Please help me design a chip amp

[pingu]

Hi i've been reading the forums for awhile now, and must thank you all for sharing such a great wealth of knowledge, ingenuity and creativity!

now ive buttered you nicely up maby you'll help me with my project?

My girlfriend had a arcam alpha 3 amp and tried to change the fast blow fuses whilst it was still plugged in, lucky she didn't get to the point of removing the fuses whilst live but accidentally dropped a handful of fuses onto the circuit board causing random shorts here and there and a explosion of sparks! Well i don't think i'm going to try to fix it as i have no experience with electronics thus far and the problems may be numerous!
Since i've been looking at making a chip amp for awhile i will take this opportunity to salvage the transformer and give chip amp a go!

don't drop conductors onto live boards!


Ok, i don't know what out put this transformer gives. How can i measure the out put safley? i have a multi meter and a digi scope, so well equipped here.

i found a bit of spheel from the arcam website: 'Every amplifier also has a heavy duty toroidal transformer, which ensures that they deliver a high power output for their size, along with minimal background hum and noise.'

Will i be able to make a stereo amp with this transformer? Heres a pic of the output from transformer
transformer meets board

p.s any tips on inserting images in here?

thanks!

[Nordic]

measure the output of the transformer with AC setting on multimeter... DC it can supply is that figure times about 1.414

[Nuuk]

Pingu, here is a similar project to the one that you are contemplating. I suspect that traffo will be putting out something like 25 VAC but measure it to be sure. If it is 25 volts, you can copy that A60 clone more less to the letter!

(Do remember to glue on the lid so your girlfriend can't get inside again! )

[Nuuk]

Pingu, another option is to phone Arcam and ask them, or even ask for a service manual. They are very helpful! But it is not difficult to do what Nordic says!

[pingu]

thanks for the link!

[jaycee]

Your girlfriend is lucky she wasnt killed! Even the DC voltage between rails could kill you.

Arcam should give you the service manual. If memory serves the transformer is a 25-0-25 160VA unit. The "R" versions of the amps have an additional 9VAC tap which will be black wires.

Disconnect the two orange and one blue wire from the board, near the capacitors. Screw them into some terminal strip to be safe. Then, measure between one of the orange wires, and the blue wire, with your meter set to AC. For the DC voltage that'd produce when rectified and smoothed, multiply by 1.41.