AD843's or OPA627's with +-5V rails?

Stew · 8th February 2006, 06:00 PM

I’m rolling output buffer opamps in my Yamaha CDC-745 and have tried AD-826, AD-823, and OPA2134 (Originals were NJM5532) with the following results:

AD826 sounded dynamic and detailed with great bass. Clear but recessed mids/vocals. Highs were detailed but a little sharp.

AD823 had the best mids,vocals, highs that I've heard. Translucent and somewhat detailed. Unfortunately upper mids and highs were also overemphasized and lower mids and bass were severely lacking.

OPA2134's sound warm but somewhat veiled. Vocals and dynamics are not as good as the AD chips but they are more balanced.

I'm considering AD843's or OPA627's with brown dog converters. Will these work OK with +-5V rails? The datasheets say they will but how do they sound with +-5V's? How do these two chips compare?

Also, I’ve seen OPA627’s on ebay for much less than retail but the ones I saw don’t have the characteristic white Burr-Brown logo. Instead they’re marked BBOPA 627AU 0103 in dark yellow type. Are these legitimate OPA627’s or fakes?

Stew · 9th February 2006, 01:27 PM

Has anyone tried AD843 or OPA627 with +-5v rails?

maxlorenz · 9th February 2006, 02:49 PM

I don't, but, why don't you try an independent power supply for them? (+/-12 or 15V)
I have OPA627 with 14VDC and they sound excellent to me.

Just a thought.

Good luck.
Mauricio

Stew · 9th February 2006, 08:10 PM

According to the datasheets, these chips will both work from +-4.5v to +-18v. The specs don't appear to change dramatically over that range so hopefully they'll sound good with +-5v. One of my concerns was clipping but with a preamp input sensitivity of around 150 mv, I assume clipping won't be a problem. Is that a reasonable assumption?

If I decide to add an independent power supply, what should I look for and what do they typically cost?

8th February 2006, 06:00 PM	#1
Stew diyAudio Member Join Date: Nov 2005	AD843's or OPA627's with +-5V rails? I’m rolling output buffer opamps in my Yamaha CDC-745 and have tried AD-826, AD-823, and OPA2134 (Originals were NJM5532) with the following results: AD826 sounded dynamic and detailed with great bass. Clear but recessed mids/vocals. Highs were detailed but a little sharp. AD823 had the best mids,vocals, highs that I've heard. Translucent and somewhat detailed. Unfortunately upper mids and highs were also overemphasized and lower mids and bass were severely lacking. OPA2134's sound warm but somewhat veiled. Vocals and dynamics are not as good as the AD chips but they are more balanced. I'm considering AD843's or OPA627's with brown dog converters. Will these work OK with +-5V rails? The datasheets say they will but how do they sound with +-5V's? How do these two chips compare? Also, I’ve seen OPA627’s on ebay for much less than retail but the ones I saw don’t have the characteristic white Burr-Brown logo. Instead they’re marked BBOPA 627AU 0103 in dark yellow type. Are these legitimate OPA627’s or fakes?

9th February 2006, 01:27 PM	#2
Stew diyAudio Member Join Date: Nov 2005	+-5v rails Has anyone tried AD843 or OPA627 with +-5v rails?

9th February 2006, 02:49 PM	#3
maxlorenz diyAudio Member Join Date: Oct 2003 Location: osorno , Chile	I don't, but, why don't you try an independent power supply for them? (+/-12 or 15V) I have OPA627 with 14VDC and they sound excellent to me. Just a thought. Good luck. Mauricio __________________ Cheapest horn speakers: https://picasaweb.google.com/lh/phot...eat=directlink

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9th February 2006, 08:10 PM	#4
Stew diyAudio Member Join Date: Nov 2005	According to the datasheets, these chips will both work from +-4.5v to +-18v. The specs don't appear to change dramatically over that range so hopefully they'll sound good with +-5v. One of my concerns was clipping but with a preamp input sensitivity of around 150 mv, I assume clipping won't be a problem. Is that a reasonable assumption? If I decide to add an independent power supply, what should I look for and what do they typically cost?

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