I decided to try and build a ruby amp as my first build, but i encountered a problem. In the schematic for the ruby, theres a wire that's labeled "in" that goes to the first pin in the transistor and I thought that meant the positive from the input jack, so I connected it like that and sent the ground from the jack to ground. All I got when I turned it on though was a hiss and some radio frequencies. The radio frequencies makes think that the amplification circuit is fine, it just has something to do with the input. I was using a mono jack and a pcb layout for the amp on General Guitar Gadgets had three wires coming from a stereo jack. Can you guys give me a hand?
You need to be a member of Cigar Box Nation to add comments!
Not sure if you ever got your amp working? Ive built this circuit a few times and thought I would give my 2 cents.
The cap values you listed are correct. One problem Ive come across a lot with this circuit is unwanted distortion and a crazy squeal. I found that connecting a 220uf cap across pin 3 and 6 of the 386 fixes the problem. Not sure why it works, it just does.
I had it set up on a breadboard, which is why I think it picked up the radio frequencies. The other thing I was wondering about was that I used the parts list on General Guitar Gadgets and when I looked at the schematic I noticed three capacitors have their values listed as N not UF, but capacitors I had where two 0.047 uf and .1 uf so I looked up cap values and didn't study it very well and just hooked 'em up. Do you think that might be the problem? I don't have the specified capacitors so I can't check.
You connected the input right. THe third wire from a stereo jack socket is for switching the 9 volt automaticly on when you insert the jack. Check all your solder connections: no shorts between different paths? Good connections? All used parts the right value? Orientation of the JFET transistor and the IC? A JFET transistor is very sensitive to static electricity and can be blown by touching it while you are not grounded. Did you use sockets for the JFET and the IC? Otherwise they can also be blown if you overheated them with the iron. Hope this helps and you get it working cause it's a great amp.
Replies
Not sure if you ever got your amp working? Ive built this circuit a few times and thought I would give my 2 cents.
The cap values you listed are correct. One problem Ive come across a lot with this circuit is unwanted distortion and a crazy squeal. I found that connecting a 220uf cap across pin 3 and 6 of the 386 fixes the problem. Not sure why it works, it just does.
Double check all of your connections, especially the transistor ones. Is the MPF102 connected properly?
You connected the input right. THe third wire from a stereo jack socket is for switching the 9 volt automaticly on when you insert the jack. Check all your solder connections: no shorts between different paths? Good connections? All used parts the right value? Orientation of the JFET transistor and the IC? A JFET transistor is very sensitive to static electricity and can be blown by touching it while you are not grounded. Did you use sockets for the JFET and the IC? Otherwise they can also be blown if you overheated them with the iron. Hope this helps and you get it working cause it's a great amp.