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DIY Stompboxes => Building your own stompbox => Topic started by: nightingale on April 06, 2004, 09:13:18 PM

Title: flashing LED EA tremelo problems again.. voltages posted
Post by: nightingale on April 06, 2004, 09:13:18 PM
this circuit has been giving me alot of problems~
so i put it on the shelf for a while.. i built it eacltly to the specs at: http://runoffgroove.com/eatremolo.html

it's the one with the flashing LED..(gez's mods)..

i just got some higher gain tranny's in the mail 2n5089/88... i thought i might not be getting Q3 to kickstart the oscilator.. but the high gain tranny's arent doing the trick either..

here are some voltages of the 2n5089 in the Q3 position:

2n5089: hfe 753

battery: 9.47v

C:         6.61
B:         2.18
E:          5.95-6.0 not stable...

drain of the mosfet:   4.49v

i'm really stumped here, i am building this for a friend.. any help would be appreciated..
thanks,
Title: flashing LED EA tremelo problems again.. voltages posted
Post by: B Tremblay on April 06, 2004, 09:34:14 PM
First, is there any signal making it out of the circuit?  Are you sure of the orientation of each transistor?

The emitter of Q3 should be at zero volts since it connects to ground.  Check the wiring around there.
Title: flashing LED EA tremelo problems again.. voltages posted
Post by: RDV on April 06, 2004, 09:35:50 PM
What type caps are you using for the 1uF?

Regards

RDV
Title: flashing LED EA tremelo problems again.. voltages posted
Post by: nightingale on April 06, 2004, 10:01:18 PM
thanks guys~
i get a signal, that will even go louder than unity.. but no trem!
i will do downstairs and look at the tranny wiring again.

rdv~
i am using iuf electros..
Title: flashing LED EA tremelo problems again.. voltages posted
Post by: nightingale on April 06, 2004, 10:15:05 PM
ok ok~
i forgot to ground Q3..:oops:  thanks a million B..! i guess it's been a while since i've built on perf.. kinda used to all of the offboard connections  coming off the top off the board(PCB style)..

actually, i can't beleive how damn good this little trem sounds, it's really quiet, and the trem effect is very authentic.. nice project B..!
Title: flashing LED EA tremelo problems again.. voltages posted
Post by: gez on April 07, 2004, 03:38:15 AM
Glad you got it going Ryan, but just for the record the LED mod isn't mine, I merely suggested using a MOSFET for the amp.
Title: flashing LED EA tremelo problems again.. voltages posted
Post by: B Tremblay on April 07, 2004, 07:45:22 AM
I'm glad you figured it out!  This a great example of why posting voltages helps tremendously.