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General => General Technical Chat => Topic started by: DavidDLC on November 27, 2012, 07:28:15 pm

Title: ECA324E very old op-amp
Post by: DavidDLC on November 27, 2012, 07:28:15 pm
Hi, I have looked on the www for the ECA324E datasheet and was not able to find it.

I want to know the features of this op-amp to look for a replacement. Does anybody have the datasheet of this circuit by a chance ?

Or do you know where can I buy this ancient IC ?

I can use the LM324 as a replacement, but I would like to know a better quality quad-opamp to be used instead of the LM324.

Please guys post your comments.

The David.

Title: Re: ECA324E very old op-amp
Post by: nitro2k01 on November 27, 2012, 07:56:24 pm
It's a standard pinout, so there are loads of compatible devices. The standard answer would be TL074. Of course, there are better speced parts than that. Google for TL074 substitute and read your brains out.
Title: Re: ECA324E very old op-amp
Post by: poptones on November 27, 2012, 09:34:42 pm
That can be a dangerous assumption. LM324 has a low gbp, liw input and offset current, fairly low input impedance and inputs can swing to ground. A bifet amp in the same position could behave very differently.

If an LM324 was used there originally chances are it doesn't need to be anything better. Why not just put one back in there?
Title: Re: ECA324E very old op-amp
Post by: c4757p on November 27, 2012, 10:36:08 pm
Quote from: poptones on November 27, 2012, 09:34:42 pm
That can be a dangerous assumption. ... A bifet amp in the same position could behave very differently.

I second that from experience, from a circuit I was just working on. The 324's output can swing to ground, so it can be operated in comparator mode. The TL074's output won't even drop below a VBE threshold, let alone swing anywhere near ground, so you can't use it as a comparator without throwing something in (I used a ~4V Zener) to drop the voltage.
Title: Re: ECA324E very old op-amp
Post by: DavidDLC on November 27, 2012, 11:43:48 pm
Thanks for your comments, I totally forgot to comment that is used on a Teac equalizer that I bought as non-working unit on Ebay, I already probed that replacing the damaged ECA324E with a LM324 works.

This is a picture that I found on the internet from a different equalizer, but the boards are exactly the same.

Will the TL074 work here ?

The David
Title: Re: ECA324E very old op-amp
Post by: poptones on November 27, 2012, 11:46:40 pm
A tl074 may work in that. It will change the frequencies a bit and may cost you some headroom, but will probably sound better when used within its limits. Changing one without changing them all will, however, be pointless.
Title: Re: ECA324E very old op-amp
Post by: free_electron on November 28, 2012, 01:40:49 am
oh wow. the bottom two still sport the olde Samsung logo... like from mid 80's ...