Here is one I designed a Few Years Ago. This is the Upper Frequency Board with filters at 1kc, 1.5 kc, 2kc, 3kc, 4kc, 6kc, 8kc, 12kc, 16kc and 24kc. 20 Segment LM3915 Displays.
I Planned to make another for the Lower Frequencies, but Lost Interest and Never Followed through. Its now sitting in my Junk Bin.
You Want it, You can Buy it, Quite Cheap, below parts cost.
($60.00 plus Postage?)
Contact me through my website at: **broken link removed**
I can also give you the Positive Artwork for the PCB, for free.
And I can supply additional displays and LM3915's Real Cheap.
Sorry I don't have Spare TL074's
I made this board in 1997 and it is designed so it solders directly to the lower frequency board as to make one LARGE Board for all the frequencies. Length of this board is 10.5 inches. completed unit will be 21 inches.
Sorry I never drew up a complete Schematic and I have lost the notes I made. But its not that difficult to figure out.
A "Pink" noise generator should be used to calibrate it. but a signal generator will work.
Bigger Picture, E-mail me and I'll send it to you.
Supply voltage is +/- 12 or 15 volts.
IC's are TL074's, and LM3915's