I certainly am! Check your emails
Brent
Ordered mine too!!!!
Still gonna be messing with my 63, but I'm also picking up one of these tomorrow!!!
This is possibly the finest sounding CD Player I have ever heard. When it came up on eBay, I HAD to have it! Sold my M3 and gone back to a cheaper car just so I can buy it!!!!!
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I want one too, Ray!
@Stabby: That makes sense, and is actually not such a bad idea. While we can't compare sound quality, I think it might be possible to do a course grain test to tell if there is a problem with the frequency spectrum this way.
Now this is not very scientific because we're using music tracks, and different ones at that - it would be better to use a standard test tone sweep and recording method - but I have used Audacity to plot the log spectrum of normalized samples of your CD53 (blue), my CD63 (green) and a stock CD67 (red). It does seem to support what you think you're hearing.
@Stabby: That makes sense, and is actually not such a bad idea. While we can't compare sound quality, I think it might be possible to do a course grain test to tell if there is a problem with the frequency spectrum this way.
Now this is not very scientific because we're using music tracks, and different ones at that - it would be better to use a standard test tone sweep and recording method - but I have used Audacity to plot the log spectrum of normalized samples of your CD53 (blue), my CD63 (green) and a stock CD67 (red). It does seem to support what you think you're hearing.
Really can't see that working Ben! None of the equipment is the same! the losses you are seeing could be anything in the chain used to produce the original wav. Your 2 traces are close and that would make sense as all the equipment used to record is the same. The difference in the 3 really cannot be proved to be anything to do with the CDP performance! Coule be the mic, deck, software etc......
I agree for the most part, and I was doing my best to make that same point. However, unless Stabby used a graphic equalizer or something, I thought a 20dB difference from 60Hz and below was significant enough to be worth sharing, especially as it seems to support what he is hearing. I don't think either of us used a microphone, did we? I sampled using a direct line level connection to my PC sound card. I've previously tested this method with a CD of sine waves and test sweeps and found it to be quite accurate.
Hi Ricardo,
In the previous situation, the actual current through the output buffer depended not only on the 1k8 resistor but also on the voltage at the gate of the output buffer. This voltage lands at the 1k8 resistor minus the FET's Ugs. So any small change in the input circuit would directly change the buffer's current as well. Plus, when the circuit is driven with an audio signal, this causes an AC voltage across the 1k8 resistor which in turn also changes the working point.
The CCS sets a more stable working point because the current hardly changes anymore. The result is less distortion and lower output impedance.
Ray
Nice player Ian! You are going to tweak it I hope? Are those four nasty Nitai bipolar electrolytics the output caps?
Oh, what did I stir up... I almost feel like a malicious dealer
It sounds very well indeed. The obvious differences are easy to be noticed at first, but there are also a lot of subtle details that come out once you listen more concentrated. I can say this put my player another step in the right direction
Yes, that shouldn't be a problem. The DOS' output buffer is a source follower as well. Or an emitter follower if you use a BC517. All it does is buffer the voltage that appears on the gate or base pin.
The only thing you have to make sure is that the current is set correctly. Do you have a schematic?
Regards,
Ray
I knew it!
I must mod this if I ever want to sleep again
Oh, what did I stir up... I almost feel like a malicious dealer
It sounds very well indeed. The obvious differences are easy to be noticed at first, but there are also a lot of subtle details that come out once you listen more concentrated. I can say this put my player another step in the right direction
Thank you Ray
You made it perfectly clear to me
Can a CCS be used instead of a source resistor in a Common Drain = Source Follower amp ?
Yes, that shouldn't be a problem. The DOS' output buffer is a source follower as well. Or an emitter follower if you use a BC517. All it does is buffer the voltage that appears on the gate or base pin.
The only thing you have to make sure is that the current is set correctly. Do you have a schematic?
Regards,
Ray
Nice player Ian! You are going to tweak it I hope? Are those four nasty Nitai bipolar electrolytics the output caps?
mmm, I'm 99% sure they are only in the balanced output path. The main output caps are hovland as std but I'm likely to replace with at least Mundorf Supreme. There are a couple of mods to do for starters. There is an analouge volume comtrol chip that needs bypassing and i'll also swap any opamps in the signal path. There are 10 regualtors so i'll also be looking to swap the key ones out for soemthing more exotic. I beleive I need to be careful with the CD-Pro2 as its very fussy about the order the rails come up. I guess to start, it'll get its own 9v PSU for the drivers and of course I need to investigate clocking on transport itself. I beleive the STARS processing on the dac takes care of sychronus reclocking as well as all filtering and other clever stuff so I'll keep away from there to start. I'll be sure to keep you posted!!!
Thank goodness
. Yes, out with the Hovlands, I like the Mundorfs much better as well. Looks like the player has plenty possibilities. The many regs are nice, makes it a lot easier to upgrade certain sections.Ray
Thanks for making the graph, Ben! That is indeed a big difference. How could I solve this?
I'm not really sure - I'm just an amateur at this stuff.
I think it would be best if you try this experiment in controlled conditions. Do you have access to a 'known good' CD player? You could try repeating this test with a standard track and recording method and confirm the difference. Ideally, if you also have access to a CD burner, you'd use a sine wave test sweep.
If you're convinced there's a problem, I think it's always worth taking the superstitious approach of using your DMM to check the resistance/connectivity between all your recently soldered components and adjacent ones in all directions. I find sometimes if it looks a bit matte grey, sometimes some solder might just need sucking and redoing, making sure you get a good amount of that nice rosin smoke going.
I hope that helps. Hopefully someone more knowledgeable will chime in.
I think it would be best if you try this experiment in controlled conditions. Do you have access to a 'known good' CD player? You could try repeating this test with a standard track and recording method and confirm the difference. Ideally, if you also have access to a CD burner, you'd use a sine wave test sweep.
If you're convinced there's a problem, I think it's always worth taking the superstitious approach of using your DMM to check the resistance/connectivity between all your recently soldered components and adjacent ones in all directions. I find sometimes if it looks a bit matte grey, sometimes some solder might just need sucking and redoing, making sure you get a good amount of that nice rosin smoke going.
I hope that helps. Hopefully someone more knowledgeable will chime in.