ruby question

[birt]

so i made a ruby with 2 chips.
i combined the ruby and the little gem MK2

i the normal little gem and the ruby there is a 220uF cap before the output. what does that do and why is it left out in the mk2?

and if i want to add it.. how should i wire it in with those 2 chips?

[birt]

*bump*


i really wanna know  :oops:

[B Tremblay]

The 220uF cap blocks DC voltage from the speaker.  Since the output of the 386 normally measures half of the supply voltage and the negative speaker terminal is grounded, the cap is quite necessary.  Without the cap, the battery would drain quickly and the 386 would get very hot, then probably die.

The cap is not needed in the bridged version (LGMkII) since both 386 are at the same voltage.

[birt]

The 220uF cap blocks DC voltage from the speaker.  Since the output of the 386 normally measures half of the supply voltage and the negative speaker terminal is grounded, the cap is quite necessary.  Without the cap, the battery would drain quickly and the 386 would get very hot, then probably die.

The cap is not needed in the bridged version (LGMkII) since both 386 are at the same voltage.

thanks!

so it doenst do anything tonewise  
that's what i wanted to know

[B Tremblay]

Well, if you use a smaller cap in the Ruby or Little Gem, bass will be cut.

With a 220uF cap and 8 ohm speaker, the corner frequency is 90hZ.  If you used a 100uF cap and 8 ohm speaker, then the corner frequency moves up to 199hZ.  That means beginning at the open G string, lower frequencies will be cut at 6 dB per octave.

Use a 470uF cap to be sure that you're getting all the bass you want, but a 220uF cap will often suffice.