didn't change the LT version in the last 2 years on this computer...but i don't think this is the problem.
Marcel, which very low offset opamp, affordable, would you suggest as an alternative to the LT1037?
I would like to avoid using a blocking cap or a DC servo.
I would like to avoid using a blocking cap or a DC servo.
For your sim you can take opamp2 at the end of the opamp list to simulate the opa1652 or opa1656.
In this model you can insert the BW, slew rate, voltage noise En, kneepoint Enk.
Current noise can be skipped and left at zero.
You won’t get the distortion you are looking for, but distortion for these opamps is very low anyhow.
You could mount the opa1652 or opa1656 in a smd to dip adapter.
Hans
In this model you can insert the BW, slew rate, voltage noise En, kneepoint Enk.
Current noise can be skipped and left at zero.
You won’t get the distortion you are looking for, but distortion for these opamps is very low anyhow.
You could mount the opa1652 or opa1656 in a smd to dip adapter.
Hans
I just commented on their noise performance. It's a pity when you buy expensive ultra low voltage noise op-amps and end up with relatively poor noise performance, because they are also ultra high current noise op-amps.
Regarding the LT1037, Linear Technology has been using its old trick again of specifying the current noise under unrealistic conditions, that is, with equal impedances driving both inputs. From the internal schematic, I estimate that with unequal impedances, the noise current will double to 0.8 pA/sqrt(Hz). That's not too bad, but an NE5534A or a good FET op-amp can easily outperform it for moving magnet.
With a sensible amount of gain in the first stage, the second stage should not be critical for noise.
Certainly it is POSSIBLE to lay out your PCB so it will accept either single opamps or dual opamps. M2X IPS7 does this; photo below. Click on the image to see it full size and undistorted.
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Guess so, but it should be quite tricky.
Perhaps design it for dual IC should work. Then using two-singles to one dual adapter, now a bit difficult to find.
My first idea, some pages back, to use a RIAA kit sold by Airexpress and eBay, might be a better one.
Deciding on the better schematic and chip it's the important decision, I guess.
Two double op-amps are ideal in your circuit...OPA2228P can work for both stages .As long as you stay below +-18v supply with this op-amp and you have more than 5x gain(which you do) this is even better than ne5534.
I have made a subcircuit called OPA1656 based on the UniversalOpAmp 2.
Have entered all the specs from the OPA1656 into it, see first image below.
For a subcircuit you have to make a .asy and a .asc file and place both in the directory that you are using for your model, they are in the .zip file below.
Then I inserted this newly created OPA1656 into a schematic and checked it with a FR sim.
You know how to insert a subcircuit into your model ?
Do as if you are going to select a component by pressing the And gate in the Menu Bar as you normally do, but now at the right of the Top Directory line press the little arrow pointing downwards and you will get the OPA1656 in the area below. Press it and place it in your model.
Succes,
Hans
Attachments
I may have a few OPA2228 around, that I got as samples a long time ago.
But I also should have OPA627/637 from those times too. Better options for RIAA to try perhaps. I am not sure I can use the 637 for that, though their minimum gain would be fulfilled.
I was just curious about these other FET options. These are single ones too.
But I also should have OPA627/637 from those times too. Better options for RIAA to try perhaps. I am not sure I can use the 637 for that, though their minimum gain would be fulfilled.
I was just curious about these other FET options. These are single ones too.
as long as you wash your vinyls before a one time use there shouldn't be any problem in an active riaa circuit.OPA627 is well known for being quite hard to tame and needs appropriate PCB design.Basically this is a very tough choice for a phono preamp.If you want to have a preamo that you can use any time on any dusty record very few preamps can do the job and valves are preffered by far for such a task. There was only one op-amp used with some external components that could do the same as a valve circuit but now long extinct. M5220 and one other op-amp i can't remember were made with phono use in mind having a max supply of +-25v .OPA604(2604) is +-24v too, but most praised ss phono preamps are high voltage discrete ones runing at +-35...+-43v supply .This was discussed a lot too...
By the way just a few minutes back scrooling for philips ah-209 control preamplifier, i found another gem of the past : TA7322, a low noise ic which could take +-30v supply
file:///C:/Users/neanderthal/Downloads/Philips-22-AH-209-Service-Manual.pdf
TA7322P Datasheet PDF - Datasheet4U.com
It looks like the semiconductor manufacturers completely abandoned vinyl lovers a few decades ago...
file:///C:/Users/neanderthal/Downloads/Philips-22-AH-209-Service-Manual.pdf
TA7322P Datasheet PDF - Datasheet4U.com
It looks like the semiconductor manufacturers completely abandoned vinyl lovers a few decades ago...
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really? care to say more about this?
i'm curious - my experience has been almost the opposite for the OPA627.
mlloyd1
i agree. i don't know why some people complain about it being "too old".
it is a great part for MM preamps.
just rather expensive.
mlloyd1
well...then your opinion is different than the one i read on this ic on multiple threads.It might be that you're right and they're wrong.I never used it.
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