Can I make a simple distribution amp with a CD4050 hex buffer IC?

Question

I've got a 555 circuit hooked up to a Stylophone-type keyboard. I'd like to duplicate the audio tones—which I assume are square waves (coming out of pin 3)—a couple of times and run them through an octave-up circuit and frequency divider, and then on to a mixing circuit and see if I can get the tones to be more complex and chord-like.

I've seen the bare-bones distribution amp circuit on this site (Active audio splitter (Line levels)) comprised of op amps. But, I found this PRL-414B diagram online and have been wondering if it could be even simpler.

Image source: Pulse Research Lab - PRL-414B - 1:4 TTL/CMOS Fanout Buffer and Line Driver

IF SO, since the output of a 555 timer is buffered, would I even need the first buffer on the left? Input and output resistors? 1K on the input? Suggestions?

OR will the hex buffer chip not accomplish what I want it to?

(Sorry about the previous version of this question. I was just happy that I managed to include an image. I have trouble with this site. I can't find a search function on it to save my life. And apparently I no longer get email prompts with regards to replies.)

Answer 1

A single CD4041 gives you 8 strong outputs (≈10mA each) - 4 of each polarity. Connect all the inputs (pins 3, 6, 10, 13) to the 555 output. The 555 and 4041 can be powered from the same voltage source, anywhere between 5 and 12V*. Add a 1uF ceramic capacitor between 4041's power pins 7 and 14. Pins 1, 4, 8, 11 provide "positive" (non-inverted) outputs, while pins 2, 5, 9, 12 provide inverted outputs.

For this application, the 4041 is hard to beat probably.

There's no need for series output resistors after the 4041 outputs.

I found this PRL-414B diagram online and have been wondering if it could be even simpler.

That is a circuit made for a specific application - not at all what you need. You can do it all with a single chip, whether it is a CMOS digital buffer like the 4041, or a quad op-amp - either CMOS or LM2902/324.

* NE555 and CD4041 will work together up to 15V, but there's no switching speed benefit to that. So unless you really need the high output swing, 12V is a very reasonable option.

Answer 2

Yoo can probably connect the output of the 555 directly to your other circuits without an explicit distribution amplifier.

If you are dealing with actual audio signals, rather than the square waves that the 555 generates, then the CD4050 or other digital logic parts are not suitable - you would need op-amps or other analog circuits.