I've been thinking about trying to find a preamp, but if you buy them new they seem pretty pricey. Anyone have any luck with using a preamp to a power amp? IE - Dean Markley (or any other brand) preamp to PA or something?
Brian is setting me up with a couple lm1875 kits and maybe a lm4780 kit. They should be in by the beginning of next week. Who is interested?
I don't know exactly what I'll be getting, so I can't garantee anything till it comes in the mail, but its kinda first come first serve. I'll just have you pay shipping. Oh, and Brian wants whoever gets the kits to build them and take a bunch of photos.
Chipamps are designed so that they don't need a preamp, however, that is for when you are running a lineout from a computer, CD player etc. This means that you need to get guitar signal up to that strength by way of a preamp.
So, here is what we need in a preamp:
- Gets us up to linelevel - basic EQ (probably 3 band) - protection, ex-someone pluging in AC power to the input - input buffer of around 1m
The lm1875 makes a really killer 20w guitar amp! I just tried it out and wow! It only has as much clean headroom as any other 20w amp, but its plenty for practice. Crank it up and throw on a distortion pedal in front of it, and damn! Very much loud! I wasn't expecting it. But I guess it makes sense, with the right speaker even my 15w dean markley gets pretty loud. Anyway, it would make a sweet practice amp power chip if someone is interested. Brian is suppose to start selling PCBs for the lm1875 soon also, so you won't have to make your own or anything.
Well, my brother wanted a small bass amp, so I figured a TDA2003 circuit would work well...well, no. It sucks actually lol. Virtually no useable clean headroom, I would dare say the lm386 is better. Its no looker either lol.
**edit** I should say that it worked pretty well with guitar. However, I like the lm386 better even though its not as loud.
Ok, so we are going to base this thing off from the K-20X preamp because its simple and has great tone. But, we are going to ditch the OD for simplicity's sake, plus then people can add their own OD later, and we are going to add a buffer to the front. Anyone want to throw up a quick schematic of their best idea for it? If we get this thing looking good, we can get some PCBs printed up with ssguitar.com on them and sell them for cheap.
My first little gem. It runs on one 9v and is in a cheap treasure chest that I bought for $2 at a dollar store. The 1/8" jack isn't a headphone jack, but an external speaker jack for my pot cab.
Here is my little gem clipper. I can hook it onto my pocket and walk around playing guitar in my apartment. No volume control, I just use the guitar's volume...and leave it all the way up anyway. The switch on it goes from clean to OD. It runs on 3xAA.
The schematic is available at runoffgroove.com and in the schematics section of the forum.