Fuzz face transistor hfe puzzle

[holio cornolio]

So... I'm a noob, lots to learn, lots read, lots more to read. Ive built a few 2 transistor fuzz face circuits now. I've only ever used bc108 and BC 109 series transistors. They're fine, I like them, but I thought I would mix it up and add some mojo. I found some c1016 trannies on eBay which are apparently bc10x equivalents. But they're not, I have a handful and they are consistently measuring an hfe of 170. The bc10x that I have measure 260+. So anyway, I figured throw a couple of these in a circuit and have a low gain fuzz face, could be fun. Well no, it's not. I've put in transistor sockets and the same circuit with bc108 and a bc109 sounds normal. Swap in ta couple of c1016 and there is almost no sound at all. Never mind any fuzz. The circuit is working and there is some sound coming through., But should I be making some component value changes to compensate for the lower gain trannies?

[mozz]

Do you have a bias adjust pot on 8.2k or 33k in place of the resistors?

[GibsonGM]

This might help, Holio...welcome, BTW. Because you changed transistors, you may need to adjust the bias for the 1016's. Best way to do this is to use a trim pot in place of Q2's collector resistor.   You should be able to easily find more info on this with a search here, very common topic!

EDIT: Corrected for typo, pot should be on Q2's collector.

https://www.diystompboxes.com/smfforum/index.php?topic=104888.0

[holio cornolio]

Thanks all. I have a 10k bias pot on q2 collector, but just a fixed 10k resistor on q1 collector.
Is it also worth playing with the value of the resistor between the emitter of q2 and the base of q1? Currently this is a fixed 47k resistor, maybe something bigger is néeded???

[anotherjim]

The Axis Face Silicon is tweaked to handle medium-gain parts...
https://fuzzcentral.ssguitar.com/axisface.php

Not saying you copy it exactly - just for ideas of what to tweak.

[antonis]

Is it also worth playing with the value of the resistor between the emitter of q2 and the base of q1?

It depends on what you're looking for..

Its presence there ensures Q1 Bias where its value sets the amount of negative feedback..

P.S.
OK, its value is also involved into Q1 bias, hence Collector current, but only for values > [(Q2V_Emitter - Q1V_BE)*hFE] / Q1I_Collector

[duck_arse]

So.... I found some c1016 trannies on eBay which are apparently bc10x equivalents..... a couple of c1016 and there is almost no sound at all.....

I can't find any sensible datasheet for the c1016. is that the correct part number? if so, what does the datasheet you have at hand tell you about the location of the base pin for the c1016, especially when compared to a standard BCxxx base?

[R.G.]

Try 2SC1016 or KSC1016. The Japanese "2S" numbers were often left off. The 2SC1815 for instance, is often labeled C1815.

[holio cornolio]

So.... I found some c1016 trannies on eBay which are apparently bc10x equivalents..... a couple of c1016 and there is almost no sound at all.....

I can't find any sensible datasheet for the c1016. is that the correct part number? if so, what does the datasheet you have at hand tell you about the location of the base pin for the c1016, especially when compared to a standard BCxxx base?

good question and one that I don't have a good answer to. C1016 is what's printed on the transistor. The seller listed is as c1016TUN. I don't have a datasheet to refer to but am confident about the pin layout. I measured collector voltages with the c1016 and they are a long way off. It's not possible to get q2 collector even close to 4.5v and q1 collector is over 2..5v so some work with pots needed to find a sensible bias range I guess. In other news I tried subbing in some bc546c just for shots and giggles. These have a hfe value in the region  of 500, and they bias fine and sound almost the same as the bc10x types. Weird no?

[duck_arse]

when I searched 2sc1016, I got RF power output, not small signal transistors. this led me to the sensible comment. if yours are the ones I saw in an ebay listing [can you link to the ones you bought, pleeze?], I don't think they are "2SC1016", but "C1016". of some description. they look like very nice things, and if they came with real uE packaging, probably ARE really nice things. the people at micro ELECTRONICS should have some sort of data archive, no?

and as they are the TO106 package, you can throw them into your multimeter hFE tester [you have?] as tho they were BCxxx and get a reading. [ignore the TO92.]

[holio cornolio]

when I searched 2sc1016, I got RF power output, not small signal transistors. this led me to the sensible comment. if yours are the ones I saw in an ebay listing [can you link to the ones you bought, pleeze?], I don't think they are "2SC1016", but "C1016". of some description. they look like very nice things, and if they came with real uE packaging, probably ARE really nice things. the people at micro ELECTRONICS should have some sort of data archive, no?

and as they are the TO106 package, you can throw them into your multimeter hFE tester [you have?] as tho they were BCxxx and get a reading. [ignore the TO92.]

ok I don't follow what you're asking here. I've already masured hfe on my multi meter which is how I know these have hfe around 170 I have 10 and they all measure between 163 and 180. My multimeter won't give any reading if you orientate the transistor incorrectly, so I'm confident about pinout and hfe. Question is really about biassing and how to get these to make fuzz. Here's a link to the eBay auction though. They are lovely trannies. https://www.ebay.co.uk/itm/C1016-TUN-HI-SPEC-PLASTIC-BC107-BC108-BC109-GENERAL-PURPOSE-MATCHED-NPN-fd6d53-/402267650932?mkcid=16&mkevt=1&_trksid=p2349624.m46890.l6249&mkrid=710-127635-2958-0

[Rob Strand]

All I've managed to find is Micro Electronics did produce parts with part numbers Cnnn and Cnnnn and they are not the same as BCnnnn or 2SCnnnn.      They did make TO-106 package devices.

There's a few pics in this advert,
"C1016 TUN HI SPEC PLASTIC BC107 BC108 BC109 GENERAL PURPOSE MATCHED NPN fd6d53"
https://www.ebay.co.uk/itm/402267650932

Marking uE C1016 TO-106 with red dots.  (uE = mu E = Micro Electronics)
Bags dated 1984.

I'm trying to remember what BCxxx variant devices came in TO-106 packages.   Maybe BC209 etc maybe even BC4xx.   I do rememeber many projects in the 60's with BC108's parts would also spec 2N3565's.  Around 1970 the 2N3565 disappeared and you only saw BC108.


Based on the BC209 idea I got this lead,

LOTTO ODL MI Micro Electronics BC209B TRANSISTOR 100
https://www.ebay.it/itm/274946285664?hash=item4004136060:g:GpMAAOSwRG1gsK4l

So Micro Electronics did make BC209B's in a TO-106.
So are the C1016's the same? (or the same as BC207/BC208 whatever).

This might help confirm the pinout (take note of top and bottom views),
https://www.datasheet4u.com/datasheet-pdf/SGS-Ates/BC209/pdf.php?id=685919

duck_arse's pinout pic is as viewed from the bottom and agrees with SGS doc.

[fowl]

...maybe even BC4xx...

https://smallbear-electronics.mybigcommerce.com/npn-dot-bc407b/

[Rob Strand]

From what I can see

- Micro Electronics made BC207/BC208/BC209 and 2N3565 in TO-106.
  The Micro Electronics datasheet for both of these agree with duck's pinout pic.

   If you keep the same pin formation as a BC107/BC108/BC109, the BC207/BC208/BC209
   pins should line-up correctly.  The BC10x tag on the TO-18 package should line-up with the
   champfer  "E' pin on the BC207/BC208/BC209.

- I couldn't find a Micro Electronics BC407. So perhaps these were Philips/SGS maybe National Semiconductor

- Absolutely zero info on the C1016 number, and nothing relating it to any of the above transistors.
  I did find some stuff about Micro Electronics using Cnnn etc numbers.

My vote goes with BC207/BC208/BC209.  As for the ABC gain category I've got no idea.
Best bet would be to measure the hFE on a few based on the expected pinout.

[Rob Strand]

I guess it is still an assumption the C1016s are what is advertized.

This guy built a silicon tone bender using the same part so you should be able to get it to work but he does not give any build details or pinouts.
https://www.youtube.com/watch?v=VhU4GRfxiHA

. I measured collector voltages with the c1016 and they are a long way off. It's not possible to get q2 collector even close to 4.5v and q1 collector is over 2..5v so some work with pots needed to find a sensible bias range I guess. In other news I tried subbing in some bc546c just for shots and giggles. These have a hfe value in the region  of 500, and they bias fine and sound almost the same as the bc10x types. Weird no?

To me a high Q1 collector voltage is pointing to a major problem.   

So one possibility is C and E are reversed.

What you might see here is Q1 collector voltage high and Q2 collector voltage low.  Q1 is off and Q2 is on either of which will block all the signal.   But that's not the only possibility.

ok I don't follow what you're asking here. I've already masured hfe on my multi meter which is how I know these have hfe around 170 I have 10 and they all measure between 163 and 180. My multimeter won't give any reading if you orientate the transistor incorrectly, so I'm confident about pinout and hfe.

What pinout have you worked out so far?

Does it agree with the common TO-106  package pinout spec?   
    chamfer = Emitter (E), centre = Base (B), the other pin Collector (C)?


You could be right here but given it's not working I strongly suggest falling back on to simpler and more reliable methods to at least verify the pinout.

Try following this post to identify the pins,

https://www.diystompboxes.com/smfforum/index.php?topic=120151.msg1124333#msg1124333

Given we may have a C and E swap issue I suggest following the method of determining C and E in this post.  Also, post the diode tester voltage results.

If this pin identification method agrees with your existing pinout and it agrees with the common TO-106 pin out spec then I'd say you could be *very* confident of the pinout.   If any one of those doesn't agree the it would point to an issue.  If your hFE tester and the previous method agree then next in line would be to go with that.    Not all transistors follow the common TO-106 pinout but in this case I'd be suspicious if it didn't.

Question is really about biassing and how to get these to make fuzz.

If the pinout is wrong you could be making the circuit voltage correct and even making the circuit work to some degree under false conditions and it definitely won't work correctly

It would help a lot to choose two transistors at random, measure the base-emitter voltage and base-collector voltage using the diode tester, measure the gain (hFE) using your DMM.   Put them in the FF circuit.  Post all your circuit values and voltages.


After some checking:


I'm fairly certain the C1016 transistor follows the standard TO-106 pinout,  the same pinout as the BC207/208/209 and 2N3565

chamfer = Emitter (E), centre = Base (B), the other pin Collector (C)


This Reeves Tonebender MK2 clone uses the Micro Electronics C1016 transistors with the red dots.

https://reeveselectro.co.uk/product/reddotsound-vintage-fuzz-with-nos-transistors-and-bias-control

The Tonebender MK2 is a three transistor circuit with the last two transistors wired up as a Fuzz-Face type circuit.

Top View,
https://reeveselectro.co.uk/wp-content/uploads/2021/06/RedDotSound-19-scaled.jpg
Front View
https://reeveselectro.co.uk/wp-content/uploads/2021/06/RedDotSound-34-scaled.jpg
https://reeveselectro.co.uk/wp-content/uploads/2021/06/RedDotSound-35-scaled.jpg

You can see the top left transistor in the pics:   On the right hand side is the pin with the chamfer, this is wired to a 100k + 1k to gnd + electro to ground.  This is what you would expect for the emitter of Q2 in fuzz-face circuit, the only difference is a fixed 1k resistor instead of a 1k pot.   So the chamfer pin is the emitter.
- The centre pin wires directly to the transistor below it.   As would be the case for the base of Q2 wiring to the collector of Q1 in a Fuzz-face.
- The remaining pin is wired to a 4k7 resistor.   As would be the case for the collector of Q2 in a Fuzz-face.

So a lot of evidence there for the standard TO-106 pinout.

FWIW, a standard FF circuit should produce a reasonable result with hFEs of 170.     All FF's needs some tweaking.   If your pinout is correct then there has to be something else wrong.

At a stretch the FF Q1 collector resistor on that Reeves unit might be 10k instead of the usual 33k, but I'm not 100% certain.  It could be 10k going off to a 100k bias pot.

[holio cornolio]

Thanks Rob, I appreciate your efforts here. I've been much less scientific, than you, but basically I'm cast iron certain that the center pin is base, and I know the orientation that the circuit requires so I've socketed for the transistors so I can just flip them through 180 degrees. One way makes sound, the other doesn't... To be totally honest I selected 2 transistors from the 10, one with a hfe of 183 and the other 165 and I've tried both in both spots in the circuit in both orientations. I will try the other from that batch in case one of these is a dud.

[danfrank]

The C1016 sounds like a house number that one manufacturer used... Try using a component tester or multimeter to figure out what the actual pinout is and if it in fact an NPN device. My guess you're getting the pinout wrong or it's actually a PNP or some other type of device. If it were an NPN transistor, even with way off specs it would work in your circuit if you're getting the pinout right. It might not sound great but it would work.

2SC1018 (or C1018) was a common Japanese NPN transistor used in a lot of pedals. It has a different pinout than the BC1xx transistors.

[Rob Strand]

Thanks Rob, I appreciate your efforts here. I've been much less scientific, than you, but basically I'm cast iron certain that the center pin is base, and I know the orientation that the circuit requires so I've socketed for the transistors so I can just flip them through 180 degrees. One way makes sound, the other doesn't... To be totally honest I selected 2 transistors from the 10, one with a hfe of 183 and the other 165 and I've tried both in both spots in the circuit in both orientations. I will try the other from that batch in case one of these is a dud.

For the socketed transistors the C1016 should be orientated like the BC108's but things like the 2N3904's will be flipped 180deg.

You can build an NPN version of RG's transistor tester by making the emitter the negative rail.  So flip the circuit part to the right upside down.

http://www.geofex.com/Article_Folders/ffselect.htm

At this point it might be worthwhile getting second opinion on the transistor gains by using this set-up (I measure transistors like that all the time).    The advantage of RG's circuit is you can see leakage.  The leakage should pretty much be zero on a silicon transistor.  If you see leakage, especially strong leakage, I'd be thinking the part is dead or the pinout is wrong (so try orientating the pins differently).   Low gain would mean E and C are reversed.   Who knows maybe some the part's aren't all the same, some might have different pinouts than others.  Normally that would be far fetched but with Ebay anything is possible.

The thing bugging me is your voltages seem to imply the gains are low.  Leakage usually makes the gains look high.  Nonetheless it's worth double checking on RG's jig.

An additional good test is to change RG's 2.2M resistor to 1M we would expect the output voltage to double (actually x2.2).   The aim here is to see the doubling not to modify RG's jig (which has the right values for direct measurements).  If you don't see the doubling then it would cast doubt on the measurement.     You get this effect when a bad transistor fortuitously creates a sensible measurement - which could be occurring on your DMM.

Another good check on RG's circuit is to measure the base-emitter voltage when in the hFE measuring mode.  It should be around 0.6V to 0.65V.

There's something weird going on but it's not obvious.  Part of that could be we are assuming the transistor gains are normal because your tester shows them as normal.    Doing those crosschecks would certainly show-up a problem or at least confirm all should be good.

If you can post all your results it might help.  Even the voltages in the FF circuit are useful.  From the voltages it's sometimes possible to back-engineer the cause of the fault.

[Phend]

Do you have a bias adjust pot on 8.2k or 33k in place of the resistors?

Being a beginner myself, I have bread boarded a Fuzz Face with unknown germanium transistors.
The EBC voltages I get are no way near the Q1 0.00 0.60 1.40 and Q2 0.80 1.40 4.50 that is shown on the GGG instructions.
So I put in a trim pot on Q2 C and am able to get 4.50.
Questions:
Should I do the same for Q1 C to obtain 1.40 ?
Should I expect Q1 B and Q2 E to become what is stated ?
OR are these recommended voltages different for different transistors ? Sans Q2 E.
Thanks in advance for any enlightenment
Paul

[PRR]

> voltages I get are no way near

How much un-near? Is "1.40V" coming out 0.5V? 13V? What?

> Q1 0.00 0.60 1.40 and Q2 0.80 1.40 4.50

Accept the things you can not change. The 0.00V at Q1 B is inevitable. Q1C==Q2B every day. If Q1 base resistor is not large then Q1 C comes out two junction drops.