Garbage switch

[tvrgeek]

I recently upgraded from an old Nad C530 to a new 565. First impressions were great. More detail, sharper but right. Then I played some older CD's. Arrrrg. What you learn real quick is just how bad the old CDs were. Early Beatles? 14 bit Sony transcriptions of a bad tape.

I need a switch. Good and bad CD. The older NAD kind of masked the problems of really poor CD's. Of course, it did not do the detail of better CD's.

Transformer? Analog low pass? Tube? What ideas are out there? Oh, it sounds just about like my external DAC. The answer is not a thousand dollar DAC.

[Mooly]

Try a simple one or two transistor FET buffer stage to add a bit of even harmonic distortion to the mix.

----------------------------------------------------------------------------------------------------------------

Not familiar with the NAD but it might be worth looking at the output stages of the player. It could be worth considering different opamps (assuming it uses something like 5532's) that can offer subtle but real improvements to sonics. That wouldn't spoil the sound you get from better CD's either... you might like them even more.

[tvrgeek]

Actualy, they have some of the latest parts. This is their $800 unit. My old C530 had 5532's. Op amps don't make this big a difference. How well they are used does.
No, like I said, a well mastered CD sounds better. Clean, crisp, accurate. A bad CD is more clearly bad. Truth can hurt. So I am looking to DEGRADE it's performance optionally. A buffer with limited BW may be a reasonable idea. A couple poles of LP may help. 18K maybe?

[DF96]

An HF shelf might smooth things a little. Alternatively, try a Bessel filter - very round corner so more amplitude loss but a good approximation to linear phase so no timing distortion. From memory, a double-pole (e.g. Sallen-Key) filter should have Q=1/sqrt(3) for Bessel response (Q=1/sqrt(2) is Butterworth i.e. maximally flat).

[stephensank]

I think you are just finding out that your C565 is not as good as it's cracked up to be. Whenever I do an evaluation of the sound of a player/dac that I've upgraded or just checking out, or an output stage I've designed, I always play not just my best recorded cd's, but also certain of my worst. A unit that sounds great on a great recording isn't necessarily great. A bad recording can reveal a lot about the real quality of the unit. For me to consider a unit/circuit really great, it has to sound great with great recordings, and make bad recordings sound no worse than they actually are. My personal experience with players using Wolfson dacs, like your C565, is that they have a metallic, ringing character to the top end that does not become obvious until you play a cd that has top end that is excessive or less than smooth, at which point the Woflson dac chips I've heard so far have chased me out of the room. Fast. And this has been the case even when I have upgraded the heck out of the output stages & power supplies to give the dac chip it's best chance of sounding good. I frankly think they are just plain awful chips. I think people get dazzled by how clean & clear they sound on a great recording, and are misunderstand that the bad sound they hear from bad recordings is actually being made a lot worse by the dac.

[Mooly]

Nicely put Stephen...

it's also very much how a system as a whole sounds and comes across to the listener. It doesn't matter what technical attributes all the components may have. If you don't like what you hear then its not doing its job.

The amplifier used can make a huge difference in the "whole system" concept too.

[tvrgeek]

Hmmm. I had not heard that criticism of the Wolfson chips on the higher end. That is about how I would describe what I am hearing. It also could be the speakers being asked to do things they had not before. I'll plug in my external DAC. It has a PCM1793/DIR9001 chipset in it. It's power supply is not the best and I am suspicious of some of the analog. ( $100 Chinese special) It is better than than my last two CD players. The preamp is a Nak CA-5 feeding my modified DH120 amp.

Where I want a unit to make the best of a good recording, as in be accurate, I don't consider a unit that masks things enough to make a bad recording better to be great. That is exactly what I want to do, but have an option; clean or masked. Breadboarding up a quick little filter should not be too hard. Of course, one reason I got this one was to get a one year warrantee. It IS an NAD.

All is not lost. My absolute requirements were it was a CD player, so it starts fast, and it fits on a 12 inch shelf. If I have to go to an outboard DAC, so be it.

[stephensank]

You have what I consider the best sub-$2k solid state preamp around in that CA-5. Good choice, which only needs soft recovery diodes to be about as good as it can get. The DH120, though, is certainly an amp that would be, without major redesign, "excited" to be harsher by a dac that has eccentricities in the top end like the Wolsons(IMO). A Nak PA-5(w/LF corner freq 10uf film enlarged by addition of at least 150uf/50v Nichicon lytic to remove subsonic BW limit) would be a huge improvement on a low budget, and can be relied upon to NEVER exaggerate any top end nasties.
Have to say, I would not touch an NAD piece with a ten foot pole, speaking as a 30+ year exp servicer, knowing how unreliably virtually every piece they make is built, due to combo of lackluster engineering and severe corner-cutting for cost.

[tvrgeek]

Stephen,
Well, I would agree fully, but the 120 has a vastly improved power supply, Exicon outputs, cap replacements, and the compensation is moved from the VAS output to Miller compensation. Inputs are matched to better than 1% and the other 4 compensation circuits are removed. Let me tell you, it was a real pain to get it stable and match the slew rates of the outputs. Is it great? No. It is darn good. At least until I can afford to bid on a PA-5 it will do fine. As I have an ST-7 tuner, why not? It is just my little office system. Maybe I should have bid higher on that last Linn.

Anyway, just did a careful listen to my BB DAC and the NAD. The BB happens to have an analog-in bypass so it was a simple A/B. Listening to the Grado's, I would not bet I could hear the difference. Granted my BB DAC is a Chinese DAC/phones special (MUSE) and it is not world class, but it was a darn sight better than the old C520. I never really compared it to my big Rotel. I need to get on with my speaker projects. Embarrassingly, I still have Kef Q1's here. I build a lot better. I just have to get around to it. I have four speaker projects going.

I have to agree with the questionable NAD quality. 3 of 5 I have owned have failed. The C520 was really just too long in the tooth. Can't really call it a failure. But it HAD to fit on a 12 inch shelf. The only other one I found was a used Arcam. I really know nothing about them other than being respected. I will say, 2 of 4 HK's have failed and every single Sony, every one, failed. Never a failure in a Denon, Marantz, Nak, Rotel, Hafler, B&K, Luxman, Kenwood, Pioneer, Sanyo, JVS, MXR, DBX, Behringer, KLH, Eicho, Knight, Heath, Thorens, Philips, Yamaha, and , hmmm. what else have I had? Oh, I had a CM Labs amp that even the factory could not get stable. Gave up after three times. I do think NAD has gotten a bit better, or at least I am telling myself that.

One of these days I'll look inside the CA-5, but as right now I don't even have a sub, the LF corner is not an issue. I really do need to look at the power supply. Anything this old needs caps, and I have had very good luck with diodes lowering the noise floor.

I guess the message here is the CD is OK. I need to address the speakers. I am a bit surprised none of my bottle head friends have suggested a tube buffer. =D

[stephensank]

It's the PA-5 power amp that has the too-smal LF corner cap. Nakamichi was very paranoid about their own first run of stasis amps & receivers(which Nak designed, not Nelson), so the first PA-5 & PA-7 had the subsonic cutoff & oversensitive protection mute circuits(easy 2 resistor changes to cure that bit), but are otherwise terrific even without further upgrading.

You will NOT need to replace ANY caps in the CA-5 for at least another 20 years, and would be wise to leave them alone. All of the lytics are top shelf Nichicons, rest are film caps. Literally only the rectifiers are the only place for any meaningful upgrading. Four soft recovery diodes, some Triflow spray into the controls, and you're done.

You could make a damn nice all-Nak system by adding, for usually around $100, a CDP-2A. Uses a surprisingly well implemented TDA1541A w/simple & easy to upgrade output stage, and is a lovely sounding player, with a cheap but very reliable(other than periodic loading belt & tracking rail lub every 10 years or so) Sony mech. It's a great little player. Other really good one in same range of cost/sound is the CDPlayer4/CD-4(same player, different front panels), which uses the venerable AD1864 dual 18bit r2r ladder dac, the better version of the AD1865 used in the Audio Note dac & so many others. Also has a very simple output stage for easy upgrading(although the opamp is a SIP package that requires an adapter to install an SOIC-8 packaged nicer opamp, e.g., OPA2134UA), and damn nice sound in stock form, and essentially same Sony mech as the CDP-2A. Either one will sound really sweet on good recordings, and still very listenable on bad recordings, because they intrinsically don't suck.;-)