Muffin Factory 106NU70 Transistor Substitute

[jeffhess74]

I'm preparing to order and build the Muffin Factory. I've sourced all the parts from Tayda.com except for the 106NU70 transistor. I'm having a hard to finding these. Is there a alternate, similar transistor that can be substituted. Sorry if this is an obvious question—I'm relatively new to electronics/pedal building.

Any help appreciated.

 

[Robert]

You need a pair of NPN germaniums if you want the Si/Ge switch to function as intended.

They don't necessarily have to be the 106NU70 though. You're shooting for ~60 hfe. (66 / 54 in the original)

 

[jeffhess74]

Thanks, I found the 2N404 Germanium PNP Transistor on Amazon. It has an hFE of 85. Will it still work?

 

[Mentaltossflycoon]

Thanks, I found the 2N404 Germanium PNP Transistor on Amazon. It has an hFE of 85. Will it still work?

I only have a general warning that Amazon is not a trusted source for many things so I've never bought transistors there. I've kept it to leds or the occasional pack of resistors that "fell out of my tayda cart."

 

[Nic]

I've had good luck buying a brand new nte102 lately on amazon. The 106NU70 for my muffin factory came from ebay.

Maybe look on smallbear for NPN... not PNP.

 

[Betty Wont]

Thanks, I found the 2N404 Germanium PNP Transistor on Amazon. It has an hFE of 85. Will it still work?

You want NPN, not PNP. Perhaps a simpler project….

 

[jeffhess74]

Yeah, I had my reservations, too, and realize that I need the NPN not the PNP (still learning). So, I found these on SmallBear: https://smallbear-electronics.mybigcommerce.com/germanium-transistor-russian-mp38a-38/

 

[Laundryroom David]

Yeah, I had my reservations, too, and realize that I need the NPN not the PNP (still learning). So, I found these on SmallBear: https://smallbear-electronics.mybigcommerce.com/germanium-transistor-russian-mp38a-38/

do you have a transistor tester?

 

[Nic]

One thing to note, even with the faceplate, it's an advanced build : stacked boards, lots of switches, lots of places to go wrong.

 

[szukalski]

And tricky drilling. The faceplate definitely helps to hide your sins.
That said, it's the BMP which gets my favourite BMP tones.

 

[jeffhess74]

You want NPN, not PNP. Perhaps a simpler project….

do you have a transistor tester?

I don't but I see the need.

 

[jeffhess74]

One thing to note, even with the faceplate, it's an advanced build : stacked boards, lots of switches, lots of places to go wrong.

I know. I'm just so intrigued with the idea of this build. If I'm lucky it'll work when I'm done. If not, I'm sure I'll learn a lot from such as big fail—I always do.

 

[Laundryroom David]

I don't but I see the need.

You can figure out hfe and leakage other ways, but a tester is a worthwhile investment.

Some lots of transistors are remarkably consistent … others not so much. I’ve had a couple good results (believe it or not) just picking at random without testing but most often that approach results in a bad bad. I don’t love sockets for transistors. This may be a good time to use them tho.

 

[Robert]

There was a Tayda drill template floating around here somewhere so you didn't have to fool with manually drilling the rectangles.

EDIT: Found it.

1590BB - Muffin Factory - Tayda 1590BB Drill Template

Took a shot the Tayda Drills for the Muffin Factory project board I ordered. (The Tayda Drills Tool is actually pretty easy to use.) Did up the drills template (being sure to add the 0.2mm for powder coating), submitted it and ordered a nice shiny new black 1590BB enclosure with the new drill...

forum.pedalpcb.com

The most important thing is to make sure you have the dipswitch module installed correctly and aligned so the dipswitches are at an acceptable height (and level) before soldering the pinheaders to the main PCB. You really don't want to have to remove that once it's soldered in place.

 

[Nic]

There was a Tayda drill template floating around here somewhere so you didn't have to fool with manually drilling the rectangles.

NO, No, no ... filing rectangle holes forges character !

More seriously, just make sure the holes fit the type of switches you use.

 

[DeadAirMD]

When Small Bear sends you transistors, you never get the exact hfe your hoping to get when you buy. They ALWAYS send you a range of hfe. The only way you can get something specifically tested it to buy their single/double packs which are usually specifically for a certain circuit like a Fuzz Face. Still a good option for transistors though, it's just a crap shoot.

 

[jeffhess74]

Thanks for the insight. Any recommendations for decent, affordable transistor tester?

 

[jeffhess74]

Well, I got it all together and it works. I socketed the GE transistors and does anyone know what the 39nF cap does? Got to design a graphic and get some better knobs for it but it's together at least.

I haven't fiddled with the settings yet but out of the gait it seems to have an overall dark tone. Anyone else experience this?

 

[jeffhess74]

Updated the pedal with paint, knobs and a few decals