X FUZZ

[Mario44]

It makes the sound choke and leds stop lighting when I play but nothing else

[deadastronaut]

try adjusting the value of the 10k that goes to the 470k pot..

i just tried a 100k as an extreme  and it definately gets synthy....

[Mario44]

100k resistor makes more difference but it's still not the same as on the video, no synth

[Mario44]

Couldn't sleep and just had a thought. What type of capacitors did you use in your xfuzz?
Maybe I can't get no synthy because I'm using ceramic ones

[Mario44]

All right
Got checked the voltages and there was a faulty wire comming from Q2 emitter to ground.
Now this fuzz seems to have more synth than before. Thanks for helping.

[deadastronaut]

brilliant...glad you got it going. 

[haveyouseenhim]

Good to hear, Mario. I'm populating my PCB now. Hopefully it will fire up first go. *fingers crossed and satanic prayers chanted*

[deadastronaut]

nice one mike, let us know if it pops..

[axemurderforhire]

Just built the X ROCK today and holy crap its loud.

I used the schematic on page to but had to replace the first pot (1m) with a 500k cause it was all i have  and used mpsa18's in Q1 and Q2. I just need to swap out the L.E.D as the one i put in to it was damaged and i had to jimmy a connection to another one and if that wasn't bad enough my battery was going down ,Just scrapping 7volts of power but even at that it sounds like a beast.

I have to say Rob you make some of the most fun and easy builds here. Which is good for me cause i end up nearly burning the house down and the wife keeps saying she'll send you guys the bill for a new kitchen table cause i keep leaving the iron on it HA HA. But this is my second working build after the beginner project and your very own "Spitfire" that i have been able to get work. So im chuffed as chips and think a pint or two is in order  And while im on the high stool ill drink to your health and your next project ha ha

[deadastronaut]

Cool, ill have a beer tioo...

yep it is loud, could do with a resistor before the vol pot to keep it tamed....or not...

[haveyouseenhim]

I finally got the pcb built. So far it's a nice fuzz. Just no synthy sounds. I tried changing the bias pot to 1M and it doesnt help. I may just try some different transistors or just deal with no synth. The fuzz alone is great.

[deadastronaut]

Hmmm that's a shame, my hfe are around 300 on Q1/Q2...if that. Helps, hows the switch pop btw?

@mario, could you post. My. Voltages for mike that i pm,d you....im not at home today...cheers.

[Mario44]

I have cleaned up my message box 
Got it a paper sheet, but I tore it up aswell when I was cleaning my room
Look like the measurings are more or less, @da you can confirm if this is right
Q1
C 2,05
B 0,62
E 0

Q2(not sure about C and B)
C 1,9 with 10k coming from v+
B 0,62
E 0

Q3
C 6,05
B 1,48
E 0,91

My problem was I got no synthy because Q2 didn't have good conection from emitter to ground and voltages appeared to be close to 9V

[WhiskeyMadeMeDoIt]

I've noticed I get good synth sounds through my headphones and an amp on very low with almost no sound when clean. When it's cranked it is less obvious. Have you cranked this up on a hot amp Rob?  Did you hear a difference?  I have built this three times on breadboard with and without mods.  I also used components from different suppliers.  Either way it still an awesome fuzz. 

[Mario44]

Btw
I've checked this fuzz on 9V battery and already another 7V battery.
Synth became more synthy with lower voltage, but more stutter aswell.
IDK how about 12V and more

[haveyouseenhim]

Hmmm that's a shame, my hfe are around 300 on Q1/Q2...if that. Helps, hows the switch pop btw?

@mario, could you post. My. Voltages for mike that i pm,d you....im not at home today...cheers.

I don't know about pop yet because I have the in and out jacks directly wired.  I'll throw a 3pdt on it later and check. I added a spot on my layout for a pulldown resistor just in case.

I tested my hfe and they are both right at 308.

I'll check voltages later.

[haveyouseenhim]

Battery 9.47

Q1
C 2.77
B 0.61
E 0

Q2                             
C 2.78      With 250k bias pot     0.67
B 0.61      With 250k bias pot     0.537
E 0

Q3
C 8.3
B 0.78
E 227 mV

[karbomusic]

Kudos!

Just threw this on the breadboard (X ROCK) and it sounds just like DA's video except... it has horrible white noise that is very loud...

OK, C8 (220pF) is the source of all the noise. What does that little fella do in this circuit (be gentle). 

[Lurco]

C8 creates a pulsating DC ripple voltage, because the LEDs between collector and base are orientated only oneway, like in a power supply rectification, as opposed to a bilateral diode configuration as usual in those kind of fuzz stages?

[deadastronaut]

UPDATE: made a few last minute tweaks before i finally build mine,

added a 1M pulldown just for good measure, (but i'm sure with the 'tonepad wiring 5' scheme it'l be fine anyway)..

i now have a 22k from gain pot lug 1 to ground...this gives a warmer/thicker tone at minimum gain.  (much better imo)

put a 220k before the last 100nf,  and used a 100k vol pot to tme excessive output,.... it works out about right for max vol, and still enough there to make the vol up on synthy settings..

going to stick a 4.7n/10nf switch from gain pot 2 ..10n gives a nice fat but creamy sustain...4.7n gives a nice bite..

as for hiss, while i'm still on BB ive been messing with sticking a cap to ground fom the Q2C...1n/2.2n...cuts off the very top hiss, but doesn't affect the tone hardly...

been playing through my marshall (clean channel) and sounds very cool....especially drop D etc...

open to opinions on hiss taming?..tried bigger caps on the C/B's but loses the magic somewhat...

anyway................

i did notice a big difference in less noise with using the leds bilateraly (as usual) but the clean up on guitar wasn't as responsive....hmmmmm