I have discover this new operational amplifier:
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The ADA4627-1 is a wide bandwidth, high precision, JFET input amplifier from ADI’s Advanced Bipolar Trench Isolated Process, iPOLAR. These amplifiers have low offset, drift, and bias current. Operation is fully specified from 8 V to 36 V single supply (±8 V to ±18 V dual supply).
The ADA4627-1offers better AC performance compared to the OPA627, higher slew rate, higher bandwidth, and better capacitive load drive capability.
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perhaps of interest for OPA627 user's
For more information and download of datasheet go to
http://www.analog.com/en/amplifiers...fiers-op-amps/ada4627-1/products/product.html
Unfortunately I cannot find the simplefield schematic and there are no DIP-8 outline, only the outlines for surface mounted design
========================================================================
The ADA4627-1 is a wide bandwidth, high precision, JFET input amplifier from ADI’s Advanced Bipolar Trench Isolated Process, iPOLAR. These amplifiers have low offset, drift, and bias current. Operation is fully specified from 8 V to 36 V single supply (±8 V to ±18 V dual supply).
The ADA4627-1offers better AC performance compared to the OPA627, higher slew rate, higher bandwidth, and better capacitive load drive capability.
========================================================================
perhaps of interest for OPA627 user's
For more information and download of datasheet go to
http://www.analog.com/en/amplifiers...fiers-op-amps/ada4627-1/products/product.html
Unfortunately I cannot find the simplefield schematic and there are no DIP-8 outline, only the outlines for surface mounted design
is this the circuit diagram? go to
Boliven Patents - US7071781: High speed, high resolution amplifier topology - Reader
I do not rule out the possibility, that this could be the internal circuit of this new IC and that from National Semiconductor (LME series)
Any feedback
Hi Guys
I discovered this amp through a great modder of pro audio gear (Jim Williams of Audio Upgrages).
I tried them in my mic preamps where I have LM6171's and they sound fantastic. Wonderful lows and mids. Everything sounds BIGGER compared to the LM6172s.
I'm not much of an EE though. I thought to try these in analog ins and outs of my digital multitrack recorder (Jim put 6172s in there) but I'm not sure how to compare them in order to feel somewhat safe dropping a pair in the check them out? Brown Dog makes a 2:1 adapter.
I'd really appreciate any advice you learned folk could give me?
Thanks and Best
F5
Hi Guys
I discovered this amp through a great modder of pro audio gear (Jim Williams of Audio Upgrages).
I tried them in my mic preamps where I have LM6171's and they sound fantastic. Wonderful lows and mids. Everything sounds BIGGER compared to the LM6172s.
I'm not much of an EE though. I thought to try these in analog ins and outs of my digital multitrack recorder (Jim put 6172s in there) but I'm not sure how to compare them in order to feel somewhat safe dropping a pair in the check them out? Brown Dog makes a 2:1 adapter.
I'd really appreciate any advice you learned folk could give me?
Thanks and Best
F5
Hi Bonsai
I did not know that LM4562 = LME47910. Thanks
I've got no problem soldering SMD Op Amps.
Saw the nice tutorial here (Thanks Mooly) and the one posted on the Brown Dog website.
I have spent the last couple of days pouring through all the threads on Op Amps! My head is spinning! But You all have given me more options to choose from.
I think I'd like to try the LM4562, LME49860, adapted (2:1) 4627-1 and possibly adapted LM6171. I'd like the recorder to have a nice neutral but lively and spaceous sound.
I did see some folks state the LM4562 is a great replacement for the NJM4565s. Those are the analog output amps and I would guess the LM4562 might be good for upgrading the NJM2115 input chips as well?
It also appears to be a good idea to put .1uF monoceramic caps from pins 4 (-V) and 7(+V) to ground to prevent any oscillations?
I'll do a channel of each qualitatively and then get my hard to get over buddy over with his O scope.
I was also reading somewhere that it is better to use single op amps if you can (so maybe a pair of LM6171s on a Brown Dog adapter would be even better than the LM6172?). If I remember right, it had to do with dual amps not having proper grounding? What do you all think about this exercise?
I am also going to check the voltages at the in/out op amps as well to narrow down the op amp choices. Schematics show input operates at 5V and the output operates at 15V
One other thing I was curious about that maybe you guys could help me with?
I was also thinking of putting 0.01uf polyprop Wima bypass caps on the blocking electrolytics near the in and out amps. Since there isn't a lot of room on the board, I will bend the Wima leads so that the cap sits directly under the elytics. Do you have to worry about these cap leads being long-ish. I remember reading somewhere here that you want the 0.1uf caps no more than 10mm away from the legs of the op amps.....but I think that had more to do with helping high frequency power supply getting into the amps or was it the converters (those do have both electros and 0.1uf SMD ceramics around them)?
Head is spinning! But I am having a good time!
Thanks for any feedback
All the Best
F5
I did not know that LM4562 = LME47910. Thanks
I've got no problem soldering SMD Op Amps.
Saw the nice tutorial here (Thanks Mooly) and the one posted on the Brown Dog website.
I have spent the last couple of days pouring through all the threads on Op Amps! My head is spinning! But You all have given me more options to choose from.
I think I'd like to try the LM4562, LME49860, adapted (2:1) 4627-1 and possibly adapted LM6171. I'd like the recorder to have a nice neutral but lively and spaceous sound.
I did see some folks state the LM4562 is a great replacement for the NJM4565s. Those are the analog output amps and I would guess the LM4562 might be good for upgrading the NJM2115 input chips as well?
It also appears to be a good idea to put .1uF monoceramic caps from pins 4 (-V) and 7(+V) to ground to prevent any oscillations?
I'll do a channel of each qualitatively and then get my hard to get over buddy over with his O scope.
I was also reading somewhere that it is better to use single op amps if you can (so maybe a pair of LM6171s on a Brown Dog adapter would be even better than the LM6172?). If I remember right, it had to do with dual amps not having proper grounding? What do you all think about this exercise?
I am also going to check the voltages at the in/out op amps as well to narrow down the op amp choices. Schematics show input operates at 5V and the output operates at 15V
One other thing I was curious about that maybe you guys could help me with?
I was also thinking of putting 0.01uf polyprop Wima bypass caps on the blocking electrolytics near the in and out amps. Since there isn't a lot of room on the board, I will bend the Wima leads so that the cap sits directly under the elytics. Do you have to worry about these cap leads being long-ish. I remember reading somewhere here that you want the 0.1uf caps no more than 10mm away from the legs of the op amps.....but I think that had more to do with helping high frequency power supply getting into the amps or was it the converters (those do have both electros and 0.1uf SMD ceramics around them)?
Head is spinning! But I am having a good time!
Thanks for any feedback
All the Best
F5
Someone has to make a A/B test against the OPA627, and tell us the tonic flavor.
I am willingly to do the job also and express my thought sometimes soon. Have to obtain the OP and make DIP adoptors. By the way, there is also an ADA 4637-1, I wonder whether it is over-specification in the case of pre-amp. And, is it stable at low gain? similar as the case of OPA 37/ OPA637.
cheers,
fjc
I am willingly to do the job also and express my thought sometimes soon. Have to obtain the OP and make DIP adoptors. By the way, there is also an ADA 4637-1, I wonder whether it is over-specification in the case of pre-amp. And, is it stable at low gain? similar as the case of OPA 37/ OPA637.
cheers,
fjc
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Yes, strangely, it follows the BB rule, 4637 is not stable at gain<5.
I have tested the sonic effect of ADA4627-1, at gain of 10. It is good, sonic performance is beautiful(OPA637BP was replaced by ADA4627-1 ARZ).
I have trying to test the 4637-1 ARZ first, but fail, I think overheat soldening might be the reason. By improve my technology ( reduce heat time, use constant temperature ceramic heat soldering gun and use lower M.P lead solder), the make of soic 4627 is fine. I will try another pair of 4637, with already made of the heavy lost of very costlt pair of 4637. I will present my thought in the next mail.
ADA4637-1
The problem may comes from soldering I guess. After a careful work, the new pair of ADA4637 performs well. Even the old pair becomes normal after a long run (self-healing?). It seems the a version of 4637 outperform even the more expensive B version of 4627. I am interesting to do a A/B sometimes now and try to be able to feel the difference.
The problem may comes from soldering I guess. After a careful work, the new pair of ADA4637 performs well. Even the old pair becomes normal after a long run (self-healing?). It seems the a version of 4637 outperform even the more expensive B version of 4627. I am interesting to do a A/B sometimes now and try to be able to feel the difference.
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At the level of these op amps subtle circuit implementation details are likely more audible than the chips themselves
you might try "wringing out"/"blueprinting" the circuit's measurable performance before subjective comparison
high speed 'scope, function gen can help verify stability, matching bandwidth - spot gross noise/EMI which may differ between power supplies or setups
free sw like RMAA, AudioDiffMaker could help
if you can difference the outputs in a resistive summer amp you can look with good resolution with even a cheap soundcard - with ~40 dB notch from the difference the distortion performance requirement of the soundcard is much reduced in the comparison
I consider good subjective testing far too time consuming, difficult, error prone to not do everything possible with good measurements 1st
once everything matches within 0.1 dB, 1% between circuits in frequency response and your listening level is matched too, your switch box is proved transparent, blinding protocol doesn’t “leak” info… you will almost certainly need lots of trials, good statistical analysis to have a chance at picking out op amp differences starting with such good chips
you might try "wringing out"/"blueprinting" the circuit's measurable performance before subjective comparison
high speed 'scope, function gen can help verify stability, matching bandwidth - spot gross noise/EMI which may differ between power supplies or setups
free sw like RMAA, AudioDiffMaker could help
if you can difference the outputs in a resistive summer amp you can look with good resolution with even a cheap soundcard - with ~40 dB notch from the difference the distortion performance requirement of the soundcard is much reduced in the comparison
I consider good subjective testing far too time consuming, difficult, error prone to not do everything possible with good measurements 1st
once everything matches within 0.1 dB, 1% between circuits in frequency response and your listening level is matched too, your switch box is proved transparent, blinding protocol doesn’t “leak” info… you will almost certainly need lots of trials, good statistical analysis to have a chance at picking out op amp differences starting with such good chips
4527 vs 4637
"I consider good subjective testing far too time consuming, difficult, error prone to not do everything possible with good measurements "
Now a pro is talking. So I will try to get the A/B sonic performance test result and keep it to myself, unless I can do a surgical analysis then to publish here. Yes, the test will be too subjective.
Thanks for the suggestion.
"I consider good subjective testing far too time consuming, difficult, error prone to not do everything possible with good measurements "
Now a pro is talking. So I will try to get the A/B sonic performance test result and keep it to myself, unless I can do a surgical analysis then to publish here. Yes, the test will be too subjective. Thanks for the suggestion.
Subjective OP test.
Thanks for the encouragement.
I will try the A/B test in my system. It is not difficult to do. I will put 4627 in one channel, 4637 in a separated channel, use separated step ladder volume with 0.1% -0.5% and tested resistor for the volume match. Input by bi-wire phono jackets from a single channel CDP, test will be switched in 60 sec., also I will try to hear the direct sound; sit by in front of the speaker to avoid room effect, plus, switch position on right and left speaker.
Yes, the test still is subjective and might be misleading to different person, please keep this in mind.
Thanks for the encouragement.
I will try the A/B test in my system. It is not difficult to do. I will put 4627 in one channel, 4637 in a separated channel, use separated step ladder volume with 0.1% -0.5% and tested resistor for the volume match. Input by bi-wire phono jackets from a single channel CDP, test will be switched in 60 sec., also I will try to hear the direct sound; sit by in front of the speaker to avoid room effect, plus, switch position on right and left speaker.
Yes, the test still is subjective and might be misleading to different person, please keep this in mind.
Amen.
Subjective differences between opamps tend to miraculously vanish once they're being used sensibly. If the circuit designer has a fussy type oscillate, uses a TL072 for driving headphones or operates a noisy part at high gain, that's their fault, not the opamp's. A good part doesn't make a good circuit at all, but it can make a good one even better.
Sensible use involves knowing the parts' little ifs and buts. And a row of measurements (e.g. Samuel Groner style) sure tells a lot more about these than subjective evaluation in just one predefined circuit ever could.
Test on sonic difference,
Anyway, I made listening test on ADA4627 Brz and 4637 Arz.
Sonically they are not much difference. Check the spec, 4627 has a 18 V/us slew rate, normally this should be enough for an audio purpose OP. 4637 has much faster slew of 100s. My feeling is the resolution of 4637 is slightly better,but the major difference is the sense of the instrument locations. It is more alive and sharper image for 4637. In other words, 4627 is more flat. I vote for the 4637, even it is a cheaper A version used.
Anyway, I made listening test on ADA4627 Brz and 4637 Arz.
Sonically they are not much difference. Check the spec, 4627 has a 18 V/us slew rate, normally this should be enough for an audio purpose OP. 4637 has much faster slew of 100s. My feeling is the resolution of 4637 is slightly better,but the major difference is the sense of the instrument locations. It is more alive and sharper image for 4637. In other words, 4627 is more flat. I vote for the 4637, even it is a cheaper A version used.
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