ever hear of a 34418 transistor?

[pinkjimiphoton]

i found an old kay vanguard 708 guitar amp today, gonna be a few days until it comes in so no idea if i'll need them or not, but checking the schematic on prowess amps
http://www.prowessamplifiers.com/sch...ges/Kay708.pdf
it says q1 (2 of 'em actually... they use the same name for in some cases up to 5 transistors apparently) is 34418, but i've searched high and low and can't find anything at all about them.

i'm assuming it's a medium gain pnp germanium, but am not confident enough to be sure. the last kay amp the forum helped me with had a dead transistor in the second stage, so i'd love it if someone could please give me some info on these, so i can try and find a decent cross ref if i need to.

pretty sure the transistors themselves will be unobtanium.
thanks so much!!

[J M Fahey]

Not under that code but pretty certain that it's a Kay "house number" , useful for them for inventory control but most probably some Germaniun PNP transistor, popular in that era.

Meaning that loking at transistors used in other same vintage stuff might give you a clue as to what JEDEC code they actually were..

Search this table to pick suitable ones by parameters and function:
Jedec-code

That's the *easy?* part, then you'll have to actually find some

[Enzo]

Or wait until you have the amp and find out if we even need to know anything about the transistors.

You can easily tell if they are NPN or PNP (aside from the schematic) with your hand meter on diode test. Also same for germanium versus silicon. Silicon junctions measure ROUGHLY half a volt, while germanium junctions measure ROUGHLY 2/10 of a volt.

Unless they flat out don't work, or are burnt up, in my experience you will need to worry a lot more about the caps in the amp than the transistors.

[pinkjimiphoton]

Not under that code but pretty certain that it's a Kay "house number" , useful for them for inventory control but most probably some Germaniun PNP transistor, popular in that era.

Meaning that loking at transistors used in other same vintage stuff might give you a clue as to what JEDEC code they actually were..

Search this table to pick suitable ones by parameters and function:
Jedec-code

That's the *easy?* part, then you'll have to actually find some

well, lucky for me, the amp works. the tremolo is dead and it sounds like it needs a few caps replaced, but for all intents, sounds great!!
looked at some other schems from the series, looks like pretty much any pnp ge should do the trick if i need it.
thanks for the help JM....
as for the part numbers, i tried using a motorola cross ref cuz all the other transistors seemed to be motorolas... but no dice.
rock on!

[Mark Hammer]

Hi JImi,

There used to be a HYEEEEWWWWWGE cross-reference, printed in tiny font on thin onion-skin paper, which would list all the known house numbers, and cross-reference them to the manufacturer's number. Think of it like a super-immense NTE catalog.

Of course the last time I ever saw it was around 1987 or so, so I doubt it is in production in any form, let alone paper or even digital. When one considers the sheer number of house-numbers that have occurred since then, updating such a thing would be impossible.

At the same time, if you are trying to find out what actual device is lying under an older house-number, ask the techs in the nearest university, who may just have a copy of the 1980-whatever version sitting gathering dust in the corner. That's where I learned about it.

[pinkjimiphoton]

thanks for the tip mark!!

yeah, i believe it's gonna be hard to find. somewhere in a box, i have a whole set of cross ref guides for tubes and transistors from the 50's to the early 70's, but haven't seen it in years... either packed away still, or lost to the sands of time.

[Enzo]

Looking it up in an old ECG/NTE or SK series book might give a clue to what it is.