LM13600/LM13700 = two CA3094's?

[D Wagner]

Hey Pedal Fiends,

Can the LM13600 and LM13700 dual OTA’s be considered a direct replacement (circuit wise, not pin wise) for the CA3094?  Comparing the circuit equivalent schematics in the datasheet,

http://www.national.com/pf/LM/LM13600.html

there are a few resistors “missing” from the LM13*00’s, and I wasn’t sure if it made a difference.  I do realize that the diode bias inputs aren’t used on the LM chips.

I like the idea of using a dual OTA for space savings, as opposed to adding the Darlington pair to a CA3080.  However, the use of a 3080 and transistors in Darlington configuration, would allow the addition of the resistors that would equate to a CA3094.  Would the extra components make a difference in a MicroSynth or phaser clone, or is the dual OTA chip close enough for DIY?

Thanks in advance,

Derek

[Mark Hammer]

Check out the "Ropez" at tonepad.com and the "Piedrita" at the same place.  The Ropez is a clone of the Ross phaser that attempts to copy the Small Stone.  The Small Stone used/uses 3094 OTAs, the Piedrita subs a 3080/Darlington combo as a cheaper and easier-to-get alternative, and the Ross/Ropez uses 13600's for the samee thing.  Compare these circuits and that might answer your questions.

[Fp-www.Tonepad.com]

Mark,

Did you ever build the "Ropez"?

And if you did, any comments?

[D Wagner]

Thanks for the info Mark.  

I checked out the schematics and layouts at tonepad, and the LM13*00's look like the way to go for a compact layout.  FP does some fine work, and I may 'borrow' a design cue from him if I can find the time to get the thing into CAD.  

I'm updating two bathrooms and the kitchen with new cabinets, countertops, lighting, sinks, plumbing, paint, switches and outlets, so I don't have any time for fun stuff other than an occasional perusal of the Forum.  That and we are still living out of boxes, having moved to the area just weeks ago.

DSW

[anyuser00]

Bump!

D Wagner, did you ever work this out.  It would certainly cut the costs down on building the Micro Synth.  6 ca3094's @ $4.75 each vs. 3 LM13600's @ $0.50 each

[D Wagner]

Bump!

D Wagner, did you ever work this out.  It would certainly cut the costs down on building the Micro Synth.  6 ca3094's @ $4.75 each vs. 3 LM13600's @ $0.50 each

No.  I am still in remodel mode right now.  I have had some time to dabble into effects, but nothing like before my move.

I have some high resolution scans of an original EH MS, and it has 7 CA3904's and uses an 11V regulator instead of the 10V regulator in the schematics that most people have been working from.  FWIW, it was a non functioning unit that I got a chance to look at closely, but never got working.  

I have most of the parts for the build, but haven't set aside any breadboard time to experiment.  I got 8- LM13600's and 8- LM13700's for when I do get the time.  Hopefully this summer, the house will be done!

I'll will certainly post my results, problems, questions here on Forum.

Derek

[anyuser00]

Well thanks. :wink:

[Maneco]

i've built my clone using lm13700,only the one that's on the envelope generator is difficult,you'll have to build the buffer stage from discrete transistors...

[uncle boko]

I would generally use this chip where specified - for christ's sake, how much do you spend a year on cigarettes to set light to??

[Paul Perry (Frostwave)]

for christ's sake, how much do you spend a year on cigarettes to set light to??

If you spend more than ZERO on cigs, you are a damn fool.
But I think the real point is that CA3094 is damn hard to find, compared to the 13600/13700 (even though only NJE are making them, since the Philips analog chip factory burnt down in December).

[ExpAnonColin]

for christ's sake, how much do you spend a year on cigarettes to set light to??

If you spend more than ZERO on cigs, you are a damn fool.
But I think the real point is that CA3094 is damn hard to find, compared to the 13600/13700 (even though only NJE are making them, since the Philips analog chip factory burnt down in December).

Not damn hard to find through smallbear, but then it goes from hard to find to waaay too much @#$%ing money.  Especially since you can score 13700s for way below a dollar apiece.

-Colin

[anyuser00]

The point was actually that the MicroSynth needs 6-7 of those bad boys which at about $5.00 each is pretty d**m exspensive!