Would it kill me to not use these caps and resistors

[peranders]

Originally posted by theChris
Rb is to reduce DC offset

This is not the main reason here. Just read what Rb is in the datasheet, very good described. This resistor is to avoid possible damage at low voltage conditions.

[theChris]

Originally posted by MC
heh, I guess I'll get them all as soon as I can figgure out what Cs is suppose to be

Cs - Supply Capacitance. in general, analog circuits use bypassing capcacitors located close to the IC. most professional circuits at least. Cs is typically an electrolytic capacitor between 1000uF and 10000uF with the preferance being to 1000uF for the gainclones. sometimes a 100nF or 1uF mylar (or some other cap) is used as close to the IC pins as possible. the idea to to improve the high frquency preformance of the capacitor combo.

My testclone is at heart just 2 100nF caps and 2 resistors on the lm1875 ICs with hot glue preventing it from touching the heatsink which is a few mm from the pins on 2 sides... located further away from the ICs is a 4700uF capacitor on each rail (the PSU caps). this gives a little over 1000uF per IC per rail voltage. there is no volume control or power switch... or case...

there is a difference buffer followed by an active crossover before the lm1875s.

there is a bit of DC offset, and the lack of sheilding means the signal wire needs to be further from the transformer. otherwise the amp works fine.

the lack of a volume control or power switch is annoying.

also, you do realize that you need a transformer and full-wave bridge if you plan to run this circuit from AC?

[millwood]

Originally posted by Nuuk
Yes, that should be 30mA. Thanks for pointing it out, I'll change it.

if it is indeed 30ma, you may need to redo the calculation and upsize the resistor to match.

[Nuuk]

Oops, see what you mean, it should be 0.03mA not 0.003mA! Damn those decimal points!

Thanks again.

[millwood]

Originally posted by Nuuk
Oops, see what you mean, it should be 0.03mA not 0.003mA! Damn those decimal points!

Thanks again.

are you sure your LED will lit up at 0.03ma or 0.003ma? that's a very small current, even for a LED, .

it is like either 3ma (a little on the low-side) or 30ma (on the high side). In your example, a 7k, 1/4w serial resistor will do that job for 3ma; or a 750ohm, 1w serial resistor for 30ma.

I would personally go with the first one.

[Nuuk]

Hey - what are you doing up at this time of day?

The If is 30mA although that is the MAX figure. Perhaps it would be better to run it at say 20mA so I'll alter the text.

[millwood]

it will work at 20ma, tho you need a beefy resistor. Mine is working at 3ma and 1ma respectively (rated at 20ma).