Good replacment for BB OPA 2604/604

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carlosfm

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Nuuk said:
But if an opamp has a particular sound, it should be so in any circuit, depending on how much the rest of that circuit affects the sound quality!
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The same op-amp can sound quite different depending on how it is implemented.
As an example, the OPA2132 and OPA627/37 have an overblown bass when the PSU is not right.
The problem is, as always, that the fat, untight bass robs all the detail from the midband and treble. It gets really murky.
Hey, the sonic effect is very similar to a high capacitance PSU without the snubber on a GC.
So, from disgrace to gorgeous sounding there's a thin border.
With the same chip.
 
Peter Daniel

Peter Daniel

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audiosector.com
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Gaucho said:
What are your opinions of the AD826 and the OPA8620? I have yet to try them. And please tell me what are your favorite op-amps, I'm still searching for my Holy Grail.
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I tried AD8610 in the preamp, and preferred OPA627BP. Maybe because I run them both at 15V (and lower voltage is recommended for AD8610). 8610 was more lively and a bit more involving, but I didn't like the way the highs were presented, to the point of being artificial and somewhat etched. Some might not like initially OPA627 as it may seem a bit dull, but after a while, you'll get used to it and it sounds fine. There is a tiny difference in sound between BP and AP versions, and for instance I went for BP in the preamp, but preferred AP at the output of Samsung DVD.

I never tried AD826, but have AD823 as I/V chip in a preamp and it's better than OPA2604.

To me OPA2604 never really sounded bad, it's definitely not artificial sounding like some of the new chips, it's just a bit veiled and not detailed enough.

LM6172 sounded just right without exaggerating any frequencies (pretty neutral).

Yeah, I remember the contact you gave me.
 
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carlosfm

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The AD826 has a recessed midband.
Voices come from under the bed.:D
Not neutral.

If we are going to put single op-amps in the game, then here's another very good one: AD843.
I don't like the AD8610/20 because they have a "girl" treble. Thin.
Midband is not natural too.
The AD825 sounds curiously very similar to the AD826: muted midband.
The AD843 is very good.
 
Gaucho

Gaucho

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Re: Re: Deal?

moving_electron said:


If anyone has any JRC 4558 op amps where the numbers stamped on them are 4 digits (rather than 5) I seriously would be interested in trading.

The application is recreating a vintage guitar effect box.
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You probably are looking for the real deal the but TI's RC4558P (avaliable from DigiKey) is said to be a great replacement. I may have another JRC4558 around somewhere, apart from the one in my Ibanez pedal ;). I'll drop you a line if I find it.
 
moving_electron

moving_electron

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Re: Re: Re: Deal?

Gaucho said:


You probably are looking for the real deal the but TI's RC4558P (avaliable from DigiKey) is said to be a great replacement. I may have another JRC4558 around somewhere, apart from the one in my Ibanez pedal ;). I'll drop you a line if I find it.
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I got some of the reissue JRC4558s that are supposed to be to the same specs but of course they are not from the original fab and process.

Apparently the 4558 has a fast recovery ability of some sort that helps there performance in some distortion circuits.

Thanks for the tip on the RC4558P.

If you find a JRC4558 with a four digit stamp, I'll trade you for a MN3007 analog delay if you have ambitions to build a chorus or phlanger.
 
SimontY

SimontY

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Good day everyone,

I'm about to order the following dual op-amps from Farnell. Can someone please confirm I'm ordering the 'right' parts, and not accidentally buying surface-mount or otherwise?

OPA2132 (OPA2132PA) PDIP (£2.67)
http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=8467528&N=401

AD826 (AD826AN) 8-DIP (£3.37)
http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=3035785&N=0

LM6172 (LM6172IN) 8-MDIP (£2.04)
http://uk.farnell.com/jsp/endecaSearch/partDetail.jsp?SKU=3160658&N=0

I believe all three of these are pin-compatible replacements for the OPA2604, JRC2114 etc.

Nuuk, I am going to leave out using any daughterboards and single op-amps *for now*. The expense and time spent comparing 4 or 5 dual op-amps is enough, for now ;) (going to cost nearly 20 pounds to try 3 new ones!)
 
SimontY

SimontY

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Gaucho

Gaucho

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SimontY said:
I'm about to order the following dual op-amps from Farnell. Can someone please confirm I'm ordering the 'right' parts, and not accidentally buying surface-mount or otherwise?

I believe all three of these are pin-compatible replacements for the OPA2604, JRC2114 etc.
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Referencing the datasheets I did a double check for you. The package types and pin-outs indeed seem correct for the items you have selected. I look forward to hearing your opinions on these amps.:)
 
SimontY

SimontY

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diymediahome.org
Originally posted by Gaucho
Referencing the datasheets I did a double check for you. The package types and pin-outs indeed seem correct for the items you have selected. I look forward to hearing your opinions on these amps.:)
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Gaucho,

Appreciate the double-check, thanks!

I actually tried to order these parts, and some 33uF 'bypass' caps and some sockets this afternoon.

However, Farnell wanted nearly £13 for delivery becuse the AD and LM parts are 'direct' items or some other c ra p like that! So I made the order with only one of three op-amps :bawling:
 
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carlosfm

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Gaucho

Gaucho

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Joined 2004
However, Farnell wanted nearly £13 for delivery becuse the AD and LM parts are 'direct' items or some other c ra p like that! So I made the order with only one of three op-amps
Click to expand...

That's to bad especially regarding the LM6172, the more hours I put on this op-amp the better I like it. I swapped in a cold LM6172 and can verify the very real sonic benefits of burn in.

On a postive note I think the OPA2132 will certainly fix some of the problems you are experiencing with the OPA2604. Of all the places I tried it the 2132 performed best in my DAC.
 
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