NPD: weird Fuzz face, expertise requested!

GoFish

Wow, wow, wow!?

Shout out to @soma1975, @ICBM and @breadfan for very useful suggestions.

So, @Choivert, are you saying that you had a dream where Hendrix visited you, burnt some "Midnight Lamp", had some fun times and when you woke up this was left on your chest as a quid pro quo? Cause that's what I heard  

springhead

In his 60’s octavers Roger Mayer used Radio Spares audio transformers. This not using an RS device doesn’t mean it wasn’t one of his but it is different. He also used perfboard not pcb for them.  Certainly worth sending him the photos and asking in case it’s a later transition version before he redesigned it with a transistor based phase splitter. 

soma1975

I totally called this.

Choivert

On TGP Scott linked to a 111 page forum post on metropoulis: https://forum.metropoulos.net/viewtopic.php?f=33&t=43932&start=120 where Dave Weyer (a tech for JH's amps) was sharing information about Jimi's gear. Which lead to another forum member making a clone of what Dave calls the West coast mod fuzz. 

Pic of the clone: https://imgur.com/a/8a2wO ;

More pics of the clone: https://imgur.com/a/8a2wO
Here is a screenshot of the right page on metro: https://imgur.com/gallery/uTmcnsN

Choivert

soma1975 said:

I totally called this.

Absolutely, bang on the money

springhead said:

In his 60’s octavers Roger Mayer used Radio Spares audio transformers. This not using an RS device doesn’t mean it wasn’t one of his but it is different. He also used perfboard not pcb for them.  Certainly worth sending him the photos and asking in case it’s a later transition version before he redesigned it with a transistor based phase splitter. 

I've emailed Roger Mayer and will let you know if he gets back to me. 

I've also posted on metropoulis as a question too, to see if anyone else recognises it. 

bbill335

might be worth posting on stompboxes.co.uk forum. they'd probably enjoy looking at it over there!

Choivert

I've posted in stompboxes.co.uk will see what they say. 

From what I can this is the circuit. The 1?,2?,3? Are the pins at the bottom right of the PCB. 

Choivert

In case anyone is interested I made this circuit (with switchable modification) on Falstrad.com/circuit similator. 


Here you can see low input volume and we get a clean signal:


Exact same settings with high input volume and we get a distorted 'square wave'




I've noticed that the third Transistor in the circuit very rarely does anything, (usually it is is static in cutoff or saturation depending on fuzz pot) 




If anyone wants the file to construct I can email it to you, however, if you save the below as filename.circuitjs.txt and then upload to the simulator

$ 1 0.000015625 1.3241202019156522 61 5 50 5e-11

r 304 224 304 176 0 4428.46

r 304 176 304 128 0 330

w 304 128 224 128 0

c 304 176 432 176 0 1e-8 8.66600527355504 1

g 432 240 432 256 0 0

R 224 128 128 128 0 0 40 9 0 0 0.5

c 160 256 96 256 0 0.0000022 0.556889757543908 0.001

w 512 384 512 336 0

w 512 416 512 448 0

r 224 128 224 224 0 33000

w 304 272 304 320 0

174 304 320 304 400 1 1000 0.5990000000000001 Fuzz

r 192 320 304 320 0 100000

t 160 256 224 256 0 1 -0.5801399385092704 0.5581699359854974 60 default

w 160 256 160 320 0

t 224 240 304 240 0 1 -6.343174082990598 0.5660080940530058 120 default

w 224 224 224 240 0

w 304 256 304 272 0

w 320 368 336 368 0

w 336 416 304 416 0

w 192 320 160 320 0

r 512 336 448 336 0 1500000

r 432 400 384 400 0 10000

w 384 400 384 368 0

w 448 352 448 336 0

w 512 448 544 448 0

l 544 448 608 448 0 0.55 0 0

174 432 176 432 240 1 100000 0.005 Volume

w 448 208 496 208 0

s 336 368 384 368 0 0 false

t 464 400 512 400 0 1 0.2981800032635263 0.3776252510810153 100 default

209 448 416 448 464 0 0.00001 0.000999999999980128 0.001 1

w 432 400 448 400 0

w 448 400 464 400 0

w 448 416 448 400 0

w 448 352 448 400 0

s 48 256 96 256 0 0 false

R 48 256 -16 256 0 1 366.4 0.0028000000000000004 0 0 0.5

209 336 368 336 416 0 0.000019999999999999998 0.37973658068842925 0.001 1

w 512 448 512 496 0

w 304 496 320 496 0

w 320 496 512 496 0

w 224 416 224 496 0

w 304 496 240 496 0

w 224 272 224 384 0

g 224 496 224 512 0 0

209 512 336 608 336 0 0.00001 0.000999999999996573 0.001 1

w 304 496 304 416 0

w 240 496 224 496 0

w 224 416 224 384 0

o 28 4 0 xc1012 0.07691538964795755 0.0001 0 4 1 0.2 0 0 28 3 0.000049999999999999996 0 0 37 0 0.1 -66 0 37 3 0.000025 0

38 0 F1 0 1 8200 -1 Bias

38 37 F1 0 0 0.04 -1 Input\svoltage

38 37 F1 3 10 1000 -1 Input\sFreq.

soma1975

No word from Roger yet?

Choivert

Not yet no, I've been trawling through this very long thread http://https//forum.metropoulos.net/viewtopic.php?f=33&t=43932 to try and understand whether any of the described mods to Fuzz faces are relevant to mine. The closest I can find is Dave Weyer's (West coast organ and amps) description of a three transistor fuzz but no real luck (pg 20). I haven't been able to post to metropoulis as I'm not sure any of the moderators are still around to approve new users' posts.

soma1975

How funny. I read that recently. Surprised they have not commercially released that fuzz. There's even someone selling PCBs for it. 

Whether is was used for Woodstock or BOG or not, it sounds like Jimi DID use it at some point so there would be interest. 

springhead

There’s a guy making the Weyer 3 transistor always on fuzz. Mate of mine - very skilled Hendrix style player - has bought one recently. 

In your sim above where are the cap and choke heading? And is it a choke or a transformer? 

soma1975

springhead said:

There’s a guy making the Weyer 3 transistor always on fuzz. Mate of mine - very skilled Hendrix style player - has bought one recently. 

In your sim above where are the cap and choke heading? And is it a choke or a transformer? 

Would love more details on this if you have them 

Choivert

springhead said:

There’s a guy making the Weyer 3 transistor always on fuzz. Mate of mine - very skilled Hendrix style player - has bought one recently. 

In your sim above where are the cap and choke heading? And is it a choke or a transformer? 

So the layout with the second cap ungrounded is the current circuit. I've used an inductor instead of a transformer since only two pins of one side of the transformer are connect to the board. In it's current format, both cap's lead to dead ends and the other side of the transformer also lead to a dead end. In the photo from 2021 from AnalogMan it looks like the top cap is connected to ground. I've been experimenting with both/one cap(s) going to ground and as soon as the second cap gets grounded the transistor sees zero voltage or current but grounding the first current will allow the third transistor to cycle through all three phases (only when fuzz is at about 1/3). I still have no idea what the transformer/inductor may be for (smoothing something or low cut?)

springhead

soma1975 said:

springhead said:

There’s a guy making the Weyer 3 transistor always on fuzz. Mate of mine - very skilled Hendrix style player - has bought one recently. 

In your sim above where are the cap and choke heading? And is it a choke or a transformer? 

Would love more details on this if you have them 

This guy I think

https://www.instagram.com/glen_rsvt/?hl=en

I've yet to hear it but he's very impressed.  My chap also has a Weyer style Superlead, plus original 60's Univbes, FF's, Wah's etc.  Hopefully he'll get it all together for a gig before long.  Hendrix covers and improvising in that style, not tribute act.

springhead

Choivert said:

springhead said:

There’s a guy making the Weyer 3 transistor always on fuzz. Mate of mine - very skilled Hendrix style player - has bought one recently. 

In your sim above where are the cap and choke heading? And is it a choke or a transformer? 

So the layout with the second cap ungrounded is the current circuit. I've used an inductor instead of a transformer since only two pins of one side of the transformer are connect to the board. In it's current format, both cap's lead to dead ends and the other side of the transformer also lead to a dead end. In the photo from 2021 from AnalogMan it looks like the top cap is connected to ground. I've been experimenting with both/one cap(s) going to ground and as soon as the second cap gets grounded the transistor sees zero voltage or current but grounding the first current will allow the third transistor to cycle through all three phases (only when fuzz is at about 1/3). I still have no idea what the transformer/inductor may be for (smoothing something or low cut?)

Odd isn't it.  Whatever someone intended that choke and 3rd transistor to do it isn't wired to do anything now.  It's been converted back to a Fuzz Face.  I guess it was a filter of some sort.  From the underside of the PCB looks like it was never used as a transformer, only one winding connected.  It does look like a homemade PCB.  Or small company making small quantities.  Curious!  

Choivert

springhead said:

Choivert said:

springhead said:

There’s a guy making the Weyer 3 transistor always on fuzz. Mate of mine - very skilled Hendrix style player - has bought one recently. 

In your sim above where are the cap and choke heading? And is it a choke or a transformer? 

So the layout with the second cap ungrounded is the current circuit. I've used an inductor instead of a transformer since only two pins of one side of the transformer are connect to the board. In it's current format, both cap's lead to dead ends and the other side of the transformer also lead to a dead end. In the photo from 2021 from AnalogMan it looks like the top cap is connected to ground. I've been experimenting with both/one cap(s) going to ground and as soon as the second cap gets grounded the transistor sees zero voltage or current but grounding the first current will allow the third transistor to cycle through all three phases (only when fuzz is at about 1/3). I still have no idea what the transformer/inductor may be for (smoothing something or low cut?)

Odd isn't it.  Whatever someone intended that choke and 3rd transistor to do it isn't wired to do anything now.  It's been converted back to a Fuzz Face.  I guess it was a filter of some sort.  From the underside of the PCB looks like it was never used as a transformer, only one winding connected.  It does look like a homemade PCB.  Or small company making small quantities.  Curious!  

Yeah, it really is very odd. It is definitely just working as a normal fuzz face now. What is strange is there are 4 pins on that side of the board, with tracks going to them (two tracked together). So there must have been intended wires for three of those pins but there doesn't seem to be any solder marks left. The only solder marks are one on the bend of the capacitor and two on either side of the 1.5M resistor. It may forever be a mystery. It is a great sounding fuzz but I would love to know what the extra bit of the circuit was meant to do or sound like. It may never have worked...

thermionic

Could those unused pins have been intended to be wired to a toggle switch to switch in the mystery side of the circuit? Fascinating thread.

Choivert

So playing around with the sim, one of the capacitor pins could be a toggle on/off switch. If you ground it nothing gets to Q3. 

Analog Mike has suggested it is close in topology to the Dunlop BOG fuzz. 
If this were the case, it is missing a voltage into the collector and then one of the capacitor would act as output. I'm currently working on building a sim of a BOG fuzz. 

The thing I am struggling with is reading the label on Q3, I thought that it was a bc183c, which would have pinout ecb, but someone else read it as bc169 with pinout bce and it could be bc169c? Any suggestions?

Choivert

I've been playing around with simulations. (The breadboard and components are on their way but for now this will have to do). 

I've made a circuit of both a FF and a BOG FF (Band of Gypsies) and had a look at their outputs. 

You can seem them here, the purple is BOG and green is FF

My hypothesis is that the fuzz face I have is was originally 'always on' but switchable between a normal FF 'on' and a BOG style FF 'off'. All I have had to do to modify (modify virtually) is add a 4.5v source to one end of the 1.5M resistor (already has a solder mark), then take one capcitor to be output 2, then a DPDT switch will when 'on' will ground cap 2 (nullifying Q3) and take the usual output 1 (FF mode) and when the switch is 'off' it will unground cap 2 (engaging Q3) and take the output 2. Output 1 gives you your usual FF shapes and output 2 gives waveforms much closer to the above BOG FF. 

Here I have just hit the switch from FF to BOG FF, you can see on the graph on the bottom right the waveforms go from FF (green line on left graph) to BOG waveforms (orange line on left). 



If you click on this link you can play with my FF and BOG FF model FF and BOG FF  
If you care about my 'switchable mystery FF you can follow this link: Mystery FF  
There are definitely a few things wrong and biasing is a little tricky. For example the output of the 'BOG' option on my mystery fuzz is too high and I haven't worked out yet how to get a 'cleanish' 4.5v course from the top line of the circuit, any suggestion very welcome.