Ad8099

[audioPT]

Check this link or this (PDF)

I've just received the Sollutions Bulletin from Analog Devices and I wonder if this is a good opamp to make a RIAA preamp.

Regards

Pedro Martins

[jcx]

no, not as the input stage - the advertised 1 nV/rtHz low noise only applies over 100KHz

the noise graphs show a typical device with 1/f noise corner at 10KHz and huge current noise, you will need less than 100 Ohm source for the voltage noise spec to apply

there has been little innovation in low noise audio frequency op amps, as far as i know the AD743/745 still lead in the fet category (which would be suitable for mm cartridges) and AD797/LT1028 are the bipolar op amp noise leaders

you can find some discrete fet input designs using japanese fets with ~1 nV/rtHz Vn specs but you might have to select for low 1/f noise yourself

[peranders]

If you are after good opamps for RIAA amps, these are OK:

LT1028, LT1115, AD797, NE5534 (low cost) and a couple more.

[audioPT]

jcx and peranders,

Thanks for the replys.

Yes I know that the LT's and the 'excellent' NE5534 are the best ones in low noise (peranders, let me guess: you are a devoted of the NE5534?? As I am???).

About the noise of the new AD, I've been reading more carefully the specs and I've found that the LT's and NE5534 have better noise figures.

You know, I'm portuguese and still have some difficulties in reading some technical things

[askbojesen]

Tjek this out for AD8099:

New ultralow noise, high BW op-amp from ADI

- Ask

[jean-paul]

NE5534 has excellent noise figures and that makes it one of the best opamps specwise. There are not much opamps out there that beat NE5534 in that aspect. If noise is your concern you can skip trying most other opamps.

However if you like listening to music instead of more or less noise there are some other choices that maybe are less in specs but sound a lot better.

BTW layout will be very critical with a 550 MHz opamp like AD8099, ADI did not change the pinout for nothing. There is a chance that the preamp will be a RF transmitter ...

[audioPT]

jean-paul,

NE5534, I have more than 100 in my stock

About the pcb design, the AD8099 has one innovation: check the pinout. It has a feedback pin that helps making the pcb easier.

[jean-paul]

NE5534, I have more than 100 in my stock

Hi Rick PT, now just imagine that would be 100 pieces OPA627BP and you just got the bill


I am a subsciber to ADI Solutions Bulletin and I was intrigued by AD8099 too. A pity that it is not made in DIL form but I guess in DIL it would not have the specs it has now. It seems that its specs are somewhat over the top for audio-purposes though

[audioPT]

Originally posted by jean-paul


Hi Rick PT, now just imagine that would be 100 pieces OPA627BP and you just got the bill

He! He!

I know I'm portuguese...
I also know RickPT...
But... I'm audioPT!

Yes... I've spent about 20€ on those NE's... AAbout OPA's... maybe more than 200€

Regards

Pedro Martins