I recently acquired an Azur CD player and, like many other owners of this well-built machine, was impressed with sound stage and detail but found the overall performance to be a little on the mechanical side. I feel this player is within a sneeze of being a stunning performer and am looking at mods that might do the job, possibly by replacing the NE5532 opamps that appear to be on the output. There are three of these for each channel and its not clear to me that all are doing output duty, or how they are configured to do so.
I have recently had great success replacing the NE5532s on a cheap Chinese Dac https://www.ebay.com/itm/333542970314?hash=item4da8b5d3ca:g:l6sAAOSwC2hgn6q5
with LM4562 opamps and doubling the capacitance on the surrounding electrolytics to 100uf. This significantly improved refinement and sorted out the bass but was still on the fatiguing side. Inspired by a capacitor shootout on the Lampizator site that showed tantalums providing a superior upper end, I bypassed the new Nichicon audio grade caps with 35v 10uF tantalums (the largest value I could get my hands on quickly).
Conscious that tantalums can be spiteful if abused I waited for the bang, but was rewarded with rich and full music that greatly exceeded expectations and showed potential to match vinyl, at least in my system. Repeating the experiment on a Rotel 820B produced an equally satisfying result after opamps and surrounding electrolytics had been given the same treatment.
As noted, the Azur 651c has three NE5532s that appear to be performing some function in the output of each channel with a 470uF capacitor nearby. The opamps are surface mount and it would require some kind of adapter to enable new opamps to be trialled. This looks like a solution: https://www.ebay.com/itm/312812470169?hash=item48d5137f99:g:f3YAAOSw8ENdHJIp
While I could just plunge in and see what happens, I would welcome any thoughts on proceeding.
I have recently had great success replacing the NE5532s on a cheap Chinese Dac https://www.ebay.com/itm/333542970314?hash=item4da8b5d3ca:g:l6sAAOSwC2hgn6q5
with LM4562 opamps and doubling the capacitance on the surrounding electrolytics to 100uf. This significantly improved refinement and sorted out the bass but was still on the fatiguing side. Inspired by a capacitor shootout on the Lampizator site that showed tantalums providing a superior upper end, I bypassed the new Nichicon audio grade caps with 35v 10uF tantalums (the largest value I could get my hands on quickly).
Conscious that tantalums can be spiteful if abused I waited for the bang, but was rewarded with rich and full music that greatly exceeded expectations and showed potential to match vinyl, at least in my system. Repeating the experiment on a Rotel 820B produced an equally satisfying result after opamps and surrounding electrolytics had been given the same treatment.
As noted, the Azur 651c has three NE5532s that appear to be performing some function in the output of each channel with a 470uF capacitor nearby. The opamps are surface mount and it would require some kind of adapter to enable new opamps to be trialled. This looks like a solution: https://www.ebay.com/itm/312812470169?hash=item48d5137f99:g:f3YAAOSw8ENdHJIp
While I could just plunge in and see what happens, I would welcome any thoughts on proceeding.
AFAIK 651c is a discontinued model, using cirrus logic / wolfson WM8742 DAC chip. can you post pics of the unit's rear panel and the pcb area with NE5532's and output stage?
I wouild recommend that with SMT and the finer PCB trace widths, design mods, then review and update design, then replace op-amps only once.
I wouild recommend that with SMT and the finer PCB trace widths, design mods, then review and update design, then replace op-amps only once.
if the 470uf caps are non-polarized / bi-polar then consider replacing with Nichicon Muse BP. I would stick with SMT for the op amps.
Thanks for that. I'm still curious as to the mode of operation of the opamps given there appear to be three per channel. Not sure if it would be necessary to replace them all.
try replacing the non-polar 470uF caps first and listen over an extended period of time before making any additional changes. if you still want to change the op-amps after that, and assuming the analog stage of your unit is based on the WM8742 DAC datasheet reference schematic, the two op-amps closest to the DAC chips would be the ones to change out as they perform an LPF function. third one is there for summing of the differential outputs and can probably be left alone.
SMT electronics technicians often have a saying about desoldering smt parts (you can either save the chip or the board, but not both). obvious choice is the save the PCB in this case. there are some (expensive) specialty cutters by Diamond, Erem, Lindstrom, etc. with ultra-narrow heads that can fit between and cut the legs of the SOICs right at the chip body (one at a time), then de-solder each remaining leg stubble and clean out each pcb pad, finally remove the chip body (note that some PCB's glue down SOIC's so you will have to study how to loosen the glue without damaging the pcb). take pics before de-soldering anything and observe orientation with the replacement part (double check this when the first pin is attached, and before soldering down all the pins)
SMT electronics technicians often have a saying about desoldering smt parts (you can either save the chip or the board, but not both). obvious choice is the save the PCB in this case. there are some (expensive) specialty cutters by Diamond, Erem, Lindstrom, etc. with ultra-narrow heads that can fit between and cut the legs of the SOICs right at the chip body (one at a time), then de-solder each remaining leg stubble and clean out each pcb pad, finally remove the chip body (note that some PCB's glue down SOIC's so you will have to study how to loosen the glue without damaging the pcb). take pics before de-soldering anything and observe orientation with the replacement part (double check this when the first pin is attached, and before soldering down all the pins)
hanks, your help is much appreciated. Will try the Muse capacitors first. There are Fujicon NKs in there at present. I don't know much about them.
Just to update. Replaced a couple of the 47uF Fujicon bipolars with Muse caps that were available. The improvement in sound suggests more can be achieved by continuing along this line although rolling caps on this pcb isn't exactly easy. In the meantime have 90% recapped the aforementioned Rotel 820B with significant tightening in sound. The Azur 651c will be challenged to equal this old-timer.
The Nichicon Muse BP are very good. About the operational ones, my favourite for their sound quality are the AD826, you might want to try them:
https://www.ebay.es/sch/i.html?_from=R40&_nkw=ad826&_sacat=0&_sop=15
https://www.ebay.es/sch/i.html?_from=R40&_nkw=ad826&_sacat=0&_sop=15
I'll suggest something opamp wise that might make toes curl but I'll suggest it anyway. The 5532 is a great opamp when used in linear applications but I believe it and also the single 5534 are not always the best option when faced with noisy/hashy signals which anything from a DAC is.
So I'm going to say (gulp) replace the 5532's with genuine TL072's and I think you will find that makes a notable difference to the subjective performance. There are countless other more modern devices but the FET TL072 series can be impeccably behaved in this type of duty and in my experience it will not have hard unforgiving edge to the audio presentation.
Having said all that you should still always back up any such changes with some scope checks and measurements to make sure nothing untoward has happened.
So I'm going to say (gulp) replace the 5532's with genuine TL072's and I think you will find that makes a notable difference to the subjective performance. There are countless other more modern devices but the FET TL072 series can be impeccably behaved in this type of duty and in my experience it will not have hard unforgiving edge to the audio presentation.
Having said all that you should still always back up any such changes with some scope checks and measurements to make sure nothing untoward has happened.