Any idea for an AMP (no tubes please)?

[zener]

I'm going to build a practice amp. I'm planning to hook up my Little Gem as the preamp and something you might suggest that would sound good as its power amp (schematic) . I can still replace the Little Gem with something you may also suggest, but just in case, this gem is just in "standby".

I'm listing some things you might want to know more. I'll be away for one whole day, so I can't get back sooner.

I got a 8" 8ohm 18w speaker. I will make my own wood chassis.
My crappy guitar's pickups are H/S/H and I mostly play just H and H.
I want something for the power amp just the usual volume, bass and treble (if there would be mid or gain, better ). There might be a switchable drive/clean, probably in the preamp. In the Little Gem, that could be through LM386 pin1 & 8, right?  

BTW, my friend gave me an amp circuit a several minutes ago. It reads 15w, has vol, bass and treble each at 50K, one IC BA5406 http://www.ozitronics.com/data/ba5406.pdf, one transistor whch I cannot identify and runs at 12v. I haven't tested it so far because two of its 1000uf caps were desoldered, so I still have to see the local store.

I read somewhere about putting a speaker inside a plastic bucket would produce an interesting sound. I'm not sure about that one. Any tricks?

Any ideas for this stupid guy who's planning to build an amp?

Thanks for any help :wink:

Zener[/url]

[Fret Wire]

Here's some pretty simple amp kits that might go well with your Little Gem:

http://www.electronickits.com/kit/complete/complete.htm

http://kitsrus.com/

[Mark Hammer]

The BA5406 is not rated quite that high in terms of output power, and certainly not at 12v supply into 8 ohms.  It's one of those car radio amps that really needs to have very low impedance speakers (2-3 ohms) to do any damage.  It also needs an unpleasant number of caps.

Go with a TDA2003, or maybe an LM380 or 384.  For that matter, a pair of LM386-4's, wired up in bridge mode, will deliver a couple of watts to your speaker, with much less trouble and cost.

Note that the LM386 (can't speak for the JRC type) comes in several suffix varieties, with higher numbers indicating a higher power dissipation capacity.  A 386-4 is comfortable handling 3/4 of a watt at 12v without needing heatsinks (though obviously not for extended periods).  A 386-1 pushed that hard would require some means for keeping it cool.

[Nasse]

:? http://www.mif.pg.gda.pl/homepages/tom/files/tramp.gif

Someone posted this site few times ago and there was nice looking solid state amp circuit from Elektor. Dont remember the magazine year or month but maybe I´ll find it someday. It was a nice project because there was single sided PCB pattern with the article, so a back issue might be helpful for intersted diyers, or maybe it can be found in some library.

Maybe it has too much parts for simple amp, and you can buy ready made units or used gear cheap sometimes. But anyway there is nice snippets, like the filter at output or effects loop part and other things that might be useful for some other project...

[ejbasses]

Hey zener why not go with a lm383 for more power? its an integrated circuit in a to220 package and it only uses a small number of parts. You can also use 2 of these and bridge them for 16 watts of output.

for a preamp use something similar to a fender preamp or you could check out www.headwize.com for EQ ideas. just add a jfet buffer on the front end or something else you might fancy.

peace bro,

ejbasses

[petemoore]

Using an already existing amp, I have an example here. Panasonic, no output rating other than 8 ohm.
 By finding one with more than enough power for your needs [so you have alot of headroom], so as to avoid the nast clipping associated with driving these things, it seems with a reasonable amount of power, it could be made to sound at least interesting/?
 I'm sure that's what many of us started out on. Dude had a modded boom box that used to crank out some nasty distortions, albeit not so refined.
 I've never tried rehousing an amp section from one of these all in one stereo units, but I come across them fairly readily around here, on the curb, often with terribly scritchy pots, in this case radius slider pots, otherwise functioning properly...well except the cassette deck which obviously was subjected to the same conditions that decroded the pots.
 Anyway for whatever that kind of 0$ available power is worth.[?>...
 Some of these old amps like Sony, Onkyo, etc. have actual big irons and heat sinks, boasting reasonably high output levels.
 I don't fully understand transistor hi fi's and everything about why they often troubled [clipping, blowing, sounding harsh, lacking bass definition etc.] by guitar signal inputs.
 I think they'd look radio on a 4x12'', and you can run other programs with the switching inputs they have. Nice big heavy jobberz, not exactly meant for heavy road use.
 Anyway as available as some of this fairly extensive units are, [I had some BIg ones...I think one is now in Blackfire/TS/Rosscomp] is there anything that can be done for them to make them more guitar friendly?

[mr_winter_]

I recently find a good power op amp of 40W >>> TDA2052, yo can get the PDF with a circuit recomended by ST in http://www.st.com

I hear it and it´s good!!!

[zener]

Thanks for the replies .

I tried the amp with BA5406 and it was weak indeed as Mark said.

I'll just try the LM383 http://www.web-ee.com/Electronic-Projects/data/lm383.pdf. Do you know of any schematic for this one or I'll just use the schem in the datasheet?

BTW, can I implement right away any tone stack from here http://amps.zugster.net/articles/tonestacks/ or I still have to mess up with a buffer at the end. I'm eyeing the Baxandall or the 3-knob Marshall.

Thanks a lot :wink:

l

[Mark Hammer]

Some literature I've seen indicate that the TDA2003 is a replacement for the LM383, which I think has been discontinued.  The TDA2003 is widely available and can be bought for under a few dollars.

[campj0le]

Here's a schematic link that might be helpful.

Forgot the link:
http://www.kbapps.com/audio/schematics/tubeamps/marshall/Default.htm

[zener]

Yeah, I was able to take note of that just a while ago.