Salvage component from an old amp ?

[NyxOne]

Hi everyone,

i'd like to build my first gainclone amp soon but unfortunately i'm not so rich right now so i'm asking you what you think of this :

Let's say that i plan on buying the LM3875 Basic kit from AudioSector and then salvage an AKAI (AMU310) to get the PS and accessories.

The is supposed to be 100 watt RMS amp so theorically the Tranfo should be powerful enough but i'd like to measure if possible.

Does any know how i can do that? Aslo, will it work with the kit ?

Thanks
---------
Chuck

[MJL21193]

Hi,
Does the Akai work?
I saw somewhere that the power output from the AMU310 is ~40watts per channel so the transformer that's in there will be good for a chipamp. I have salvaged components from old receivers too, including an old Akai (can't remember the model). The case can be used too, along with the heatsink. You can be creative and put a new face and back plate on over the old ones.

Here's the Akai mentioned above. Just the case with a new front and 6 LM3886 active amps inside.

[NyxOne]

Originally posted by MJL21193
Hi,
Does the Akai work?
I saw somewhere that the power output from the AMU310 is ~40watts per channel so the transformer that's in there will be good for a chipamp. I have salvaged components from old receivers too, including an old Akai (can't remember the model). The case can be used too, along with the heatsink. You can be creative and put a new face and back plate on over the old ones.

Here's the Akai mentioned above. Just the case with a new front and 6 LM3886 active amps inside.

WHOAAA!!! Nice looking amp!!! I wish mine is going to be as good looking as that one!

May i ask how you have determined how much juice is coming out of the transformer ?

I'm mean the output voltage that's getting out! 2*xx volt !?

My transformer have 2 green, 3 blue and one brown wire on what seems to be the output.

I have multimeter, can i just try to different combination of wire or am i going to blow something ?

Thanks
----------
Chuck

[yldouright]

This is definitely a frugalphile type thread. I have an old HK AVR120 home theater amp that refuses to stay on. The case and layout are pretty good for putting in a new amp section. I would like to keep the tuner, the line stage and the software functionality but I don't think I can do this if the amps don't resemble the originals because its diagnostics will balk. Does anyone here know to get around this problem if I provided the schematics?

[digits]

What voltage rateing is on the big caps in that amp?

[PJN]

I just did the same by reusing an old trafo form a dead marantz 2238B reciever. You really need to measure the output voltage from the trafo though. A lot of old SS stuff had trafo's with voltages too high to be used with the LM 3886. Measure the output voltage with just the trafo plugged in and multiply by 1.4 to get an idea of what the rectified VDC will be. If you are going to use the PSU better measure that first too. By the way I am very pleased with the way the chipamp.com amp sounds.

PJN

[yldouright]

PJN
This amp was designed for chip amps (NE5532?) and its PS makes 15V, 5V and 3.3V rails. The trafo is a nice chunk of metal and probably good for >150VA so it should be suited for this.

digits
The biggest caps are on the subwoofer card and there are only 2 - 16V 4700uF. A piddly amount for a real amp but probably ample for a chip amp. I wouldn't be reusing those caps anyway because they are probably the reason why the amp switches off in the first place.

[yldouright]

A update to my prior post. I opened one up instead of looking at the schematics and there are 2 x 4700uF/50Von the sub woofer board and 2 x 6800uF/63V on the main board.

[yldouright]

While looking at the output curves on the LM3875, it looks like it can handle a 4 ohm load if you run it on 16V rails. It wouldn't make much power but +10dB would be sufficient for my needs. Has anyone run that chip on such a low voltage swing?

[yldouright]

Nobody?