Newbie need help with Ruby amp.

[gragonese]

I have always been interested in learning about circuits and figured id give it a shot with trying to build one.  I bought all the parts for the ruby amp and went to work with assembling it.  Well as in most cases your first time of doing something you usually suck at it and sure enough i sucked and it doesn't work. I have checked the thing over and well am lost as to what i did wrong that it doesn't work.  It has nothing going out to the speaker or maybe it could not be working at some other point.  I'm hoping someone could give me a hand in figuring out what it is that i did wrong. Thanks in advance!

[arawn]

The pictures are a good start but go to the wiki and read what to do when it doesn't work. That will tell you everything you need to know to be able to get some help.

[Jdansti]

^ +1

Welcome to the forum!

If you still have problems after following the forum troubleshooting procedure, give us some pics of the offboard components showing where each is connected to the board. It would also help to see the exact schematic or layout you're using (or links to them).  Good luck!

[Rock_on]

That's my problem also

I used 2N5458 instead of J201/MPF102 once it is not available here in our country..

I did everything right, I hear reaction when I'm touching the pin2

Also when I'm touching pin 1,8 (gain pin) I hear loud noise

I also hear reaction when I'm touching the gate and source pin..

Just doing those for testing but when I'm inserting my guitar I can't hear anything..

My guitar electronics is fine when I'm testing it with our amp..

[ncudahy]

Hi I'm pretty new here myself so you might want to let someone else confirm this, but it looks to me like when you were soldering your IC socket you on the underside of the board you treated pin 1 as pin 8, pin 2 as pin7 etc. in otherwords you maybe forgot that what you were looking at on the underside of the board is a mirror image of what you see when you are looking down a the label sid of the chip.

Looks like pin 4 is going to the 220uf cap and then to the speaker when it should be pin 5. and pin 7 is going to a pot when it should be pin 2.

anyway happy festivus

[deadastronaut]

^ yep it looks backwards to me too....

pins are in this order..when looking at it with the 'notch' up top.

1              8

2=in         7

3=in         6=9v

4=0v        5=out

[gragonese]

Well now that i have completely screwed this thing up what would be better to do.  Start new or move the components and resolder everything?

[Taylogc]

Use a socket for IC's and transistors.... They are sensitive to heat.. Plus you can easily replace those components or experiment with others...   Good luck

[Jdansti]

I agree that the IC is backwards. If it were me, I'd start over. The good news is that you'll probably never get the IC backwards again!

[deadastronaut]

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

yep start over.....you may be lucky and be able to salvage/de-sloder your bits..

but socket the ic/tranny ok....

[gragonese]

Thank you for everyones help! I started new and put everything on the correct pins and it works. The only thing is that it really isn't that loud at all.  The speaker i had laying around to test it out is a 4 ohm 30 watt speaker.  Is the speaker too much or have i done something wrong yet again?

[timd]

It won't be loud at about a watt. Is the sound quality good? I believe the Ruby was based off the ROG little gem:

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

"The volume at maximum is slightly louder than normal conversation..."

[PRR]

> 4 ohm 30 watt speaker.  Is the speaker too much

No, that's fine.

8 ohms might be a trace louder (4 ohms is a strain on a LM386) but no big deal.

Power is critical especially with the low impedance. A cheap/weak 9V will suck-down real bad when a '386 works hard into low impedance. Use a fresh good-brand batt or a 9V >400mA supply. (Be sure you don't use a cheap "9V" supply which soars over 17V idle.)

It's usually not a Whole Watt. But unless you use a subwoofer or other real-dead-midrange speaker, a part-watt should be loud enuff to annoy the whole house.

[ncudahy]

at the risk of insulting your intelligence, is the speaker in any kind of cabinet yet? makes a huge difference in the volume.

[pinkjimiphoton]

it's nowhere near a watt... probably more like a third of a watt.
but it should be able to drive a guitar cab loud enough to hear.

a raw frame speaker won't sound too good...no bass response without a cab.

cranked up half way, it should be about the same volume as an accoustic guitar roughly. dimed, it should be as suggested a little louder than normal conversation, with a nice overdriven "tube-y" tone.

glad ya got it running, i LOVE my ruby!! use it all the time for all kindsa stuff. it's almost loud enough to play with a drummer thru my 4x10 if he's dynamic enough and i don't need to solo.

[deadastronaut]

stick an lm386n-4  in it...  1 watt!.    not a 1/4 watt.

[pinkjimiphoton]

hmmm, interesting, didn't know that. thanks rob!!

i guess now i know why some of them chips sound better in overdrives than others!!   

[deadastronaut]

http://pdf1.alldatasheet.com/datasheet-pdf/view/8892/NSC/LM386N-4.html

take a look at typical applications in the 386 datasheet pdf for a bass boost...


better with a cab though....but maybe worth a shot.