LM13700

[lightningfingers]

I just found out I can get these, can they be used in the small stone/ross phaser?

I know they are dual OTAs but thats all...

TiA

[mikeb]

Yep!    :wink:

Mike

[lightningfingers]

Thanks      

[puretube]

http://home-wrecker.com/ross_phaser_black.png

[Aharon]

I built my Ross Phaser (Ropez) using the JRC13600.
Now I found LM13600AN which if the AN sufix is any indication should have better noise specs.Am I wrong in this assumption?.
What 13600 have you been using and did you hear any difference?.
I have had bad experiences with JRC chips but that's me.........
Let me know
Thanks
Aharon

[puretube]

I`ll leave the answer to s.o. else who has comparison-experience,
I do however prefer the LM13700 over the 13600...

[Mark Hammer]

Mike/Vsat will have something to say about LM13700's vs 13600's.  One is more likely to see 13700's in higher-end (or higher-aspiring) analog synth module projects, so there IS something they do better but I don't know what it is.  I'm not entirely sure that they can be inserted where a 13600 used to be with guaranteed success, so the difference is not like that of, say, an NE5532 vs a 4558.

[lightningfingers]

Now i've had time to look at the 13700 datasheet, it seems that its the same chip, same pinout, but it will "perform better" than the 13600. I don't know what that means exactly but I guess I can build a Ross phaser now......

[Mark Hammer]

Based on my own experience, you SHOULD build yourself a Ross Phaser, except make sure you use sockets for the dual OTA chips.  That is, unless someone here who has built one and used LM13700's can confirm that 13700's do indeed work well in that circuit.

Do make a point of trying the phasefilter option.  Definitely worth it.  A sound you've never heard anywhere else.  Also make a point of installing the phaser/vibrato option.  That plus phasefilter provide a really broad panorama of possible sounds and feels; much more than you are accustomed to hearing in a phaser.

[Aharon]

Wow,they are trying to charge me $3.50 for the LM13600AN,something definitely different with this chip.....(aside from the price I mean)
Aharon

[toneman]

no , the 13600 & 13700 are not *exactly* the same.
Look more closely at the data sheet.
If the circuit does *not* use the built-in darlington buffer,
then they will work pin 4 pin.  Example, PAIA 9730, 9720.
*IF* the circuit uses the 2-tranny buffer, the 13700 is the
better choice cause the buffer is completely
independent of the OTA.  In the 13600, the OTA affects
the buffer, so U might have some offset problems if
U try to substitute.  Look at the data sheet again,
around the buffer area.  Again, If U don't use the internal
buffer transistors, not a problem.  I have found the 13700
is just slightly more expensive than the 13600.  (10cents)
afn
tone

[puretube]

dunno the pinout from memory, but the schem will work with the "700", if you use the darlington like the single transistor in the "600" schematic.

In the 13700, leave its diode-bias pin unconnected.

(Will double-cross-check for 100% over the weekend...).

The 13700 will have less control-current feedthrough at the audio-output!

[mikeb]

Based on my own experience, you SHOULD build yourself a Ross Phaser, except make sure you use sockets for the dual OTA chips.  That is, unless someone here who has built one and used LM13700's can confirm that 13700's do indeed work well in that circuit.

I've been working on a phaser based on this circuit for some time - using LM13700s - and it works 100% fine, but you need to tweak the bias of the LFO circuit a little (the 270k/100k voltage divider) to get the phase range sounding good (recommended to play with this anyway). Then again, this might be because of the other things I've done to the circuit... for sure go for it though!

Mike