| smagicmans |
I have many leftover opamps for sale:
OPA627ap X 8
OPA627bp X 5
OPA627au X 5
OPA637bp X 8
OPA637au X 5
OPA2227au X 5
I am taking offers. Send me a msg if interested.
Thank You |
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| smagicmans |
| Shipping by USPS priority($3.85) and USPS global priority($5.00) |
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| tg3 |
Any comments on how these sound would be appreciated.
I'm looking for opamps for an active XO. |
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| smagicmans |
the opa627 and opa637 sound fairly similar, both are great for making headphone amplifiers or such other devices.
4 X opa637bp is pending for sale by Hugh M. |
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| Nisbeth |
Remember that the 637 is only stable at gains of 5 and over.
EDIT: So if you're in doubt, use the 627. :)
/U. |
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| KevinLee |
| I wonder if it is a coincidence that TI has samples available in quantities of 5?:scratch: |
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| roibm |
| quote: | Originally posted by KevinLee
I wonder if it is a coincidence that TI has samples available in quantities of 5?:scratch: |
LOL ;)
Some 2-3 weeks ago I had a long discussion with TI(like 30 minutes). Lucky me I had a lot of notes next to me so the sales guy was very happy with all the feedback. They should start lifting up my samples limit from 5 to 10 ;) |
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| jacco vermeulen |
I tried both the ap as the bp versions of the BB OPA627. Though the A version is said to be better i heard no noticable difference.
To my opinion the 627 and the 637 sound very well, they are not as harsh as other opamps.
In a preamplifier i built i first used the Burr Brown OP27, later i stepped up to the OPA627, a major improvement.
Both the OPA627 as the OPA637 i tried in an opamp entrance based 50 watt class A Mosfet power amplifier with a balanced input, the opamps forced in class A too.
With the amplifier in class AB the OPA637 version sounded horrible, very nervous, fully in class A it sounds rather good.
I rebuilt 2 4-channel class A car amplifiers, replaced the dual opamp KIA4558s by OPA627 and the output devices by Sanken 2sa1216 and 2sc2922. The results sound pretty good. |
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| jean-paul |
The BP version is the selected one that's better than the AP version.
Probably known but still: OPA637 can only be used at amplification of 5x or greater.
Decouple OPA627/637/AP/BP with 10 uF to 47 uF low ESR electrolytics like BG/Pana FC from both supplies to ground and use a 10 ( to 220 nF according to friend CarlosFM ) nF MKT cap with 5 mm pitch like Wima MKS 02 soldered directly on the pins. All three caps soldered as close to the pins as possible of course.
Don't believe it, please try it.
EDIT: sorry, I did not see the post of Nisbeth.... |
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| jacco vermeulen |
I'm sorry, typo, you are right, the BP is better than the AP.
Offset voltage is about a third of the AP's, and OLVG and CMRR is a few db higher for the BP versions. |
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| jonclancy |
Hi J-P,
sorry to go off topic: I coudn't email you direct, but would appreciate it if you were able to spare me a few moments to point me in the right direction on the 627 decoupling?
If you have the time, perhaps you could PM me?
Many thanks
Jon |
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| smagicmans |
Left: yes,
OPA637BP Qty 4
OPA627AU 5
OPA637AU 5
opa2227 5 |
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| smagicmans |
| Update: I have these now OPA637BP, OPA637AP, OPA627AP, OPA6627AU, OPA637AU. and a lot of OPA2227au |
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| chris ma |
Hi Smagicmans,
Payment made thru paypal this morning for 4 units of OPA637BP.
Please check your account.
Regards,
The Butcher:D |
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| AnthonyAsh |
| quote: | Originally posted by jean-paul
The BP version is the selected one that's better than the AP version.
Decouple OPA627/637/AP/BP with 10 uF to 47 uF low ESR electrolytics like BG/Pana FC from both supplies to ground and use a 10 ( to 220 nF according to friend CarlosFM ) nF MKT cap with 5 mm pitch like Wima MKS 02 soldered directly on the pins. All three caps soldered as close to the pins as possible of course.
Don't believe it, please try it.
EDIT: sorry, I did not see the post of Nisbeth.... |
I've got very good results by:
1.Each opa627 in my Rotel individualy decouples with BG-PK 10Ufx50v and 0.1uF polypropylene between + and - pins.
2.Added Class A biasing resistors vishay 1,8k (Carlos recommendation)
And sounds good! |
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