Speaker for Ruby amp

[simop]

I'm planning to build a small Ruby guitar amp. I just don't know what kind of speakers to use with it.

I have several small speakers (2", 8OHM, 0.2W). Can I use one of those with Ruby? What about if I put two, three or four of them in series/parallel? A 4x2" cab would be cool.

I have also bigger speaker from some old car stereo. It hasn't any other markings on it except 100W. I think that it's impedance is 4OHM (see pic). What about this speaker?

[Peter Snowberg]

Welcome to the forum.

You will get some wild variation in performance between a 2 inch and a 12 inch speaker.

An LM386 amp which is quiet, buzzy, and annoying with a 2 inch speaker is able to easily get you disturbing the peace complaints if run into a 4x12 cabinet.

Try every speaker you can get your hands on!   

I get great sound from a 386 running into a full sized Leslie cabinet with a 15 inch woofer and a smaller speaker driving a horn.

[simop]

Welcome to the forum.

Thanks for your answer.

You will get some wild variation in performance between a 2 inch and a 12 inch speaker.

Really?

Try every speaker you can get your hands on!

Ok. How should I connect the speakers if I make a 4x2" mini cab with those 8OHM speakers? Four in parallel, four in series? Mixed (see below)?

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[Peter Snowberg]

Try every speaker you can get your hands on!

Ok. How should I connect the speakers if I make a 4x2" mini cab with those 8OHM speakers? Four in parallel, four in series? Mixed (see below)?

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[/quote]
Yes, parallel/series, exactly as you have it.

A little larger speaker in a box sounds MUCH MUCH better.

I've tried LOTS of speakers between 1/2 inch (modem speakers) and 15 inches. A 6x9 car speaker can work really great. I'm firmly of the opinion that a 2 inch speaker is good for novelty only. There is also a ton of variation in 2 inch speakers, but every one I've tried just sounds bad.

Try the speakers from your home stereo too!

[simop]

A little larger speaker in a box sounds MUCH MUCH better.

I'll try to find a 3-4" speaker somewhere.

I've tried LOTS of speakers between 1/2 inch (modem speakers) and 15 inches. A 6x9 car speaker can work really great. I'm firmly of the opinion that a 2 inch speaker is good for novelty only. There is also a ton of variation in 2 inch speakers, but every one I've tried just sounds bad.

Thanks for the info. I just thought that it would be cool to have a tiny head and a 4x2" cabinet under it. But if the sound is horrible then maybe it isn't so cool...

[Mark Hammer]

Three words: cabinet, cabinet, cabinet.

Do NOT judge the suitability of the speaker based on hooking up the speaker sitting on its own on the counter top.

Do NOT assume that a speaker's efficiency is independent of the accompanying cabinet.

Do NOT assume that the efficiency of the speaker is perfectly predictable from its size.

There are a lot of cheap "full-range" speakers in the 8" size that can sound petty good.  A great many of them are in the 5-10W range for sticking in ceilings as intercom/paging speakers.  These are moderately efficient, have some nice punch to them and benefit from a nicely sized cabinet.

The Ruby can be made to have more power if you power it with an 8-pack of AA's instead of a 9v battery.  If you have a 386-4 (the highest power rated one at around 1W without heatsinking) it can be surprisingly loud with a 6-8" speaker.

On the other hand, I understand if your goal is to have something very small and portable.

[simop]

On the other hand, I understand if your goal is to have something very small and portable.

Yes, I want to make a "pocet-size" guitar amp, so 8" speaker is way too big. The car speaker is also too big for that, but I asked about it because it has been without use for a long time and I wanted to know if it's suitable for guitar speaker.

[Burton]

This looks like a cool little project!  Post some pics when you're done.  I'd like to see how this turns out!   

[RLBJR65]

Try it out. What have you got to lose? I have built several 386 amps in computer speaker cabs. My favorite is a 3" Labtec 4 ohm 10 watt, they sound wonderfull.
Neat idea building a mini 4 X cab I'll have to try that.

[grs149]

My first homebuilt guitar amp used a pair of Pioneer 6x9 car stereo speakers in a sealed cabinet. I thought it sounded pretty good (although I was only 19 at the time and had little experience with "real" guitar amps). Anyhow, I would say that a car speaker is worth a try. They tend to have failry stiff surrounds (compared to hi-fi speakers), which is a good attribute for a guitar speaker. You might want to leave the option to have your cabinet open or closed back, so that you can try it both ways.

Greg

[grs149]

My first homebuilt guitar amp used a pair of Pioneer 6x9 car stereo speakers

I should probably clarify that these were single-cone speakers - not the coaxial type with separate midrange/tweeters...

[TheBigMan]

The power you can get from a Ruby is astonishing.  With a pair of headphones with an inline volume control it's a great late night practise amp.  Into a 2x12" with G12H30s and an 18V power supply it's nearly as loud as a clean Nano Head.

I built mine with a speaker out jack in a small enclosure, so that I could hook it up to just about anything.  I took it with me to the shop last time I demoed a guitar, because then I had an amp that I was familiar with and could compare it to my existing guitars.  Got a few funny looks for trying a £500 guitar with a homemade amp. 

[simop]

I built the Ruby amp and I've tested it with several different speakers. It sounds really good and surprisingly loud with a 12" guitar speaker. It sounds quite good with that 6x9" car speaker too, sound is maybe a bit too bright.
Those 2" mini-speakers are quiet, buzzy, and annoying as Peter said. I haven't yet tried them in series/parallel.

I found a bit bigger 0.5W/8Ω speaker from an FM radio, which sounds pretty good with clean sounds, but distortion isn't so good... Maybe I'll have to keep searching.

Do they make really small (about three inches) speakers for guitar? If yes, where can I buy those? Smallest I've found are 6,5". Or do I just have to use speakers from old radios, computer speakers, etc?

[Burton]

I found a bunch of 4" speakers for pretty cheap ($5-10 a pair).  They are meant for auto and I haven't tried them out yet, but I think I'm going to use a pair of 4" in my custom Ruby, which I'm going to build this weekend.  Check 'em out www.cybergiftcenter.com  (go to the electronics/auto section).