Delay time technics on BBD

[teknoman2]

I am just messing around reading some schematics on the net.
I am thinking making a BBD analog delay using 4x mn3008, ( I know there is an already thread about it and also a double delay pcb on shared projects).
My main question is when we want to use 4 bbd chips should we have to use two clocks (mn3101) or only one?
I saw today the schematic of M@xon Ad900 and they used two clocks.

Probably Scruffie will have a answer for that.....

[Scruffie]

He does!

A MN3101 is specified to drive up to 8192 stages, so 2 x MN3005 or 4 x MN3008, both have the same amount of capacitance on the clock pins in total.

So you can use one.

If you want, rather than 2 x MN3101 you can also use a CMOS buffer (4049, 4069 etc) on the clock lines to keep them nice and square, this will be more of an issue at shorter delay times.

Short answer, one is close enough for jazz unless you're getting fancy.

[teknoman2]

great, now everything makes sense.

Despite that I am trying to understand comparing aquaboy DLX vs AD900 how Delay time  works on AD900.
Is there a reason they put these three transistors on pin 5 (Ox3) on mn3101?
Is it some kind of filtering ?

[Scruffie]

I don't have the schematic so I can't help.

I could guess it might be to do with syncing the 2 clocks to one pot.

[teknoman2]

here is the sch,

I am just curious, probably is what you saying I don;t know for sure...

[ThePastRecedes]

[hijack]

Hey,

Scruffie where's the best place to learn about BBD delays and their circuits? I have the basic knowledge and understand fuzzes and the like but I've got no idea about where to start. I'm an ECE student but I'm sure that BBD won't be covered in getting my degree...

Thanks for any tips

[/hijack]

[Scruffie]

here is the sch,

I am just curious, probably is what you saying I don;t know for sure...

It makes the MN3101 delay time voltage controlled rather than resistance.

[hijack]

Hey,

Scruffie where's the best place to learn about BBD delays and their circuits? I have the basic knowledge and understand fuzzes and the like but I've got no idea about where to start. I'm an ECE student but I'm sure that BBD won't be covered in getting my degree...

Thanks for any tips

[/hijack]

Umm, don't know if I can be much help really, practically my entire knowledge is self taught and i've never read an electronics book.

I'd imagine the principals behind BBDs will become clear even though it wont specifically be taught and then I suggest you study designs and the datasheets.