Debugging a Raw Fuzz - Fuzz War 2

[sohosteve]

Hi there
I've recently built a Raw Fuzz -  a kit sold by Fuzz Dog in the UK which does a fairly close soundalike of Death By Audio's Fuzz War 2.
The pedal works fine - up to a point - however I have a couple of issues with the sound and function of it and wondered if someone could kindly lend a hand.
I must admit that though I can built a kit and change out components I don't have any electronics knowledge and cannot even read a PCB/Schematic!
So any assistance would need to be fairly graphic for me to utilise it.
Regardless, I would be grateful for any help or assistance anyone is kind enough to take the time to proffer!

Anywayze...

I've made a demo video to highlight the problems and added time references in the description to illustrate the issues.
I'll copy and paste them here to give anyone interested a head start!

Firstly there is a problem with the Fuzz control - it jumps very rapidly from it's lowest setting (between 7 & 9 O'clock) to very distorted too early on. The Fuzz War on the other hand has a very smooth transition throughout it's pot's sweep.
You will hear this on the video from 2 mins 30 secs.
The Raw Fuzz seems to have way more gain throughout and becomes over-saturated compared to the Fuzz War.

Secondly, whereas the Fuzz War has quite a pronounced and detailed middle, the RF is a little too fizzy in the top end as well as being a little too bass heavy.
This also causes it sound like it has a nasty low end hum (around 50Hz and below).
Check the video from 6 mins in to hear this problem.

Here is the Youtube clip https://youtu.be/50JW2YgE0iE

Thank - you!

[Kipper4]

Welcome Steve

We will need more info to help. Go here and report back with the info.
Host some pictures if needs be on a host site.
Then you can post some pictures in your thread.
Rich

[sominka]

Basically you are not a happy bunny. It needs sorting.

[sominka]

Your build sounds pretty wicked. There is a lot of interference sound wise. perhaps go through the circuit and do the usual stuff, check for shorts etc. What caps are you using? Don't use ceramic where film caps should be. Check your leads guitar etc.
I'm sure i'ts a simple fix as your pedal is working fine.
Kind Regards
Jan

[sohosteve]

Hi there

Thanks for your replies.
I've added some images of my pedal which I took during the build at the bottom of this reply
And here's a link to the actual kit I constructed which hopefully will answer any questions regarding components http://shop.pedalparts.co.uk/Raw_Fuzz/p847124_8389179.aspx

By the way, sorry maybe I didn't make this quite clear in my original post but the pedal is not faulty.

Firstly the interference is mainly caused by the guitar I used for the demo which has a 1950s single coil P90 - so obviously not humbucking and very noisy with the level of gain involved with a fuzz box while sitting next to a computer and a large bunch of rack gear!

Secondly there are no dry solder joints or shorts. And I have also cleaned the whole solder side of the PCB using an cotton bud and lighter fuel.
It's clean and shiny and works without issue.

However there are discrepancies in the sound.
I'm trying to adjust the clone to match the original circuit more closely.
The pedals do actually sound similar but do differ tonally, even though they are supposed to be exactly the same component and circuit wise.

As I mentioned in the original post the Raw Fuzz sounds more bassy and trebly whereas the Fuzz War seems to have a more pronounced and detailed middle.
The Fuzz control does not operate in a linear way between all the way down (around 7 o'clock) and up to around 9 o'clock - you can hear this leap in gain quite clearly in my video.
The clone also seems more saturated throughout.

So my question is, is it possible to add or swap any components in the circuit for ones of a different value to
1. Make the Fuzz control act in a more linear way without a sudden jump in gain at any point throughout the sweep?
2. Slightly reduce the amount of gain in the circuit?
3. Reduce the amount of low bass and high frequency fizz?

Does this help to make things a little clearer?

[sohosteve]

Welcome Steve

We will need more info to help. Go here and report back with the info.
Host some pictures if needs be on a host site.
Then you can post some pictures in your thread.
Rich

Cheers Rich!
As you'll see in my main reply (above this onee) I've uploaded some shots and answered a few questions.
Hope that helps :-)
Steve

[Bret608]

Cool looking build! I've been wanting to try this one out too. I check out Fuzz Dog's build doc for this. The main issue I see when comparing to your pictures is that your volume and tone pots are wired in backwards. I'd just try reversing the red and green wires on those two and see if it helps. The drive pot looks to be wired in okay, so I'm not sure what would improve the performance on that one.

[Plexi]

As I recently mentioned in this thread: http://www.diystompboxes.com/smfforum/index.php?topic=77626.40

Mine's sounds a bit fizzy too.

Which transistors did you use?

[sohosteve]

Hahahahaha!
Yep, I did have them back to front, but that was in the early stage of the build - the old dyslexia got the better of me!
I did actually reverse the wiring on those two pots and they operate as they should - apart from my issues with the overall tonal balance of the pedal.

Transistors were as supplied with the kit - Q1-4 2N5088

Here's a list of all the components and the schematic
R1 1K5
R2 470K
R3 100K
R4 390R
R5 1k
R6 15k
R7 15k
R8 8k2
R9 100k
R10 100R
R11 470k
R12 8k2
R13 43k
R14 470k
R15 15k
R16 390r
R17 6k8
R18 33k
R19 430k
R20 10k
R21 2k2
R22 100k
R23 100k
R24 1M
R25 2k2 (CLR)
C1 100n
C2 100n
C3 100n
C4 100n
C5 470p
C6 470p
C7 100n
C8 680p
C9 2n2
C10 6n8
C11 100n
C12 100n
C13 100n
C14 100u
D1,2 1N34A
Q1-4 2N5088
TONE 100KB
VOL 100KB
DRIVE 100KB

[duck_arse]

seeing as the first three stages are near identical, you could possibly tame "too much" fizz by adding a 470pF or less-ish across the R14 470k. like a muff.

[sohosteve]

seeing as the first three stages are near identical, you could possibly tame "too much" fizz by adding a 470pF or less-ish across the R14 470k. like a muff.

Please excuse the luddite in me but I'm not an electronic engineer, just a nut case with a soldering iron and a deep yearning for homebrewed fuzz!

So could you kindly clarify your instructions for the electronically challenged, please?

Would I be correct in assuming that the 470pF is a capacitor?
And when you say 'across' do you mean attaching this new component to each of the legs of R14?

[Kipper4]

In parallel just like c6 is to R11

[duck_arse]

exactly so. C5 and C6 on your parts list are 470pF capacitors, so whatever you have fitted there, that's the sort of thing you want. mind, there are very many things that match the descriptor "470pF capacitor", as long as they fit they will suffice.

and across the resistor, exactly as C5 is to R2, and as C6 is to R11, so your new cap would be fitted to R14. and yes, one end of the cap to one end of the resistor, repeat for the other end. it doesn't have to be physically connected to the resistor, it just needs electrical connection, wherever you can find/fit.

I'm not guaranteeing this as a fixxe, remember.

[sohosteve]

Thanks for the advice.
I shall try that.

Any suggestion how I could lose some low end from the Raw Fuzz pedal throughout the whole sweep of the tone control?
It's a fair bit more 'bassy' than the Fuzz War.

[duck_arse]

duncans tone stack calculator. it don't run on linux, but you go/get and then plug in values, see the effects. I think you'd want to look at the "bmp" style.

[sohosteve]

duncans tone stack calculator. it don't run on linux, but you go/get and then plug in values, see the effects. I think you'd want to look at the "bmp" style.

Sadly wouldn't be able to use it as I work on a Mac...

[Plexi]

I would like to add another observation: when I put backward the last transistor, it sounds super creamy and compressed, in a good way.
But, lost a LOT of volume.

Why it happen?

[Cozybuilder]

It could be you don't need the final gain stage. You might take the 100nF output cap (C13, connected to Q4 collector) and move that connection to Q4 emitter- that turns the final transistor from an amplifier into a buffer. If you wanted to try that, remove (desolder) the C13 leg closest to Q4, and jumper it to the Q4 E- the opposite side of the transistor that the PCB trace that now connects C13. If you like the sound, make that connection permanent.

[Cozybuilder]

If you like the sound, a neater permanent job would be to swap resistors R19 and R22, and change Q4 from NPN to PNP, say 2N5087. Be sure to turn the new transistor around, so that E is placed where C is now for the 2N5088.

[Plexi]

Cozybuilder: great solutions!

Up Snoopy!!!