One last check on the ruby amp

[moody07747]

So i got all the parts in today and put the ruby together most of the way.

i wasn't sure what connected to ground or what ground in the circuit was but i did just do a paint drawing of how i think it should be wired.
also i wasn't sure how they had the pins numbered on the gain and volume pots...they call them one two and three but I'm not sure which way that was...I'm sure ill get that straight when i power it up and try it though.

anyways does ground from the board connect to the neg. of the power and sleeves of the in/out jacks?

this is how i think it should be wired but may be wrong.

http://s2.photobucket.com/albums/y22/moody07747/Projects/Ruby%20amp/?action=view&current=rubywiring2.jpg

blue dot equals a solid connection, click it once you open the link to expand it to 100%

[darron]

hey dave. a few of things here. ground connects to the shielding that warps around your audio signal in hte lead, which is the sleeve, yes (: and in this case you can and should hook that up to negative also.

you are using a DPST switch to turn the amp on or not. you COULD use a SPST or SPDT to switch the power to both the LED and the power to the board in one connection, but your way will work also.

also, if you connect the LED right up to the 9 volt source it will probably burn the LED and stink. put a 1.5k resistor between one of the legs of the LED and the power supply and it will prevent it from burning out. if you are using a high intensity LED then you could use a 56k resistor or so to dull it down and save a lot of battery power. you get the idea.

in regards to the pot terminal numbers, go here: http://sound.westhost.com/pots.htm and scroll about half way down and it has a diagram. looks like you got it correct.

hope that i didn't forget anything... good luck (:

edit: ohh.. by the way. do you plan on hooking up a speaker to this unit? that's the kind of amp that it was designed to be, this would go on the output of course instead of the audio jack. you could make a little cabinet separate that you plug in the jack hehe.

[moody07747]

Yea I'm planning a half size cab for this amp...right now I'll be testing it on this though:

http://s2.photobucket.com/albums/y22/moody07747/Projects/Mini%20Speaker%20Cab/

Yea the switch was just so I could fit all the wires on there...I hate putting any more than two wires on a small lead like on the switch I'm using so I got the DPST

As for the LED its a high output  blue but I like it and yes I have a 1.5k on the lead..just didn't put it in the drawing because it was just to make sure the wiring was all correct.  in the board to the controls.

edit, OK it's all almost done..wiring is done and the amp chip is installed. however I went to the local radio shacks and they didn't have an FET I needed so I had to order from online and that will be in later today.
after i plug that in ill be able to test it out.

I put it in the case and took some pics, (click to expand).

Front panel:





Left to right: Input jack, Gain knob, Volume knob, Power switch, sweet lookin blue LED


Back panel:



Left to right: Power jack, 25mm mini altra neat lookin fan  , Output jack

[moody07747]

Okim getting a strange short with the power jack im using

it looks to be a switch craft brand jack and i have more in another size so ill try that

when I unplug the plug from the jack im not getting any short and when i plug it in im not reading continuity between the soldler tabs.
however when I plug in i can see the spart and read 0 volts so i know its a short.

i took the wires off the jack and hard wired it to the power supply and its working fine.....



any suggestions other than trying another jack?

[darron]

what do you mean that you are getting a short? is the power jack isolated? is it possible what the the negative grounding of your enclosure is touching the positive outer casing of the jack?

[moody07747]

the only metal in the case is the front and back panels and there's no way the + is grounding to the back panel where the jack is mounted

the jack is mounted with metal threads directly onto the metal panel in the back so i could see getting a short if the whole case was metal but.......i'm just clueless on this one right now.

ill have to switch to another jack tomorrow and see what happens..I have had this type of problem with another project.........same type jacks too but a different size.
i ended up swapping out one jack and they all worked, (it was a guitar pedal power unit)

[moody07747]

ok im an idiot...

the case sides are metal and are grounded due to them being connected to the grounded input and output jacks.
the threads on the power jack are energized with (+) and so when i had it in the case it was shorting.......that one really had be going for a while.

anyways ill just reverse the connections for center pos. on the power jack and reverse the power cable plug thing....it should work then.

edit, bring on problem #2....no sound.

my power unit that  came from allelectronics was rated at 9VDC but puts around nearly 12 so I figured I wouldn't use it as the chip is only rated at 9 max.

I got out the old electronic box and found a variable supply rated between 3 and 12 volts and set it for 9.  max output in current is only 300mA though so my though t is I'm not getting enough current into the amp to make any sound...sound   about right?

My AE power unit was rated for 900mA so I would like to be able to use that if possible.

The chip I'm using is a LM386N

http://www.allelectronics.com/cgi-bin/item/LM386N/search/LOW_VOLTAGE_AMP_.html

http://www.datasheet4u.com/html/L/M/3/LM386N_NationalSemiconductor.pdf.html

the only thing im getting is a nice little blue LED light.......
Maybe ill just make it into a flashlight 

[darron]

reversing the power at the jack and then at the adaptor will be alright. your power supply could possibly read 12 volts because you are reading it without a load on it? it's possible that you have fried components now also. messy. i'd hope for someone with more knowledge than me to reply.

[moody07747]

I don't think that dead short between ground at the jack and all the ground points did much damage but I'm no expert at electronics..
ill swap out for another amp chip and FET as i have a few of them just for this type of situation.
ill also try the other supply under load and read the voltage with the amp on.

if i fry some chips ill just plug more in..


edit.  changed out the FET and chip and tried with both power packs..still nothing.
everything in the amp looked fine too...no burned parts and everything is wired exactly to the wiring sheet...

it will be interesting to find what the  problem is with this amp......it will bug me until I find it too...lol

[moody07747]

Ok at another electronic board I'm going over the problem of the fan not running.  It seems to be getting 9V instead of 5....in turn, this wont let it turn on.

In the amp problem I'm not getting any audio.............

I'm Just about ready to send this to someone on this board to troubleshoot and get running...

[moody07747]

Ok guys I made a power regulator circuit next the amp to change the 9V to 5V for the fan and thats working but now I'm not getting sound..never was actually.

I have an audio probe but have no idea what ares I should be getting sound from.

I'm just asking for someone to put an X on this wiring layout image where I SHOULD NOT be getting any sound from the audio probe.

Thanks.





I hope I get this wrking soon...or even at all because I've hard this amp sounds great but I've yet to hear it..........

[ambulancevoice]

the dc jack you are using must be insulated (with some sort of non-conductive polymer) from the metal parts of the chassis, other wise it will just short out, if you cant be bothered, by one of those plastic dc jacks
here is a picture of how to wire the dc jack you are using
http://www.smallbearelec.com/Detail.bok?no=92
and here is the plastic dc jack
http://www.smallbearelec.com/Detail.bok?no=93
and on the volume lug, conect lug one to ground

[moody07747]

the dc jack you are using must be insulated (with some sort of non-conductive polymer) from the metal parts of the chassis, other wise it will just short out, if you cant be bothered, by one of those plastic dc jacks
here is a picture of how to wire the dc jack you are using
http://www.smallbearelec.com/Detail.bok?no=92
and here is the plastic dc jack
http://www.smallbearelec.com/Detail.bok?no=93
and on the volume lug, conect lug one to ground

That was happening at first but then I switched the polarity and everything so I'm running ground on the outside and pin (+).
The only spots I'm getting audio with the probe are pins G and S, Pin #2 on the LM386, and all lugs on the Volume pot...
everything else dead quiet.

My FET:
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&pa=26403&productId=26403

My 386:
http://www.allelectronics.com/cgi-bin/item/LM386N/search/LOW_VOLTAGE_AMP_.html

I have 10 FETs and 3 ICs...I've tried all the ICs as well as 3 of the FETs

right now, lugs 2 and 3 are being used in the circuit for the volume, ill ground #1


nope, no difference with that grounded lug...but I wasn't expecting much change from that......

I'm not sure  if it helps but when using the audio probe, I'm not getting any audio at the bottom of the 1M5 and 3k9 resistors on my board.

everything is reading continuity with the solder joints so I know its not a bad solder joint...nothing is shorted out with solder on the back of the board either.

I'm stumped on this one....

[ambulancevoice]

the dc jack you are using must be insulated (with some sort of non-conductive polymer) from the metal parts of the chassis, other wise it will just short out, if you cant be bothered, by one of those plastic dc jacks
here is a picture of how to wire the dc jack you are using
http://www.smallbearelec.com/Detail.bok?no=92
and here is the plastic dc jack
http://www.smallbearelec.com/Detail.bok?no=93
and on the volume lug, conect lug one to ground

That was happening at first but then I switched the polarity and everything so I'm running ground on the outside and pin (+).
The only spots I'm getting audio with the probe are pins G and S, Pin #2 on the LM386, and all lugs on the Volume pot...
everything else dead quiet.

My FET:
http://www.jameco.com/webapp/wcs/stores/servlet/ProductDisplay?langId=-1&storeId=10001&catalogId=10001&pa=26403&productId=26403

My 386:
http://www.allelectronics.com/cgi-bin/item/LM386N/search/LOW_VOLTAGE_AMP_.html

I have 10 FETs and 3 ICs...I've tried all the ICs as well as 3 of the FETs

right now, lugs 2 and 3 are being used in the circuit for the volume, ill ground #1


nope, no difference with that grounded lug...but I wasn't expecting much change from that......

I'm not sure  if it helps but when using the audio probe, I'm not getting any audio at the bottom of the 1M5 and 3k9 resistors on my board.

everything is reading continuity with the solder joints so I know its not a bad solder joint...nothing is shorted out with solder on the back of the board either.

I'm stumped on this one....

are you grounding yourself when you handle the IC?
and are you using sockets for the transistor and the IC?

[moody07747]

yes and yes

Although the chips from Allelectronics came in a plastic case with tape at each end where it was packed in a plastic bag and then in foam peanuts.
The plastic was far from anti-static...

There any ways to test these LM386N chips?
I should call AE and see if they wont send a few more in an anti static bag...

[moody07747]

I am happy to say i finally found the problem...i forgot a small connection to the power input pin on the 386 chip...
just had to take a few minutes to trace every single wire on the board with the printout.

I powered up and plugged in a guitar...great sound..not much distortion but great cleans on this amp.

[ambulancevoice]

try it at 12 volts, with the gain all the way up, and with the volume to your liking
if that doesnt produce a good enough distortion for you
use a booster pedal or eq to pre drive the amp

[moody07747]

try it at 12 volts, with the gain all the way up, and with the volume to your liking
if that doesnt produce a good enough distortion for you
use a booster pedal or eq to pre drive the amp

yea I'm going to run my Digitech EX7 though to it.  A DS-1 could also be good to get  and I could use it as a boost for those Joe Satriani songs I'm always playing.

My LM386N is only rated for 9V but my power supply is putting out around 11.......
it doesnt seem to be bothered though.
I found I had a bad contact on the output port as I was playing and moved the amp and had a huge volume boost...thats fixed now too.

[ambulancevoice]

lm386 can take up to 12 volts, and down to around 6 or 4 (cant remember which)