Hi all
I just find out that digital out can’t be send to other DAC when listen to SACD.
So to make sound better I can upgrade opamps on this dvd and since I love upgrade I did on CA 640C want to try do the same with dvd.
The dvd89 have a 3 x C4558 SOIC 8 so is going to be slightly more difficult...
the question is what will be good replacement? LM 4562 was the opamps I replace in 640c domyou think I con do same on dvd ?
Thanks for any help
I just find out that digital out can’t be send to other DAC when listen to SACD.
So to make sound better I can upgrade opamps on this dvd and since I love upgrade I did on CA 640C want to try do the same with dvd.
The dvd89 have a 3 x C4558 SOIC 8 so is going to be slightly more difficult...
the question is what will be good replacement? LM 4562 was the opamps I replace in 640c domyou think I con do same on dvd ?
Thanks for any help
First thing is to be certain that the 4558's are in fact in the audio chain. Its not always a given...
Secondly, can the power supply feeding three 4558's handle three 4562's ? It may seem trivial given how low power consumption is in absolute terms, but you do need to be sure.
If the supply is a resistor/zener shunt supply then it may well not without altering things.
The 4562 is a terrific device but don't overlook other alternatives. The old TL072 could be a good choice, FET input, immunity to HF noise on the inputs causing odd non linearity and low level distortion, and it has low power consumption. Something like that could well be the one to go for initially.
Fit sockets and you can always easily try other alternatives in future.
Secondly, can the power supply feeding three 4558's handle three 4562's ? It may seem trivial given how low power consumption is in absolute terms, but you do need to be sure.
If the supply is a resistor/zener shunt supply then it may well not without altering things.
The 4562 is a terrific device but don't overlook other alternatives. The old TL072 could be a good choice, FET input, immunity to HF noise on the inputs causing odd non linearity and low level distortion, and it has low power consumption. Something like that could well be the one to go for initially.
Fit sockets and you can always easily try other alternatives in future.
Thanks for your reply. Unfortunately no socket can be done as they surface mounted and for that reason I would like go for 4562 since I like it on 640c.
So what you saying that 4562 may not work because power supply? Can this two chip data sheet be compere to see if they the same and need same power supply?
So what you saying that 4562 may not work because power supply? Can this two chip data sheet be compere to see if they the same and need same power supply?
The 4558 draws around 3ma, the 4562 over 10ma. Trifling amounts...... but what if the 4558 supply is a resistive feed from a higher supply.
This shows an 8 volt rail derived from a 20 volt supply using a common shunt stabiliser. Fit the higher current draw opamps and this kills the supply. Change the the feed resistor to something more suitable and it all works correctly.
Your player may use something totally different and the opamps might be fed from a high current rail... but you need to know first and be sure.
This shows an 8 volt rail derived from a 20 volt supply using a common shunt stabiliser. Fit the higher current draw opamps and this kills the supply. Change the the feed resistor to something more suitable and it all works correctly.
Your player may use something totally different and the opamps might be fed from a high current rail... but you need to know first and be sure.
Attachments
The six output opamps (incl. video) are 4580 inverting active filters. The +/-9V power supplies are Zener shunt regulators
fed from 21V through 330R., so about 35mA total current (Zener plus load). There are other circuits on the load besides the
opamps, so there may not be enough available current to switch opamps for higher current ones.
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If they are for audio (and you are sure) then try the TLO72 which is available in SOIC outline. I've never been disappointed sonically with these and would certainly consider them a big step up from a 4558.
The opamps shown on the schematics are NJM4580 and not 4558s. The circuit is an active low pass filter. The 4580 has a higher GBW than the 4558 and TL072. Installing a slower part will reduce the effectiveness of the low pass filter in cleaning up the digital hash from the DAC. The 4580 is spec for 0.0005% THD vs 0.003% for the TL072.
Better upgrade is remove the output coupling capacitors or increase the value from 10u to 100u.
Better upgrade is remove the output coupling capacitors or increase the value from 10u to 100u.
The two opamps are pin compatible but from a designer point of view I wouldn't stick a 4558 on that spot. The op amp is used as an active device for a 3rd order MFB filter with a 6dB gain. I can only speculate why yours have 4558 but the bottom line is they simply don't belong there. The 4558 is too slow for the job.
Similar DVD players like the Oppo DV-980H used 5532s on that same spot with slightly different component values.
Similar DVD players like the Oppo DV-980H used 5532s on that same spot with slightly different component values.
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