ruby amp wiring help

[Fndr8875]

ok so i have a couple questions regarding ruby amp wiring.

http://www.runoffgroove.com/ruby.html

I am referencing this diagram.

in the perfboard diagram it shows a 10 ohm resistor wired to a 47 nf cap, but in this layout it looks like there are 2 100 nf caps and no 47 nf cap and no 10 ohm resistor. Also there are several spots where one leg of one component is not soldered to the pad where it enters the perfboard, like the 100 uf cap etc. I dont think it matters but i am new to all this so just wondering. I am having trouble figuring out where  or how to wire my switch(dpdt) and led. ive done some searches and cant find anything that makes sense. Also for a speaker I have some what seem a good match, it is a 8 ohm 8 watt 61/2" speaker off of an old surround sound system. Ill post a pic of the sticker on the back of the speaker when i have a chance.

Any responses much appreciated.

[GibsonGM]

Hi Fndr...you are just seeing the 10 ohm/47n network using that path to ground...it is still just as it was in the schematic...a practical shortcut for wiring was used.   See how it goes down and to the right, to ground?  That's all.

They COULD have soldered that 100u cap where it goes thru, they just didn't - they chose to use its leg as a lead to the next thing down the line.  It is ok, doesn't need much stability. 

As long as all electrical connections are made, the physical ones can be "negotiable"...that comes with experience!  Depends on how much you need to protect the parts from vibration and stuff.

By all means, use that speaker for now.  Hi fi speakers are TOO hi fi for guitar - they don't sound too good.  But right now, we're wanting to get this up and going for you      


I suggest you just wire it up like the perf diagram, get it working, then we'll worry about the switch things! Use jumpers and so on, to test it with your guitar & a speaker.   

Welcome to the forum

[Fndr8875]

Im talking about the actual perfboard pic, i dont see the 10ohm resistor wired on the perfboard. The films caps seem to be the same, just by looking at the size, my film caps a 100nf a double the size of a 47nf. There are only two film caps on the perfboard so its gotta be missing one since the schematic shows 2 47 nf and 1 100 nf, the 10ohm could be hiding under the 220uf el cap but doesnt look like it on the reverse soldered side. Just wondering why those were left out on the official runoff grove site. I could understand if it were a random persons build but i would think they would wire it the same as the schematic. What effect would leaving those components out have on the sound? I wired mine up and i have no sound, i know there is a ground issue bc when i plugged power in i had my finger on the 386 chip and it immediatly began to get hot, so i unplugged it immediatly. Does anyone know if there is a pcb for sale for this build? there is a little gem on GGG, i was under the impression the ruby was an improved version of the little gem, Im really new to this and thinking i should prob go ahead and just buy a pcb. This is the second time ive tried wiring this up and no luck so far. How can i trouble shoot a grounding issue without applying power and burning components up? It gets hot real quick.

[GibsonGM]

Wow, good eye, Fndr, ha ha!  I think you may be on to something.   Ok, for any actual assembly, please use the DRAWING of the circuit (I use the actual schematic) to put it all together, NOT the perf they've already done!  They probably only show it as 'decoration' of sorts.  It's not that big a circuit - you should be able to get it together by following the drawing.

You probably (definitely) have a short, if the chip is getting hot...not really a 'grounding issue'.  Remove battery.  I'd carefully remove the chip, too, if it is in a socket.  Take a multimeter (you have one, right?) and set it to 'continuity' (beeper), or to resistance if it doesn't have the beeper setting.      Connect one lead to the "-" wire and one to the "+", note what happens.   A beep is bad.   So is a low resistance reading.

When we get a build that isn't working, we have to go back thru EVERY connection to be sure there are no solder bridges.  10 to 1, you have a solder bridge at the IC, so check - use a magnifying glass!    It's frustrating, but everyone has gone thru it, and it gets easier if you stick with it.   You might find it by eye and be able to correct it, no meter needed.

Revisit that drawing, make sure your stuff is connected as shown...

[duck_arse]

the parts missing from the built perf are the zobel network parts, meant to keep an amplifier stable at high frequency when loaded funny. something like that. it may be the prototype worked ok without it - it ain't necessary, will work without those parts - but may become unstable, oscillate, and get hot. and so they added it later.

can we see photos of what you have built, top and bottom? please?