Suggestions for low hfe PNP silicon transistors?

[davent]

On hand i have some BC560's, MPSA92's and 2N3906's. Plan to visit a few shops on the weekend and have come up with 2N3905's, 2N4402/3's and 2N2907's (that in a nice little can package, TO-18), all to keep an eye out for.

Any others to add to my shopping list, especially those that come in not so common packages. Have loads of different low gain NPN's in a big variety of shapes and sizes and would like get some low gain PNP eye candy as well to try in a Rangemaster in conjunction with some odd looking Russian ge PNP's.

Thank you!
dave

[Pyr0]

From my stock, keep an eye out for some 2n5401 (Hfe ~ 150), or some cool looking button/mushroom BC205 (Hfe 100-150)
I have a bunch of metal can PNP's with ranges from 60 to 120, but they are unmarked - was a lucky dip buy.

But if you are going to build a silicon rangemaster, I would just use some of your low gain NPN's and reverse the polarity of the electrolytic caps and the power. It will give you a much better range to choose from, plus you won't have any problems daisychaining the power with other pedals.

alltransistors.com is good for finding similar transistors.
Check this link out http://alltransistors.com/crsearch.php?mat=Si&struct=PNP&pc=&ucb=30&uce=30&ueb=3&ic=0.6&tj=135&ft=10&cc=20&hfe=60&caps=

Edit: Oops, you might want to play around with the search parameters on that site, that search returned 1000's of hits.

[davent]

Thanks Alan, i've added those to my shopping list.

The Rangemaster schematic i want to play with is a hybrid using a GE PNP with a Si PNP. I have a baggy of low hfe  Russian Ge PNP's to play with, going to try them in a Darlington setup as well as the hybrid. Will be running  with a charge pump negative rail to help it get along with other pedals.

http://revolutiondeux.blogspot.ca/2012/04/fred-briggs-rangemaster-mkii-build.html

[PRR]

Get some 2N3055.

Yes, these are big. Old ones had low Beta. New ones have decent Beta at the high currents the monster package suggests, but lower Beta at the much smaller currents used in pedals.

[davent]

^Thank you, I've one of those kicking around to sample, might be tight in 1590A.

[davent]

Back from shopping and only now come across this. http://www.beavisaudio.com/techpages/Transistor-Pinouts/index.htm

Oh well...

[digi2t]

I've used a 2N2904A in a Rangemaster circuit, and a 2N2905A as Q2 in a fuzz circuit with good results. I especially like the 2N2905A. I found the 2N2907's too harsh (ice-picky highs).

The 2N2904's generally run an hFe in the mid 70's, and the 2N2905's are in the 150 to 175 range.

[davent]

Thanks for that, i was able to come home with some 2N2905A's, 2906A's, 2907A's, 2N3905's and some 2N4403's so have a measured range of hfe's from under 100 to over 200 (the 2N2907's), should be able to come up with something from all the different ones i now have, to go with my Soviet Ge's. Hopefully the 2905A's are as sweet sounding as they are funky looking.

dave

[reveal]

FYI, This article at smallbear describes pairing up resistors.  Link is in next post...  Dumb  

[reveal]

This article at small bear talks about pairing low gain germanium with other germanium and also low gain silicon, the concept of darlington pairs and Sziklai pairs would also apply to all silicon pairs. 

https://www.smallbearelec.com/HowTos/GeDarlingtons/GeDarlingtonPairs.htm

[brett]

Hi
I've used BD140s (and npn BD139s) a lot to replicate vintage silicon devices. hFE is usually around 150 (they are labelled into ranges, but I haven't seen many that are lower than the 'high' range (~150)).

ps they are power transistors (a couple of watts), and like TIPs, 2N3055s and other power devices they have low hFE, high cutoff currents, high capacitance (by small signal standards) and other characteristics just like older transistors.
cheers

[IvIark]

2N3703's are very low gain, 30 to 150 hfe in the datasheet

[davent]

Have breadboarded the Sziklai and will revisit that with the new selection of transistors. Haven't tried the darlington Ge pair yet or the Ge->Si mixed setup  but hope to get to them soon.

Added the BD140 and 2n3703 to the next shopping list, (do have some of the BD139's).

How 'bout some of the TIP transisitors, TIP30, anyone experimented them?

MJ2955?

Thanks all!

[Gus]

Years ago I posted about using a TIP29 as the transistor for a treble boost circuit like a RM.  Or the first stage transistor in a FF.  Med power devices can sound nice in boosts and fuzzes and overdrives and...

[pinkjimiphoton]

some of the tips are hissy as hell in fuzz circuit, my drummer gave me a whole bunch of them... i was really psyched until i tried them.

these guys are closed on sundays, but have some nos low gain pnp ge's WICKED cheap... hfe's between about 30 and 150.

i bought 50 of 'em, enough to last me a long time, so, what the hell..my secret's out. bet they won't have 'em very long once i hit "post".


sorry, don't remember the part numbers, but once you go there, it should be obvious.

[Plexi]

Reborn thread!
I received for error four KSP92, hfe around 40.
I saw this ones can handle a lot of voltage... tomorrow I'll try, I hope they fix my "oscillation machine" Fuzz Factory.