I became a man yesterday!

[TheDriver]

That's right I built my first chip amp! I used an schematic I downloaded from gainclone.com for and inverted LM3875. I went to radio shack (I know, I know I'm never going there again) and got all the parts except the LM3875. So just to build one I used my friends HA17741. I bought two 25.2v center tap transformers. I bread boarded the power supply and everything else. I had to adapt the design to the HA17741 from the LM3875. It wanted 18+/-v. So I just used resisters to drop the voltage on each side and wired everything else accordingly. I plugged up a cheap RCA radio shack special 8ohm speaker with a sensitivity of 85db. Anyways it worked! Sounded like **** though. So I played with it for a while. I connected the signal ground and power ground. That helped. So I was like how much voltage can I run to this thing. I removed the resistors on both sides to run 25v+/-. I blew one of my fuses. I had wired a 2A slow blow fuse between each transformer and the rectifiers. So I removed the fuse and ran it with out it. I blew up the 1000uF cap oe the (-) side. Learned my lesson on that one.

Anyways, now for my questions. I want to build the best possible LM3875 I can. I don't want any filters or buffers, just a simple LM38575 this time around.

1) What are the best products to use? Without thinking about price. (Transformers, resistors, caps, diodes, jacks, wires, solder, etc..) Has anyone gone all out and posted the results or a link?

2) Where to get the above product of the net?

3) LM3875T of LM3875TF?

4) Inverted or non-inverted?

5) PC Board or wired?

Thanks, I'm sure I’ll have more questions later though. I had a great time building my first amp! And I'm looking forward to building one that actually sounds good.

Matt

[ble0t]

Just do a search of the Chip Amp forum...there are more than enough threads to answer all of your questions

[karma]

..i became a man yesterday..

good for you now have some kid's and get a mortgage

brian sell's kit's that are nice if you wanted to here a good gainclone



http://briangt.com/


http://briangt.com/order/

[TheDriver]

Got the mortgage. I have to get a boat before I get the kid(s)

[karma]

[Ropie]

I'm sure if you had let your first amp burn in for a while before you broke it, the sound would have mellowed out and improved over a few days.

Have faith in your own abilities, do some reading to find the best parts you can (though a very good amp can be made with parts that are not necessarily considered 'the best'). If you can follow a schematic and make your own gainclone then there is really no need to get a kit.

LM3875T/TF - no difference; TF is insulated, T needs isolating from the heatsink, that's all. Inverted or Non-inverted? Try them both and keep the one you prefer (the inverted is supposed to sound better with a buffer of some kind) Importantly, don't throw all your money at the amp; there are probably other parts to your system that could do with a share of the wealth

[karma]

true. my first one was ptp and it sound's better and better the more i use it. i just dont have the time to make the pcb's. so it's nice to order it for once

[Jay]

Originally posted by Ropie
Importantly, don't throw all your money at the amp; there are probably other parts to your system that could do with a share of the wealth

Yow. Buy an expensive speaker and a CD player, and build cheap Gainclone amp with a buffer. May be someday somebody invent Gainclone speaker

[zagisrule!]

Here is the GC speaker...

That is right, the cone is an alcohol bottle with a home-wound voice coil. The spider is some rubber bands, and the surrounds are electrical tape. The best part is the refrigerator magnet.

The cool thing is that it works.





-Matt