Ths4131
Hi Folks,
I might be exposed to this problem soon upgrading my pre-amp and power amps to balanced circuits from this board ... but with an active crossover (i.e. tons of opamps - Orion Linkwitz www.linkwitzlab.com) between the beautiful discrete circuits described on this thread. I thought slipping in some of these devices might be a nice touch.
Has anyone thought about using the THS4131 or 4130 to solve this problem? They are fully differential op-amps from Texas Instruments.
There is a small circuit in theTI product notes which outlines this. The nice thing is it has X-ed topology, so we are still using a Nelson Pass technology!
Perhaps someone cleverer could tell me if the THS4131 etc. can also be used as a balanced to unbalanced converter??
Regards,
George.
Hi Folks,
I might be exposed to this problem soon upgrading my pre-amp and power amps to balanced circuits from this board ... but with an active crossover (i.e. tons of opamps - Orion Linkwitz www.linkwitzlab.com) between the beautiful discrete circuits described on this thread. I thought slipping in some of these devices might be a nice touch.
Has anyone thought about using the THS4131 or 4130 to solve this problem? They are fully differential op-amps from Texas Instruments.
There is a small circuit in theTI product notes which outlines this. The nice thing is it has X-ed topology, so we are still using a Nelson Pass technology!
Perhaps someone cleverer could tell me if the THS4131 etc. can also be used as a balanced to unbalanced converter??
Regards,
George.
Re: Ths4131
You may want to check the OPA1632. Specifically designed for audio use. The problem with the THS'es is that they are very high speed, and you really need RF PCB techniques to tame them. I tried, difficult.
Since the 1632 (and the THS) are differential in, differential out, you can use them from anything to anything. Diff in to se out? Just use one of the outputs only.
Jan Didden
GeorgeBoles said:
You may want to check the OPA1632. Specifically designed for audio use. The problem with the THS'es is that they are very high speed, and you really need RF PCB techniques to tame them. I tried, difficult.
Since the 1632 (and the THS) are differential in, differential out, you can use them from anything to anything. Diff in to se out? Just use one of the outputs only.
Jan Didden
Thanks for your thoughts, Chaps.
Nelson, if I were going to use these chips, I would use the SOIC version (1.25mm spacing legs) with some loupes that were about to be discarded at work, go to bed early, not go to the gym, avoid coffee for breakfast, do the work in the morning before I get tired, plus all the usual tricks around ... exhale before pulling the trigger, and one of those home-made hot air solder gun thingies (with the aquarium pump) ... all before I get to old to ever try it. (Except for the "pulling the trigger" bit and hot-air solder gun, I do all the above things if I have fine tasks to perform at work, the most onerous preparation of all being the avoidance of coffee
.)
I don't think the OPA1632 uses X-topology
(beware the zealot), but I do know that using either will probably send me blind and cramp my neck.
Thanks for the advice, Janneman. I note that both have 150-180Mhz gain range, the same slew rate and noise levels, so wouldn't both be just as tricky to implement - or are there other parameters which I am missing? Have you tried the OPA and found it easier to use?
That will do for this little note,
Cheerio,
George.
Nelson, if I were going to use these chips, I would use the SOIC version (1.25mm spacing legs) with some loupes that were about to be discarded at work, go to bed early, not go to the gym, avoid coffee for breakfast, do the work in the morning before I get tired, plus all the usual tricks around ... exhale before pulling the trigger, and one of those home-made hot air solder gun thingies (with the aquarium pump) ... all before I get to old to ever try it. (Except for the "pulling the trigger" bit and hot-air solder gun, I do all the above things if I have fine tasks to perform at work, the most onerous preparation of all being the avoidance of coffee
.)I don't think the OPA1632 uses X-topology
(beware the zealot), but I do know that using either will probably send me blind and cramp my neck.Thanks for the advice, Janneman. I note that both have 150-180Mhz gain range, the same slew rate and noise levels, so wouldn't both be just as tricky to implement - or are there other parameters which I am missing? Have you tried the OPA and found it easier to use?
That will do for this little note,
Cheerio,
George.
I built this unbalanced to balanced converter, it distorts sound a lot.
http://emusician.com/images/DIY-Fig.-1_lg.gif
before I start debugging it, could someone tell me what those c1 and c2 caps do?
http://emusician.com/images/DIY-Fig.-1_lg.gif
before I start debugging it, could someone tell me what those c1 and c2 caps do?
Hard to say, since I have not seen the internal schematic, but since your
post TI has licensed the patent.
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