Hey, paulbostaph. I don't know if you noticed or not:

1) Phil Elliot sells PCB's for his project 3a

2) Data box in the link shows 100 watts, with 35 volts into 4 ohms.

3) Near the top of the web page there is a link to a very detailed construction guide that a reader made.

I agree with Gene and Scubasteve, building such an Amp is complicated. The double sided supply this amp needs is equivalent to a single supply of 75 volts, using + and - 35 volts, so that equals alot of headroom, massive volgage swing available. If you do build this, please be careful with the power supply.

Basically, a double-sided power supply with equal plus minus values is equivalent to two supplies in series, like 2 batteries, with all ground connections made where the plus and minus connect the 2 supplies together.

Plus lead here------{+ _ }---{+_ }---------minus lead here
/
/
/
ground lead here

The most common way to construct this is to use a step down transformer with a center tap on the secondary side. The 2 outside secondary output leads go to a full bridge rectifier and are the positive and negative connections, and the center tap directly from the transformer is the ground.

The project does show the supply wired properly, but I believe there is a typo under the transformer in the schematic. It is labeled: 25-0-25, it should read: should be 35-0-35.

 

OOPs, messed up my drawing.

Plus here----{+ _ }---{+ _ }----------minus here
.............................../
.............................../
.............................../
ground here --------* where both supplies connect

 

you guyz and gals are really nice pple to warn me about all these shortcomings. Really appreciate it. I'll ask my friend who study's electronics to see whether he can help me make this one. But i'll put this making of the amp as my last resort due to your suggestions. I'll check out the price of new and used amps first. The only problem is getting the prices of hi-fi amps as i don't even know who sells them. But anyway i'll get it solved. I need this hifi amp not only for the drums but i want to try it for guitars for some reasons. Thanks again for all your concerns and warnings.

 

Hey paulbostaph,

The funny thing about making your own stuff in electronics is that it usually costs more then just going out and buying it commercially.

The only advantages that we can get, is that we can make it better or more specific to what we need. In the case of an amplifier, commercially available amplifiers are much cheaper. Even buying the nice shiny aluminum extruded cases directly from the manufacturer in small quantity will probably superseed the cost of a finished unit! I would know, I have looked into building a nice amp for my car.

Steve

 

the more the reason for me to buy it off the rack. around how much would such an amp be (90W). Im not looking high end here as it might just not work for me. Oh yeah, i don't think i need a real hiFi amp as long as the signal is not changed in characteristics too much. I know im not being specific here but i hope you have the idea. Any estimations will do i wont quote you on it even if its far off :wink: .