The Opamp thread

[svyr]

I feel so sad today, I accidentally let all the magic smoke out of my OPA690s.
My IEM's were so upset that all the magic smoke came out of them too...

I guess thats the last time I will let the OPA690s play with +- 12 volts!

The internal junction breakdown voltages are relatively low for these very small geometry devices. These breakdowns are reflected in the Absolute Maximum Ratings table.

ABSOLUTE MAXIMUM RATINGS(1)
Over operating free-air temperature range, unless otherwise noted.
OPA690 UNIT
Power Supply ±6.5

http://focus.ti.com/lit/ds/symlink/opa690.pdf

So you knew it'd fry it, but still tried?

 

[Avro_Arrow]

I am very familiar with the rated voltages for the op amps I have...but it still
doesn't stop you from forgetting to change to voltage on the power supply
just that one time...I was rolling a group through my test amp to see how
they sounded at different voltages.
 
Quote:

Quote:

I feel so sad today, I accidentally let all the magic smoke out of my OPA690s.
My IEM's were so upset that all the magic smoke came out of them too...

I guess thats the last time I will let the OPA690s play with +- 12 volts!

Quote:

The internal junction breakdown voltages are relatively low for these very small geometry devices. These breakdowns are reflected in the Absolute Maximum Ratings table.

ABSOLUTE MAXIMUM RATINGS(1)
Over operating free-air temperature range, unless otherwise noted.
OPA690 UNIT
Power Supply ±6.5

http://focus.ti.com/lit/ds/symlink/opa690.pdf

So you knew it'd fry it, but still tried?

 

[svyr]

I am very familiar with the rated voltages for the op amps I have...but it still
doesn't stop you from forgetting to change to voltage on the power supply
just that one time...I was rolling a group through my test amp to see how
they sounded at different voltages.

fair enough, my condolences, hopefully opa690 isn't too expensive(I could find a datasheet, but not where to buy one ) . Otoh, you'll probably have somewhat of a reflex for checking the psu voltage some time to come =)

 

[majkel]

Mouser should have the OPA690. You can also try Farnell or RS Components.

 

[Avro_Arrow]

It's not really a problem...I have eight more...

 

[Avro_Arrow]

I must report that after I adjust the power supply to a less vigorous voltage
that the magic smoke stayed inside where it belongs and the OPA690s
sounded great! 

 
The only bad news is the IEMs are down and out for the count...

 

[igor0203]

Which opamp you suggest for swapping instead of LME49720HA or LT1028? I wanna try something "better". I'm using Club3D Agrippa DTS 7.1 which is just like Auzentech X-Plosion.

 

[svyr]

Which opamp you suggest for swapping instead of LME49720HA or LT1028? I wanna try something "better". I'm using Club3D Agrippa DTS 7.1 which is just like Auzentech X-Plosion.

mm, I second the question. I have a pair of LME49720HA (detailed but not harsh, maybe a bit on the warm side of mids, and a bit too expensive ) and they're the best I tried, but I'd be interested to know if there are 'better' things out there

 

[Mad Max]

ADA4627-1B is what you want.  Only comes in soic form.
That is as good as it gets.



 
Quote:

(www.head-fi.org/forum/thread/432749/the-opamp-thread/3300#post_7069711)

 

 

[Mad Max]

Edit: to type under a quote, click on Source and then add:
 
<p>
</p>
 
at the very bottom.

 

[SpudHarris]

x2 in almost any of my amps these sound amazing.
 
Why can't I write under the quotes anymore?
 
 
Quote:

ADA4627-1B is what you want.  Only comes in soic form.
That is as good as it gets.


 

 

[dlaloum]

Quote:

What is the reason you like 627 more than 637? Is it stability, heat, sound quality?

 
During a few weeks listening to the 637, I found that it seemed there was more detail in the highs.... a "well lit" sound... seemed a bit more space too - but it was fatiguing to listen to, which is usually a sign of some form of distortion/grunge in the highs.
 
Going back to the 627 -  definitely darker - but also never fatiguing - I can listen for hours to this, and just keep going.
 
Part of the issue may also be that I am using DT880's - I believe with the more recessed highs of something like the sennheisers the 637 might be ok or perhaps even better than the 627.... not sure. I did like the fact that it wasn't as dark as the 627 - but fatiguing is a no-no, and usually a good indicator of distortion - so it might be some form of instability.
 
One other possibility - the 627's are SOIC on a top/bottom adapter - very short traces.... the 637's are dips on a side/side adapter....
 
I have measured more distortion and grunge/noise on DIP's in the side/side adapters - and with chips like the AD797 and OPA637 that are fairly sensitive - this may be the reason they don't score well with me.

 

[SpudHarris]

I forgot about the LT1468 until last night when looking through some old correspondance with Ryuzoh (Fi-Quest) he suggested it as a more stable replacement for the OPA637. I have these in my P3+ with stacked buffers and with Ground and Virtual Ground both bypassed. The LT1468 really suit this circuit and the P3+ sounds very open, very nuetral but lightning quick - Very, very nice..........
 
Anyone else tried these?

 

[Mad Max]

1468 has a weird sound in my gear.  I didn't like it.

 

[qusp]

really loving the OPA827 again at the moment, that and OPA1641 are on rotation at the moment, great chips