FY-2 Germanium build...

[LucifersTrip]

since so many like the Shin-Ei FY-2 si, I thought I'd note that I posted a quick build report for the FY-2 ge under the "Mosrite FuzzRite Ventures 1590A 2000 Pound Bee"    ....the thread started with Fuzzrite and moved to the FY-2 ge when tubelectron posted that old "manuscript" looking schematic:



http://www.diystompboxes.com/smfforum/index.php?topic=90579.msg792143#msg792143

[jrod]

Cool! Thanks for the build report!

[tubelectron]

Hi LuciferTrips,

I report here your trails about that Ge FY-2 you've posted in the Mosrite FuzzRite Ventures 1590A 2000 Pound Bee.
(http://www.diystompboxes.com/smfforum/index.php?topic=90579.0)

That's great!  I made the 1.5k correction to the schematic...Yes, on the datasheet online it shows 2SB56 hfe 80. Did you actually measure the hfe's of the original you had in hand?

Unfortunately no... It wasn't mine and I lacked time to do it ! 

But let me know the result if you made a trial ! I am very busy these times on tube amps, but I'll try to get on it ASAP...

A+!

Ok...I breadboarded with this schematic:


I used 2 transistors with  approx 80 - 85 hfe with very low leakage.

It worked right off and actually is a very nasty fuzz!  There is one problem...the 50K volume.
When I turned the volume from 0 to 10%, there was a much larger increase than expected...it was already at unity by 20% or 30%. Also, as the volume increased, the bass increased. By the time you get to 100%, it's insanely loud and totally bassy & muffled. It's similar to what would happen if you remove diodes from a diode-clipping fuzz...you'd be left with way too much volume and a big muddy mess.

I slowly decreased the volume pot. When I used a 10K it was pretty cool. The volume increases a little too fast and the last 30% was too bassy and muddy....but a 5K did the trick! ...a perfect, steady increase in volume and only little bass increase as you go. I almost want to think that the schematic has an error.

One more note...you may want to use a fuzz pot up to around 30 or 40K. I get a max fuzz at around that point.  In the last 10 - 20K, the fuzz will start to gate....and go downhill.

So, all in all a pretty loud, nasty fuzz. Now, I'll start experimenting with different transistors to see if I can get a better tone.

The voltages (e,b,c):

Q1: -.15, -.36, -.67
Q2: -.46, -.67, -2.40

The issues you have from the pot values are unusual - I discard the lack of progressivity that you can probably solve by the choice of a log taper, fo course - but what makes me curious is this change in tone (from nasty to bass and muddy) when you turn the pot.

I am akeen to suspect some external influence :

- was the effect alone between the guitar and the amp ?

- are you shure you hadn't any parasitic oscillation or RF radio effect superimposed at certain settings ?

It's nonetheless a simple device worth to try fro me... ASAP !

A+!

[glops]

I bread boarded this last night.  Changed polarity and went with some Germ NPNs.  Q1 is 250 hfe and Q2 is probably around 30.  Instead of the fuzz pot I put a
10k in it's place.  Really good fuzz tones.  Nice and full.  Still has some 60's buzz to it.  Like it a lot.  I have more bass and fuzz with the volume up as well and then it cleans up a bit when you turn it down.  I think it's a keeper...

[Govmnt_Lacky]

Q1 is 250 hfe and Q2 is probably around 30. 

Is this a typo? Q2 = Hfe 30 

[Mark Hammer]

Could this circuit be considered to share the basic Fuzz Face topography?  Apart from the specific values, and the emitter components on Q1, it sure looks that way.

[glops]

Q1 is 250 hfe and Q2 is probably around 30. 

Is this a typo? Q2 = Hfe 30 

Hfe just measured at 37

[superferrite]

Sweet!   Thanks for the experiments.

[LucifersTrip]

Could this circuit be considered to share the basic Fuzz Face topography?  Apart from the specific values, and the emitter components on Q1, it sure looks that way.

Yeah...it does look that way...Q1C straight to Q2B and the old Q1B to Q2E resistor...though, it really doesn't sound like one. So far mine actually sounds closer to a Fuzzrite variant...it's surprising, but I did alter the vol pot, which removes fatness

The fact that's it a FF variant (basically) leads me to believe that I should try to get close to the classic 4.5v on Q2C...that's next.

[LucifersTrip]

Q1 is 250 hfe and Q2 is probably around 30. 

Is this a typo? Q2 = Hfe 30 

Hfe just measured at 37

if you have time, what's Q2's collector voltage?

[LucifersTrip]

just did a quick test by subbing a pot for the 22K on Q2's collector

I got 4.5v at 15K, but it's actually worse...much more harsh

At 29K it starts to gate...it's 1.0v at that point.

I did a blind test and stopped the pot where I thought it sounded best. 2.2v, 24K

Unlike a FF where if you get down to 2-3v, you'll get mush and a large volume decrease, you don't have to worry about that here. It's so loud and brutal, that softness actually helps.

If you want the harsh metallic tones, raise to 4-5v by lowering that collector resistor. You'll get similar tones is if you raise
both the resistors in scoop of the silicon version (I modded the si version with 50k & 100K pots subbed for the 10K & 15K resistors in the scoop)

Also, when I hit 4.5v I started getting some massive feedback/wailing when the volume was full...no problem at 2-3v

But even at 2-3v I was getting a little sizzle and the treble can be a bit brutal. Just like with a FF, a small cap across Q1BC worked great. I used a 100pf.  At this point, it's easily good enough to box, but I'll try other transistors 1st...

[jrod]

Hey LucifersTrip

I just set this up on the breadboard
and was getting 5.6v on Q2C.
Also I was getting a lot of interference.
But I thought the fuzz sounded cool.
I had to kind of rig the pots up with
alligator clips so that may be where
the interference was coming from.
I'll try to mess with it all later and
try to dial in some different voltages.

Thanks for your report!

[glops]

I'll try to measure my voltages, as well.  I couldn't sleep last night so I started breadboarding this at 5 in the morning.  After trying PNP and not getting results I switched things over to NPN and was nice and surprised with the sounds on my headphones.  I got some fuzzrite like tones, as well, with some added beefy.  With a 250 hfe germ in Q1 and a 37 hfe in Q2 I got some serious great sounding fuzz.  Definitely gonna box it up, sounds better than any fuzz I've done lately...

[LucifersTrip]

Hey LucifersTrip

I just set this up on the breadboard
and was getting 5.6v on Q2C.
Also I was getting a lot of interference.

Firstly, what were the hfe's you used?  If you used ones with 70+, then I say:

"exactly"....raise the 22K on Q2's collector to drop it to around 2.5-4v and put a very small cap 100pf across Q1's BC.
I got alsmot the EXACT same result with my 80 hfe's.

But I thought the fuzz sounded cool.
I had to kind of rig the pots up with
alligator clips so that may be where
the interference was coming from.
I'll try to mess with it all later and
try to dial in some different voltages.

Thanks for your report!

I use only alligator clips. With vol at 100%, this one is super loud and can get a lot of feedback & interference, especially if the voltage is over 5v
============================
That being said, I experimented further. The original uses 2SB56's with hfe max 80, so I used all Japanese transistors with hfe's no greater than 80...and let me tell you this has to be the greatest fuzz for any beginner who wants to get his/her feet wet with germanium, because whatever hfe I threw in there gave me a nasty, loud fuzz (80/80, 80/40, 40/80, 80/20, 20/80,40/40, etc....) 

Though, I can conclude a couple things. 1) For me, it always sounded better with Q1 higher hfe than Q2 when there was a significant difference between hfe's. When you swap the two (ie 80/40 or 40/80) you get similar voltage readings on Q2's collector....but 80/40 sounded better.

2) If you use higher hfe's, it sounds better with Q2's collector voltage smaller, but not lower than 2v.

...but it can sound excellent with Q2's collector at 4.5v if you use low gain transistors....and that's actually what I have in there as the "best" right now.

Believe it or not I have Q1 30, Q2 45 and 4.5v ...there's no feedback or interference and it's still loud & nasty. This is no Fuzz Face.

[LucifersTrip]

I'll try to measure my voltages, as well.  I couldn't sleep last night so I started breadboarding this at 5 in the morning.  After trying PNP and not getting results I switched things over to NPN and was nice and surprised with the sounds on my headphones.  I got some fuzzrite like tones, as well, with some added beefy.  With a 250 hfe germ in Q1 and a 37 hfe in Q2 I got some serious great sounding fuzz.  Definitely gonna box it up, sounds better than any fuzz I've done lately...

I haven't tried gains that high, but again, you probably didn't check the leakage on that 250. I was laughing when you said you started at 5 am.
I was getting everyone around me annoyed in the mid afternoon because at that point it was untamed...but your headphones saved you. Wait till you crank it thru an amp.

[glops]

headphones saved them!  my ears are still bleeding.

on my bridge pickup, I get the perfect tone when I roll back the volume a bit.  full tilt there's a little too much bass but it's a pretty damn
good sounding circuit without too much tweaking to get some great sounds.  I made a fuzzrite variation a few weeks ago and it is still missing something.
At the right spot this gets that perfect fuzzrite sound I've always wanted. 

[LucifersTrip]

headphones saved them!  my ears are still bleeding.

that's great...it is an ear-ringer

on my bridge pickup, I get the perfect tone when I roll back the volume a bit.  full tilt there's a little too much bass but it's a pretty damn
good sounding circuit without too much tweaking to get some great sounds.  I made a fuzzrite variation a few weeks ago and it is still missing something.
At the right spot this gets that perfect fuzzrite sound I've always wanted. 

killer...and it's basically a FF variant...btw, before you pull it off the breadboard try a 5K instead of the 10K vol pot, don't roll off the vol and see if there's still too much bass...

and remember, if 10k's too bassy at full and 5K's too trebley, then put a resistor across the 10K to get a 7-8K and you might hit a perfect spot where you can turn it up 100% and still like it...it'd be a sin to have to roll back the volume on this one!

[LucifersTrip]

Here's my final version.

Firstly, since the original 2SB56 had a max hfe of 80, it makes sense that the 2 choices would be lower than that. I upped the hfe a bit from my last "best" to 54 / 70. This also makes sense since it's a Fuzz Face variant and a FF sounds cool with 60-90 / 100-130 ...so this is in similar proportion.

Secondly, I noticed when the gains are at this level, you can actually get a good fuzz with a Q2 collector voltage all the way from ~ 2v - 6v.
That is why you can pretty much thrown anything in there and get a decent fuzz. Changing the voltage gives me more variation than the 50K fuzz, so since I decided to make it a 2 knobber, I set the fuzz to max, which for me was 30K.  It's easy to find that point. Simply turn the 50K pot to max. You should get a mild gating (I did no matter what Q's I used). Then, turn slowly back while hitting chords and stop a short amount after the mild gating disappears.

Thirdly, like I wrote, I got a decent tone from 2v to 6v on Q2's collector. For me, 6v was around 8-9K and 2v was around 28-29K...so, 9K + 20K pot.

Lastly, the 100pf tames any noise/fizzle/harsh highs, etc...This one's is loud as hell (even with low hfe's) so it is more prone to noise at max vol.

[jrod]

Hey LucifersTrip

I just set this up on the breadboard
and was getting 5.6v on Q2C.
Also I was getting a lot of interference.

Firstly, what were the hfe's you used?  If you used ones with 70+, then I say:

"exactly"....raise the 22K on Q2's collector to drop it to around 2.5-4v and put a very small cap 100pf across Q1's BC.
I got alsmot the EXACT same result with my 80 hfe's.

I used 2SB176. Q1 - 80, Q2 - 108
I have a bunch of other Japanese transistors
and I will try your suggestions. THANKS!

Those are really interesting results. I went with
Fuzz Face type hfe readings because of how the
circuit looks, but am anxious to try out what you found.
I did notice how super loud this circuit is!

[LucifersTrip]

Rookie error!  I love using vintage components but this time it hurt me.

It just didn't seem right that the vol pot was that far off, so I double-checked all hookups...good. then, i measured all the components. the
.002uf (a pulled one from the 60's) was closer to .02uf than .002uf

That would probably explain the 10-fold downsizing of the vol pot from 50K to 5K . At least I know my ears are right on the money.
Here's the correction:


I replaced the vintage dud with a brand new .002 and the 50k now sounds cool. For me, it still gets a bit bassy in the last 10% so I put a 500K pot across the 50K vol pot and turned it down till I got the right sound. It turns out that a 45K pot (50k pot with 400K resistor across outer lugs) sounded the best for me.

With the correct .002 and 50k it's very similar to what it sounded like with the .02/5k, but it's a little more saturated.

I noticed that I could get away with a smaller taming cap if I put it across Q2BC, so I went with that...a 50pf

And lastly, after playing for hours, the best tone with those lower gain (54/70) transistors I used was when Q2's collector voltage is in the 6.5-7v range. This gives the exact type of saturated fuzz with chords and the buzzy fuzz with single low-string notes I'd expect.  If I dropped to 4-5v the chords still sounded cool, but the single low notes start to become metallic and clangy. If you drop down to 2-3v, it softens a bit, but starts to mildly gate. 

I got the best fuzz at 32K and the pot on Q2's collector goes from 8v (bumblebee fuzz, 5k) to 2.5v (still decent, but starting to gate, 25k)

So here is my final second version with the corrected output cap: