Guitar amp plans

lliw · June 04, 2006, 09:03:09 AM

Hi, im looking around for plans to make a solid state pratice amp.

Looking at 30-50W maybe?

I play mostly metallica, acdc etc.

Can anybody help me out?

Thanks

joecool85 · June 04, 2006, 09:06:18 AM

Your best bet would be to build a bridged LM1875 poweramp or a single LM3886 poweramp setup. Either way I could probably set you up with a cheap set of boards.

SECONDandBOWERY · June 04, 2006, 05:02:51 PM

As far as pre-amps go, you might want to look into various distortion pedals that you could build into your amp.

Rock'n'Roll,
--Andy

lliw · June 04, 2006, 07:59:45 PM

Righto, im not to sure what you mean by "bridged LM1875 poweramp or a single LM3886 poweramp setup" im guessing they are some sort of setup, im only like a beginner to electronics.

I found this amp http://sound.westhost.com/project27.htm but its 100W and im not sure if I would need one that big,not looking for a loud amp, ,I just want it to sound good and cheap.

So yea Im kind of looking for instructions as well

How much would it cost to make the one you mentioned?

Thanks

joecool85 · June 04, 2006, 08:39:15 PM

If you did a stereo LM1875 it would cost you $10 to get the boards and chips etc, normally around $10-20 for a heatsink on ebay and 20ish for transformer. So plan on $50 to get you going. Normaly the boards/chips would cost more, but I got some for free and then you just pay shipping plus a couple extra parts that didn't come in.

As far as being a beginner, thats not a problem. Just less than a year ago I was too. Sometimes I'm not the best at explaining everything in detail right off. The good news is, we have a bunch of smart people on here that are great at answering questions. SO, ask away!

A good resource is the wiki btw. The link is at the top. Also, it is good to read the stickies in the power amp and preamp sections of the forum.

SECONDandBOWERY · June 04, 2006, 11:09:53 PM

Exactly how loud do you want it to be? If this is just a amp for practicing around the house, you could probably get away with using a single LM1875 which would push about 20watts. Then you could use the preamp from that link you provied.

Rock'n'Roll,
--Andy

lliw · June 04, 2006, 11:12:18 PM

Sweet thanks mate,

ive decided to mave a few stomp boxes first.

How close would that solid state amp be to sounding like the amp in the link below with a distortion effect pedel?

http://ax84.com/dp.php?pg=projects&project=p1-extreme&file=/media/ax84_m269.mp3

lliw · June 04, 2006, 11:16:29 PM

Yea not loud at all, Just so I could play in my room and maybe sometimes with mates. No gigs lol.

Just the important thing is i want it to sound good, i have a 10W ashton amp atm but it sounds really bad with gain turned up, havent had a distortion pedal on it yet, will be interesting to see how much better it will be.

SECONDandBOWERY · June 04, 2006, 11:25:12 PM

Are you ever going to want this thing to sound clean, or is this a distortion only amp? I mean you said that you like Metallica and AC/DC, so I'm assuming you'll maily be playing with distortion, but of course, it's always good to be able to have some clean sounds.

Rock'n'Roll,
--Andy

lliw · June 04, 2006, 11:45:50 PM

Yea i would like it to be clean as well, but yer most of it will be distortion.

Would it be a good idea to just have one clean chanel on the amp and then have the effects via stomp boxes?

SECONDandBOWERY · June 04, 2006, 11:49:35 PM

Yessir - quite an excellent idea!

Rock'n'Roll,
--Andy

lliw · June 04, 2006, 11:58:52 PM

Sweet, so what type of voltage would be needed from the transformer? the same 35V from that other 100W amp?

it will be a cheaper option to make a smaller wattage amp will it or not really?

SECONDandBOWERY · June 05, 2006, 12:19:33 AM

Well, that 100watt amp uses transistors for the power amp. It could be alot easier (and less expensive, I think) to use an op-amp. One opamp could replace several transistors. The highest wattage you can get out of any opamps that we here at the boards use is 68watts, and that's using a LM3886.

Rock'n'Roll,
--Andy

lliw · June 05, 2006, 01:07:51 AM

Righto, how much cheaper would it end up?

would you have to use bigger speakers for the 100w amp?

Are the speakers expencive?

SECONDandBOWERY · June 05, 2006, 01:15:45 AM

I don't know exactly how much cheaper it would be, or how much speakers cost off the top of my head. I'm pretty sure with most speakers though, it's the impedances that need to mach, as power handling shouldn't be that big of an issue. The actual size of the speaker (8" speaker vs. 12") doesn't depend on the wattage of the amp at all.

Rock'n'Roll,
--Andy

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Guitar amp plans