Zonk Machine with high gain Ge transistors

[MarkALeuchter]

I've got a bunch of Toshiba 2SB54 transistors with moderately high leakage (250-350uA) that I usually like in Q1 and Q3 of a Tonebender Mk I...but the are far too high gain (190Hfe to about 250Hfe).  I've seen a few posts on various discussion boards where people have noted that they've used high gainers in a Zonk Machine, though others have noted that they've used gains that are more typical of the Tonebender Mk I circuit (60-70 for Q1 and 80-100 for Q3). 

I typically use a low leakage device in Q2 sitting around 110-120 Hfe for a Mark I build.  Any thoughts on using these high gain 2SB54's for Q2-Q3 in a Zonk circuit?  Will the higher gain require adjustments to some resistor values, or will the gains on these really work against the properties of the circuit?

[antonis]

Thanks to R.G.

[mozz]

Usually those Japanese transistors aren't that high in leakage. You sure they were at room temp when testing, not holding in your fingers?

Edit: just measured a bunch of Toshiba 2SB54 transistors, i get about 120 gain and 120ua leakage average. I know i have NOS here and they are higher gain. There is a triangle with a letter above it, so there are different gain buckets or it is a lot marking.

[mac]

Usually those Japanese transistors aren't that high in leakage. You sure they were at room temp when testing, not holding in your fingers?

I have a lot of Toshiba 2sb54/56, <leakage> = 150u
OTOH Toshiba 2sa49 have similar gain but <leakage> = 50ua

Old jap pocket radios from the 60s have Toshiba 2sa52/3 and 2sb54/56.
I found way cheaper to buy a radio than a pack of germs.

mac

[Phend]

This question I should know:
The Zonk uses negative power opposed to positive like Most of the current effects.
Once more:
Can you connect both negative and positive effects together with cables ?
If you know what I mean.....

[R.G.]

This question I should know: The Zonk uses negative power opposed to positive like Most of the current effects.
Once more:  Can you connect both negative and positive effects together with cables ?
If you know what I mean.....

It helps to think of this as negative-GROUND and positive-GROUND power supplies. If you think of it that way, it should become clearer.
With only a single power supply, you can't ground both positive and negative sides. This shorts the positive and negative sides of the power supply together through the cable grounds.
You can work around this two ways. One is to used a second power supply to get both, for example, +9V and -9V relative to a shared ground. That used to be a bigger problem than it is today, as a second negative-side power supply can be as low as $30 and supply a zillion positive-ground pedals.
The other way is chancier. For the positive-side-grounded pedals, you rewire them so they think that +9V is "ground" and that the 0V from the single power supply is their "-9V".  This can and has worked. However, unless you spend some effort and parts trying to decouple the fake "ground" and "-9V" in the pedal, you can in some situations get oscillations that can't be stopped other than by using a dedicated negative power supply.
The simple and sure solution is to use a second -9V and ground power supply.

[Mark Hammer]

I find the simplest thing is just to use a 9V battery for such circuits.  They tend not to draw a lot of current, so even cheap batteries can last a long time (if you disconnect power when not in use.)

When I try to explain positive ground circuits to novices, I pitch it this way.  Imagine you have a bipolar power supply.  That is, you have +9V, and you have -9V.  They are both referenced to 0V, in "the middle".  The vast majority of pedals will only require the +0v side.  And some Ge-based fuzzes, and occasionally others, will use only the -9V side and ground.  Some will use +/-9V but those tend to be rarer.  Although that ground IS 9V more positive than -9V, that doesn't mean you can simply flip the leads on the power jack; especially if the chassis is ground.

(Just occurred to me that one or two of the cabs I made for my big modular system have +/-9V supplies to accommodate a bunch of older Craig Anderton and magazine circuits.  I can probably stick PNP-based fuzz circuits in that cab and only use the negative side.)

[Phend]

So another way to look at it might be:
You have Two effect pedals, one is neg gnd and the other is pos gnd.
The power supply has multiple +9v "Isolated Outputs".
Will a "Reverse Polarity" cable work for for the pos gnd effect ?
I assume yes.

BUT the input / output jacks on the effects will be different polarity since the rings on these jacks are connected to "ground",
One ring is pos and the other ring is neg.
SO I assume you would NOT want to connect the two effects together.
Even if Battery powered.
Is this true ? Or am I missing the boat ?

[R.G.]

So another way to look at it might be:
You have Two effect pedals, one is neg gnd and the other is pos gnd.
The power supply has multiple +9v "Isolated Outputs".
Will a "Reverse Polarity" cable work for for the pos gnd effect ?
I assume yes.

BUT the input / output jacks on the effects will be different polarity since the rings on these jacks are connected to "ground",
One ring is pos and the other ring is neg.
SO I assume you would NOT want to connect the two effects together.
Even if Battery powered.
Is this true ? Or am I missing the boat ?

You're thinking (which is good!) but missing it just a little. But don't worry about that - it can get complicated.

If you have two isolated supplies - that is, the two supplies have no common conductors - you can connect one to your negative-ground pedal and one to your positive-ground pedal. The wiring in the pedals attaches the negative side of one power supply to signal ground and the positive side of the the supply to signal ground. If you plug the two of them together, the signal ground becomes common between the two pedals and supplies, and nothing bad happens. Should work fine, which is what you were thinking. I think.

Whether the reverse polarity connector would cause a problem or not depends on how each pedal's internal wiring and power-input socket works. now it gets complicated.

The pedal-industry doesn't have any standards. Most pedals use a 5.5mm x 2.1mm center conductor DC barrel jack, and further they expect the incoming DC plug to be center-negative. So most pedals use a DC insulated DC power jack and hook the center-pin contact to the outside of the metal box and the outside rings of the signal jacks, to suit their negative-side-grounded power use. As a result, all of the single- and multi-output pedal power supplies that I know of have outputs that are center-negative.

Positive-side-grounded pedals throw a major wrench into the works. Some positive-side-grounded pedals use the same physical socket-jack arrangement, but expect the center pin of the DC to be positive polarity, not negative like all the rest of "normal" pedals. These are the pedals that need a polarity-reversing plug to work from a multi-output isolated power supply. Some positive-side-grounded pedals use the de-facto pedal standard socket-plug polarity of center-negative, but hook the outside barrel positive to signal ground and the signal jacks. Some positive side grounded pedals have a 1/8" phone jack for power, and a few don't have any DC jack at all, only battery snaps.  The company I work for has had to figure out all these different possible arrangements and make adapters and so on.

The bottom line is that you will have a difficult time coming up with a general rule, because there are several variations. The simplest thing to do is to pick up the pedal that you're thinking about using, take your multimeter, set it to beep for continuity, and test whether the center pin of the incoming DC socket/jack connects to the input/output signal jack rings or the negative/outside contact does. (To be fair, there are some old Boxx pedals that won't even do this correctly - ugh!) This test tells you whether the pedal expects the incoming DC plug to have a center positive (like the rest of the world) or a center negative like the rest of the pedals in the world.
When you know that, you can figure out whether you need a polarity reverser plug adapter. A polarity-reverser plug adapter just criss-crosses the incoming DC wires from (in the pedal world) center negative to center positive. It doesn't do anything about whether the insides of the pedal connect the incoming center pin to signal ground, or the outside barrel.

Bottom line - you got to figure out which incoming DC power polarity is connected to the signal ground rings on the signal jacks.

Yeah, it's confusing. I realize that I should be drawing a set of pictures.

[Phend]

Found at General Guitar Gadgets ;

"FF5 Project - Powering the Fuzz FaceTM PNP circuit
with a Charge Pump
Version 2014November19 Copyright 2014 JD Sleep
Permission refused for posting/serving this file from any site other than www.generalguitargadgets.com
We ran across a forum post long ago where R.G. Keen suggested using a charge
pump to convert the power input of a PNP circuit from positive ground to negative
ground. This provides a solution for those of us who like to daisy chain a power
supply to all of our stompboxes. If you've ever tried to daisy chain your modern
pedals (Boss, Ibanez, etc) with a Fuzz Face (or an old 70's Big Muff Pi or any PNP
transistor circuit pedal), you know you can't do it. Now you can!
From the DC jack or battery, the charge pump circuit is a negative ground circuit.
From the output of the charge pump circuit, we use the ground and -9v outputs to
power the Fuzz Face. The Fuzz Face circuit sees a positive ground (0v is more
positive than -9v). So here is the solution for the FF5 PNP versions in diagram and
photo. This is a great "wrapper circuit" to install and probably well worth the time in
the long run. Here's a photo of a Dallas Arbiter type Fuzz Face replica with the
charge pump."