Jordan Bosstone and Bossboost pictures

[PRR]

> Unsorted: 35 to 470

Low price. Specially in 1967.

The collector feedback greatly reduces bias variation. hFE=35-470 makes only 2.3:1 change of current.

Anyway, what's the worst can happen? It distorts. Isn't that what they were selling?

And as you note, some of these whole-hog bargain numbers were available dot-sorted.

[Rob Strand]

Anyway, what's the worst can happen? It distorts. Isn't that what they were selling?

To me the biasing can make it or break it.   

I guess there's two angles: one is to make a representative clone, the other is to make it as good as it can be.   The last thing we want is to make clones that don't sound like the original or don't sound good!   That's how a lot of germanium fuzz clones end up.   At one point I made notes about vintage fuzzes from youtube videos and some of the worst and best were actually the same circuit!

[Rob Strand]

Stuff found on my hard disk.

Code Select Expand


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Boss Tone Info and Chrononology
Rob S, 2021/02/21

I've kept the common circuit numbering (1 to 5) from the web, but there's a bit more to it.
Also there's a difference between manufacturing build and the schematics alone.

All models are au-0606 until we get to the 6248 Sho-Sound
Alhambra (1967, 1968, maybe 1969)
Pasadena marked au-606 but has Nashville circuit

Features identifying versions:
- external labels
- pcb color and pcb number etched on solder-side
- transistor packages and location of transistor on boards.
- The California circuit puts the transistors on opposite corners of the PCB.
  and the Nashville put the transistors in the same corner.
- parts marked ***

Revision History:
- added info on Pasadena unit
- added info on PCB markings
- resolved some of the transistor markings
---------------------------------------------------------------------------------------------------
California 1 schematic V1.0

C2 should be 220p
The transistors have dots which indicate the hFE's; see details below.
---------------------------------------------------------------------------------------------------
Circuit 1

Schematic: California 1

Label: Alhambra Calif,   au-0606

PCB: IC-0193 B ; solder-side marking
PCB has a large square pad between the PCB number and mounting hole.
*** Diodes orientated across PCB;

Transistors:
2x2N3397 NPN, Package TO-98 skirt, orange dots
Orange dots => hFE=135, based on same process 2N2926
TO-98 is like a TO-92 with a round skirt at the bottom

Knobs: two different markings.


Circuit 2

Same design as Circuit 1 except different PCB

Schematic: California 1

Label: Alhambra Calif,   au-0606

PCB: Likely IC-0193 C ; solder-side marking
*** Diode orientated along PCB
*** 100k orientated along PCB
(*** 33k & 470R loaded on PCB)

Transistors:
Both NPN, TO-92 but no dots.  I expect 2xMPS6513
---------------------------------------------------------------------------------------------------
Circuit 3

Schematic: California 2

Label: Alhambra Calif,   au-0606

PCB: IC-0193 C or D(?)
Ground hex post does not have a tinned area.
*** 100k (located near wires) mounted on an angle,
100k moved to mount Transistor in different holes,
red wire also moved.

Parts:
Links loaded in place of 33k & 470R.
Q1 feedback resistor 10MEG

Caps: 2x20n
Output cap: 20n
Feedback cap: 220p

Transistors:
Q1 2N3397 NPN, TO-98 skirt, yellow dot
Yellow dot => hFE=225, based on same process as 2N2926
Q2 Motorola MPS6513, NPN, TO-92, gold leads ; hFE = 90 to 180 @ 2mA, calc avg hFE = 135

Example: (Sir H C, 2006)
"California Bosstone, 2N3397 (yellow dot) and MMPS5513 (face down) vertical cap is 220k,
cap under other is .02 also, can not read diode values."
Note first M is the Motorola logo not the part number.


Circuit 4
Schematic: California 2 + cap mod

Same as circuit 3 except output cap is 470pF; Solar 470M Z5R.
The cap is thicker and is not stacked with the other caps in
the middle of the PCB.
---------------------------------------------------------------------------------------------------
Circuit 5 Nashville circuit with both transistors next to each other.
The upper transitor is the NPN and the one nearer the corner the PNP.
This have a number of sub variants.


Pasadena

Uses the "Nashville" circuit.
Has red white blue wires

Schematic: Nashville

Circuit: Nashville

Label:
Pasadena, South Pasadena California

PCB: Text "IC-0193 F"
Brown color on component-side
Dark green soldermask on solder-side

Parts: 100n input cap (Solar brand)
Others? (Solar brand)
2x 18k's

Transistors: Q1: Motorola SPSxxxx, NPN, TO-92, gold lead
Q2: ???, PNP, TO-92, gold lead

Diodes: 1N4001?, 1A rectifiers, Black, Motorola


Not fully Identified:
Similar to previous but different transistor packages.

Schematic: Nashville
Circuit: Nashville
Label: ?
PCB: Brown color on component-side
Parts: 10n input cap
Transistors Q1:  NPN, TO-106 button
Q2:  PNP, TO-92
Diodes: 1N4001


Not fully identified: (from a schematic)
Schematic: Nashville
Circuit: Nashville
Label: ?
PCB: ?
Parts: caps 2x18k, 3x10n
Transistors:
Q1: F70N1 1142812  (maybe E70N1), NPN; Probably F = fairchild
Q2: M852 95232, PNP ;implying M= motorola symbol 8 = 1968, 52 = wk52, part no. = 95232

A part source indicated: NTE159 = 2N3906 = 95232

Diode: 1N4001

Comments:
I have a suspicion the Fairchild part might be a TO-106 button head.
That would essentially be the same as next version with he 2N3565.

Nashville
Schematic: Nashville

Circuit: "Nashville" Circuit

Label SHO-Sound, Nashville

PCB: No PCB number.
PCB is light green semi-trasparent fibreglass
PCB tinned but with no soldermask.

Parts: (Sir HC unit)
3x10n
18k + 18k

Transistors:
Q1: 2N3565. NPN, TO-106 button package
Q2: Motorola 924 95232, PNP, TO-92
The M at the start of M924 is a Motorola Logo not the part number.
Likely to be date 1969 and part number 95232.
\E B C/  botton view, gold leads

Diode: GI (General Instrument)
look like 1A rectifiers.

Variants:
*** Caps seem to vary: 10n, 20n, 50n


Not fully identified:
Label: SHO-Sound, Nashville
PCB: ?
Parts:
RLBJR65 (Richard Boop)
Re: Jordan Bosstone and Bossboost pictures
« Reply #9 on: August 20, 2006, 11:05:42 PM »
"Interesting! I've also seen the Sho-Sound Nashville model with
3 - .05uF, 1 - 50pF, Q1 - MPS6513 and Q2 - 2N4249, unreadable diodes, ..."

Q2: 2N4249 hFE = 100 to 300, PNP, Silicon

Comment on this:   
MPS6513  NPN is a TO-92 package, and the PNP 2N4249 is a TO-106 button.
This swaps the position of the TO-92 and TO-106 compared to previous versions.
One example of a board with this build had a blue component-side PCB.

I can only assume these are later manufacturing runs.
---------------------------------------------------------------------------------------------------
Transistor packages:

TO-92 common flat-face plastic package
TO-98 like a TO-92 with a round skirt at the bottom
TO-106 Small button head
---------------------------------------------------------------------------------------------------
Bias points

For ckt1,    calc Q1 at VC1=3.4V
For ckt3,4,    calc Q1 at VC1=3.2V
For ckt1, 3, 4 calc Q2 at VC2=3.05V
For the Nashville circuit, VC1=5.3V, VE2=5.9V
---------------------------------------------------------------------------------------------------


[allesz]

Interesting tread!
I do love the bosstone topology; I like the California version with bigger caps (22 to 47 nF) and no clipping diodes. Also I like to mix Si for q1 and Ge for q2.

Always been curious about the boss boost, there are not schematics on line, nor videos on YT or reviews... He said with sweaty hands :-)

[hair force one]

I'm posting this schematic here because some photographs has been useful for perfboarding it. It's verified and gives some variety to a Boss Tone v1 that shares the same board.


Build it with  two 2n3904 and didn't have the 2.2 megohm so i put two 1 megohm resistors.

[hair force one]

Used 100k log pots as well, i put 100k lin on the schematic, assuming that it was the same pots in the Bosstone.

[bmsiddall]

Just built another Bosstone (Nashville cct) as I couldn't get octave notes on a previous build (Russian diodes fv > 0.7V), even when i increased input/output caps.  The new build was stock apart from switchable asymmetric clipping (1 Ge diode switched in/out of cct), this time with KD521A Russian silicon diodes (fv < 0.6V).  Used low hfe transistors (< 150 i think?). 

Nice, gnarly octave down notes at certain points around the fretboard, but these disappeared as soon as the Ge was switched in.  More compression obviously, but it was interesting how the diodes affected the Bosstone in a simlar way to the Harmonic Percolator.

[pee-j]

I built the CA version and must confess was disappointed. Good crackly fuzz, but quick gated sustain. Real old school in a bad kind of way.

I switched the PNP to an NPN ( e to ground, b in and c out) and this little guy came roaring to life! Pretty damn good fuzz. Fuzzy with plenty of bass and nice sustain.
[....]

hello from 2023!

just for curiosity's sake... and clarity's...
what Dan N talks about / what you talk about, Dan N,
involves some errors, right?
(I'm no expert)

first: that it sounds bad
cause others love the circuit...
there may have been some glitch, like a bad transistor, right? -- or wrong?   wrong transistor orientation using a socket, maybe?

2nd: connecting:
"e to ground, b in and c out"
should have said "switch e and c"?
"c out" I can render meaning to but "b in" goes off the map, in my head

but does this even work like that? as simple as that?
sure, I've read this:
https://www.nutsvolts.com/questions-and-answers/semiconductor-sex-explained
and this:
https://barbarach.com/npn-to-pnp-transistor/

[Rob Strand]

One of the errors that kept coming up was the 47pF cap on the Nashville circuit. 
47pF is what is in the units, not 47nF or 47uF.

The "odd" transistor connection is actually well known. It's called a Sziklai pair.
https://www.theengineeringknowledge.com/introduction-to-sziklai-transistor-pair/

The addition of the BE resistor sets the operating current of the first transistor.

A Sziklai pair is sort of a like a Darlington.  You will see extra BE reisistors on Darlingtons for the same reason.

In the Nashville circuit the Sziklai pair is acting like an NPN transistor.

There's an old post analyzing the finer points of this circuit.  As I recall the effect of the 47pF cap was
analyzed and I seemed to remember something happens when the value is around 10nF (can't remember
if it was good or bad).  It's some time back so you might have to update the image URLs.