| JoeBob |
| Anyone have a preferance between these two for a preamp stage? I ask because many like the 637 for phono and the 627 for IV, but what about a simple preamp? |
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| peranders |
| Both types are excellent as long as they work in optimal conditions but also there are at least a dozen of good other opamps, which are substantially cheaper. |
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| Doh |
| I once built a headphone amplifier which used the 627, followed by a 634 buffer. Swapping the 637 for the 627 resulted in a much more rounded, natural sound to my ears. Both sound great. Just note that the 637 is not unity gain stable and needs a gain of at least 5. |
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| JoeBob |
| Thanks, I already have some of both and was wondering which to use, I think I'll give the 637 a go and see how I like it. |
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| PMA |
| 637 is stable for gain 5x and more, 627 can be used for gain 1x and more and has lower basic distortion. |
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| analog_sa |
| quote: | | once built a headphone amplifier which used the 627, followed by a 634 buffer. Swapping the 637 for the 627 resulted in a much more rounded, natural sound to my ears |
Impression seconded in a phono stage. What i really don't get though is why JoeBob is lazy to compare them himself. Too much work? |
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| JoeBob |
I did compare, I just wanted to see what other peoples opinions were on these parts.
I tried them and my preferance was the 637, gave better sound in my opinion. I liked it alot more, not just a small preferance. But for unity gain, I tried the 627, but in this place I liked a monolythic buffer more ( I used the EL2001). |
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| PGW |
Does anyone know how the 627/637 compare with the regular OP-27/37?
Are the 627/637 quite different internal architectures but designed to do (essentially) the same job as OP-27/37, i.e a pin-for-pin replacement in the appropriate circuit but with "improved" performance? |
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| KevinLee |
Hello,
I am just today replacing my AD826 in my pre-amp stage with (2) OPA627AP.
I will let you know how I like the new op-amp.
It is a chore to do this swap without the Brown Dog adapters.
Cheers
KevinLee:) |
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| PMA |
| quote: | Originally posted by PGW
Does anyone know how the 627/637 compare with the regular OP-27/37?
Are the 627/637 quite different internal architectures but designed to do (essentially) the same job as OP-27/37, i.e a pin-for-pin replacement in the appropriate circuit but with "improved" performance? |
You will find the differences in the datasheets (www.ti.com and www.analog.com).
For integrators - use OP27
For audio amplifiers - use OPA627
They are pin compatible, except for external trimpot offset pins (usually not needed). |
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| peranders |
| quote: | Originally posted by PGW
Does anyone know how the 627/637 compare with the regular OP-27/37?
Are the 627/637 quite different internal architectures but designed to do (essentially) the same job as OP-27/37, i.e a pin-for-pin replacement in the appropriate circuit but with "improved" performance? |
The two products are totally different and has nothing to with each other.
OPA6x7 is a precision JFET type with rather low noise
OPx7 is a bipolar type with low noise type and also MUCH cheaper. |
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