NAD 5420 CDP opamps - Page 6

Mooly · 2nd June 2008, 06:45 AM

Look here www.burr-brown.com The link will redirect you to Texas Instruments who now own Burr Brown. In the top right box under part number enter opa2604. When that page loads click on opa2604 under the part numbers offered. You can now download the pdf data sheet for this I/C . The applications given might help you make sense of it all more, and it describes the IC in detail. The TL072 is a Texas part, check that out as well, the LMxxxx are National Semiconductor.

parrot · 2nd June 2008, 06:47 AM

ok ... that all makes sense.

I've looked at opamps in Wiki but I'll have a look at Butterworth etc.

Some of this is way above my head but at this point it seems that trying a few different opamps will be safe and interesting and that's the goal.

So ... thanks again Karl. I'll order a few opamps, solder in some sockets for testing and see how it goes [in the middle of building a sub at the moment so I'm a bit ahead of myself here but it gives me time to think about options].

parrot

parrot · 2nd June 2008, 06:49 AM

aaaugh,

typing while you posted but yes, I'll be checking that one out too.

parrot

Mooly · 2nd June 2008, 06:59 AM

I would be interested to know what YOU think of the different I/C 's . The OPA2604 (and 604) certainly do it for me. They made my MicroMega Stage 2 really sing. I can't fault them. I also used them in the preamp section of my latest amp build.
As I said earlier though, try different ones and do try a couple of 4558's, they cost peanuts, they are as bad as it comes ( for audio), and it's just really interesting to see how far we have come ( or not ! ).
It's a bit like washing powders.

. In the 80's it seemed that a new improved version was advertised every other week, and this went on for years, so by definition, the first ones must have been spectacularly bad.

parrot · 2nd June 2008, 07:07 AM

LOL ... gotta say the idea of trying something "as bad as it comes" has a certain quirky appeal.

I'm looking forward to doing a bit of swapping. Having replaced the output caps with wire, it seems the longest part of any process is taking the box apart though with the sockets in place that won't be necessary.

parrot

Mooly · 2nd June 2008, 07:16 AM

Make sure you use solder braid to remove the old I/C's and this maybe sounds obvious but we have all done it

, when you try and remove I/C/s from sockets prise a bit at a time each end. Try and do it in one go or using fingers and it will flirt out, pins at 90 degrees, probably embedded in your finger. We have all done it

Edit, I will add, when you remove a part clean the pcb (solder) with a cotton bud and iso or meths to get any old flux off. Any mods you do should be indestinguisable from a factory fitted part.

parrot · 2nd June 2008, 10:14 PM

Hmm, yes ... not particularly looking forward to removing the opamps but I've used braid before so I'm not quite starting from scratch.

Thanks again for the tips ... I'll be reporting back on the results.

parrot

Mooly · 3rd June 2008, 07:10 AM

Hi,
Braid is easy, the secret is a hot iron with a large bit well tinned-pleanty of fresh solder on it.
Sounds mad but don't be afraid to add a little fresh solder to the braid as you actually apply it, the flux will help it all get sucked up instantly. Should take about 1.5 to2 secs total per pin on the IC, do each pin one at a time, bend the braid over the tip in a U shape and pull tight as you apply to the pin to unsolder.

glennb · 3rd June 2008, 01:47 PM

I find using a solder-sucker much easier than braid. Its a simple suction device with a manual plunger and trigger. Does one pin at a time.

3rd June 2008, 01:47 PM	#59
glennb diyAudio Member Join Date: May 2004 Location: Melbourne	I find using a solder-sucker much easier than braid. Its a simple suction device with a manual plunger and trigger. Does one pin at a time. __________________ Glenn.

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2nd June 2008, 06:45 AM	#51
Mooly diyAudio Member Join Date: Sep 2007	Look here www.burr-brown.com The link will redirect you to Texas Instruments who now own Burr Brown. In the top right box under part number enter opa2604. When that page loads click on opa2604 under the part numbers offered. You can now download the pdf data sheet for this I/C . The applications given might help you make sense of it all more, and it describes the IC in detail. The TL072 is a Texas part, check that out as well, the LMxxxx are National Semiconductor.

2nd June 2008, 06:47 AM	#52
parrot diyAudio Member Join Date: Aug 2004 Location: NSW	ok ... that all makes sense. I've looked at opamps in Wiki but I'll have a look at Butterworth etc. Some of this is way above my head but at this point it seems that trying a few different opamps will be safe and interesting and that's the goal. So ... thanks again Karl. I'll order a few opamps, solder in some sockets for testing and see how it goes [in the middle of building a sub at the moment so I'm a bit ahead of myself here but it gives me time to think about options]. parrot

2nd June 2008, 06:49 AM	#53
parrot diyAudio Member Join Date: Aug 2004 Location: NSW	aaaugh, typing while you posted but yes, I'll be checking that one out too. parrot

2nd June 2008, 06:59 AM	#54
Mooly diyAudio Member Join Date: Sep 2007	I would be interested to know what YOU think of the different I/C 's . The OPA2604 (and 604) certainly do it for me. They made my MicroMega Stage 2 really sing. I can't fault them. I also used them in the preamp section of my latest amp build. As I said earlier though, try different ones and do try a couple of 4558's, they cost peanuts, they are as bad as it comes ( for audio), and it's just really interesting to see how far we have come ( or not ! ). It's a bit like washing powders. . In the 80's it seemed that a new improved version was advertised every other week, and this went on for years, so by definition, the first ones must have been spectacularly bad.

2nd June 2008, 07:07 AM	#55
parrot diyAudio Member Join Date: Aug 2004 Location: NSW	LOL ... gotta say the idea of trying something "as bad as it comes" has a certain quirky appeal. I'm looking forward to doing a bit of swapping. Having replaced the output caps with wire, it seems the longest part of any process is taking the box apart though with the sockets in place that won't be necessary. parrot

2nd June 2008, 07:16 AM	#56
Mooly diyAudio Member Join Date: Sep 2007	Make sure you use solder braid to remove the old I/C's and this maybe sounds obvious but we have all done it , when you try and remove I/C/s from sockets prise a bit at a time each end. Try and do it in one go or using fingers and it will flirt out, pins at 90 degrees, probably embedded in your finger. We have all done it Edit, I will add, when you remove a part clean the pcb (solder) with a cotton bud and iso or meths to get any old flux off. Any mods you do should be indestinguisable from a factory fitted part.

2nd June 2008, 10:14 PM	#57
parrot diyAudio Member Join Date: Aug 2004 Location: NSW	Hmm, yes ... not particularly looking forward to removing the opamps but I've used braid before so I'm not quite starting from scratch. Thanks again for the tips ... I'll be reporting back on the results. parrot

3rd June 2008, 07:10 AM	#58
Mooly diyAudio Member Join Date: Sep 2007	Hi, Braid is easy, the secret is a hot iron with a large bit well tinned-pleanty of fresh solder on it. Sounds mad but don't be afraid to add a little fresh solder to the braid as you actually apply it, the flux will help it all get sucked up instantly. Should take about 1.5 to2 secs total per pin on the IC, do each pin one at a time, bend the braid over the tip in a U shape and pull tight as you apply to the pin to unsolder.

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