Sam Ash Fuzzz Boxx

[LucifersTrip]

edit (my last one with hfe's and voltages):

[nocentelli]

I'm interested in the reversed perfboard construction of your board - How do you get the iron in to solder the legs of components to the pads? And what are the advantages of having the board "upside down"?

[LucifersTrip]

I'm interested in the reversed perfboard construction of your board - How do you get the iron in to solder the legs of components to the pads?

small iron, good eyes, steady hand

And what are the advantages of having the board "upside down"?

here's a few things that come to mind:

1) makes it easier to build (less chance of error. no flipping the perf upside down looking at a mirrored image).
2) easier to troubleshoot and build since it looks almost identical to the schematic
3) easier to hold components in place when soldering
4) you can solder wires after the board is mounted so wires can be measured to almost exact length and kept shorter
5) you can easily add or remove components without removing the board
6) bottom is smooth so it can easily mount with double-sided tape
etc...

[deadastronaut]

i smell something fishy with that demo...

the guy has a lot more 'hair' on it than he tries to let on really, in fact it sounds like its got a big wig on... , but when the  pedal is off he just lightly 'tickles' the strings,trying not to expose how much wig is actually on it..

then when on,  he bites into them properly.....hmmmm....

at the end, its very very clean, then when pedal is on its got more balls than when he had it with a ''little hair'' ......just my cynical marketing observation..

(love the old style ad poster though, look nice framed up. )

[LucifersTrip]

the guy has a lot more 'hair' on it than he tries to let on really, in fact it sounds like its got a big wig on

yeah...a bit too much at the beginning for a proper demo. it sounds good, but should've had the amp clean to start

at the end, its very very clean, then when pedal is on its got more balls than when he had it with a ''little hair'' ......just my cynical marketing observation..

that actually makes sense since now you're hearing more of the effect and less of the amp...which is why fuzzes usually sound nastier on top of a clean signal. I can "smooth" out most of my fuzzes if I play em over the amps distortion.

[Kipper4]

What is a good substitute for the 2N5366.
would a Ac128 Ac125 do the job please?

those things are just expensive here. I think i can get Ac's cheaper

[Davelectro]

Why Ge? This circuit asks for silicon transistors.

I've build an Astrotone and it sounds really good. More of a vintage heavy overdrive than a typical over-the-top fuzz, though.

Now, the tone control is absolutely useless. Don't waste your time with it.

[Kipper4]

Just because they're pnp.
I'll research alternative Si pnp

[Davelectro]

 

They're not PNP (unless we are looking at different schematics?).

Go get a pair of 2n2222 or 2n3904. They are ubiquitous and cheap as hell. They'll do just fine.

[Kipper4]

Thanks Davelectro
I'm sure i have those in stock I'll give it a shot.
Cheers
Rich

[Mark Hammer]

It may be just my own view, but when a circuit depends on a diode pair for clipping, it is not going to be especially fussy about the transistors used.  As long as they are withn a reasonable range.

Think of it like this, if you make a pot of sauce, and dump in a whole bottle of habanero or scotch bonnet sauce, does it make a huge difference if you use purple onions vs white or yellow onions?

[Davelectro]

Sure. I used a pair of 2N2222A (hfe ~300) and the pedal sounds very good with them. Fuzzy, yet very articulate. Now, I didn't try any other transistors in real life but I modeled the circuit in multisim and, according to it, different transistors don't make any difference. As far as I know, Q1's biasing method is responsible for that.

[nocentelli]

Now, the tone control is absolutely useless. Don't waste your time with it.

Swap the 1k8 resistor on the tone pot for a 470r, and it becomes quite useful.

[Davelectro]

Swap the 1k8 resistor on the tone pot for a 470r, and it becomes quite useful.

Actually, 470R is what I'm using. It works, but I find it too subtle.

[nocentelli]

Ok, I remember it being fine at one extreme (maximum low end) but far too thin if you strayed from there. I also remember it being great for clean up with the guitar volume knob rolled back, but badly affected with a buffer infront. 

[Davelectro]

My build is based on analogman's version. The output capacitor is 470n instead of 47n. May be that's why the tone control behaves different.

Now, clean-up is perfect with any pickup type and it doesn't get muddy with humbuckers.

This circuit is really good at that.

[Gus]

Q1 does matter as well as the biasing
The collector voltage matters because of the ratio of the clipped waveform positive or negative that then goes to the diodes

If you change the collector to base resistor to adjust the collector to the correct voltage you will change the gain of the first stage
Remember with a gain stage like the first stage in this circuit the gain is partly set by the C to B resistor divided by what is before the circuit
Could be a guitar LRCs and cable or something else.  
In this case the effect is reduced because of the use of  a 100K input volume control
This is why a buffer before it with the input volume turned up has a lot of gain If you want to "fix" this add a resistor between the wiper and the cap going to the base of Q1.   I would try 10K to start and then go up and down in value from there.

I have been posting ways to decouple the AC gain from the DC bias in circuit like the first stage of this fuzz

Also note the biasing of the emitter follower(EF)output the emitter is at a lower than 1/2 power supply voltage
BUT there is a 1.8 K emitter resistor and a 10K volume control for good drive
I GUESS this was done because the signal is clipped before the EF and the designer like the sound.
http://www.diystompboxes.com/smfforum/index.php?topic=104006.0
http://www.diystompboxes.com/smfforum/index.php?topic=103688.0
http://www.diystompboxes.com/smfforum/index.php?topic=104613.0
I can post a DC sim screenshot for some ideas

[kingswayguitar]

"snotty"
"not super overdriven"

i'd love to hear his impression of distorted!! lol

anyway, love that amp
oh, and the pedals are great
yes, "sonically' similar but the old one is hiss-ier

thanks for bumping and
cheers

[Gus]

A screenshot of a DC sim of a circuit like this fuzz
Note the 10K at the input and the biasing of the first stage
It is an example to show the adjustments you can do with the first stage
If I was to build it I would use a lower hfe first transistor

[Gus]

I have question.  I have not seen much response to this bias feedback adjustment I have been posting about.  
Is it because what I am posting is not understood?

I think it is a kind of cool adjustment.
I have built a circuit with this type of bias AC feedback network close to the last screen shot in this thread http://www.diystompboxes.com/smfforum/index.php?topic=103688.0 And I am finishing a bass fuzz build with another circuit close to this.

You can even use this in HP like builds

And you can use the parallel cap and resistor(or reostat and fixed resistor)  with the circuit from the build LucifersTrip posted to reduce the first stage gain if you want