Building The 9v Ruby Amp

[Ofek Deitch]

Hi everybody!

This week I thought about building the ruby amp.
Here's the schem:


My questions are:
A. How can I find out if a speaker I found is working, and if it is possible to use it in this amp?
B. Is it possible to connect two more little speakers I found under my bed in parallel to the big speaker?
C. Are the speakers I've got good for this amp?

Here's the big speaker:



The small ones:



Thanks a lot everybody!
Ofek Deitch

[arawn]

have to know what the impedance is on the big speaker. I would suggest using the little speakers in series the ruby likes higher impedance speakers, reportedly

[Ofek Deitch]

How can I measure the impedance of the large speaker?

[PRR]

Tap the speaker leads to a battery. The sound tells you it "works". (Not how well it works; just that it isn't totally dead.)

Use your ohn-meter. An "8-ohm" (audio) speaker typically measures 6 to 8 ohms on the (DC) ohm-meter; 3 ohms is a "4 ohm" speaker, etc.

[Ofek Deitch]

Well, the big speaker works, and the small ones too...
Using my meter, I got 4.2 ohms on the big speaker.

Is that okay? Can I use it in my the Ruby amp?

[arawn]

absolutley

[Ofek Deitch]

Is there any way to connect the two small speakers to the big one (in series or in parallel) and then connect them to the amplifier?
If yes, then how?

Thanks!

[DavenPaget]

Is there any way to connect the two small speakers to the big one (in series or in parallel) and then connect them to the amplifier?
If yes, then how?

Thanks!

Small speakers in parallel , and then connect the parallel small speakers in series with the big speaker , it should give you 4+4 = 8 . Perfect .

[Ofek Deitch]

Is this the correct way to wire my speakers?



Have I understood you right?

[DavenPaget]

Is this the correct way to wire my speakers?



Have I understood you right?

Yep .
But i think this should be the right way

OOPS , swap the + and ground on the inputs , my bad .

[Ofek Deitch]

Okay great
thanks!

[Ofek Deitch]

I've got another question about the Headphones Mod:

Here's a link I found:
http://www.generalguitargadgets.com/pdf/ggg_ruby.pdf?phpMyAdmin=4a28f86a515b7883e7bc35a68d4e7b6d&phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

At the bottom of the pdf there's an example of how to wire your speakers in order to get a headphones jack.

My question is:
First of all, is the diagram correct? If I'll wire a stereo jack as shown, will the speaker be disabled when I connect my headphones?

And second, is the schematic I made correct? (According to the pdf..)



Thanks!

[Ofek Deitch]

??

[Ofek Deitch]

Anyone?

[jefe]

You've got the ring and tip wired to each other, so I don't think that will quite work. I think you need a special switching jack, like maybe a Switchcraft #12A or something. I'm not much help, am I?

Have you seen runoffgroove's faq page? It seems to be often overlooked. 2nd question down, may provided some insight:
http://www.runoffgroove.com/faq.html

[jefe]

Also see:
http://www.diystompboxes.com/smfforum/index.php?topic=63679.0

[Ofek Deitch]

The jack in the schematic is a "normally closed" switched type. When nothing is plugged into the headphone socket the tip is connected to the + of the speaker. When you plug a jack in the connection to the speaker is broken and you just get sound out of the headphones.

Where can I get these "normally closed" jacks? I'm not even sure how they look like...

Thanks again!

[Seljer]

Where can I get these "normally closed" jacks? I'm not even sure how they look like...

Thanks again!

They look like any regular audio jacks, just that they have another connector under the contacts for the tip/ring parts of the plug that loses contact when a plug in inserted and the contacts are pushed outward:
http://www.jacksmusicfactory.com/images/products/50148-2.jpg
also available in the black plastic enclosed or pcb mount variety

[DavenPaget]

Where can I get these "normally closed" jacks? I'm not even sure how they look like...

Thanks again!

They look like any regular audio jacks, just that they have another connector under the contacts for the tip/ring parts of the plug that loses contact when a plug in inserted and the contacts are pushed outward:
http://www.jacksmusicfactory.com/images/products/50148-2.jpg
also available in the black plastic enclosed or pcb mount variety

Something like the Switchcraft 113EX