I'm ready to GAINCLONE!!!!

[davidlzimmer]

After buying my Son an MP3 player for Christmas I started looking into songs I could down load for him. I really got in the mood to seriuosly listen to music again. I even got the pair of little Bose out of the closet and hooked them up to a small amp and CD player. Knowing that even tho it was enjoyable, the little 5 watter was robing my of the full sound.

So, needing a good amp, I started searching on the net and got into the DIY/Gainclone thing. Since I have a very small budget, I realised that after I got the amp and built it, I would have to save again untill I got the transformer. Then, lo and behold, (this must be a sign ), I had one slapped in my hand from a buddy who had no idea of my new project!

So here is the plan. I am convinced that the best way to go about this is to get the LM3875 kit from Chipamp.com. It's a convient pacage with enough left to do that you still feel like you built yourself. For the supply, I have a 250VA center taped transformer that puts out 36 volts to center tap.

I have a pair of Bose 201 speakers (8 ohm) that I will use as "close feild monitors". No real intensions to fill up a room. In fact IMHO, close feild monitoring is the best way to hear the sound the producer intended, sense room accoustics hardly inter into effect.

Any opinions as to what results I will get, or problems I should anticipate are very much appreciated.

Thanks in advance,
David
Fairmount, GA USA

[Variac]

Seems like a fine plan. The chip amp will be good enough that you are on a logical path towards a decent system. It won't need to be replaced, so you can next focus on building some good cheap speakers!

The amp will be louder than you expect..

[davidlzimmer]

Thanks. BTW, the Bose 201s make excellant close field monitors.

[Bazukaz]

I would like to ask , what are real advantages of gainclone ?

[pinkmouse]

Originally posted by Bazukaz
I would like to ask , what are real advantages of gainclone ?

If built coreectly, they sound much better than they should for very little money.

David, just to check, is the 36V your transformer puts out before or after rectification? If before, it will likely be a little too high for a gainclone, 36x1.41=50V DC.

[Vikash]

Simplicity, cost, and sound quality.

Trafo might be too high. You want 18-25v trafo for lm3875.

edit: doh! the mouse beat me to it.

[pinkmouse]

'S ok. It's always nice to have backup!

[davidlzimmer]

Bazukaz and pinkmouse,

Ok so..... Am I back to day one? Help me with this. Is it possible that I could use a Zener to get the voltage down? Or do I need to shop for another transformer?

If the latter, does anyone know where I can get one cheap? :-)


Thanks to all for posting!!

[pinkmouse]

You really need the correct transformer unless you want to get complicated and use a voltage regulator. If you do a search in the chip amps thread you should find many recommendations.

[davidlzimmer]

Ok, you've convinced me. It's kinda embarassing but, I'm really limited on my budget. I have an ex employer who has a huge surplus of 120/24V single secondary transformers. I'm pretty sure he would let me have a pair. Would that work well? What VA would you recommend for minimum?

Thanks all.