Vox - Cry Baby Wah ( Thomas Organ )

[The Rotagilla]

Probably the best sounding Cry Baby I have ever heard. Values are listed as "marked value / measured value". I cannot measure the capacitors or inductor. The only markings on the transistors are a number 2 with a circle around it followed by 5117. Any info on the trannies would be greatly appreciated. I think my close up work is getting better.

[analogguru]

I assume that you measured the resistor values in-circuit (470k/360k) ?
Then some of the values will be falsified.

Its a Vox/(Thomas Organ produced) Wah. Must have a look for more infos on the trannies.

here the original patent for more info:
http://analogguru.an.ohost.de/001/paten ... 24_Wah.pdf

analogguru

[The Rotagilla]

I assume that you measured the resistor values in-circuit (470k/360k) ?

Values were measured in circuit. Unfortunately it isn't mine to take apart.

[Torchy]

IIRC this was mooted ages ago on Aron's and they were 2N2925's (ECB pinout though) ... may be in archive somewhere ...

[The Rotagilla]

IIRC this was mooted ages ago on Aron's and they were 2N2925's (ECB pinout though) ... may be in archive somewhere ...

Found...thanks.

[noelgrassy]

Yep, those photos are the bee's knees Rotagilla. Is your camera one of those little digitals or an SLR? With respect to the circuit, I've seen alot of different caps in the 3.9uf's position. Is this tantalum cap polarized? I have a Cry Baby from the same period that I've modded so many times I can't remember what was there in the first place. Mine uses a Molex type connector to sum all the leads though. Same colored board, inductor, carbon comp R's, and those poly [?] caps.

[soulsonic]

Yes, the tantalum is polarized. The side with the white dot on it is the positive.
Bajaman has suggested on numerous occasions that a nonpolar film cap in that spot improves the sound.

[noelgrassy]

Thanks soulsonic. I thought that white mark was the "9" and the orange the"3". Is there a prefered manufacturer or use any of the many tant types currently manufactured.

[soulsonic]

Well... personally, the only Tantalum that ever impressed me is the Sprague 150D - they are of incredible quality, and I've had excellent results with them.

[Redhouse]

IIRC this was mooted ages ago on Aron's and they were 2N2925's (ECB pinout though) ... may be in archive somewhere ...

Yeah, EdG said they were 2n2925's a few times on DIYSBF.

I have been trying to verify that ever since (and cannot, so far) maybe Ed can chime-in and tell us where he found out.

[The Rotagilla]

Yeah, EdG said they were 2n2925's a few times on DIYSBF.

Actually, I think it was stated that the 2N2925 was the current production equivalent.

[Redhouse]

Yeah, EdG said they were 2n2925's a few times on DIYSBF.

Actually, I think it was stated that the 2N2925 was the current production equivalent.

Well ok, but if you do a search on 2n2925 over there, you get exactly 4 hits, the oldest (April 06, 2006) is the first one EdG mentions the x-ref:

http://www.diystompboxes.com/smfforum/index.php?topic=35742.msg319769#msg319769

"...The 2n4401 to me sounded closest to the "5117" trannys, which I found out X-ref to 2n2925..."

and the next oldest one is January 18, 2006:

http://www.diystompboxes.com/smfforum/index.php?topic=41000.msg295567#msg295567

"The "5117" is a Thomas Organ part number. It won't cross-reference to anything, but it is actually a 2N2925"

then the last two hits are other DIYSBF members now re-referencing EdG's earlier posts as current fact. Don't misunderstand me, my only concern in verifying things is that a couple posts doen't exactly make something a fact (except on the iNet, were things can run away over a word)

I like the idea that EdG seemingly has an answer for the mystery 5117 transistor, but I hope we can validate that ticket if you know what I mean?

No harm intended to Ed or any of the others that have posted citing the x-ref to 2N2925, but as Jack Webb used to say "Just the facts m'am"

[Torchy]

From http://www.organservice.com/thomas/thomas.htm the prefix for transistor part numbers is '86-'

Checking http://www.organservice.com/SearchPart.htm with part number '86-5117' we get

86-5114-2 TRANSISTOR, NPN 2N2924
86-5115-2 SUB 71447-003
86-5116-2 TRANSISTOR, NPN 2N3404
86-5117-2 ORDER PART#71226-015
86-5118-2 ORDER 550-033-00 2N2925

2N2925 is on the next line though ...
The Cross-Reference package costs $79.00 but I'm not that curious ...
http://www.organservice.com/crm/crossreference.htm

[analogguru]

No harm intended to Ed or any of the others that have posted citing the x-ref to 2N2925, but as Jack Webb used to say "Just the facts m'am"

I like this....

so let´s go to the facts:
There was a period where Thomas Organ of Vox had a production run of Wahs. In this period of time they also produced the King Vox-Wah, the Stereo Fuzz-Wah the Cry-Baby 95-910511 and some boosters.

In the factory schematic of one of the boosters - the V8161 - is written for the used transistors: 86-5050-2 Transistor (2N 2924)

The schematic of the V8162 is nearly identical to the Stereo-FuzzWah and in ther service information is written: 09-5961-0 Transistor.
De facto were used BC 208A as you can see here:

In the original schematic of the Stereo-Fuzz-Wah somebody wrote for this transistors: 5117
The Wah transistors were marked as: 5115

Interesting.... as Torchy wrote:

86-5114-2 TRANSISTOR, NPN 2N2924
86-5115-2 SUB 71447-003

A logical result could be: 5115: 2N2925
and:

86-5117-2 ORDER PART#71226-015
86-5118-2 ORDER 550-033-00 2N2925

a 5117 could be a 2N2924

An intersting situation: we have 5115 and 5117 - whatever they are.
The case of 2N 2924 and the case of 2N 2925 are the same as used for the 5117.

BC 208A: 20V/200mA/300mW ß: 125-260/2mA fg>150Mhz
2N 2924: 25V/100mA/360mW ß: 150-300/2mA fg: 200Mhz
2N 2925: 25V/100mA/360mW ß: 235-470/2mA fg: 200Mhz

2N 2924 and 2N 2925 differ only in the ß. But a 2N 2924 could also be a 2N 2925. that´s is nothing uncommon, cause it is the same chip from the same wafer which is selected for the desired specs.

The original patent application calls for Q1 : 2N 3900A and Q2: 2N 2924
2N 3900A: 18V/100mA/360mW ß: 250-500/2mA fg: 160MHz

hmmm... 2N 3900A has a similar ß than the 2N 2925.... so it could be replaced... which would result in a combination 2N 2925 and 2N 2924.

Hmmm....why not use 2 x 2N 2925 ?

so this are the facts .... now its up to you which transistors you like to use.

analogguru

[Redhouse]

From http://www.organservice.com/thomas/thomas.htm the prefix for transistor part numbers is '86-'

Checking http://www.organservice.com/SearchPart.htm with part number '86-5117' we get

86-5114-2 TRANSISTOR, NPN 2N2924
86-5115-2 SUB 71447-003
86-5116-2 TRANSISTOR, NPN 2N3404
86-5117-2 ORDER PART#71226-015
86-5118-2 ORDER 550-033-00 2N2925

2N2925 is on the next line though ...
The Cross-Reference package costs $79.00 but I'm not that curious ...
http://www.organservice.com/crm/crossreference.htm

Ah, I see the connection now, thanks Torchy, and analogguru and of course EdG.

So putting 86-5117 in the search function at http://www.organservice.com/SearchPart.htm we get 71226-015, then putting that number in again gets: 2N2925

86-5117-2 x-ref's to: 71226-015, which x-ref's to: 2N2925
and
86-5118-2 x-ref's to: 550-033-00, which x-ref's to: MPS2925

I can see what EdG was saying and that's verification enough IMO.

Additional google'ing finds this interesting datasheet from General Electric Semiconductor Data Handbook 1977 has the 2N2925 listed and the little drawing in the upper right corner shows the package style (TO98) like the 5117 transistors had:

http://www.datasheetarchive.com/pdf/221074.pdf

also interesting is that Mouser x-ref's 2N2925 to Fairchild's BC184L and (much less interesting) to NTE123A