Smokey not working

[Also Wik]

Okay, I've read up on how to hardwire a speaker to one of the headphone amps (whether it be Smokey Clone, Gem, or Ruby), and how to wire it up for use with a 1/4 output jack for headphones.

What i want to know is, can i build a small speaker cab (with something like an 8 or 10 inch speaker), and connect the amp to the cab using a normal cable? Also, can i install a 1/8in headphone jack, so as to be able to use normal headphones, and not big bulky studio phones?

Thanks in advance.

[gez]

Think of the speaker size in a Smokey and that's the sort of thing you should stick to.  If you want to drive bigger speakers you'll need a more powerful chip.

As for wire, check the data sheet of the chip, it'll tell you typical power out at 9V...700mW for the sheet I looked at (might be variance between different manufacturers).  Once you've done that, check the rating of the wire you intend to use.

You can instal whatever jack you like...

[Also Wik]

Thanks.

[Also Wik]

Another question: since i cant really fit a big 1/4in jack into my tiny enclosure, would it affect anything to use a 1/8in jack as my input as well, and just use an adapter to plug in?

[gez]

Use whatever you like, it's not critical.

[Joecool85]

I beg to differ about the speakers you should use.  I've used pretty much every size from 2" to 10" speakers.  The loudest and best sounding was the 8" speaker in my dean markley K-20X.  Just because its a 1/2w amp doesn't meant it can't drive big speakers.  A couple guys in here said their best sound was drive a 2x12 cab.  The thing is, little speakers can only get so loud, and yeah, bigger speakers require more watts to get their full potential, but the thing is that 1/2w is enough to get quite a bit of quality sound out of a good 8"-12" guitar speaker.

[gez]

All depends whether you want volume or not, and I would if I were using a large speaker.  If it were me, I'd use a more powerful chip, but it's all personal choice at the end of the day...

[Also Wik]

Well right now im just trying to get the little bugger to work. Can't get it to work with headphones let alone a speaker

[Also Wik]

I was poking around the circuit with my multimeter, and everything seemed to be getting a signal (i'm still not 100% sure how to use the thing, but i know hwo to tell when a signal is being passed), but when I got to the negative side of the 47uF output cap, i got absolutely nothing. Does this mean that a bad cap is my problem?

[gez]

I was poking around the circuit with my multimeter, and everything seemed to be getting a signal (i'm still not 100% sure how to use the thing, but i know hwo to tell when a signal is being passed), but when I got to the negative side of the 47uF output cap, i got absolutely nothing. Does this mean that a bad cap is my problem?

You mean the 47nF cap?  Could be you've got the pinout wrong on the FET.  Best thing would be to post DC voltages for the FET and the chip.

[gez]

Whoops, I assumed you were building the Ruby!  Can you link to the schematic (plus post voltages)?

[Also Wik]

Sorry if i wasnt clear about the circuit i was building. The schem is down near the bottom of this page:http://www.geocities.com/tpe123/folkurban/fuzz/snippets.html#smokeyclone

I mean, it's not a complicated circuit at all - very hard NOT to get everything wired up right. I'll go see if i can get some exact voltages now, but like i said, i rough-tested everything and the only place that didnt seem to be getting any current was the negative side of the output cap.

[gez]

Are you trying this with just a guitar plugged in, or are you sticking an effect in the path beforehand?

[Also Wik]

Just the guitar.

Dunno if i took them right, but if i did, somethings definately going wacky...:

Battery - little less than 9 volts almost new

IC1:
P1 - 4.8v
P2 - 0v
P3 - 2.2v
P4 - 0v
P5 - .5v
P6 - 8v
P7 - 1v
P9 - 4.8v

[gez]

Give me a while to find the data sheet.

Do you have active pickups?

[gez]

Can't find the data sheet, but I'm assuming it's the same as a bog-standard 386 amp, in which case the voltages are pretty out of whack.

Both inputs rely on a path to ground and in this case that means your guitar pickup for the + input.  You've got 2.2V on the +ve input, which is a little odd.  Are your pickups active and if so is there any leakage (check for DC voltage when unplugged from the amp)? 

[gez]

Both inputs rely on a path to ground and in this case that means your guitar pickup for the + input. 

Having had a glance at the schematic that's not quite right, there are internal resistors to ground.  It is odd that the + input is so high though...

[Also Wik]

No, i don't have active pickups - regular old passives. Is it possible that there might just be an issue with the IC itself? I didn't use a socket so i'm kindof worried i damaged it somehow.

[gez]

No, i don't have active pickups - regular old passives. Is it possible that there might just be an issue with the IC itself? I didn't use a socket so i'm kindof worried i damaged it somehow.

Yeah, it could well be damaged.  Check over all your connections again just in case though.  If you've soldered it up try reflowing joints.  Failing that, it's probably toast...

[Joecool85]

I don't know...I soldered and resolder my first lm386 like 3 times, with a 30w iron...and its fine.  I never use sockets on lm386s lol, I know I should, I just always forget and then start the project and don't want to wait, so I just do it without a socket.