A Christmas Present

[mac]

Do you have some unused low gain, med leakage germs?
Here is a classic 3 stages circuit I built this weekend using some unused 2SA101 Matsushita PNP Ge about (50; 150ua)
It also works with Ge as low as 20-30; you can try lower inter-stage resistors.
It can easily be adapted for low gain silicons like TIPxx, BDxxx, MPSA92, etc. Just replace those 22k with 33k.
D1 can be omitted, I did not use it.



Enjoy!

mac

[DavidM]

Gracias por compartir!

[mac]

Posted on: Today at 11:42:35 AM Posted by: DavidM
Insert Quote
Gracias por compartir! Wink

de nada

mac

[Morocotopo]

Nice Mac. Thanks.

But what really interests me is...

you have a time machine???

You made this in 2014??

How are things next year? The weather? What should I invest my money in?

[jrod]

Thanks for posting this, Mac!

[mac]

Nice Mac. Thanks.

But what really interests me is...

you have a time machine???

You made this in 2014?Huh?

SHHHH... I stole Mr SCHLOBOWITZ his TIME MACHINE, the GEFILTER a device of musical genius !!! 

How are things next year? The weather? What should I invest my money in?

I see big waves and a hot summer here.
And I should invest in preferred stocks of Qualcomm NASDAQ:QCOM and American Tower NASDAQ:AMT

mac

[duck_arse]

but, mac, what does this pedal sound like in the future, or do we have to wait for you to tell us?

[tubegeek]

It's gonna sound futuristic! But not by the time we get there....

[mac]

but, mac, what does this pedal sound like in the future, or do we have to wait for you to tell us?

It will sound NOS Ge

I'll record a sample this weekend... hopefully 

mac

[Kipper4]

Thanks Mac.
What does it sound like. ZZish?

[toneman]

thanks, Mac!

That was a RUSH!!!

[Kipper4]

I just built this.
Thanks Mac. Sweet touch that switchable input cap.
I might need to play with the transistors a little as most of the low gain Germs I have, have got high leakage.
I might try some Russians in there.
I'm using Ac153.
Sounds good to my ears. I'm not a big fuzz fan but if I turn the fuzz down and use it more like a fuzzy booster. it has a sweet spot where it adds lots of harmonic content and sustain.
I Like it. Thanks for the christmas present Mac.

[mac]

I just built this.
Thanks Mac. Sweet touch that switchable input cap.
I might need to play with the transistors a little as most of the low gain Germs I have, have got high leakage.
I might try some Russians in there.
I'm using Ac153.
Sounds good to my ears. I'm not a big fuzz fan but if I turn the fuzz down and use it more like a fuzzy booster. it has a sweet spot where it adds lots of harmonic content and sustain.

Glad you like it.
I use it at half gain most of the time.
I have 3 NPN 2SD352 Matsushita right now, I sold the PNP 2SA101. Two different sounds due to the very low transistion freq of those 352s.
For those who want to experiment, the input resistor can be a 25k to 50k pot. With zero resistance and the switch open I have more nasal sounds.
I also noticed that disconnecting Q2 bypass cap is a nice addition.
And a 1k series resistor with the fuzz pot to avoid zero gain.

ACxxx might be a perfect choice for this circuit. If they are high leakage collectors will be above 3.5v which is fine. The low freq transistion will roll off unwanted highs.

The primary idea behind this circuit was to find a use for those unused Ge.

I Like it. Thanks for the christmas present Mac.

Ho Ho Ho!!!

mac

[Kipper4]

Q2 bypass cap = c5 right?

[John Lyons]

^ C8 is what I think Mac meant. Less gain without that cap.
Looking forward to trying this Mac. Thanks

[Kipper4]

Thanks John. It was a 50/50 toss up between those two and I picked the wrong one. Thanks for putting me right. Appreciated

[Gus]

I sometimes like the collectors at a lower voltage I have a two stage fuzz (+9VDC, 2n3904s)with the collectors at about 2.5VDC

A fun thing to do with series gain stage distortion or fuzz is to switch out or change the emitter resistor bypass cap values.  I did see switching out the 2nd stage bypass cap posted in this thread.

Maybe start with a .068uf to .1uf at the 2nd stage for more lead mid range boost

[Kipper4]

Hey Mac
Heres my perfboard layout.

https://www.dropbox.com/sh/7ma9n53c5jqdgsr/toM7nd2VUE/tres%20hombres/Tres%20Hombres%20Fuzz.pdf

[Gus]

One of the gain stages in this schematic would make a good Ge test circuit

Build one stage don't use the emitter bypass cap

Use a Known good battery or power supply

Use a socket for the transistor.  Plug in the transistor and measure the collector, emitter and base leads VDC to see if they are in a good range.  Also measure the battery when connected to the circuit.

This should be a good simple test.  You could do a fast DC test or use it as a gain stage to hear the tone.

You could even flip the voltage for NPN if you do not use polarised caps(that is why I posted do not use a emitter bypass cap)

[mac]

I sometimes like the collectors at a lower voltage I have a two stage fuzz (+9VDC, 2n3904s)with the collectors at about 2.5VDC

A fun thing to do with series gain stage distortion or fuzz is to switch out or change the emitter resistor bypass cap values.  I did see switching out the 2nd stage bypass cap posted in this thread.

Maybe start with a .068uf to .1uf at the 2nd stage for more lead mid range boost

i'm trying a few things with your suggestions.

One of the gain stages in this schematic would make a good Ge test circuit

Testing Ge for noise before building is a must

BTW, happy new year guys!

mac