FIRST POST -- What kind of transistor is this?

[pingjockey]

Hey all,

FANTASTIC forum here.  Thanks for such an invaluable resource.  Gonna try to find some balance between browsing and reading and managing the rest of my life. 

Having recently salvaged some components from an old shortwave radio, I found some old-schoolish transistors.  Pretty sure I didn't screw them up when de-soldering, either.  Can anyone identify this one?  It has a domed top to it.

The markings read: FCS9101B and 708W.  Google hasn't yielded much of squat.

Many thanks!

[LucifersTrip]

as with many of those, the #'s could very well be house numbers...

but it's really not a big deal. the most important thing is the hfe

If you want to use em in something that originally had transistors like that, an early Big Muff Triangle



or an Astrotone:



would be a cool start.

I have FS1078, FS1079, FS1060 which are from ~ 1964....The hfes are generally around 40-60 with some hitting 150 - 200. I used one in Q4 in my Triangle Muff.

[pingjockey]

Awesome.  Hopefully the DMM I'm getting will give accurate results for the HFE readings.  It's this one, an Elenco LCM-1950 ( http://cs-sales.net/lcm1950.html )

that triangle muff picture is super cool.  Would love to do a more advanced pedal like that one day.  In fact, the whole reason I'm getting into this is to build a couple of fuzz pedals, just not sure where to start with a beginner fuzz.  Really nice design, at least aesthetically!

Thanks for the detailed and quick reply.

[Pyr0]

Well the FCS bit is for FairChild Semiconductor, but as LT says, just measure the Hfe and try them out.

[LucifersTrip]

Awesome.  Hopefully the DMM I'm getting will give accurate results for the HFE readings.  It's this one, an Elenco LCM-1950 ( http://cs-sales.net/lcm1950.html )

It actually doesn't matter as long as it gives accurate voltage readings (and if it doesn't, throw it in the trash...haha)
You can always use RG's test for ge's and it'll be easily close enough...
http://www.geofex.com/Article_Folders/ffselect.htm

that triangle muff picture is super cool.  Would love to do a more advanced pedal like that one day.

yes, it is larger (and the bigger, the more possibility of errors), but the funny thing is that it's actually "easier"  in many ways than, say, a Fuzz Face.

A Big Muff is 4 linear stages (2 of them practically identical):
http://www.pisotones.com/BigMuffPi/psst/schm-triangle-1.jpeg
A Fuzz Face has a "loop" from Q1 to Q2 (100K),
http://fuzzcentral.ssguitar.com/fuzzface/fuzzfacepnpschematic.gif
which makes it a little more difficult to breadboard or perf, since you have to jump over or under traces.

With a Big Muff, if you use any silicon transistors with a "reasonable" gain (80-500+), you'll still get a cool sound. With a Fuzz Face, the gains alter the sound a good amount, plus you have to worry more about biasing to closer specs. You can get crap very easily...

In fact, the whole reason I'm getting into this is to build a couple of fuzz pedals, just not sure where to start with a beginner fuzz. 

After building a load of fuzzes, other than the Bazz Fuss, which is cool for it's simplicity, but not amazing
http://www.home-wrecker.com/bazz3.png

I would have to say one of the easiest fuzzes to get to sound cool is a silicon Fuzz Rite.
http://www.luciferstrip.com/fuzz/fuzzrite-silicon.jpg

low parts count, common values (use 50K, 500K for fuzz & vol) and not as critical about transistors or biasing as Fuzz Face variants.

(triangle muff picture is super cool)...Really nice design, at least aesthetically!

thanx...regarding the design...I just cut a perf that I think it'll fit on and improvise directly from the schematic (after breadboarding) so no two are identical

good luck...hope ya add some fuzzes into the world

[garcho]

might find this interesting, by forum member Tcobretti. hope he doesn't mind I'm including his scheme from the gallery.

[LucifersTrip]

anything that includes the ge orpheum is great...saw that before but never bookmarked it...thanx

[pingjockey]

I would have to say one of the easiest fuzzes to get to sound cool is a silicon Fuzz Rite.
http://www.luciferstrip.com/fuzz/fuzzrite-silicon.jpg

low parts count, common values (use 50K, 500K for fuzz & vol) and not as critical about transistors or biasing as Fuzz Face variants.

This is exactly the kind of rec I think I need right now.  I tried a silicon fuzz based on the Orpheum a few weeks ago but no matter of alignment of the components would work for what I was doing.  I will definitely try that silicon fuzzrite.

My continued hurdle that I need to conquer is translating what I see in a schematic (such as the Triangle one you provided) to how the components should connect on a breadboard.  I know how the breadboard works, but sometimes the interconnection of certain components -- and allowable shortcuts in the configuration -- escapes me.

Perfect example is all of the resistors related to Q1 in the triangle schematic.... I will likely be at a loss as to how to logically and easily connect them all with Q1 in a way that all of the components are serving their specific purposes.

[garcho]

does something like this help? this is how i do all of my breadboarding - draw it out first.



EDIT: forgot to mention, using this schematic, from gaussmarkov.net, from diystomboxes.com 

[LucifersTrip]

My continued hurdle that I need to conquer is translating what I see in a schematic (such as the Triangle one you provided) to how the components should connect on a breadboard.  I know how the breadboard works, but sometimes the interconnection of certain components -- and allowable shortcuts in the configuration -- escapes me.

Perfect example is all of the resistors related to Q1 in the triangle schematic.... I will likely be at a loss as to how to logically and easily connect them all with Q1 in a way that all of the components are serving their specific purposes.

the great thing about the Muff is that you can breadboard one stage at a time, testing after each one.

here's stage one...try it as an exercise. you should get a boost with around 4 - 5V on the collector


tho, it might not match the exact breadboard type you have or the breadboard style you like to use (I do not like using + and - together on the bottom or middle. I use bottom of breadboard for ground and top for the other), SB did a pretty good tutorial:
http://www.beavisaudio.com/techpages/SchematicToReality/
https://www.smallbearelec.com/HowTos/BreadboardSiFF/BreadboardSiFF.htm

If you look at my Triangle Muff perf and the schematic, you will see that you could almost superimpose one on the other.

Also, you can always post a pic a of your breadboard for help.

[pingjockey]

Gary, do you have a pic of the schematic that you drew out on paper?  Just wanting to check my own logic with how I think you chose to board it.  I have tried drawing it out but haven't settled on a method for representation.  I like the way yours is presented and will try it.

LT, I haven't been in the practice of taking voltages on my work.  Such a noob.

If you look at my Triangle Muff perf and the schematic, you will see that you could almost superimpose one on the other.

Yeah, I had noticed that.  I will make a run this weekend at breadboarding the simple fuzz circuit you posted and post some pics here.  That cool?

[LucifersTrip]

LT, I haven't been in the practice of taking voltages on my work.  Such a noob.

set the meter to > 9v (many times 20V). black lead on grnd & red lead on point to measure

Yeah, I had noticed that.  I will make a run this weekend at breadboarding the simple fuzz circuit you posted and post some pics here.  That cool?

of course...someone'll help if it doesn't work...

good luck

[garcho]

do you have a pic of the schematic that you drew out on paper?

right here

When I look at a schematic and try to map it out for the breadboard, I look for what components 'touch' each other. For instance, in the schematic listed above, the base of transistor 1 'touches' C1, C2, R2, and R4. Therefore, however I wire up the breadboard, those 5 components must be routed together somehow. It's a little like doing a pencil maze when the circuits get big. Echo Base was challenging. 

[garcho]

unverified

[pingjockey]

I would have to say one of the easiest fuzzes to get to sound cool is a silicon Fuzz Rite.
http://www.luciferstrip.com/fuzz/fuzzrite-silicon.jpg

LT, can you explain the pots in this drawing?  Not sure what the "500K + 1.2M" means. 

Will different values work?  I believe I have 100K, 50K and 1M laying around.

Also assuming the trannys are silicon of the same type.  Just use any until I get a sound I like, correct?

Thanks!

[garcho]

The schematic calls for 350K pot, which is hard/impossible to find, so instead you use a 1M2 resistor in parallel with the 500K (easy to find) pot to achieve 350K Ohms of variable resistance. Google 'parallel resistors' if you're confused. If you don't have 1M2 resistor, use a 1M. Same goes for the 33K pot.

The two pots in this schematic are being used for 2 different things. The 350K pot is combining two signals to a variable ratio. The 33K is sending a variable amount of signal to ground, thereby diminishing the output (volume). You'll start to notice that's a volume control in many, many pedals.

Also assuming the trannys are silicon of the same type.  Just use any until I get a sound I like, correct?

As long as they're silicone and NPN, yes. You'll know that's the case because schematics nowadays note the need for Ge transistors and the emitter symbol (the flag on the transistor symbol) 'points out' instead of 'in', meaning that it's a NPN transistor (as opposed to PNP, a different type of transistor). You'll find silicone NPNs are the most common, although there are 3 or 4 other common types (PNP, MOSFET, JFET).

[pingjockey]

Gary, using your format, this is what I came up with first time around.  Haven't breadboarded it, but want to see if the route makes sense.

[garcho]

You're a little off, but on the right track. I'll draw one up for you to compare to, give me a few minutes.
Remember to ask yourself 'what's touching'. For instance, the base of Q1 is 'touching' C1 in the schematic, but on your breadboard diagram, it's 'touching' the collector, not the base. Also, keep in mind that the 'rails' (the voltage source and ground in this case) are going along either side of the breadboard, so you could have a 470K resistor go directly from the collector of Q1 to the 9V bus, for instance (you don't have that wired correctly on your diagram).

[pingjockey]

I see your point.  Hoping this is better.  Seems right.

The schematic calls for 350K pot, which is hard/impossible to find, so instead you use a 1M2 resistor in parallel with the 500K (easy to find) pot to achieve 350K Ohms of variable resistance.

I searched some threads here on the how's/why's.  Thanks for the tip.  Is it ok to solder the resistor director to the pot at lugs 1 and 3?

[garcho]

looks good to me, bravo

Is it ok to solder the resistor director to the pot at lugs 1 and 3?

yes it is. important to keep your soldering tidy, though.