Ruby mini-amp finished! (Was: Ruby's volume pot doesn't work)

[simop]

I built Ruby mini-amp. It seems to work as it should and the sound is pretty good with a 6x9" car speaker. Only problem is that the volume potentiometer (10k/log.) doesn't work at all. The volume is always the same no matter in what position the pot is. I've checked the circuit several times and I can't find any mistakes, but maybe there still is. Could you tell me what to do to get the volume pot working? The potentiometer itself isn't broken and I tested with other one too. The FET I used is 2N5457 and IC is GL386.

I noticed that if I remove the FET from its socket and just connect G and S the amp works the same way as with the FET. Could this mean that the FET is broken? Could that cause the non-working volume pot?

Any help greatly appreciated. I want to get my amp completely working...

[Burton]

Are you 100% sure the pot is wired correctly? People get it wrong all the time! 

[simop]

Are you 100% sure the pot is wired correctly? People get it wrong all the time! 

Well, nobody can be 100% sure about anything, but I'm pretty sure that it's wired correctly.
The center pin of the pot is connected to pin 2 of GL386 and the righthand pin is connected to the 47nF condenser. Isn't that right?

I tested the amp with headphones and noticed that when I turn the volume pot to the max I noticed that hissing increased slightly.

[Burton]

Hmm.. be sure you know which "lug" (as they are called) is which, on the pot.  Looking at it from the bottom, the one on the left is lug 1, lug 2 is center, and lug 3 is right.  Make sure you have lug 1 grounded, because you didn't mention that. It should be wired exactly like this:

oh, also be sure that you have you're IC oriented correctly.. that could really mess things up!

[simop]

Hmm.. be sure you know which "lug" (as they are called) is which, on the pot.  Looking at it from the bottom, the one on the left is lug 1, lug 2 is center, and lug 3 is right.  Make sure you have lug 1 grounded, because you didn't mention that. It should be wired exactly like this:

Thanks a lot! I hadn't grounded the lug 1. Now it works.

[Burton]

It works? That's awesome! I'm glad I could help.  I've never built the circuit and I've just started teaching myself shematics, so I'm glad I could identify your problem.  Looks like I'm learning!  So how does this thing sound? Can you post any clips?

[simop]

Now the amp is completely ready. Its enclosure is a case of a blood pressure meter, the speaker is from FM radio.
The amp sounds really nice and looks very cool!

Pictures and sound clips are available at: http://koti.mbnet.fi/simopot/rakentelu/vahvistin.php
The site is in Finnish, but you'll understand it. Even a child in Finland understands Finnish, so it can't be hard for you.

Here's some help:
  kuvia = 'images'
  ääninäytteitä = 'sound samples'
  puhdas = 'clean'
  särö = 'distortion'
  kustannukset = 'expenses'

[Burton]

Wow, that sounds awesome! Even with the 2 inch speaker! How'd you get that distortion - just by turning up the knobs all the way, or some pedal?  Also, is that a completely stock ruby (besides the headphone/speaker output)? and one last question.. what is that toggle switch for - something to do with speaker/headphone selection, or is it distortion?  I love it!!

[mat]

Wautsi !

Komeat saundit  What kind of mic did You use for recording ?

My ruby can be found at:  http://koti.welho.com/mtiilama/My%20Amps.htm and soundsample at: http://koti.welho.com/mtiilama/sound/ruby.mp3

Thanks for shearing,
mat

Now the amp is completely ready. Its enclosure is a case of a blood pressure meter, the speaker is from FM radio.
The amp sounds really nice and looks very cool!

Pictures and sound clips are available at: http://koti.mbnet.fi/simopot/rakentelu/vahvistin.php
The site is in Finnish, but you'll understand it. Even a child in Finland understands Finnish, so it can't be hard for you.

Here's some help:
  kuvia = 'images'
  ääninäytteitä = 'sound samples'
  puhdas = 'clean'
  särö = 'distortion'
  kustannukset = 'expenses'

[simop]

Wautsi !

Komeat saundit  What kind of mic did You use for recording ?

Jaa, täältäkin löytyy muitakin suomalaisia. Kiitos vaan kehuista.
Sivullahan se käyttämäni mikki luki? Näössä vikaa?

Clips are recorded with Shure SM57 mic.

My ruby can be found at:  http://koti.welho.com/mtiilama/My%20Amps.htm and soundsample at: http://koti.welho.com/mtiilama/sound/ruby.mp3

Cool amps, you're a pro!

[mat]

Moi,

Jaa, täältäkin löytyy muitakin suomalaisia. Kiitos vaan kehuista.
Sivullahan se käyttämäni mikki luki? Näössä vikaa?

Argh! Niinpäs näkyy, klikkailin heti kuvia ja teksti jäi näkemättä  Omassa rubyssä on virtalähteenä 8x1.5v D-koon patteri. Saundaa jotenkin 'avoimemmalta' kuin yhdellä 9v paristolla.

Kiitos itsellesi kommenteista.

mat

[vanhansen]

Very nice.  This amp is one of my favorites when it comes to the small amp category.  I built mine last year and still use every now and then.  I have some clips up of it running through a 4x12.   They've been posted before but it's been a while and worth sharing with some who haven't heard them to get an idea of what this little beast can really do.

http://diy.erikhansen.net/ruby.htm

[simop]

Omassa rubyssä on virtalähteenä 8x1.5v D-koon patteri. Saundaa jotenkin 'avoimemmalta' kuin yhdellä 9v paristolla.

Miten se muka voi vaikuttaa saundiin? No, pitänee kuitenkin kokeilla.

[MrChameleon]

Good onya

Glad you were finally able to Finnish it

[mat]

Omassa rubyssä on virtalähteenä 8x1.5v D-koon patteri. Saundaa jotenkin 'avoimemmalta' kuin yhdellä 9v paristolla.

Miten se muka voi vaikuttaa saundiin? No, pitänee kuitenkin kokeilla.

8 x 1.5v = 12v vs. 9v. Foorumista löydät paljon tietoa 9v vs 18v vaikutuksesta.

mat

[simop]

8 x 1.5v = 12v vs. 9v.

No just joo, mullahan taitaa olla näössä (tai matikkapäässä) vikaa.
Katoin jotenkin, että siinä olisi ollut 6x1,5v...

Foorumista löydät paljon tietoa 9v vs 18v vaikutuksesta.

Siis varmaankin 9v vs 12v?

[vanhansen]

Don't take this the wrong way guys, but there's a lot of folks on here that don't speak or read Finnish.  I can understand a greeting or salutation in your native tongue to a fellow countryman but please post in English so anyone else who reads the threads can at least understand what you're talking about and possibly even learn something. Thanks.

[simop]

Don't take this the wrong way guys, but there's a lot of folks on here that don't speak or read Finnish.  I can understand a greeting or salutation in your native tongue to a fellow countryman but please post in English so anyone else who reads the threads can at least understand what you're talking about and possibly even learn something. Thanks.

Sorry... 

Mat said that his own Ruby sounds more "open" with 8x1,5v batteries instead of one 9v battery. I asked how it can affect the sound, because I misread that as 6x1,5v. Then mat said that a lot of info about 9v vs 18v can be found in this forum (he probably meant 9v vs 12v).

That's what we were discussing about in our "silly" language.

[simop]

Wow, that sounds awesome! Even with the 2 inch speaker!

Thanks.

How'd you get that distortion - just by turning up the knobs all the way, or some pedal?

Distortion samples were recorded with both pots at the maximum, no pedals or other stuff.

Also, is that a completely stock ruby (besides the headphone/speaker output)?

Yes. The headphone and speaker jacks both have a switch that mutes the Ruby's own speaker. Headphone jack has 100µF capacitor to reduce hissing and 10ohm resistor to reduce the output level. Like this:

Code Select Expand


HEADPHONE                       RUBY
JACK             

tip    o--\
          |-----+-------------o signal
          |     |
          |    100µF                   
ring   o--/     |           
sleeve o--------+---10ohm-----o ground


and one last question.. what is that toggle switch for - something to do with speaker/headphone selection, or is it distortion?  I love it!!

It's a power switch - on/off.

[vanhansen]

Don't take this the wrong way guys, but there's a lot of folks on here that don't speak or read Finnish.  I can understand a greeting or salutation in your native tongue to a fellow countryman but please post in English so anyone else who reads the threads can at least understand what you're talking about and possibly even learn something. Thanks.

Sorry... 

Mat said that his own Ruby sounds more "open" with 8x1,5v batteries instead of one 9v battery. I asked how it can affect the sound, because I misread that as 6x1,5v. Then mat said that a lot of info about 9v vs 18v can be found in this forum (he probably meant 9v vs 12v).

That's what we were discussing about in our "silly" language.

Ahh, I see.  Yeah, I can see where the use of more lower voltage batteries would have an effect.  Instead of sucking the juice out of one source, it slowly trickles the current from multiple.  A little more efficient.  (at least I think that's right).  There is a lot of info here on using 12v and even 18v circuits.  More headroom will have a nice affect on it.  Just make sure you build it with parts than can handle the extra voltage.

I wouldn't call it "silly".  It amazes me how folks across the pond can know 5 different languages like it's nothing.  Here, we're lucky if we know two.  My 2 year old will know more Spanish than me because they're teaching it in the schools earlier now.  Heck, she can count to ten in Spanish....and English.  That's more than what I could do at that age.