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DIY Stompboxes => Building your own stompbox => Topic started by: mac on October 24, 2006, 11:59:38 AM

Title: 2N3440, 2N1613. Nice low-gain NPN Si
Post by: mac on October 24, 2006, 11:59:38 AM
I've found this transistors when I was testing Tone Benders MKII & 3-knob Si versions.
hfe: 40 - 120/160.
An alternative to the 2N2369 used in the Axis Face that can pick some RF.
Another with the same hfe is 2N2218.

In the 100-300 range I tried 2N2219 & 2N1711. My Si FF is made with a couple of 2N2219 (hfe: 110 & 117)


mac
Title: Re: 2N3440, 2N1613. Nice low-gain NPN Si
Post by: birt on October 24, 2006, 12:04:38 PM
i've got loads of those 2N1613..so they are low gain?
Title: Re: 2N3440, 2N1613. Nice low-gain NPN Si
Post by: Dragonfly on October 24, 2006, 12:08:31 PM
also...look at 2N3903...they're cheap, easy to find, and all of them that ive tested (probably around 500 of them) have been in the 90-125 hfe range...really good for fuzzes....
Title: Re: 2N3440, 2N1613. Nice low-gain NPN Si
Post by: mac on October 24, 2006, 04:05:13 PM
Quote
i've got loads of those 2N1613..so they are low gain?

Well, you know, datasheets and the real thing sometime differs a lot. I have some 2N5088 with hfe<200, out of specs.
My 2N1613 are in the 40 - 120 range.

Quote
also...look at 2N3903...they're cheap, easy to find, and all of them that ive tested (probably around 500 of them) have been in the 90-125 hfe range...really good for fuzzes..

I tried to get some of these but I could not find them. There are others Si with low-gain to be used in early fuzzes, mostly metal can low power devices, 2n1893, 2n2102, 2n2193, 2sc1213 B, etc.

mac
Title: Re: 2N3440, 2N1613. Nice low-gain NPN Si
Post by: Bernardduur on October 24, 2006, 04:34:24 PM
I use BC140's a lot
Title: Re: 2N3440, 2N1613. Nice low-gain NPN Si
Post by: zjokka on October 24, 2006, 07:38:52 PM
hi all low-gain hunters,

I was wondering: when I experimented with the Multi Fuzz (SI) I tried out a whole bunch of transistors, and I noticed clear difference between different types of transistors with identical gain. Did you guys find any that had perfect gain (80-120) but crappy sound or were unstable, susceptible to RF, oscillations or motorboating etc...

or are these just a result of high gain?

When piggybacking silicons, I found the circuit very stable and no noticeable sonic difference in the transistors used.

zj

Title: Re: 2N3440, 2N1613. Nice low-gain NPN Si
Post by: mac on October 24, 2006, 08:23:04 PM
When I built my Si FF I tried low-gain transistors, 2n2369, bd139, bd237, mpsa42 and 2n2219, all between 65 and 125. They all worked nice, but there were some audible differences among transistors or combinations.
The 2n2369 area good chioce but they pick a lot of RF. Anyway I decided for the 2219 for their fat fuzzy sound.


mac
Title: Re: 2N3440, 2N1613. Nice low-gain NPN Si
Post by: Dragonfly on October 25, 2006, 12:43:46 AM
Quote from: mac on October 24, 2006, 04:05:13 PM
also...look at 2N3903...they're cheap, easy to find, and all of them that ive tested (probably around 500 of them) have been in the 90-125 hfe range...really good for fuzzes..
Quote
I tried to get some of these but I could not find them.

mac

digikey  ...  http://www.digikey.com/scripts/DkSearch/dksus.dll?KeywordSearch (http://www.digikey.com/scripts/DkSearch/dksus.dll?KeywordSearch)  ...not stocked, but available

mouser ...  http://www.mouser.com/search/refine.aspx?Ntt=2n3903 (http://www.mouser.com/search/refine.aspx?Ntt=2n3903)  ...in stock, a whopping $.09 each for the  Fairchilds !  ...............unless your like me and buy in quantity....$.04 each in a quantity of 250, so $10.00 plus shipping gives you 250 USEFUL transistors !

most every other supplier should have some, but mouser and digikey definitely do....

heres a pdf of info on the 2n3903's ....  http://www.fairchildsemi.com/ds/2N/2N3903.pdf