New Member

[Trent]

Hey all.

Just joined up for the knowledge. I am doing a TAFE class that requires me to build something rather technical, and because Ijust started learning how to play the guitar I picked an amplifier. I figured it would sufficiently test my skill to learn in a reasonably short timeframe (4 months). I have a basic understanding of electronics, have fairly high soldering skill but I know next to nothing about guitars and music. So i'll be learning on all fronts.

Anyway, I will be sure to do the obliged n00b thing and ask many questions and whatnot. I intend to keep this amp so would like to do a resonable job on it. Ideally something that sounds decent to just practice on at home when I eventually get an electric. And potentially build myself another even better amp in the future.

I will poke around the forum when I get time but i'm at work now so I gots to go.

Cheers

[polo16mi]

Hi Trent:

Welcome to the board.

May i suggest you to go straight forward to the Ruby amp.

It is ideal for begginers. It is easy, very cheap, the parts are very common, and best of all, if you make every step reasonably well, it work pretty good. It´s only disadvantage is very low power (about 1 W), but is ok for a practice bedroom little amp.

Here the link www.runoffgroove.com/ruby.html

Basicaly this circuit use an LM386 chip, which is an operational amp. Here you got the datasheet of him. LM 386 Datasheet

Ruby has an improvement of the suggested circuit at the datasheet, and use a FET as buffer stage, it really worth it.

By my little experience with this amp, it will sound as good as good be the speaker that you use with him. Maybe you can try several til you get one that you like.

Any question, don´t hesitate to make it.

[joecool85]

I agree the Ruby is a good one to start on, although I have a personal preference to the more simplistic Little Gem circuit myself: http://runoffgroove.com/littlegem.html

And it's true about the speaker.  I've had mine running on a 10" Dean Markley speaker cab and it was loud enough my wife told me to turn it down lol.  But on a small 2-3" non-guitar speaker that is much less efficient it's real quiet, just enough to practice on.

[Trent]

Hey guys,

Thanks for the input but unfortunately I don't think that one will be complex enough for the class. It needs to have a few adjustments (tone bass etc) and have a preamp stage and power amp stage. So is there anything you know of that you could reccommend? I found the project 27 amp that another guy on this forum said he was building and that one looks ok if a little complicated. But I reckon I could pull it off. But a liitle simpler amp would be good to.

Also I have a 10in sub I had for my car that never got put in so I was going to use that. Here is the link to the spec sheet http://www.alpine.com.au/files/current_owners_manuals/SWS-1043D.pdf Its the SWS-1043D. Will it work ok? It only has to be decent and if this project turns out any good I will possibly replace it with a better speaker later on.

Thanks for all your help,

Trent

[J M Fahey]

Try to build Project27 preamp which fits what you need, and a TDA2030 or TDA2050 power amp, which is much simpler than the 100W one suggested by Rodd Elliott.
You'll have the equivalent of a commercial 15W practice amplifier.
You can design a board for the preamp in Veroboard using Bancika's excellent DIY Layout Creator, available online for free.
It already has an example with a 15W TDA2030 amp.
A car subwoofer is about the worst guitar speaker you can find, but it will do nicely at a school classroom level.

[polo16mi]

I already mounted an about 15 W amp stage using TDA2005 datasheet circuit (bridge one). It work pretty good too.

Simple, few commons components and it work with 12V.

It is another option that you could choose for use with Projet 27 preamp...

About your speaker, i think that the main bad think it has is it´s  frecuency response (31hz-700hz), because guitar´s frecuencies goes from few hertz til around 6 Khz. Probably your guitar will sound very bass, and without any bright.

I used a satellite speaker from my home theather in a try with Ruby Amp and it sounded really good.

[Trent]

Thanks for all the help guys.  :tu:

You know i'm actually finding this kind of interesting  To the point that I might even attempt a proper amp once I get my guitar.

Anyway im quite impressed and confused at the amount of info out there.  So after alot of looking I thought I might build a ruby amp, but also attempt some sort of preamp to go in front of it, maybe the umble that I saw on runoffgroove.com.

Also if the sub I have is a bad idea, what is a good cheap speaker? If the amp is run off a 9v battery then something small yes? about 6in? Will anything with a frequency response up to about 6khz do?


Once again sorry for all the questions.  And feel free to tell me anything else you may think I need to know.

Thanks heaps,

Trent

[phatt]

Hi Trent,
          Re speakers;
Use the *search box here* or google some words you obviously have not heard of. :tu:

As complex as it maybe portrayed by never ending supply of over tecky types,,,There are in fact only 2 types of speakers you need to understand.

*High complience and Low compliance*

A Woofer is a high compliance driver as it needs to *Comply* to a certain dimension box to work effectively.

most stuff is HC,, which is intended for HiFi or for monitoring pre-recorded sound.

With LC (as hopefully you have already caught on) it matters little whether its inside a box or bolted to a flat board.
As long as there is some panel or open back box to seperate the phase to some extent they deliver close to the same sound,, in or out of a box.
these do not need to *Comply* to any particular size box (within reason)

In years gone by these LC drivers where often the only type used whether it be Hifi or vocal PA use.

Back In the 40's a rolled edge long throw woofer would have been very rare.

Most HiFi/Car stereo type speakers are *Woofers of very limited bandwidth* and often have shocking SPL figures (hence they need 10 times the power to be as loud as a guitar speaker)

So yes an *LC* or *full range* or now called *MI speaker* is what you need.
(MI = Musical Instrument)

Dead easy to pick the difference between LC and HC;

Just look for the rolled edge on a woofer with a loose easy to move cone.

An LC speaker has a *spider rippled edge* and the cone will be very tight and hard to move. (they only ever move about a 1/4 inch)

Teemu and a few other savvy folk have written some good explanations about all this right here at SS guitar,,, but I can't seem to find it?
Joe cool,, might know where that went?
Phil.

[polo16mi]

I would look two main characteristics for a speaker (behind of its size, of course).

First:  Bandwidth ( from around 30-50 hz to 5800-6000 hz ).

Second: SPL  (the higher value, the better) SPL is how much sound pressure produces the speaker with 1W of signal, measured at 1 mts of distance. The unit for this are [db] so a difference of 3 db means twice the sound pressure. You actual Alpine speaker push 84 db. If you find the same speaker model but with 87db, it pushes twice.  Figure that with the same ruby you produce a lot more of noise  :trouble

[J M Fahey]

As a basic seat of the pants rule, what Phatt said can be translated into:
1) thick cardboard cone, foam/rubber edge (sometimes black cloth "wet" with a sticky liquid), if ypu look closely you can see the cloth thread, easy to move cone (more than 1/4" back and forth with slight finger pressure, low resonance (you tap the cone with your middle finger and it sounds with a low note, similar to a bass drum)= high compliance/Hi Fi woofer/car audio (that Alpine you have)
They have no highs, no attack, (your strings sound as if made of putty), and low efficiency, they need *lots* of watts to make some sound.
2) thin cardboard cone, cardboard edge (sometimes  "wet" with a sticky liquid), if you look closely you can see it's still "painted" cardboard, hard to move cone (no more than 1/8" back and forth with stronger finger pressure, high resonance (you tap the cone with your middle finger and it sounds with a higher note, similar to a tambourine)= low compliance/guitar/TV speaker (not Home Theater but the cheap junk they use in the TV itself)
They have lots of highs, good attack, (your strings sound as if made of metal), and high efficiency, they need only a couple of watts to become obnoxious.
They look cheap, are cheap, great!
Can be reclaimed from TVs, car radios, etc; where a couple watts must count.
EDIT: google "Jensen Mod Speakers" and look at the pictures of MOD 6" , 8" and 10" , that's what you want.
Compare these to the Alpines or any other audio/car speakers.
The alpine is 84 dB ; the worst Mod (6") is 90db; the 8" 92 or 94; the 10" around 95dB; ten times as loud as the Alpine, go figure !!!
Did I mention they are cheap?

[joecool85]

If you want to build a real amp, may I recommend building a K20-X.  I already have the preamp all vero-ed out here: http://www.ssguitar.com/index.php?topic=1885.msg12904#msg12904

For the power amp you could use most anything, in stock form it uses a TDA2030 poweramp circuit.  You could hook it up to a Velleman kit, chipamp.com kit or anything else similar.  For the price I would recommend using the Tiny Giant for the power amp: http://musicpcb.com/pcbs/tiny-giant-amp/

[Hayden]

I just got my Tiny Giant kit and started identifying and dry fitting the componants in place and I'm having some trouble. Some of the rectangular caps don't physically fit next to each other. Also there is one rectangle printed on the board with no info inside, and 2 more holes on either side of that marked 1uF. If I could see a photo of the componant side of the board that would be helpful. Also there are 2 solder pads under were the tl072 sits. Connections there? Any help would be great

[Trent]

If you want to build a real amp, may I recommend building a K20-X.  I already have the preamp all vero-ed out here: http://www.ssguitar.com/index.php?topic=1885.msg12904#msg12904

For the power amp you could use most anything, in stock form it uses a TDA2030 poweramp circuit.  You could hook it up to a Velleman kit, chipamp.com kit or anything else similar.  For the price I would recommend using the Tiny Giant for the power amp: http://musicpcb.com/pcbs/tiny-giant-amp/

I had a read through the thread for the K20-X preamp and that looks promising. But what would this output buffer that is referred to entail? Seems you guys think its necessary but I need some elaboration on the details of how and why.

And that tiny giant amp looks good too. I like the idea of using an old laptop power supply.

Thanks again for the help,

Trent

[Trent]

Is this the schematic you used fro the vero layout Joe?



There are a few schematics in that thread and I dont know which one you used  I like the idea of having a clean and overdrive channel. But instead of a stompbox I might just put a switch in the amp.

Cheers,

Trent

[joecool85]

I just got my Tiny Giant kit and started identifying and dry fitting the componants in place and I'm having some trouble. Some of the rectangular caps don't physically fit next to each other. Also there is one rectangle printed on the board with no info inside, and 2 more holes on either side of that marked 1uF. If I could see a photo of the componant side of the board that would be helpful. Also there are 2 solder pads under were the tl072 sits. Connections there? Any help would be great

This link might help: http://www.diystompboxes.com/smfforum/index.php?topic=89687.0