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January 26, 2015, 12:21:51 AM
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DIYstompboxes.com  |  DIY Stompboxes  |  Building your own stompbox  |  What transistor to replace HEP-50 for the "Glidophone"? 0 Members and 1 Guest are viewing this topic. « previous next »
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Author Topic: What transistor to replace HEP-50 for the "Glidophone"?  (Read 2092 times)
Posts: 352

What transistor to replace HEP-50 for the "Glidophone"?
« on: October 11, 2007, 07:52:58 PM »

Any ideas what would work?
Posts: 1568

Re: What transistor to replace HEP-50 for the "Glidophone"?
« Reply #1 on: October 11, 2007, 08:00:29 PM »

Try a 2N3904 or a 2N5088. You'll have to match the pinouts, because those are TO-92 plastic cases and the HEP-50 was TO-18 metal.
Posts: 550


Re: What transistor to replace HEP-50 for the "Glidophone"?
« Reply #2 on: October 11, 2007, 08:09:30 PM »

I think the HEP-50 is a fairly generic NPN Silicon transistor.  One site I found listed the NTE123A as a replacement.

The 2N3904 and 2N5088 suggestions are a good place to start.
Mark Hammer
Posts: 22351

Re: What transistor to replace HEP-50 for the "Glidophone"?
« Reply #3 on: October 12, 2007, 08:46:17 AM »

You're not gonna believe this, but part of my commuter bus reading material in my briefcase today was a Motorola HEP Semiconductor catalog from 1973.  (One of these days I should attempt to scan and post it because it's only about 90 pages of material.  If I could do it for the Jack Darr book, I can do it for this.)

The NPN HEP-50 is the very first transistor in the listing.  Its listed specs are as follows:
Collector-Base voltage - 25
Collector-emitter voltage - 15
Emitter-base voltage - 4.0
Collector current - 300ma
Total device dissipation - 400mw
Operating junction temperature - 175 C max
Typical cutoff frequency - 250mhz
Typical current gain (hfe) - 85
Typical collector cutoff current - 100na, 20v

A quick scan through the cross-reference listings shows it as being a "replacement" for the following devices:
2N431/32/33, 2N702/703/706/708/709/715/717/728/729/742-thru-762/770-thru-779/783-thru-793,
2N834/835/839-thru-834/866/867, 2N909/913/914/916/919/920/921/922/929/930/947/988/989,
2N1663, 2N1708/1764, 2N1958/1958/1962/1963/1964/1965/1992, 2N2205/2206/2242-thru-2257,
2N2318/2331/2368/2369, 2413/2427/2432/2466/2481, 2N2501/2529-thru-2540, 2N2618, 2N2938/2952, 2N3009,
2N3242/3246, 2N3340/3341, 2N3462/3463, 2N3510, 2N3607/3646, 2N3825/3843/3880,
2N4138, 2N4259/4264/4265/4274/4275, 2N4419/4421/4449, 2N5131/5133/5186

2SC16/17/18, 2SC33, 2SC55/56, 2SC62/63, 2SC80, 2SC98/99, 2SC103/104, 2SC132/133/135/137,
2SC155, 2SC166-thru-171, 2SC203/204, 2SC237, 2SC321/323, 2SC350, 2SC360, 2SC371, 2SC395,
2SC425/426, 2SC621/622

AC124, BC108, BC119, BC125/129/130/131/132

I'll stop there because my eyes are going googley from staring at tiny numbers in columns.  No listing is given for the venerable 2N5088.  Seeing the 2N5133 and BC108 (and the 108A/B/C are cross referenced to something else), though, I'm inclined to think that a 2N5088 would probably work, though obviously a high hfe one is not required.
Posts: 1184

brian hamilton

Re: What transistor to replace HEP-50 for the "Glidophone"?
« Reply #4 on: October 12, 2007, 09:11:40 AM »

maybe a 2n2222a, i usually find nte123a to be a common replacement for those on mouser...

Posts: 352

Re: What transistor to replace HEP-50 for the "Glidophone"?
« Reply #5 on: October 12, 2007, 04:25:29 PM »

Wow! Thanks a lot guys (Ecspecially Mark, that is quite a  coincidence). I'll give it a go. It'd be nice if a 2n5088 would do the trick.
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