Annoying static on analogue outputs of CD player

[azl]

My Meridian 206 has developed an annoying static from its analogue outputs. It is really pronounced on the L channel where the sound is also highly distorted. It is much lower on the R channel where the sound is "almost' undistorted.
Its sound is crystal clear and undistorted from its coaxial digital output, through an outboard DAC.
Technically speaking this early version of the 206 uses the TD1541A crown ladder dac for D to A conversion. Its output RCA jacks appear to be directly connected to a single NE5532 dual op amp running in class A (with the help of J111 FETs as currrent sources). Any ideas as to what may be causing the static noise problem at the outputs?
Any help would be highly appreciated.

 

[Fidelity Audio]

I would swap the opamp first. It is also a good time to fit a more audiophile opamp.

Brent

 

[azl]

Thanks for your suggestion Brent.

I agree that replacing the old, no longer sonically competitive, NE5532 is the first step. I will install a dip socket so I can try a few different op amps such as OPA2604, AD846 and LM4562.

One other thing. I noticed that the static noise disappears during the quiet intervals between the CD bands. The noise is only present when there is sound. On L channel it is almost at the same level as the music. On R channel it is about 10 to 15db down. And, to repeat, there is NO noise from the digital opt.

Any chance the TD1541A dac can be responsible for the noise?
Or, possibly, the I to V circuit, which in the case of Meridian 206 is discrete?

Any further suggestions or help are highly appreciated.

 

[Fidelity Audio]

I personally like the LM4562 (LME49720) but advise using capacitors like black gates or rubycon za for the decoupling to get the best from it. Also the HA versions offer a smoother and slightly more dynamic sound.

I don't like the 2604 as I find it is a very forward sounding opamp.

Does you player have muting transistors? if so one of these could be breaking down.

Brent

 

[azl]

Thanks again for your input, Brent.

I do agree that LM4562 is good sounding and I have used them in the electronic x-overs when I updated my Meridian active speakers.

I don't have the schematic for the Meridian 206, because Meridian no longer releases schematics to the public and tracing out the circuit would be quite a chore. So, I don't know if it uses muting transistors, but I don't think so.

 

[Stones]

Any chance the TD1541A dac can be responsible for the noise?

Cut the L (and or R) output from the tda1541 from the original stage and try it with a resistor for IV conversion (i think 15 - 30 ohm would do it).

If you have same issue then your OP stage is not the problem

 

[Fidelity Audio]

Also if it is the dac then check all the gnds on the chip as i've had these cause static noise problems. On some 1541 cd players (marantz cd85) there are two dead end tracks under the dac that run parallel to each other acting as a pair of cancellation aerials. If one of these is not connected to gnd noise develops.

Brent