new please help direct me to relevant sections.

[gafhenderson]

hi,

i am looking to build myself a stereo amplifier but i don't know the relevant section where i would post questions. ideally could someone link me to a simple DIY amplifier project with relevant parts lists and instructions. looking for best bang for buck with 50-100watts into 8ohms.

if possible could someone tell me what the parts are in this picture please?

many thanks.

[wintermute]

Hi gafhenderson, and welcome to diyAudio

The picture you have posted looks like some sort of chip amplifier. Moving from left to right you have a toroidal transformer, which has two secondary windings, a power supply and finally two amplifier boards. It looks like it is a stereo amp, and is probably using two chips per channel in bridged mode for higher output power.

Across the back panel from left to right you have the mains inlet, speaker outputs and inputs. This is a straight power amp with no volume control it will need a separate preamp (unless you are using a source with its own volume control such as a pc music server).

Best bang for buck is probably going to be a chipamp or Class D amp, so check out both of those forums. Note that a lot of the chipamps will be maxing out around the 50W mark into 8 ohms unless you use a bridged configuration. I'm not familiar with Class D.

Tony,

[gafhenderson]

Originally Posted by wintermute

Hi gafhenderson, and welcome to diyAudio

The picture you have posted looks like some sort of chip amplifier. Moving from left to right you have a toroidal transformer, which has two secondary windings, a power supply and finally two amplifier boards. It looks like it is a stereo amp, and is probably using two chips per channel in bridged mode for higher output power.

Across the back panel from left to right you have the mains inlet, speaker outputs and inputs. This is a straight power amp with no volume control it will need a separate preamp (unless you are using a source with its own volume control such as a pc music server).

Best bang for buck is probably going to be a chipamp or Class D amp, so check out both of those forums. Note that a lot of the chipamps will be maxing out around the 50W mark into 8 ohms unless you use a bridged configuration. I'm not familiar with Class D.

Tony,

thanks for the indepth reply.

ok so you've confirmed my basic understanding of the parts which is somewhat comforting.

you mentioned 'PC music server' does this mean a PC soundcard as this would be the source of the signal?

which section would be most appropriate to start a questions thread? chip amplifier i think is the most appropriate for my skill/understanding of electronics as these can be bought in fairly modular stages - unless im wrong?

[picowallspeaker]

there is something strange happening with that picture !!
First , we don't need bananas inside the cabinet
Then ,at far right , we can see the heatsinks which is a CPU fan cooled type ,and the fins are too narrow , so no good ( maybe there's a fan we don't see ).
Moreover the outputs from the amplifier go back to the rectifier/smoothing board ...and there are some active devices attached to heatsinks , too : maybe they are triacs to shut off output...we don't see it much often.

Welcome to the Forum !!

[wintermute]

yes that's the sort of thing I'm talking about I have a Home Theater PC, and I run it direct into my amp with no preamp, I just use the volume control on the PC. Be careful though, I did the same with my normal pc, and found out the hard way that if you do voice calls on msn messenger it puts the volume to maximum when the call starts!!

The chip amps forum is probably a good place to start, have a read of some threads there to get a feeling for what's available, and then start asking questions Yes there are modules available pre made, and you just have to add a power-supply and chassis, or you can buy a kit of parts and build the whole thing from scratch, or if you are really adventurous you can build on verro board or point to point wiring, but from the sounds of things you want to go with modules or a kit

Tony.

[wintermute]

Originally Posted by picowallspeaker

there is something strange happening with that picture !!
First , we don't need bananas inside the cabinet

Yes I thought that there was something a bit odd there but didn't put my finger on it. Yes you would expect the output to be wired direct to the output plugs.

Then ,at far right , we can see the heatsinks which is a CPU fan cooled type ,and the fins are too narrow , so no good ( maybe there's a fan we don't see ).
Moreover the outputs from the amplifier go back to the rectifier/smoothing board ...and there are some active devices attached to heatsinks , too : maybe they are triacs to shut off output...we don't see it much often.

Not much of the heatsinks is in view so hard to say. On the output wiring, I first thought the same but it is just a case of bad routing of the wiring, I believe they just pass under the power-supply board. Ideally they shouldn't go near it, and the wires should be kept as short as practical and be twisted together.

Tony.

[picowallspeaker]

Yes they pass under it ,now I see
So they are transistors for having the supply voltage regulated ,undoubtedly !

[madtecchy]

Because the active devices on the psu board have heatsinks i would be lead to thinking they are voltage regulators, I think wintermute is on the money with the output cables routed under the psu..

Regards Ian

[picowallspeaker]

Sorry..double post
Hey !! It wasn't me

[gafhenderson]

thanks to all that have replied, very refreshing to join a specialist forum and get real answers to a question without being told to do something completely different, like just buy a new amp because making one isn't for n00bz