or clones might try out the MPS/2N3710s. They are said to be a pretty direct sub for TZ82s & the NTE85s. 2N3904s are very good, & using 2N5059s can yield a real buzzbomb of a clone for many fuzzes, including these. I have tried them on Fuzzrite clones, & they do just that.

monkeyxx = 2N222A metal can transistors

do you have an opinion on any of these? or can you suggest alternatives not listed?

Basically I want evil big fuzz sounds, evil octavey good too, but thick and full rather than tinny wasp-in-an-empty-coke-can sounds.
My only build to date is the univox superfuzz and that ticked all my boxes and pressed all my buttons. I want to get to a same-but-different place using the fuzzrite as a starting point.

Many thanks for all your ideas,

Tabby.

Ps. If admin or a mod can remove my above two brief posts I would appreciate it, as I can’t seem to do it myself. I contacted poster by pm and got the answer I needed. Thank you.

[DrNomis]

the BC547B Transistor should work fine as a substitute for PN2222, or 2N2222 transistors, you could also try BC548, which usually has an Hfe up in the 300's.....

[DrNomis]

the BC547B Transistor should work fine as a substitute for PN2222, or 2N2222 transistors, you could also try BC548, which usually has an Hfe up in the 300's.....

BC547 and BC548 are fairly common silicon NPN transistors....

[ringworm]

I think I read somewhere somewhere that 2N3391 transistors were also used/or were a sub for the original TZ82s. Or that the fuzzrite that used a transistor array was the same spec as 2N3391. I think...

[allesz]

I don't think that on this circuit the transistors type is too important, unless you try ones with really high hfe.
I like ones in the rage of 200 or less, like 2n2222a and 2n3904, or the BC family with the "a" final letter, like bc108a for example.
300 hfe can be just as good, maybe you will have to tweak some values, but I always do it afterall....