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|2/1/2001 4:34 AM|
||Ever hear of a N913 transistor?|
I bought a pack of NPN switching transistors at Radio Shack and started building a few effects out of them, all distortion so far. Has anyone ever heard of a N913 or a N824 transistor?
I've used the N824 to build an Electra Distortion, and am currently working on a Vox Tone Bender with the N913. Is the 47k resistor between the base of Q1 and the emitter of Q2 a feed-back path? If so, what will using a 10k there do? I didn't have a 1k pot handy, so I put a 2.2k in place of the 1k and the 820 ohm. On the output I'm planning to eliminate the 47k to ground. What is that there for? Is it to reduce the output?
|2/1/2001 8:03 AM|
Hey Chris, A lot of those #s in the R Shack multipacks are not trace-able. They were probably bulk purchases of leftover stock from manufacturers who had special part #s made for them. they might fit into the specs of the trannies listed on the package, they might not. Best to build your devices with sockets so you can swap a few in and out to see what sounds good.
If I were you I would at least put a trim pot [100K, perhaps?] in place of the 47K to ground so you can play with the gain of that tranny, see what happens. I wouldn't just leave it out, though.
I will let the more educated among us explain exactly what the function of that resistor is.
Same thing with the 47K between the Q2 emitter and Q1 base, build it stock ,and then deviate from there. As a reference, Fuzz faces have 100K in that position. You know, Fuzz Face and Vox tonebender= very similar.
I checked those tranny #s on my ECg cross reference, and the n824 shwed nothing, but when I leave off the 'n' it comes up as ECG 123, an NPN silicon amp trans.
The other # was a dud.
|2/2/2001 4:08 AM|
Thanks for the advice on the 47k's. I think that I'll put the 100k between Q1 and Q2, as in the Fuzz Face. As far as the 47k on the output, I'll try a 100k, then if I don't like it I'll go with a smaller value.
Some of the Radio Shack transistors don't have the ECB markings on the case. How do I figure out which leads go to what? Is there any way to test them with a DMM?
|2/2/2001 4:17 AM|
For most standard trannies the pinout is the same [usually] . Those packs that RS sold you should definetely all have the common pinout.
Here's my memory aid;
Look at the bottom, pins facing you. Make a " D', E is on the bottom-- D rhymes with E
Base is the middle, just like on schems.
|2/2/2001 1:46 PM|
Thanks! I'll have to try some of those other transistors now! I was only using the n913 and n824 because they were labeled!
|2/2/2001 7:45 PM|
I got those 47k resistors today. I went to the mall to eat and went in Radio Shack while I was there. I also got a 1k trimmer pot for the circuit. Has anyone used one of these in a circuit?
|2/2/2001 8:39 PM|
Where are you thinking of putting the 1K trimmer?
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