bypass output stage in cd 6000 ose

[Robi Medvesek]

Hi eweryone!

I'm new here and I have a question. I wuld like to bypass the output stage and replace it with a tube. Where wuld it be best to take the signal from? If anyone has done that I wuld apriciate the help.

Sorry for my english, it's a bit russty

Robi

[Fin]

Hi Robi

Welcome to the forum.

This link might help:
Thermionic valve output stage

[Robi Medvesek]

Hi Fin

Thanks for the link. Usefull reading. But not quite what i was looking for.

Really nobody has bone taht before? Or should I ask this in the tube forum?


Robi

[ThorstenL]

Konnichiwa,

Originally posted by Robi Medvesek
I'm new here and I have a question. I wuld like to bypass the output stage and replace it with a tube. Where wuld it be best to take the signal from? If anyone has done that I wuld apriciate the help.

First, the CD 6000 has two stereo DAC's, each with differential voltage output. Secondlyu, du to their "pure digital" output signal nature they require some lowpass filtering.

One option would be to sum the various signals using a classic resistor mixer into a low impedance load and then to bring up the signal back to sensible levels. This could be done without ever bothering to convert balanced to SE.

Another option would be to use a pair of transformers to convert the signal from balanced to SE and by seriesing the secondaries to "mix" the signal from the two DAC channels per Audio Channel.

All in all the 6000 is not terribly well suited to that kind of stuff....

Sayonara

[Robi Medvesek]

Hi,
I've managed to bypass the output stage.
Thanks to everyone who tryed to help me.
If you would like to do it too and dont know how feel free to contact me


Robi

[Fin]

What did you end up doing?

[Robi Medvesek]

It really is simple. I took four resistors of 10k and mede a resistor summer (I hope you understaind what I mean). First I conected one on pin 11 at the output of HDAM and the other resistor to pin 9. It's written +L and -L. And then conect the free ends of the resistors together- that's allready your output.

But the problem with this was that the right chanel (I think) was playing louder than the left. It's because the resistors 3211 and 3217 were mounted on the HDAM befor the conector 1212 and on the other chanel they were after. So I took the signal from each side of the capacitors 2211 and 2212. Now the chanels are equally loud.

Now I'm thinking to bypass it infront of the HDAM. But I'm afraid that simple resistors won't doo since the signal is choped in four chanels +L1, -L1, -L2, +L2


The schematic is here:
http://diytube.webpark.pl/cd6000b.JPG


Robi