#1
I couldn't find the EXACT transistor I was looking for (J201) and as I was already at the place, I bought the transistor that I thought out of the ones they had, would be the closest match.

The MPF102. Yep. Radio shack doesn't carry J201's anymore. Not even On-line. I didn't want to buy from Mouser or somewhere and pay $15 for handling when I was happy to buy one transistor at $1. In fact, this transistor was the ONLY one in the bin(s) marked as a JFET on the tag.

anyways. will this work in place of the J201?

(exact schem: Discrete FET Guitar Preamp )

If it would sound clean, or slightly distorted (but smooth and not sharp) I'm good with that.
STUFFZ:
SAGA ST10, IBANEZ(s): '96 ZR140BK (korea), '96 RX20 (indonesia)
Danelectro Cool Cat CC1 Chorus
Digitech Bad Monkey
Behringer BX1800A (180w 12" aluminum cone)
FOR SALE: Fender Champion 110 (25w RMS combo 10" with tank reverb)
#2
You can get J201's from Small Bear for $0.30 a piece and shipping is about $1 to $3. I ordered a buttload of trannies and ICs from them and my total price was $11.

If the transistor is an N-channel FET then it'll work fine. A J201 is prolly going to be quieter, though.
Last edited by Invader Jim at Mar 9, 2008,
#3
It will work fine, but slightly less output (from memory).
"Everybody, one day will die and be forgotten. Act and behave in a way that will make life interesting and fun. Find a passion, form relationships, don't be afraid to get out there and fuck what everyone else thinks."
#4
I truly didn't realize before how inexpensive it is to build a preamp of this sort. Some electronics components are cheap.
STUFFZ:
SAGA ST10, IBANEZ(s): '96 ZR140BK (korea), '96 RX20 (indonesia)
Danelectro Cool Cat CC1 Chorus
Digitech Bad Monkey
Behringer BX1800A (180w 12" aluminum cone)
FOR SALE: Fender Champion 110 (25w RMS combo 10" with tank reverb)
#6
here's the board. later it gets tested. (as in, when this post is done)
please excuse the dirty keyboard.



it may look like the leads from any of the components may be touching where they are not supposed to at that angle, but I assure you their not.
STUFFZ:
SAGA ST10, IBANEZ(s): '96 ZR140BK (korea), '96 RX20 (indonesia)
Danelectro Cool Cat CC1 Chorus
Digitech Bad Monkey
Behringer BX1800A (180w 12" aluminum cone)
FOR SALE: Fender Champion 110 (25w RMS combo 10" with tank reverb)
#8
nope. the wires are soldered on the bottom. but I liked the layout because it was cheap and small.
STUFFZ:
SAGA ST10, IBANEZ(s): '96 ZR140BK (korea), '96 RX20 (indonesia)
Danelectro Cool Cat CC1 Chorus
Digitech Bad Monkey
Behringer BX1800A (180w 12" aluminum cone)
FOR SALE: Fender Champion 110 (25w RMS combo 10" with tank reverb)
#10
That is one dirty-ass keyboard :x
And maybe we can fly away from here, surf on the debris of a broken scene...
#11
well the tip on my soldering gun doesn't work as well as I'd like, and I didn't want to make a mess lol. It was a more lazy approach.
STUFFZ:
SAGA ST10, IBANEZ(s): '96 ZR140BK (korea), '96 RX20 (indonesia)
Danelectro Cool Cat CC1 Chorus
Digitech Bad Monkey
Behringer BX1800A (180w 12" aluminum cone)
FOR SALE: Fender Champion 110 (25w RMS combo 10" with tank reverb)
#12
it's not even worth cleaning. it's like old seals on a car. change the oil too frequently and you'll do more harm. I'm afraid of this crap getting loose and lost underneath if I try to clean it.
STUFFZ:
SAGA ST10, IBANEZ(s): '96 ZR140BK (korea), '96 RX20 (indonesia)
Danelectro Cool Cat CC1 Chorus
Digitech Bad Monkey
Behringer BX1800A (180w 12" aluminum cone)
FOR SALE: Fender Champion 110 (25w RMS combo 10" with tank reverb)
#14
yeah. if I feel like it I can de-solder them all and re-lay it out actually using the copper etching. but yeah, anyone who knows me would say the way I did it is my style.

edit: for the sake of not double posting...

the first circuit I did outside of general guitar wiring would have been the DOD 250 I modded back in the day.
STUFFZ:
SAGA ST10, IBANEZ(s): '96 ZR140BK (korea), '96 RX20 (indonesia)
Danelectro Cool Cat CC1 Chorus
Digitech Bad Monkey
Behringer BX1800A (180w 12" aluminum cone)
FOR SALE: Fender Champion 110 (25w RMS combo 10" with tank reverb)
Last edited by jedilley at Mar 10, 2008,
#15
Quote by jedilley
yeah. if I feel like it I can de-solder them all and re-lay it out actually using the copper etching. but yeah, anyone who knows me would say the way I did it is my style.


Kind of like jumping through a window instead of using the door?
#16
not really. in that situation, using the door is much easier than working with the window. In this example, soldering the wires on the bottom together was easier than a bad tip on a soldering Iron trying to solder in small areas without overlapping. -- I'm not amazing with solder, so, go with what you know. lol

although, one punk I knew (true to the adjective) made a pact one drunken night not to ever use the front door of his apartment. living on the second story he decided to use the window (and subsequently the ?soft? bushes.) what a character.

and sometimes when my wife accidentally locks us out of the room, I do use the window to get back in.
STUFFZ:
SAGA ST10, IBANEZ(s): '96 ZR140BK (korea), '96 RX20 (indonesia)
Danelectro Cool Cat CC1 Chorus
Digitech Bad Monkey
Behringer BX1800A (180w 12" aluminum cone)
FOR SALE: Fender Champion 110 (25w RMS combo 10" with tank reverb)
Last edited by jedilley at Mar 10, 2008,
#18
I taped the piezo pickup to the body (the top horn on the back) wired it all up and ran the output to a set of powered desktop speakers. I suppose that because the desktop speaker amplifier requires a bigger signal is the reason it wasn't very loud, BUT - it doesn't sound bad!

so yeah. MPF102 in place of J201 and R3 used a 5.8K resistor... because I thought the green band was blue. it's "supposed" to be a 6.8k

it works. later tonight I'll jerry-rig it up to the output jack and have a go at it in a PA.

if it sounds pretty good, I'll finish up the job by mounting the board in the guitar, getting another piezo, and trying pickup locations + wiring in series for more signal.

I *could* run it to the mic in on the computer. quality would be low of course, but it would get a general idea goin.
STUFFZ:
SAGA ST10, IBANEZ(s): '96 ZR140BK (korea), '96 RX20 (indonesia)
Danelectro Cool Cat CC1 Chorus
Digitech Bad Monkey
Behringer BX1800A (180w 12" aluminum cone)
FOR SALE: Fender Champion 110 (25w RMS combo 10" with tank reverb)