Chalumeau TL071 instead of LM386

falco_femoralis

falco_femoralis

Well-known member
Hi all, I'm combing over the schem for the Chalumeau and I'm wondering why the design doesn't use a TL071 rather than the LM386? All the other delay designs use a regular op amp before the delay chip, what is different about this one?

I intend to lift pins 1 and 8 and set the internal gain of the chip to the lowest setting so that I can bypass the fuzz entirely.

After reviewing the data sheet for the LM386 and TL071, it appears that enough of the pins interchange that I may be able to install a TL071 instead of an LM386 with some minimal tomfoolery, with the goal being a cleaner tone with less distortion. Does this make sense?
 
They are not the same type of chip.

The 386 is an audio amplifier, while the TL071 is an operational amplifier (op-amp), and they perform different functions. "Amplifier" being in their name isn't indicative of identical properties.
 
From what I've read on the LM386, it's an audio amplifier meant to drive a speaker, and in this case it's driving a PT2399. Various other analog delays use a TL072 to drive a PT2399, so why is this one different?
 
The 386's output drives an LED directly in this circuit. Maybe the extra current drive it's capable of was needed for this purpose.

BTW, I wouldn't think that the cleaner tone with less distortion you're after would happen with a TL071. PT2399 is a pretty low fi/noisy/dirty chip at longer delay settings.
 
falco_femoralis said:
Hi all, I'm combing over the schem for the Chalumeau and I'm wondering why the design doesn't use a TL071 rather than the LM386? All the other delay designs use a regular op amp before the delay chip, what is different about this one?

I intend to lift pins 1 and 8 and set the internal gain of the chip to the lowest setting so that I can bypass the fuzz entirely.

After reviewing the data sheet for the LM386 and TL071, it appears that enough of the pins interchange that I may be able to install a TL071 instead of an LM386 with some minimal tomfoolery, with the goal being a cleaner tone with less distortion. Does this make sense?
Click to expand...
If reducing gain is the goal then you can sever the connection between pin 1 and 8. A swithc is a good way to do this to allow you to switch on and off. Alos can use a pot.
 
🎶One of these things, is not like the other, one of these things DOESN'T BELONG🎵 ...


LM386 PINOUT.png TL071-Pinout.jpeg

...in the Chalumeau.


OFFSET NULL — NOT CONNECTED

Further discrepancies can be found in their respective datasheets.
 
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