Hi, can anyone tell me how to make a delay circuit using capacitors and resistors? I know that a lot of people have asked about this before, but I'm a bit confusabubled. The circuit is for an analogue audio equalizer thing.

Thanks.

 

What will be the function of the delay?

Maybe you meant peak detector?

 

The EQ us supposed to work by splitting the input, and delaying one side by a few milliseconds, and then joining it up with the original, where the waves cancel each other in certain ways, and attenuating different frequencies in different ways.

 

It's going to be more elaborate than just capacitors and resistors - http://freecircuitdiagram.com/2008/08/19/analog-audio-delay-line-expand-your-virtual-3d-sound-space/.

 

You can use an all-pass filter which passes all frequencies but with phase shift.

http://en.wikipedia.org/wiki/All-pass_filter

 

It's going to be more elaborate than just capacitors and resistors - http://freecircuitdiagram.com/2008/08/19/analog-audio-delay-line-expand-your-virtual-3d-sound-space/.

Boy.....now THAT's a blast from the past. I built one of those bucket brigades once. Worked pretty slick. I'm surprised that chip is still around, but it is.....cool!

eric

 

Could any of you guys explain how your suggestions work, as I'm a bit of a beginner at electronics. Thanks a lot!

 

Could any of you guys explain how your suggestions work, as I'm a bit of a beginner at electronics. Thanks a lot!

A bucket brigade is a LONG string of capacitors, with a sample-and-hold circuit (generally an FET) between each one. With a clock signal, you transfer the charge from each capacitor to the next one in line. You then have to INTEGRATE (use a low pass filter) at the end to average all the charges together, and get an analog signal back out.

The SAD512 uses 512 stages of capacitors and sample-hold devices. I don't THINK you want to build this out of discrete devices...but you could!

Eric

 

A bucket brigade is a LONG string of capacitors, with a sample-and-hold circuit (generally an FET) between each one. With a clock signal, you transfer the charge from each capacitor to the next one in line. You then have to INTEGRATE (use a low pass filter) at the end to average all the charges together, and get an analog signal back out.

The SAD512 uses 512 stages of capacitors and sample-hold devices. I don't THINK you want to build this out of discrete devices...but you could!

Eric

Do you know where I can get a BB without paying a load? They seem to be pretty much obsolete now.

 

Sad to say, it looks like the remaining devices are in the clutches of warehouse operators. They have literally zillions of obsolete IC's, but usually only on bids of $500 and up. You can probably find Intel 4004's at some of them.

 

What about the diagrams here:
http://www.headwize.com/projects/showfile.php?file=equal_prj.htm ?

No bucket brigade!!!
There are quite a few sites around like this with similar circuits. Let me check my bookmarks.....:

http://sound.westhost.com/project75.htm
http://sound.westhost.com/project64.htm

etc. etc. Do you think it would be possible to use a tape, or is that ludicrously impractical?

 

Good news! You guys might be in luck. http://www.holtek.com/english/docum/consumer/8970.htm Sounds a bit digital though, with SRAM