Replacement opamp

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10-Apr-2017 10:38 AM

Fozzie13

Fozzie13

Posts: 4

What is the best replacement opamp for a TLC271CP for a 606. Is it a straight replacement or is any other modification needed? 

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10-Apr-2017 04:58 PM

Eric

Eric

Posts: 45

If i were you i would leave the TLC271CP alone. This is something i was also previously interested in changing, but many people have convinced me that any deviation will upset the stability of the amp.

I still believe in my heart that other opamps such as LME49710 and OPA627 would sound better (despite it being a DC servo), however i have decided that it's too dangerous to try.

My advise would be don't change opamps.





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11-Apr-2017 01:54 AM

EJP

EJP

Posts: 1376

There's no 'danger', but the only time I tried it I ended up with power-on/off squeals.

There is also no point. The op-amp has a low-pass filter with -3dB point at 14 Hz, so whatever difference another one may make is essentially only audible below that.

The TL271C is well chosen for this application.
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13-Apr-2017 04:42 PM

Eric

Eric

Posts: 45

If changing opamps in 909 isn't there a danger of components being damaged or HF oscillation ect?

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13-Apr-2017 06:47 PM

Fozzie13

Fozzie13

Posts: 4

After the excellent advice I've received on here I'm leaving the opamp as it is. I've just changed the electrolytic capacitors and I'll leave it at that.

Many thanks to those who send me advice.

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14-Apr-2017 03:45 AM

EJP

EJP

Posts: 1376

Eric: damaged by what? Damaged by the repairer of course, but competence is assumed. HF oscillation is ruled out by the op-amp being an integrator with a 680nF capacitor as the feedback loop.
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14-Apr-2017 08:28 AM

Eric

Eric

Posts: 45

Hi EJP. Someone suggested the power transistors could be damaged if the wrong opamp was fitted. You say you once tried a different opamp and observed power on/off squeals ect, may i ask what opamp you tried?

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14-Apr-2017 08:52 AM

EJP

EJP

Posts: 1376

I think it was probably TL071. I can't see how the power transistors could get damaged. There's a lot of misinformation out there.
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