DOS has differential input, Sony output stage has differential input
- why would it not work?
I am not a specialist but I believe the sony uses a digital filter and the dos has an analog filter built in the input.
I would like to improve the sony but need some guidance.
I would like to improve the sony but need some guidance.
What makes you think that others do not?
"While it combines a crystal-oscillator, a digital interpolation filter"
Marantz CD 63/67
Justr try it out and listen to the result. You can always bypass the DOS input filter 😉
Only five wires to connect - and the output sockets, what could go wrong 🙄
Attached are the quick simulations of both output stages.
Attachments
Sorry for the delayed reply but currently the hobby stuff has been "shelved" - home renovation is dominating.
I'll be back in some weeks 🙄
can someone pls help, my Marantz CD-67 MKII has no sound out of left RCA output, digital works fine, i recently upgraded op-amps and was using with optical no worries into my receiver but now i have Cambridge Integrated amp and need to connect via rca but only one side has sound. I have tried swapping left from right rca and will play the other speakers so rca cable or speakers is not issue. what on the motherboard could be causing the issue?? cant afford DAC atm, need to fix this.
You must try to see if the opamps you have installed have no problems, or if you have not made a short-circuit with the soldering iron on the legs of the opamp bringing the signal to ground. in any case, with an oscilloscope or a multimeter with a graphic bar, start to check (putting a cd) if you see the signal on the RD25 RD27 or RD26 RD28 resistors. If you see it go on towards the exits checking the presence of the signal on the R606 and R605 and so on. Finally, if up to C655 or C656 you see the signal and after C657 or C658 it is gone, then you probably have a shorted muting transistor (QN05 / 07 or QN06 / 08). If one of these transistors is shorted you can just throw it away and not replace it. These are the preliminary tests to do.
Greetings
I would recommend burning a cd with 1 kHz sine signal - using that it is easy to take AC measurements with a simple digital multimeter and compare output stages' left and right channels step by step.
I dont have a scope sorry and my DMM has no graphic bar. I have a DMM and a soldering iron. Can I check with resistance and continuity on these components following the traces from RCA to check for short??
i actually accidentally had one of the op-amps installed upside down at first and tuned it for only a bit and didnt play any cd before i realized, there was a slight funny smell. but then i reinstalled and played cd from optical out and sounded great.
So, in the best case if you are lucky, you just have to change the opamp and check that the R616 and R614 are not interrupted if the problem was on the right channel or the R613 and R15 for the left channel ...
so will the op amp be definately killed?? how come it plays sound so nicely from optical output? just check r616 and r614 with 50hz odbfs test tone playing holding black probe on rca shield??
The optical feed does not use or need any of the analogue circuitry.
Whether the opamp is dead or not I would bin it. It has taken a big hit and is likely to be impaired (if it even works) when compared to its specification.
Check the power supply voltages to the opamp are correct.
Whether the opamp is dead or not I would bin it. It has taken a big hit and is likely to be impaired (if it even works) when compared to its specification.
Check the power supply voltages to the opamp are correct.
The optical output does not pass through the dac, so it does not go through the Opamps either. In other words, the optical and analog signals separate before the DAC and therefore only the analog output is affected by the OPAMPs (if you remove both opamps the optical output will still work). At 90%, having reversed the opamp and then reversed V + with V- and vice versa, then the opamp will be killed. And those resistances could also be broken. To check the resistances you can use the continuity mode of your multimeter, putting the probes in parallel with the resistors. To check where the signal arrives, as you said, the black probe is on ground and the red one checks.