RCruz said:
Gain of the discrete stage is reduced slightly to compensate for higher filter output. The gain of the entire circuit remains about the same; the 820 ohm goes hand-in-hand with the different values in the filter (values between brackets, see discrete PDF).
Ray
6h5c said:
Thank you so much Ray.
Now I feel confident to start building the discrete.
After populating the PCB, is there a easy way to know if it is working, before I install it in the CDP ?
I always feel very gratefull for the feedback I get in this thread.
Regards
Ricardo
RCruz said:
Just measure the DC on the output before the cap.
oh, and it was sent Monday so should be there very soon.
Lee.
Before the output dc blocking cap, the reading should be around 6-7volts.
Just to update everyone, I have diy'd some "superregs" and added them to my player. I now have seven "super-regs" of varying kinds in there now. Also added 30va tx to the discrete supply and three smaller tx's for the decoder and servo. The sound is now pretty much awesome, probably about as good as Simon's player (maybe a little better).
Oh, and I must've learned something lately, as I did all that without breaking it, and it's fairly neat too!
Lee.
Just to update everyone, I have diy'd some "superregs" and added them to my player. I now have seven "super-regs" of varying kinds in there now. Also added 30va tx to the discrete supply and three smaller tx's for the decoder and servo. The sound is now pretty much awesome, probably about as good as Simon's player (maybe a little better).
Oh, and I must've learned something lately, as I did all that without breaking it, and it's fairly neat too!
Lee.
RCruz said:
Sorry Ricardo, I honestly can't remember for sure and I have no notes of it. I'm 99% sure it'll be exactly what's on Ray's original design specification.
The filtering caps I used are 1% tolerance polystyrene.
Simon
Hi Brentrowemeister said:
This is good... So it seems everybody is using the same type of filter.
Regarding the two diodes, why did you build a different type of current source ?
Regards
Ricardo
It was the one available at the time, I can't really see there being any difference in sound between the two TBH, just two ways of doing it.
Don't worry and build either, you will be impressed.
Brent
Don't worry and build either, you will be impressed.
Brent
Hi Brentrowemeister said:
I still have two psu pcb to use and would like to build a psu for the decoder and HF amp.
While waiting for the discrete parts, I have been reading your pdf http://www.audioupgrades.co.uk/rmcdmodlist.pdf
Just by reading, I can not determine if you use the same 3.2VA 9V tx for the decoder and the HF.
If you are using the same TX, what winding should I use for the HF amp ?
How many diode bridges did you use in your setup ?
Regards
Ricardo
6h5c said:That's better. Looks like you killed the cap--->
--->
You only need a few uF for a -3dB corner freq. that's <<10Hz (with a 47k load), but if you want to keep the group-delay low at the low-end, use 10uF minimum. You should roughly double these values for a 22k load.
Ray
Ray
Well, I ended up ordering a pair of the BG 100uf/16v N caps. I also decided to bypass these with a very small teflon cap. I've just gotten things going again, and the sound is even better than before.
I've been keeping up with the thread, Ricardo's progress, and your explanation of the circuit.
The D.O.S. is fabulous!
Steve
Sweet! 😀
Those caps are quite expensive, but they are worth it! The alternative would be a very large and even more expensive MKP, or tin-foil if you want to reach the same sound quality.
Ray
Those caps are quite expensive, but they are worth it! The alternative would be a very large and even more expensive MKP, or tin-foil if you want to reach the same sound quality.
Ray
6h5c said:
I used .01uf Sonic Platinums. They are only slightly more than the 100uf BG N cap. Seems to be a nice combo.
Hi Stevestvnharr said:
What improvements did you notice bypassing the BG ?
Thank you for reading my evolution.... This is really rewarding.
What is DOS ? (Disk Operating System?)
Regards
Ricardo
RCruz said:
I think he's referring to the discrete output stage.
I'm also using a blend of caps to good effect, but as a general rule it seems unlikely to work.
I use Black Gate AC with Siemens MKV, a physically massive and silly combination.
I think Lee has tried Mundorf MKP bypassed with Supremes and been happy.
Just Supremes would surely be excellent, but veeeery expensive.... and then you have Supreme silver in oil, silver-gold and even silver-gold in oil, if you want to pay hundreds of Euros
Also Tony Gee, famous speaker builder, recommends Clarity Cap SA (which I also rate) bypassed with Mundorf Supreme.
I agree with Ray that BG N and similar types seem not too far off decent film caps.
Simon