Building amp from schematics ?

[Buzzy]

Is it possible to build commercial amps from service manuals ? And how hard is it for a first timer to build it ?

[Jan Dupont]

Yes it is possible, however as a first timer it may not be possible...
What amp did you have in mind ?

[Buzzy]

I was thinking of something like qsc rmx850 or other pro amps for subwoofer duty.

[jaycee]

For a first timer, no. The schematic only gives you part of the whole product - the PCB is a vital component as well. Unless you already know how to lay out a PCB well for an amplifier, you are pretty much not going to be able to build it. Layout is critical and can take years to learn.

[gain]

some service manuals do include the pcb layout, but yeah i agree with the previous posters that this would be an ominous challenge if you have never done this sort of thing before. not to discourage you though, if you think you can handle it, go for it! i too want to build a vintage commercial amp or two (Quad 405, Bose 1801) from schematic/service manual once i get a little more experience in making amps from scratch, especially pcb fabrication.

[Buzzy]

Some service manual like rotel have the whole pcb layout. But i wanna like duplicate only a channel. However since i don't have any experience i might wanna try other simpler stuff first like the LYNX. But the LYNX transistors are expensive (MJ21194).

[nigelwright7557]

Originally posted by Buzzy
Some service manual like rotel have the whole pcb layout. But i wanna like duplicate only a channel. However since i don't have any experience i might wanna try other simpler stuff first like the LYNX. But the LYNX transistors are expensive (MJ21194).

What makes you think it would be any cheaper building your own ?

In my experience it usually costs considerably more.
You are buying one off transformers etc where as the pro company is buying in hundreds at fractions of the cost.

If your looking for a amp to use then just buy one.
If your interested in building your own amp for the experience then do that.

You clearly need to know what your doing if building your own amp. Even if you build it there are things you need to know before firing it up for the first time like is the bias low enough not to short out the output transistors.

I always fire up the driver board forst without the output transistors t oensure the driver board is working OK and doesnt have a fault that will fry

I also include speaker protect ccts and this has saved me a fortune in speakers.