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Flavors of Audio Op-Amps


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#16 bpribadi

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Posted 07 September 2004 - 03:27 PM

QUOTE
How much does the OPA627 cost?


S$ 37.72 per IC (5% GST included), at Farnell. Means S$ 75.44 per pair.

Not sure if Huangyong can help us to get it cheaper from TI China. If he can, we can start a group buy for OPA637/OPA627.

QUOTE
I was thinking of getting one if someone can help me fit it on a browndog adapter...


No problem, I can help you with it.

QUOTE
Really nice amp, bpribadi, btw.


Thanks!

Edited by bpribadi, 07 September 2004 - 04:16 PM.


#17 heady

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Posted 09 September 2004 - 01:26 PM

Thanks to bpribadi, I just substituted the OPA2134PA with the OPA2228 in my 3 channel CMOY and wow, the difference is startling. Nicely controlled bass with detailed highs. It may sound like less bass than the 2134 but that's because the bass is tighter and more impactful. Good op-amp.

Edited by heady, 09 September 2004 - 01:27 PM.

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#18 bpribadi

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Posted 12 September 2004 - 12:57 AM

I have received the AD8066 (dual) and AD8065 (single) from AD, and I just mounted it on small perfboard as adapter for SO8 > DIP8.

I will add my comments of how it sounds once I got time to try it with my amp.

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#19 heady

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Posted 12 September 2004 - 01:12 AM

Hi Bram, am listening to AD8620 on my CMOY. Wow, beats the OPA2228 in separation. The musical instruments are nicely placed in a distinct sound stage and not bright thru my DT880. But the 2228 is good value for money since the AD8620 cost approx S$30 each. Unless you get it free that is. biggrin.gif


"He sip no sup and he crave no crumb,
as he sigh for the love of a lady"

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#20 bpribadi

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Posted 12 September 2004 - 07:41 AM

I should come to your place and try it yes.gif AD8620 is very good in transparancy and imaging, but too bright for my Grado RS-1. So when paired with a not so bright headphone, it is a very good Op-Amp.

Heady, how did you mount them? Have you bought the SO8>DIP8 adapter?

Edited by bpribadi, 12 September 2004 - 12:56 PM.


#21 heady

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Posted 12 September 2004 - 02:06 PM

I bought them already mounted on the browndog adaptor, from Tangent, paid S$65 for two plus shipping. Ouch!!!!


"He sip no sup and he crave no crumb,
as he sigh for the love of a lady"

Yeoman of the Guard - Gilbert and Sullivan

#22 bpribadi

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Posted 13 September 2004 - 10:44 AM

I have added my small review with AD8066. This is an excellent Op-Amp! Now it stays in my headamp headphone.gif

#23 bpribadi

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Posted 30 September 2004 - 11:11 AM

Added with OPA637 yes.gif

#24 domi33

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Posted 04 October 2004 - 07:50 PM

bpribadi, I'm curious, can you post a schematic of your "ala Pimeta" ?
Thks

#25 heady

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Posted 04 October 2004 - 08:46 PM

domi33,

http://www.sgheadphones.net/index.php?showtopic=2571
"He sip no sup and he crave no crumb,
as he sigh for the love of a lady"

Yeoman of the Guard - Gilbert and Sullivan

#26 bpribadi

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Posted 04 October 2004 - 11:44 PM

Thanks Heady ! yes.gif

The schematic is PPA schematic:
http://tangentsoft.net/audio/pimeta/misc/schematic1.pdf

The differences:
1. The power supply section, I use voltage regulator.
2. The class A biasing, I use PPA 1.0 jfet cascode.

#27 bpribadi

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Posted 18 October 2004 - 01:19 AM

Added with OPA2107 headphone.gif

#28 tropicalrips

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Posted 18 October 2004 - 07:16 PM

i'm interested in the adaptor that u're using Bram smile.gif
is it DIY or off the shelf?
just ordered a few samples from AD including the 8066 to try out on the new amp, but they are all SO8 op-amps
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#29 bpribadi

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Posted 18 October 2004 - 08:49 PM

It is DIY adapter. I cut perforated board, 4x4 holes, and solder all the pins with the SO8. So far, I found it is the easiest way to work with the SO8.

2 months from now, AD will have AD8067 with slew rate 640 V/us, much faster than the AD8065/660 slew rate (180 V/uS), develop with the same process, FastFET, as the AD8065/66.

http://www.analog.com/en/prod/0%2C2877%2CAD8067%2C00.html

Edited by bpribadi, 18 October 2004 - 08:51 PM.


#30 tropicalrips

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Posted 18 October 2004 - 11:49 PM

Bram, can go into more details on how u do the adaptor? maybe on another tread
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"A camera is an instrument that teaches people how to see without a camera"
[Dorothea Lange]