amp advice

I am a speaker builder who has just wet my feet in the ocean of amplifier knowledge. I am interested in building a simple, versatile, college student budget, yet high quality amp to run a pair of medium sensitivity 8" two-ways in a small room. I intend to eventually build a larger amp to run the lows and use the amp in question for the highs.

I checked out Randy Sloane's Audiophile's project sourcebook. In these pages he describes his simplest design, the 60w basic EF amp. Kit available at Sealelectronics.com for $95 /channel plus the cost of a power supply, soft start, etc. Will this amp get adequate hf response? It isn't one of his higher quality designs. And, how much more am I paying for the kit as opposed to buying individual parts?

I am sure there are many other amp kits out there, what do you guys recomend?
Thanks in advance,
andy
 
Re: www...

Don't rule out doing a gain-clone. For close to the cost of the kit you mention you could have a nice pr of 25 W monoblocs (ie ~$100 assumming you're are good at scrounging for case & heatsinks). The chips can be had as samples if you ask nice, and Steve at ApexJr just got some 120 VA 18-0-18 toroids in that would be ideal (so new they aren't listed yet*). Add some caps, bridges and some passive parts and you have yourself a real nice, REAL CHEAP set of amps.

(* he also got some dual 42 V @ 1000 VA for any of you guys building the monster amps)

The place to go for more info (you'll have to wade thru a lot of posts -- look for Thorsten's inverted schema) is the Amp Chips Forum.

I also have a list of some useful links on my website.

dave
 
Hi,

I'd go for the Leach Amp. I managed to build it for about $50 per board in parts + box/transformer/rectifiers/caps. It is well documented on the web and there are a lot of others to help if you get stuck.

[IMGDEAD]http://www.skip.informatik.gu.se/~kmg/diyaudio/projects/leachamp/pics/002_leach_amp_open.jpg[/IMGDEAD]

Link to Leach Amp: http://users.ece.gatech.edu/~mleach/lowtim/

//magnus
 
Sorry planet10, I'm not that same Magnus. There are a whole lot of us out there. ;=)

I've mainly been into the Leach Amp and have not yet got into the speaker building area, but I soon will.

bostarob: I'd go for an amp that isn't too hard to build, and preferably a design someone nearby has built. It isn't always easy to get help when you're stuck, even if most of us here try and help as much as we can.

Regards,
//magnus
 
Sorry for the delayed response,
I estimated the cost of the sealelectronics basic ef to be around $400. Let's make that the most I am willing to spend. Of course the less I spend the better. I like $50 a board. No I cannot scrounge for heatsinks as this is my first amp. I can make a chassis, I have a big sheet of diamond patterned alum kick plate (looks very cool and easy to drill). Or I'll just use a shoe box. (joking)
After looking at the leach amp, I like it. It is more complex than the amp I was planning to build, but it also is cheaper and may be higher quality. How many watts does it put out?
Magnus, I want my amp to look exactly like yours. How much did you pay for the entire thing?
Look what this guy did with the leach amp:alt. leach amp
thanks,
andy
 
Hi,

When I first started to build my amp I had contact with Claes Malman (the site you mention), since not all parts are/were easy to find in sweden. He helped me a lot.

I bought my enclosure in a local store here in Gothenburg and the transformer in another place. They were the big investment (toghether with the input caps).

I believe that my amp cost.

* 2 x $50 for the boards
* $60 for the enclosure
* $50 for the transformer
* $50 for the caps
* $30 misc cables and rectifiers
-------------------------------------------
Tot: $300 - $400 since you never buy "only one resistor" or so.

//magnus
 

djk

R.I.P
2001-02-04 4:23 am
USA
The Leach is one of the best DIY amps you could build. But it may be a bit much for a first time project. Build the ESP 3A instead. Much simpler. Use the alternate MJ21193/94 outputs, two pair per channel, and a 30-0-30 600~800VA transformer. Later build the Leach and bridge the ESP 3A. The ESP 3A will bridge to 400W/4R as described, with the bridging circuitry already on the board. http://sound.westhost.com/project3a.htm
 

djk

R.I.P
2001-02-04 4:23 am
USA
"djk: where can I find more info on bridging? I'm very new to the concept, so a brief description would be nice. " Read this first http://sound.westhost.com/project14.htm
then, if you have a schematic for your amp do this http://sound.westhost.com/project20.htm
"The ESP looks perfect, how much do you think it will cost?" The 3A circuit board is USD$17.30 from ESP with a fee of USD$8 for postage. One board will build a stereo amp and self bridge to a large mono amp. ESP will ship up to eight boards for the same fee. Total cost will be largely determined by what you want for a chassis and heatsink, the elecronic parts are all inexpensive.