ok so im goin to put POLARISED 1uf CAPS instead of the non polarised ones and i dont know how to oriented them ???
should be this way?:
the second one after the IC is oriented that way on the sd1 schematic, but what about the first one???? ??? ??? ???
(http://i202.photobucket.com/albums/aa19/omarhowe/egwg.jpg?t=1280889971)
Hi
the second cap has almost no polarisation. A 1 uF polar cap in any orientation often works in this situation, but not perfectly.
The first cap seems to run from more negative on the left to more positive on the right (approximately Vb-0.7V on the left and Vb on the right).
Given the low cost of the caps, it seems a bit strange to go polar. Can you busk and earn that extra $1 ???
cheers
Quote from: brett on August 04, 2010, 12:05:12 AM
Hi
the second cap has almost no polarisation. A 1 uF polar cap in any orientation often works in this situation, but not perfectly.
The first cap seems to run from more negative on the left to more positive on the right (approximately Vb-0.7V on the left and Vb on the right).
Given the low cost of the caps, it seems a bit strange to go polar. Can you busk and earn that extra $1 ???
cheers
thanks for the reply
the thing about going polar it's just because of time, i want to finish this today with the materials i all ready have. :icon_mrgreen:
Omar
Signal flows from - to +, so your scheme is OK. I did it like this in my own Screamer.
You're building another screamer?
Doesn't look to me like the schematic shows polarity.
A non-polarized cap will work there.
2 polarized caps can be assigned so there is a +/_ at either end [ paralleled ] or + at both ends [series, -'s in the middle] and = 1 nonpolar capacitor.
2x value [parallel].
1/2value if seriesed...correct me if I'm wrong on the value of the 2 equal value seriesed capacitors. I vaguely remember some related equation, whatever...it'll be a smaller value and will be nonpolar.
Two ways you can figure it out
1st Look at the EF input buffer note the bias is not offset from 1/2 power supply voltage. The emitter will be lower than 1/2 the power supply voltage. The input to the opamp should be close to 1/2 the power supply VDC. So - to emitter
Out of the opamp should be almost the same at both ends of the cap so it does not matter
2nd Take you DMM set to VDC and place the probes at the cap solder pads. What if any side is more + than the other?
Quote from: WLTerry on August 05, 2010, 03:48:41 PM
Omar
Signal flows from - to +, so your scheme is OK. I did it like this in my own Screamer.
You're building another screamer?
yeah, i building one for a friend's studio.
mmmm hey but look what gus said, i measured the voltage on emitter and in the input of the opamp... the emiter reads(more or less) 3v and the input 5v
Quote from: Gus on August 05, 2010, 06:32:45 PM
Two ways you can figure it out
1st Look at the EF input buffer note the bias is not offset from 1/2 power supply voltage. The emitter will be lower than 1/2 the power supply voltage. The input to the opamp should be close to 1/2 the power supply VDC. So - to emitter
Out of the opamp should be almost the same at both ends of the cap so it does not matter
2nd Take you DMM set to VDC and place the probes at the cap solder pads. What if any side is more + than the other?
you are right gus i measured the points between the caps .
ok so by far it will be like this?:
(http://i202.photobucket.com/albums/aa19/omarhowe/Copiadeegwg.jpg?t=1281052502)
that 10k resistor to Vb is rather small, you will definitely get away with replacing it with a 100k and use a 100n poly cap instead, if you find that easier.