Axis Face Silicon Rev 3 build report.

[mac]

The size of the 2.2uF, 250V??, polyester cap is about 1 x 1/2 x 1/4 in. BIG!
As I did my own board it was not a problem to me.
The differences between an electro and a poly are minimal, something I can live with.
I used this Si FF when I played live, so any differences were shadowed.
At home I stick to my Ge version ;-)

[mojotron]

...
PS:i tried some BC108's and BC109's and liked it, but i want this pedal to be Germanium sounding, another one i build will be the normal silicon sound.....

any suggestions for my wants?  I am gonna continue to search the internet....

thanks 

I think you are going the right route for getting an early Jimi sound - if your not already there. I thought the 500k pot matched the recorded sounds IMO, but I'm not using a mid-60's plexi - full of Mullards - either.

The BC108s do make a very special FF sound though, in fact I really like the BC108 a lot, but the circuit for that is to use the original FF circuit and sort the BC108's carefully. The only substitution I use on this "Early EJ" sound (from the original FF) is a 100KA out pot, 30pF Q2 C-B cap, and a .1uF out cap. But. for the Axis Face I'm not sure if I would like the sound of the BC108s as they have a lot of noise and the upper mid range is just a little too harmonicly rich.

[formerMember1]

mojotron:
does the 50K linear pot for the smooth control sound different than a 100K linear pot like i used?

( my sound right now is close to Jimi's but not like the Fulltone '69, his is smoother and more vintage/ jimi sounding, mine sounds more heavey metal/high gain, i am looking for  vintage jimi though,) 

one other Q:
Does your axis face with mods clean up via the guitar volume?  mine does not,  i wonder if it is the fact that my transistor for Q1 is 62hfe and not above 70?

What makes the fuzz clean up via guitar?

[petemoore]

  That pot IIUC is wired as a variable resistor [two lugs used], so a 100k pot will cover the range of a 50k pot, ..'+ 50k'.

[formerMember1]

That pot IIUC is wired as a variable resistor [two lugs used], so a 100k pot will cover the range of a 50k pot, ..'+ 50k'.

gotcha ya,...

[formerMember1]

hi,
The fuzz sounds alot better now, closer to Jimi,  But i found out from tweaking it that i like the fact of being able to set it at 4.50volts on collector, and even 3.47votls on the collector of Q2 for a fizzy square waved fuzzy tone, that is very musical,  Is there a way i could remove the pc mount bias pot and replace it with a 10K pot mounted on enclosure, that way i could be able to get those different "biased" tones on the fly,  Also, Is it possible to be able to make the pot only be variable so that it changes the biasing between 3.0 volts to 5.0 volts on Q2's collector? I am thinking/hoping of having it so that when the pot is full CCW the fuzz will be biased around 3.00 and at fully CW it will be aroun 5.5volts or so...

Is this possible?   I read on AnalogMan's site that he uses a Sundial or something to accomplish this, but not sure if it is the same thing as i want.

thanks,...


PS:Or i could probably taper the pot somehow using resistors across the lugs, and just mark  dots on the enclosure for where it biases the pedal at 3.0, 3.5, 4.0, 4.5, 5.0 volts.  If so how would i decide what tapering resistors to use, 

then again i could be way off track,...

[petemoore]

Is there a way i could remove the pc mount bias pot and replace it with a 10K pot mounted on enclosure
  I used IIRC 4k7 as a stop resistor, coming off Q2 as part of Q2CR, that gets some gating, the 10k bias pot added and mounted on the top of my FF i've really been using, has the fresh everything in it, provides between 4k7 and 14k7 [gated to too open sounding for my tastes] and perfect control over fine tuning the bias.
  It mostly gets left set at 1 oclock or so, but I do adjust it, and it does make a difference in the tone, the gainpot isn't but a chosen fixed R, pregain is on box with output volume.
  Subtle difference once it's not gating, and not much more than that it gets too open sounding [boosty...less distorted face], just being able to dial it in once using a knob with a line...while playing with it...after a few weeks of this bias settings take on very a tangible 'learning lesson' vibe, you can hear what the transistors do with given bias from day to day.
  Seems like these transistors are pretty stable. 
   ...anyway it turned out turning the knob up makes louder...not sure if I typed the resistor / bias ...which one goes up when the other goes down thing right, check it out!!

[petemoore]

  This FF output pot concoction would have fixed bias...
  Actually you could make Q2C resistor a 3 connect pot [5k +], wiper being the output, it'd have to be one wierd taper, and then the FF 'top R' [1k or 470], and a carefully chosen fixed trim R between the pot and Q2C 'resistor/output pot'...seems like it'd work, like Rangemasters Level pot.
 

[formerMember1]

PETEMOORE:
Thanks that helped,... 

I used Phillips layout, so there is 3 pad holes where the pc mount trim pot is.  If i remove the trim pot to replace with an enclosure mounted pot, how do i wire the new pot?  Just send wires from the cold, wiper, and hot lugs down to the 3 pad holes where the pc mount trim pot was?

Would I use an audio or linear  pot?

Actually you could make Q2C resistor a 3 connect pot [5k +], wiper being the output, it'd have to be one wierd taper, and then the FF 'top R' [1k or 470], and a carefully chosen fixed trim R between the pot and Q2C 'resistor/output pot'...seems like it'd work, like Rangemasters Level pot.

Is this what you mean,... Say I am able to bias the Q2 collector at around 3.50volts with a 3K collector resistor, and then say i could bias the Q2 collector at around 4.50 volts with a 8.2K collector resistor.  Then couldn't I just use a 5K pot with a 3k  or so resistor in series with the cold lug, that way at minimum resistance the pot will be around 3K(biased at 3.50volts) and at max it will be around 8K(biased at 4.5 or so volts.)(obviously i would give my self the oppurtunity of going slightly higher then i need with the pot, so that i don't get to the end of pot's rotation and not be able dial in the correct volts)   <<<<<Just hypothetical, the real values i would have to figure out....

[petemoore]

Actually you could make Q2C resistor a 3 connect pot [ try it on the breadboard or think it through better first...

[formerMember1]

I tried 2K linear for the fuzz pot instead of 1K.  It makes a big improvement, in the fact that the sound is crunchier and heavier.  If you keep the smooth pot off, or don't have one, this will take it right to the crunchy heavy fuzz Jimi had on some early live performances.(thinking of purple haze and wild thing from the experience Hendrix dvd, where jimi got the red and black plaid pants on.)  But i switched it back to 1K since i have the smooth pot to make it more crunchy if i need to.

I am pretty convinced that this is how Roger Mayer modded Jimi's fuzzface along with the other Mayer mods mentioned on Geofx(8.2 K to 18K, etc...)
becuase when you make the pot 2K, it is hard to bias the pedal, not real hard but totally different.  THe fuzz sounds better at biased of 6.2volts with a 2K pot, instead of 4.5 or 5.0 volts with a 1K pot.  Bottom line is, with out a smooth pot, the fuzz is too farty and woofy, to get early Jimi fuzz, but if you bias the pedal at 4.5 volts then swap the 1K pot for 2K, it changes the sound, makes it more focused, crunchier and heavier fuzzed out.  (For me the clean up via guitar is worse this way)  Or instead of swapping the 1Kpot for 2K pot, you could just add the smooth pot (same as the fulltone's bias pot, for those who don't know) and this will actually give more variability, but not as heavy a fuzz tone.

Petemoore:
I don't know if i still want to add an external bias pot, becuase on my power supply, there is knob for simulating a dying battery.  At around 8.0volts or so(i think), it changes the biasing to around 3.0volts, so that is my sqaure fuzz tone.  Then if i turn it all the way up, i get 9.18votls and that gives me my 4.5o volts or so for my Good Fuzzface tone.
I didn't compare to see if it sounds the same as using 9.18volts and just turning the pc mount trim pot for Q2 collector R.
Sounds close to me at the moment though.

still can't get it to clean up via guitar though, i am beginning to think it is the transistors.  Becuase i modified another dunlop fuzz, with Ge trannies and it cleaned up perfect, but just didn't have good tone. so i threw it out and used the enclosure.

sorry for rambling,...  

The sound isn't as good today, so i am pretty sure it is my amp.  Becuase the same way the sound is affected today, was the same way my Rangemaster is affected on some days, and i used to think it was the Ge's fault in the Rangemaster, but now that i play the Fuzzface i know it isn't that since it has silicon trannies. and silicons aren't prone to temp,...etc....

***EDIT***

Actually you could make Q2C resistor a 3 connect pot [ 

Whoops!! Don't know how i missed that, i guess i had to many mods on my mind. 

[formerMember1]

 hi,

Funny thing happened today.  I plugged my fuzzface into my Marshall combo, which i am trying to sell.  I was making sure the new tubes were biased. Had it yp and running and decided to try the fuzzface on it.   Well, to my amazement, the Fuzzface cleans up PERFECT via guitar volume.  I don't know why it doesn't clean up on my small 5 watt tube amp.(maybe becuase the 5 watt is cranked on 10, and the marshall is around 1/2 power.)  Anyway, i am glad that the cleanup problem is resolved, but also to my amazement is the fuzzface sound very different on the MArshall.  Way closer to the smooth/crunchy fuzz that Jimi uses!!  I can't believe how different it sounds on this amp.  More like  mid 60's JIMI tones.  I can't wait to try it on a Super Lead ,(I just hope i don't get kicked out of the store.  )

I also can't wait until i build/buy an 18watt Marshall to try it on.

OT: (sorry)
oh yeah, the Rangemaster doesn't crunch up as good as on the small amp, but it gives a great clean boost full of tone, sounds like Fulltone's OCD boost.

oh yeah, The DD-6 analog man modded, sounds even better on this amp too.

The Axis Face Silicon Rev 3 just keeps getting better and better!!


***EDIT***
Further testing concludes this,
The Rangemaster sounds best on the small amp, cranked on 10, but set for a bassy tone(tone knob on 4 on amp) this gives great power tube drive, gain from RM, and alot of speaker breakup, which makes it great for Cream's Crossroads, etc..

The fuzzface doesn't sound right with above setup, it needs the tone maxed for treble to cut through the woofyness of fuzzface, and it needs the volume of amp around 6-7, the fuzzpedal also needs to not have the volume maxed out, around 3/4 of the way is good,
this setup allows good fuzz tone, but also able to clean up via guitar.

* Problem is the RM and Fuzz need an amp voiced two different ways,

NOw, on the MArshall, the (2) 80 watt speakers offer virtually no speaker cone break up, so the RM sounds  more like a clean boost, like a Tubscreamer set really low, but not as much bass as a tubescreamer,(actually better sounding though)

The fuzz sounds good on the Marshall, more like JIMI, but i am still not quite there,
THe problem definitely lies in the fact that i need a cranked super lead.

All this testing, shows me how one ingrediant could be changed to get better tone or worse tone, just backing off the fuzzfaces volume and the amps volume allowed my fuzzface to clean up.  This also goes back to what PETEMOORE was talking about when adjusting how hard the amp is hit with the fuzzface volume control!!  I guess i should i've listened more carefully....

[Jaicen_solo]

I have a question about those 2369 transistors in this circuit.
I'd like to know how they're being used. Currently, I have a 2N3904 and an AC127 in my hotrodded fuzz face, and I'm quite pleased with it. I thought I might try swapping out the 2N3904 with a 2369 for a slightly less hot sound. I already have a modern silicon sounding fuzz, and i'd like to take this more in the vintage vein for some contrast. my 2N3904 measures 140hfe by the way. No idea what gain the Ge is, just the one that sounded the best
Oh, forgot to mention. I add a 470R resitor on the input of the effect in place of the smooth pot. I have no problems at all with stray radio reception. I do get hiss though, which i'm trying to rectify.

[formerMember1]

I have a question about those 2369 transistors in this circuit.
I'd like to know how they're being used.

I am sorry, i don't understand what you want to know> 

I just used it(PN2369A) in the Q1 spot, but actually want to get a BD139 type tranny with a gain around 70 or so for Q1. I like the BD139 in the Q2 alot.

[Jaicen_solo]

Well you've pretty much answered my question
I just wanted to know wether you were using them in the Q1 or Q2 position. I see you're using it for its low gain rather than sonic capabilities, which is  pretty much what I'm looking for as i'm using a Ge in Q2 for its softer clipping. I think i'll pick a couple up and see what they sound like in my FF.

[formerMember1]

yeah, pick up at least 5, to make sure you get the "right" gain, on the last page, i posted the gains i had,...

[formerMember1]

I didn't like the way the Axis Face sounded with my wah.  I also didn't like how it didn't clean up via volume on guitar. Well i ofund the problem.  It is the mod phillip makes to the 330 ohm resistor.  He makes it a 1k2  so that it is louder.  I never liked this mod.  I finally changed it back to 330 ohm and the fuzz cleans up perfectly.  It also affect the tone, the pedal is now, way closer to a Ge fuzzface.  Like night and day when swapping that resistor.  this also explains why the Germanium fuzzfaces had 470ohm resistors and the silicon versions had 330, it is becuase the silicon ones were known not to clean up all that great, so dropping this resistor helped make it clean up via guitar.  Also the silicons were louder since they were higher gain and trebly so the 330ohm resistor helps.

The fuzz also sounds way better now, way closer to Jimi's tone.  It also works well with my wah, not fantastic becuase my wah still needs to be tweaked,but they sound better together than before.  Also, the wah had too much of a volume problem when using the fuzz with it.  this 330ohm resistor fixed the problem, I now actually have to lower the 100ktrimpot on my wah buffer to lower the volume, becuase it is too loud.

So if you want to bring your Axis Face to closer resemble the Ge fuzzface, definitely change the 1k2 to a 330ohm.  the '69 fuzzface(with germanium transistors) also uses a 330ohm, i think it makes it hit your amp a certain way that sounds better. A 470ohm might be better too.  Since when the volume pot is maxed, it is a little too trebly, if you turn it down a tiny bit, it is warmer and better. 

When turning down the volume pot with the 1k2 resistor in there, it didn't sound the same as changing the 1k2 to lower 330ohm.

[mac]

About the 470 resistor, replacing it with a 1k makes the pedal louder but trebbly. I guess that the capacitor in parallel with the 1k in the Axis schem is placed there to roll off the highs.
I dont like how this capacitor works anyway. I prefer a 47 to 150 pf cap from Q2 collector to base.
The impact of this mod is bigger in the silicon Tonebender mkII. Mine has a 470 resistor.
I should have used a 330 - 470 in my axis face... 

[formerMember1]

WEll, this is what i found out,

I learned this from the help of petemoore and others,

A fuzzface(don't know about tonebenders) respond differently to different amps, and amp volumes.  Also how high the volume on fuzzface is turned up to "hit" the amp. A 1k2 resistor made the fuzzface very loud, it hit my amp to hard, too much gain from the amp was now present, and it took away from the fuzzface pedal tones itself. Also the sound didn't clean up because of the more gain from driving the amp. When the volume is cranked to 10(on fuzzface) it is more trebly, as you turn it down, it gets warmer by naturally rolling off the highs a tad.  So with the 1k2 resistor, you had to set the volume pot to around 11:00 so it didn't hit the amp too hard, but then it was too muddy sounding,  I liked it better by putting that resistor back down to 330ohms,  It allowed me to crank the volume, or a little under, and still get nice high end added to the sound.  I now use a 470ohm resistor there becuase it sounds better, and has  a little more gain.  but, now i have to turn the volume down a tad, but not too much treble is loss, since you only turn it down a tiny bit compared to the 330ohm. 

Also what i like is the fact that if you play  it on a cranked Marshall, you need the volume up pretty high inorder to get some treble, beucase most vintage marshall's get bassier the higher you crank the volume.  So you could  now crank the volume on fuzz, and amp, with out getting too much more gain from amp, but also getting that nice treble from fuzzface to offset the added bass from cranked amp.

This is what i think Jimi did, becuase the pedal does sound closer to a traditional fuzzface when it's resistor is 330 or 470ohm.  Fulltone's '69  uses a 330ohm resistor there,... i guess he thinks it sounds good that way too,...

I love the Axis Face, by far my most favorite fuzzface of all time.  No temp probs, cheap, no more carbon zinc batteries, more stable etc...
PLus the peace of mind knowing that it isn't gonna crap out when it gets hot....

I was thinking about adding that contour pot that the '69 fuzz has, but never dealt with that mod,  Mojotron if you read this, did you put the contour/mids pot mod in your Axis Face?  What does it do exactly?  Is it worth it?  I do like the smooth/bias pot alot...I don't think i could play a fuzzface with out a smooth pot now. 

EDIT**Best Advice
Mac, try a 330ohm resistor in Axis Face, then try a 470ohm, then go up little amounts if you think you need to/want to...

[Fret Wire]

The Ge Dallas used a 470 ohm output resistor, the Si Dallas used a 330 ohm, presumeably to compensate for the Si tranny's higher gain. The Mayer mods to the Ge Dallas a 1k output resistor and a 2k fuzz pot. That ckt cleans up real well with the volume knob. So 1k2 may be a little stiff with si's/1k pot, but it works fine in the Mayer modded Dallas ckt.