i have been going through a diagram for a guitar compressor pedal (vox 1903), and came across a symbol that i thought was a capacitor, but rather than the two lines, it is boxed in and has slashes in it. but what threw me is that rather than being listed in farads, they are marked as 16v10 or 16v1. can anybody point me in the right direction?

edit: also what is the difference between JFET and regular transistors and are there any substitutions? the only thing i can find on radio shacks site that is listed as jfet is an op-amp that has a JFET input.

 

Do the slashes have an arrow on the end?

Are the slashes a solid line or a dashed line?

 

like this

 

I believe the symbols means they are 16V capacitors with a 1% tollerance or a 10% tolerance..

Is this the diagram??

 

It's odd, there's two different symbols given for capacitors. Might be an obsolete symbol for a different type of cap, one is shown as polarized. Maybe these are just caps being used as suppressors, the lines are going the same direction and spacing as the ground markings, and the majority are going between the ground and a component.

 

I'm shakin' that cobbwebs loose, here.

Would that be a 'choke' or 'coil', possibly!?!?!?!?

Dang. . . it's been 35 years since I've messed with circuits like that.

 

I asked your (muscletruck) questions to my uncle, an electronics design engineer with
around 40 years experience in the field. His replies:

=====
BTFOOM on the component. Could be an Asian version of a capacitor.

JFETs are high resistance inputs, regular transistors are low input resistance. In all
likelihood there are substitutes. I use both JFETs and transistors, both polarities. What is
its part number, do you know?
=====

 

That symbol looks like it could mean a toroid coil, but if it does, it's not the proper symbol.

Jason

 

It has been a long time since I was up on EE work...


Usually the end plates of the cap symbol are bold or darker or extend past the slash marks.

The Cap symbol with slashes is most likely an electrolytic capacitor. Older desings were polarized. I also think that symbol is old or not current standard or could be a "Chinglish" schematic. Reading the notes on the schematic make it clearer. "All caps are in Microfards", so 16V 10 would be 16 volt rated and 10 microfarads.

JFETs are Junction Field Effect Transistors, the most common type now a days. Usually just called a FET. The older BiPolar Transistors were usually NPN or PNP, P and N denotes the polarity of the material.

FETs are very high impedance input, ie they don't load down a weak signal as much as most BiPolars would.

In General FETs and BiPolar transistors are NOT interchangeable. In specific, most transistors of different part numbers are also NOT interchangeable. However, many components are close enough for substitution, but you have to understand some basic electronics to make that judgement, or have a handy substitution manual. Haven't seen a substitution manual in a long time. Even radio Shack used to sell them, quite handy.

Hope this helps a bit.

Jim Henderson

Boy, looking over the schematic in more detail, there are several strange things. The component at the output jack J2 looks like a battery symbol and maybe a ground symbol on top of it. Note their ground symbols are also not standard. The 006P marking is odd, makes me think 006 picofarad cap which is extremely small and the symbol doesn't show a cap. The transistor part numbers I believe are mostly Japanese part number types and may be a beach to find here in the US. The transistor symbols are not standard US symbology from my memory but seem to be an old non standard US symbol for PNP type BiPolars. A FET Symbol has perpendicular output lines drawn in most cases. Normal BiPolars have angled lines but not connected at a point. This is definitely at least a part Chinglish.

 

thanks for all the help guys. and yes, that is the diagram, and it wouldn't suprise me if its poorly translated, also considering the date, 1981. im thinking that the evidence points to them being capacitors (they are also tagged with a c, sure wish i could find the reference tht goes with the diagram) so im gonna hope it doesn't fry the circuit if i try it that way...

 

IIRC
The boxes are indeed electrolytc caps 16 volt 1 or 10 microfarad as shown.
You do have to watch the polarity. Most of them seemed to have a + indicated.

All the transistors that I noted were regular NPN bipolar. If you google, you can probably find modern day equivalents.

The hashed boxes on the bottom are grounds -- it's an alternative convention, although these are a little out of the ordinary.

The box by the output jack would seem to be the battery that powers the darn thing. It's set up to only power it when something is plugged in. Not sure of the voltage -- I think that the number references the style.

The CA3080A is an old op amp of a type called an Operational Transconductance Amplifier (OTA). They work a little differently than normal op amps (Which doesn't matter here, the design is already done). If you need one, you may have a little trouble finding one, but I think that they're still available.

If you need parts, I'd suggest places like
jameco.com
bgmicro.com
digikey.com
mouser.com

The first two are hobbyist outlets -- their stock varies. The last 2 are industry suppliers, and they do have minimums on some items.

 

thanks ford2go, for clearing that up.

i have also found out today, in even more research, that if i substitute or use different parts, it rarely fries anything, it just produces a different sound. sometimes ok sometimes not. I wass reading about people completely changing the size of caps and resistors, eliminating diodes and what-not. which is good, and is part of the reason that I am interested in building my own.