AI6YR Ben1d ago

Random electrical engineering question. I am looking at building an RIAA preamp (for a record turntable), and most of the circuits out there use a NE5532 dual low noise opamp.

However, I have a LOT OF 4741 opamps (a lot). Originally destined for the L1011 aircraft, lol.

My analog design skills having significantly atrophied since college (cough cough), what specifications on an opamp (aside from noise) are important for this stuff? I suspect I have to re-calculate gain and values for a different opamp? (also, bandwidth on the 4741 is 2.5Mhz... NE5532 is 12Mhz... so I assume they aren't going to be equivalent).

#electronics #opamp #amplifier

Show threadRyan1d ago

@ai6yr I let some audio person chime in but buyer beware ... TI changed the spec on their NE5532s

https://youtu.be/22ZmmZ67SMY

EEVblog 1752 - Texas Instruments SCREWED UP the NE5532!

YouTube
Show threadAI6YR Ben
@fullywoolly Ouch
Jun 23 at 1:39amWeb
Show threadRyan1d ago

@ai6yr I didn't know what an RIAA preamp was ... Looks like there is a short discussion about the "best" opamp

https://www.andyc.diy-audio-engineering.org/phono-preamp/index.html

Might help answer your questions and wipe some dust off that analog course in the process.

Got it from an Internet search so not sure about accuracy.

Phono Preamp Design Using Active RIAA Equalization

Derives the design equations for computing component values for high-accuracy RIAA equalization using a popular op-amp circuit.

Show threadAI6YR Ben1d ago

@fullywoolly Thanks! Looks like the two factors in that paper are high open loop gain and "finite gain-bandwidth product".

Per the 4741 spec sheet, "3.5MHz bandwidth, coupled with high open-loop gain, allow the HA-4741 to be used in
designs requiring amplification of wide band signals, such as audio amplifiers. Audio application is further enhanced by
the HA-4741’s negligible output crossover distortion"

Not sure why it's not used by anyone, but it most certainly CAN be used for that purpose (and designed for it), per the spec sheet.

(in other words, I should just give it a try, lol)

https://www.alldatasheet.com/datasheet-pdf/view/66696/INTERSIL/HA-4741.html

HA-4741 PDF

Part #: HA-4741. Description: Quad, 3.5MHz, Operational Amplifier. File Size: 62.55 Kbytes. Manufacturer: Intersil Corporation.

Show threadRyan1d ago
@ai6yr that's great news! Nice find!
Show threadAI6YR Ben1d ago
@fullywoolly Thanks for the help!
Show threadRyan1d ago
@ai6yr my pleasure. Looking forward to hearing how it turns out.
Show threadDewey1d ago
@ai6yr @fullywoolly nice article, that's some high gain so the 5532 makes sense. However, give it a try. Back when I was doing analog I would always pick a range of opamps and build and test prototypes with all of them
Show threadAI6YR Ben1d ago
@DeweyOxberger @fullywoolly Thanks! Looks like the other challenge is you have to build your own plus/minus supply for these, lol. Well, hopefully will be an interesting project for a weekend. (I'm sure I have all the parts... the question is the patience to build it, and do it dead bug style lol)