Perfect
I knew someone would volunteer to offer up a picture with a targetting dotted line overlay 🙂
I'm not trying to advise anyone cut up their traces though, and if they want it that bad... they'll figure out how.
But.. if you have Rev 6.1 I think there are provisions to swap the diodes to the upper rail and you don't have to cut traces or add jumpers.
I knew someone would volunteer to offer up a picture with a targetting dotted line overlay 🙂
I'm not trying to advise anyone cut up their traces though, and if they want it that bad... they'll figure out how.
But.. if you have Rev 6.1 I think there are provisions to swap the diodes to the upper rail and you don't have to cut traces or add jumpers.
OPA2134
hello all,
this is my first post here. But I´ve read almost all posts concerning the wonderful UCD modules. I´ve already build a stereo-amp using the UCD 180ST (with NE5532 opamp) and was blown away by the perfect soundstage and resolution it gives compared to my A/V receiver HK 2550 (sorry, no real audiophile equipment here 🙂).
Now my question: I´m thinking about replacing the op-amp. I want to do this more in order to get less offset-voltage and therefor be able to get rid of the coupling caps. My question is: will the OPA2134 be suitable concerning lower offset-voltage? I don´t want to try the AD 8620 due to the informations about it´s signature.
And another question: does the UCD 180 ST modules also have the biasing diodes like the newer ADs have?
Thanks in advance!
Matthias
hello all,
this is my first post here. But I´ve read almost all posts concerning the wonderful UCD modules. I´ve already build a stereo-amp using the UCD 180ST (with NE5532 opamp) and was blown away by the perfect soundstage and resolution it gives compared to my A/V receiver HK 2550 (sorry, no real audiophile equipment here 🙂).
Now my question: I´m thinking about replacing the op-amp. I want to do this more in order to get less offset-voltage and therefor be able to get rid of the coupling caps. My question is: will the OPA2134 be suitable concerning lower offset-voltage? I don´t want to try the AD 8620 due to the informations about it´s signature.
And another question: does the UCD 180 ST modules also have the biasing diodes like the newer ADs have?
Thanks in advance!
Matthias
Hi and welcome
The ST modules lack the diodes, it is one of the advantages you get with the AD. However if you have a recent enough version (what version do you have?) they'll still have the pads for the diodes, you'll see two sets of three empty pads if you have that.
The opa2134 should indeed be good enough for DC coupling!
If you decide you want to use the current regulating diodes with them, you'll have to modify your PCB by cutting the trace as I'd mentioned because they go to the negative rail and the opa2134 would require them to go to the positive rail.
Hope that helps.
The ST modules lack the diodes, it is one of the advantages you get with the AD. However if you have a recent enough version (what version do you have?) they'll still have the pads for the diodes, you'll see two sets of three empty pads if you have that.
The opa2134 should indeed be good enough for DC coupling!
If you decide you want to use the current regulating diodes with them, you'll have to modify your PCB by cutting the trace as I'd mentioned because they go to the negative rail and the opa2134 would require them to go to the positive rail.
Hope that helps.
classd4sure said:
hi and thanks for the welcome as well as for the profound answers!
Am I right, when I say, that you don´t need the diodes, but it would be another tweak?
Before cutting any traces I would prefer to just "drop in" the new opamp (Have already started with training on old PC mainboards ;-)).
I don't know about the 180, but 6.1 gives you the option of moving the CRD's to the upper rail as they include provisions for both. The AD modules will already have them to the lower rail.
You're right you don't need the diodes, but if you find that's the op amp for you once you try it, it's something you can consider later. I sure would not cut any traces unless I were 100% on what I was doing with it.
Practising on old boards is an excellent idea 🙂
I did the same. Hot air worked great for removing the op amp but you tend to reflow alot of the surrounding components as well, if you do it that way make sure your board is perfectly level and don't knock it around or they're going to go sliding around on you.
You're right you don't need the diodes, but if you find that's the op amp for you once you try it, it's something you can consider later. I sure would not cut any traces unless I were 100% on what I was doing with it.
Practising on old boards is an excellent idea 🙂
I did the same. Hot air worked great for removing the op amp but you tend to reflow alot of the surrounding components as well, if you do it that way make sure your board is perfectly level and don't knock it around or they're going to go sliding around on you.
Thanks again, so I will first try swapping the NE5532 against a OPA2134 to see if it´s the right one for me.
Well, I have a propane soldering set (portable soldering set), which has a small nozzle for use as a hot air gun. It works much better than a normal sized hot air gun. Thus I am able to really just heat the pins of a SO-8 without reflowing the components besides it. It even works to fix the replaced part into place - then I change over to the soldering iron for the final touch.
classd4sure said:
Well, I have a propane soldering set (portable soldering set), which has a small nozzle for use as a hot air gun. It works much better than a normal sized hot air gun. Thus I am able to really just heat the pins of a SO-8 without reflowing the components besides it. It even works to fix the replaced part into place - then I change over to the soldering iron for the final touch.
You're very welcome.
I use the same .. butane iron, and I also have a heat blowing tip, maybe 1/4" diameter. Even on the lowest setting and about 1.5" away from the IC or more (don't want to heat it too quickly or too much) the surrounding SMT parts will catch more than enough heat to reflow, so be careful.
I use the same .. butane iron, and I also have a heat blowing tip, maybe 1/4" diameter. Even on the lowest setting and about 1.5" away from the IC or more (don't want to heat it too quickly or too much) the surrounding SMT parts will catch more than enough heat to reflow, so be careful.
current sourcing the 2134
Where does the information that you need to bias the 2134 to the positive rail come from? Has anyone tried it both ways?
Where does the information that you need to bias the 2134 to the positive rail come from? Has anyone tried it both ways?
biasing op-amps
Most opamps require biasing from the negative rail. However if the 2134 is like the opa 637 its output stage is a PNP emitter follower and should accordingly be biased from the positive rail. This converts the device into a class A single ended output device.
This explanation is not uncontroversial because some maintain that the opamp should be biased from the rail which displays the worst PSRR. That information may be in the devices spec's.
I have not compared biasing the 637 from positive rather than the negative rail but in my callow youth biased it that way out of ignorance... It sounded better than having it unbiased!
Rob.
Most opamps require biasing from the negative rail. However if the 2134 is like the opa 637 its output stage is a PNP emitter follower and should accordingly be biased from the positive rail. This converts the device into a class A single ended output device.
This explanation is not uncontroversial because some maintain that the opamp should be biased from the rail which displays the worst PSRR. That information may be in the devices spec's.
I have not compared biasing the 637 from positive rather than the negative rail but in my callow youth biased it that way out of ignorance... It sounded better than having it unbiased!
Rob.
Robert,
Would make sense if what you say is true. However, I cannot find a schematic on the 2134 and the schematic on the 637 looks push pull to me.....so could be biased either way. I just looked at the schematic really quickly....maybe you could look at it and reply. Thanks.
Would make sense if what you say is true. However, I cannot find a schematic on the 2134 and the schematic on the 637 looks push pull to me.....so could be biased either way. I just looked at the schematic really quickly....maybe you could look at it and reply. Thanks.
Ric,
As you know the latest version of the modules makes it very easy to try it both ways. Might I recommend you do so, and post your results here? You'll also have to repeat the procedure for stock regulators and auxiliary super tweaked ultra clean supplies.
Looking forward to those results.
Regards,
Chris
As you know the latest version of the modules makes it very easy to try it both ways. Might I recommend you do so, and post your results here? You'll also have to repeat the procedure for stock regulators and auxiliary super tweaked ultra clean supplies.
Looking forward to those results.
Regards,
Chris
Actually, I have biased a 2134 to the negative rail with good sonic results. I did this when I got my first set of modules back in Dec. (maybe I imagined the benefit...expecting it....I doubt it...but maybe). Never tried the positive rail. I don't use the 2134 and have no intention of trying it again. But I think someone who is using it should try it both ways and let us know what you hear.
Why wouldn't you use it again? I've yet to hear one myself, but I understand it's certainly respectable.
I'm surprised such a tweaker wouldn't have jumped on that little test 😕
I dont' think the improvement you heard was imagined, but it stands to reason you'd hear greater improvement on the positive rail.
My 627's arrive today. When they do go in they'll loaded right the first time though. Less I play with my boards the better off they'll be.
I'm surprised such a tweaker wouldn't have jumped on that little test 😕
I dont' think the improvement you heard was imagined, but it stands to reason you'd hear greater improvement on the positive rail.
My 627's arrive today. When they do go in they'll loaded right the first time though. Less I play with my boards the better off they'll be.
How you fitting the OPA627 Chris? do you have a converter board or something?
I've now got a soldering station with a hot air gun so it should make things a bit easier, hopefully😀 just got to decide which op-amps to try AD826,OPA2132 or THS4082CD
I've now got a soldering station with a hot air gun so it should make things a bit easier, hopefully😀 just got to decide which op-amps to try AD826,OPA2132 or THS4082CD
I'm not playing with the old 180's anymore at this time (got plans for them though).
V6.1 UCD400 on the old 180 stereo supply. So it has the single op amp footprints, and footprints to swap the CRD to the proper rail as required.
If you wanted them for the 180 you're left with the ol brown dog adapters, I'd imagine that would be just fine.
V6.1 UCD400 on the old 180 stereo supply. So it has the single op amp footprints, and footprints to swap the CRD to the proper rail as required.
If you wanted them for the 180 you're left with the ol brown dog adapters, I'd imagine that would be just fine.
So you got the newer UCDs too😎
I'm not going to try OPA627 with my UCD's, it works well in I/V conversion but I didn't like its signature when trying it in a headphone amp, hopefully it will work much better in your UCD400, look forward to reading what you think🙂
I'm not going to try OPA627 with my UCD's, it works well in I/V conversion but I didn't like its signature when trying it in a headphone amp, hopefully it will work much better in your UCD400, look forward to reading what you think🙂
Hi all,
Well, I had read theat the 627 chips are a little soft sounding. I had read somewhere about the use of some I think AD825's. It was on one of the Audio Circle forums, white noise. Some guy was really happy with the sound of the 825 chips. So that's my 2 cents worth.
So Rick, what chips are you currently using on the UCD amps?
regards,
Ray
Well, I had read theat the 627 chips are a little soft sounding. I had read somewhere about the use of some I think AD825's. It was on one of the Audio Circle forums, white noise. Some guy was really happy with the sound of the 825 chips. So that's my 2 cents worth.
So Rick, what chips are you currently using on the UCD amps?
regards,
Ray
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