I'd like to build a bass amp. I have a few questions.

1. What sort of frequency response do i need? I'm not going to worry about a filter on the low end (probably at 20Hz i'll cut it off)...but how high does an averge standard tuned bass go?

2.a. Does anyone have schematics for something around 200 W amp, or ideas on how they might be built?
2.b. Any books on building power amps?

3. Has anyone used car audio drivers for building any guitar amps? I've got a pair of Infinity subs in my car, and while using an active bass, I've got enough voltage that I can use my car as a bass amp, and it sounds very good, so I'd like to use the same brand of speakers (Infinity). I assume they'll work, but maybe someone has a better suggestion?

Well....I can kinda give you some advice. I am no expert on amp building at all, in fact i'm a bit of a newb. How good are you? Can you settle on a lower wattage. If you want 200W of straight Power amp power, then go for this (A) 500W power subwoofer amp circuit (hard cicruit), If you want a preamp for this, look at the circuit for a fender Bassman (B) or other amp, or go to AX84 for some tube preamps, or do the whole Professor Tweed (C) thing. I have tried using audio chips (monolithic IC's to make amps, and they seem to work O.K. Go to my previous thread (D) to find out.

A) http://sound.westhost.com/projects-1.htm (check projects 68, 53, 33)
***Above circuits have PCb's that can be ordered***

B) Dunno where to get it

C) http://www.runoffgroove.com/professor.html

D) http://diystompboxes.com/sboxforum/viewtopic.php?t=21718

Hope that helps,

LM 250+

For a versatile and cool preamp, check this out:
http://www.lynx.bc.ca/~jc/vivaAnalog360DIY.html
Also, there used to be some information about cabinet design at Ted Weber's site (webervst.com?)

i've seen that 50W amp on a chip, and I've already ordered some to play with. I've never built an amp before...so this project is slated for the future, i've got quite a few things i'd like to build first, but I'm just trying to get ideas now.

G Randy Slone writes an incredible book on the operation of solid state power amps.  He's designed some very sophisticated amps, I'm building one of his right now, actually.  The book is called "High Power Audio Amplifier Construction Manual."  I read it and understood most of it, but I'm not new at this.  It's somewhat of a high-end book, but I would suggest you buy it, whether you get through it now or in the future.  It's a priceless part of my library.

Another of his books that might be more suited to someone who's newer at this (not necessarily you) is the "Audiophile's Project Sourcebook."  It's got all kinds of neat projects.  

If you wanna get a glimpse at some of his stuff, you can check out his website-->

http://www.sealelectronics.com

Good Luck ;-)

Hi.

im planning to build a bass amp myself. First i have to build the enclosures.

Im leaning towards using the preamp on this site:

http://www.albertkreuzer.com/electronics.htm

for poweramps i think id rather get one than build one but thats just my opinion.

keep us posted

as far as speakers are concerned, most PA-style woofers work just fine.
A bass ranges from 31Hz for the low B fundamental, to several kHz. To my ears anything above 4-5k is really ugly, if present. I don't really get tweeters in bass cabs either. A useful range is something like 40-4kHz. Most commercial cabs don't even go that low!
I have an Eminence Kappa 15" loaded cab with an f3 of about 34Hz, and a 4x10" with an f3 of 45Hz. The cabs go up to 2k and 5kHz respectively, I think.
The  "loudspeaker design cookbook" by Vance Dickason is a wonderful resource to get a firmer grasp on what youre doing.
Get yourself a (free/shareware) speaker design simulation program (such as WinISD or SPEAKER pro) and start experimenting.

Keep in mind that a car is a very, very strange acoustic environment. It reacts as a pressure chamber, and the speakers are built to suit this, without much of a cabinet holding them. They *might* not work well at all in a large room and large rigid cab. They might also not really have the upper range to work by themselves.
The best idea for a bass cab is probably a vented cab: more low end with less size.
To get an idea on the possibilities of a speaker, you need to know the Thiele/Small parameters of that speaker. Some manufacturers publish them, but with some extra gear (costs money, though) and a carpark (no joke) you could also measure these yourself.
I've had very good results with Eminence speakers myself.
Keep in mind that the lowB fundamental is hardly even heard at volume, so pushing it out might not be exactly what you want. Building cabs larger will push out more lows, but also radically increase cone excursion and "slow the speaker down"; this will allow the cone to add a kind of "reverb" on low frequencies making for a very boomy box.
There's a lot you have to keep an eye on, but between the simulator and Dickason's book, you should be able to get everything just right.
hih

I've also used Eminence speakers with good results.  I have an old Randall 2x15 sealed cab that I put Eminence deltas into.  Works quite well with a 600 watt capability.   Any speaker you go with make sure you check the xmax spec- this is a measurement of the voice coil's travel, measured in mm.  the xmax for my speakers is 2.7mm and they tended to bottom out with lots of attack at high volumes... i would opt for the delta LF which has an xmax of 4.8mm which should be enough, almost twice as much.

for building the cab, I would do one of two things: stick to a proven design or build it from dimensions acquired via a speaker building program.  You can get most measurements for other cabinets online at the manufacturers websites or if worse comes to worse, go to the music store and measure it (if they get nosy tell them you have a small car and want to know if it will fit inside)  This way you can build a cab you know you like the sound of, for example an Ampeg 8x10, and get almost the same sound you would expect.  As far as a speaker enclosure calculator, you enter all your speaker's specs and it makes out the dimensions based on those specs.  I would try several different programs to make sure they all come out in a similar size and shape.  There are quite a few freeware and shareware calculators out there, so look around.

Hope that helps.

Mike