[Ron D]

While there is no definitive answer to your question as to which one is the absolute best I can offer that up until the Audio Aero Capitole II arrived about 9 months ago the Linn CD-12 (MSRP $20K US) was reported to be the redbook champ as a single box player. There are a couple of transport/DAC combos out there like the Dcs and Accuphase set-ups that would offer excellent redbook and SACD playback. The talk since CES is that the new Meitner 6 channel DAC and Meitner's modified Philips SACD 1000 is the new set-up that raises the bar as it offers what some report as the best (as of today, who knows about 6 months from now) redbook and SACD playback bar none. At a cost of over $10K US for the pair I highly doubt I'll ever get the chance to own such a system but maybe I can sneak in an audition as Ed's Lab is in Calgary.

[tmd]

Thanks Ron, the Linn CD-12 is the one I was thinking of. If you do get in to see Eds setup, please be sure to let us know. Sounds interesting to say the least. I worked around the corner from his place for four years and didn't know it existed.  
Hopefully someone has heard a Linn and can comment on how it sounds. I would love to know if anyone here thinks it is 'worth' even close to that amount of money for what it does. Obviously people buy them so some think it is worth it. There has to be a lot of hype attached to it for the price though, right?
What would I need to do to a good $1k CD player to get it to sound like the Linn? What is in the Linn for the money? Is it a really expensive DAC chip, gold PCB, cosmic copper wiring?
Neil.

[DVV]

Thanks Ron, the Linn CD-12 is the one I was thinking of. If you do get in to see Eds setup, please be sure to let us know. Sounds interesting to say the least. I worked around the corner from his place for four years and didn't know it existed.  
Hopefully someone has heard a Linn and can comment on how it sounds. I would love to know if anyone here thinks it is 'worth' even close to that amount of money for what it does. Obviously people buy them so some think it is worth it. There has to be a lot of hype attached to it for the price though, right?
What would I need to do to a good $1k CD player to get it to sound like the Linn? What is in the Linn for the money? Is it a really expensive DAC chip, gold PCB, cosmic copper wiring?
Neil.

Well, a few things, that's for sure, no single tweak can do it.

Changing op amps usually works well. Typically used op amps in CD payers include NJR 4558 and such like, which beg to be exchanged for something serious like Analog Devices AD826AN. These cost less than $4 from AD and are, in my view, easily the best around for audio.

Changing capacitors also always works, however to different extent depending on the design. Start with power supply caps, and work your way along the signal path.

Changing at least some of the critical resistors also produces very beneficial results, though smaller in magnitude than the two tweaks above.

A tweak I particularly like is exchanging the op amp decoupling caps, typically 0.1uF, for tantalum 10uF/25V types. This is not cheap, but this planet has not yet seen anything that decouples so well as tantalum capacitors, which is why they are used in precision instrumentation, medical electronics, etc.

Or you could really hog it, and take your power transformer out, install multiple voltage heavy duty sockets, add another case and put in a big toroidal transformer custom made for you. This can't fail, it always produces better sound.

Combine the above and you should be about there.

Cheers,
DVV

[blizzard]

Hi Dejan,
  That's interesting.  I know many are using toroidal transformers for power supplies for their DACs, transports, and CD players.  But, I have heard that even if the toroidal has an electrostatic shield (which supposedly improves isolation between the primaries and secondaries), it still doesn't isolate as well as a split or dual bobbin I core transformer.
  I understand using toroidals for power amps, where more power is required.  But, why do so many use them on low powered devices?  If you are building it yourself and have a choice, why would you use a toroidal in this application?
    Thanks,
         Steve

[DVV]

Hi Dejan,
  That's interesting.  I know many are using toroidal transformers for power supplies for their DACs, transports, and CD players.  But, I have heard that even if the toroidal has an electrostatic shield (which supposedly improves isolation between the primaries and secondaries), it still doesn't isolate as well as a split or dual bobbin I core transformer.
  I understand using toroidals for power amps, where more power is required.  But, why do so many use them on low powered devices?  If you are building it yourself and have a choice, why would you use a toroidal in this application?
    Thanks,
         Steve

If you put the toroidal into a separate case, and connect the power case with the CD player with an umbillical chord, you have nothing to worry about.

As for radiation, toroidals are unbeatable in that, insofar that the center of the magnetic field should be dead in the center of the toroid. I say "should be" rather than is because much depends on how well it's made, with what materials, and how it was wound.

As to why, well, that's simple - because I have like 4-5 companies within 2 miles of me making them to order. Also, I would use a 200 VA unit for a CD player, not because it needs that much juice, but because with that much juice, voltage variations under any condition should be practically zero, well down into the academic domain level. FYI, YBA uses an 800 VA toroid for the same job.

Lastly, the isolation between secondaries - if it's galvanic and done properly, it will isolate as well as any other you care to name. Claims to otherwise were launched, I'll wager, by manufacturers of non-toridal transformers unable to find any real fault to hang on to.

Cheers,
DVV

[cmscott6]

Just curious.  I don't think anyone's mentioned switching power supply diodes to fast switching, soft recovery models.  How does this rank in the order of tweaks mentioned so far?

[blizzard]

Thanks again Dejan,
     Steve

[DVV]

Just curious.  I don't think anyone's mentioned switching power supply diodes to fast switching, soft recovery models.  How does this rank in the order of tweaks mentioned so far?

Depends who you ask.

Some will tell you fast diodes sound better, and that could well be the case in some applications. But then, I use germanium diodes (AA132) for some applications simply because no silicon equivalent can even approach them, or ever will (voltage drop 0.2V against silicon's 0.65V).

Others, like me, will tell you that a full wave bridge rectifier is only as good as the diodes making it are matched (for full symmtery). To me, this outweighs the benefits of fast diodes, especially when you bypass the bridge with 0.022 uF caps.

I think changing caps is a better option.

Cheers,
DVV

[tmd]

Given that a well put together power supply is relatively expensive to implement and on top of that, you should use a good power cable and possibly mains filtering, wouldn't it make sense to go with a pure DC source instead? Why not just use rechargeable batteries for something like a CD player? It doesn't draw much juice so the batteries would only be charged when the player is not in use.
Would you still need to regulate the supply if you could get the battery voltage very close to the required voltage for each part of the player?
Neil.

[DVV]

Given that a well put together power supply is relatively expensive to implement and on top of that, you should use a good power cable and possibly mains filtering, wouldn't it make sense to go with a pure DC source instead? Why not just use rechargeable batteries for something like a CD player? It doesn't draw much juice so the batteries would only be charged when the player is not in use.
Would you still need to regulate the supply if you could get the battery voltage very close to the required voltage for each part of the player?
Neil.

Neil, batteries look good on paper, but in real life, there are problems with them. Price for one, but let's leave that aside for the moment. The greatest problem with batteries is their inertia - they are slow to respond to suddenly increased demands.

This is not a problem in preamps, which draw little current and run in pure class A anyway, so their consumption is fairly constant, but in case of CD players, there are various motors in the drive mechanism to think of.

Also, making reliable recharge, or trickle circuits, is neither easy nor cheap, and then you need large batteries, which take up a fair bit of room, etc.

Start along that path and it begins to look less and less attractive as you go along.

Cheers,
DVV

[tmd]

Thanks Dejan. Based on your reply here are some more questions.
If I were to use batteries for the analog section, would that mean I would have less of an inertia problem, as the board would draw fairly constant current?
Then, if I used another battery supply for the DAC part, would that have the same effect?
I would probably leave the transport supplied by a more traditional supply.
Thanks, Neil.

[DVV]

Thanks Dejan. Based on your reply here are some more questions.
If I were to use batteries for the analog section, would that mean I would have less of an inertia problem, as the board would draw fairly constant current?
Then, if I used another battery supply for the DAC part, would that have the same effect?
I would probably leave the transport supplied by a more traditional supply.
Thanks, Neil.

No, the analog section runs in pure class A anyway, so its current demands are almost constant, and what difference there is is so miniscule as to be totally negligible. Work it out - nominally 2V output into just 10 kiloohms is (2/10,000) 0.2 miliamps, and in real life about one third of that. Also, since level changes are so low, a battery will do just fine.

HOWEVER, please remember, most such stages use  dual power supplies, so you need two batteries. These won't be small if you don't want to recharge them every two hours, so they will need space. Lastly, if you want to have the best, you'll need nickel-cadmium batteries, and you may find these are quite expensive.

As for the transport, you may as well continue using the traditional supply, since it will have nothing to do with the analog section at all if you got batteries.

Cheers,
DVV

[tmd]

HOWEVER, please remember, most such stages use  dual power supplies, so you need two batteries.

Dejan,
Did you mean positive and negative supplies or something else? Also, is there any advantage to supplying the DAC with its own battery source?
Thanks, Neil.

[blizzard]

Hi Dejan,
  1.  When replacing op amps in the DAC section of a CD player (or an outboard DAC for that matter), what is you opinion on using sockets as opposed to soldering op amps directly to the board?  Is there a sonic penalty when using the sockets?
  2.  Do you have any experience with Burr Brown's OPA627BP's?  If you do, do you have an opinion on them?
      Thanks,
          Steve

[DVV]

HOWEVER, please remember, most such stages use  dual power supplies, so you need two batteries.

Dejan,
Did you mean positive and negative supplies or something else? Also, is there any advantage to supplying the DAC with its own battery source?
Thanks, Neil.

Yes, most CD players I have seen use split power supplies, therefore implying you will have to mimick them with batteries.

I would say yes to supplying the DAC with its own power supply. I would always say yes to dedicated power supplies.

Cheers,
DVV

[DVV]

Hi Dejan,
  1.  When replacing op amps in the DAC section of a CD player (or an outboard DAC for that matter), what is you opinion on using sockets as opposed to soldering op amps directly to the board?  Is there a sonic penalty when using the sockets?

Well, I use them all the time. However, I use quality gold plated sockets, which are more expensive than typical junk stuff, but still well within reach of everybody. Amphenol is my choice, but there are others out there which are just as good.

  2.  Do you have any experience with Burr Brown's OPA627BP's?  If you do, do you have an opinion on them?
      Thanks,
          Steve

I make it a very firm point to stay as far away as I can from Burr-Brown op amps. I find them cold and veiled, no exceptions. They are excellent electrically, very reliable, but poor in sound and in my view tend to be overpriced.

For single op amp applications, where the gain is 5:1 or greater, I tend to use OP37 (OPA37), despite its nominally standard specifications, because I find it to sound rather good. Also, its noise floor is low at 3 nV/sq.rt.Hz.

For dual op amp applications, I use AD826AN only. In my view, it beats everything else out there in terms of sound quality, and its performance is far better than most others. In some aspects, such as settling time, it's the best out there bar none, at least to my knowledge. Lastly, I buy them from Analog Devices direct via their web site, so I'm spared the dilemma if it's real or if it's a Far Eastern copy (which has nothing to do with the real thing).

For DC servo applications, I use OP97 or LF411 - these are specific, ultra low thermal drift op amps, made for exactly such applications.

For ultra match, ultra lown noise (0.9 nV/sq.rt.Hz) dual transistor applications, I use SSM 2210 (NPN) and SSM 2220 (PNP), but while using the standard 8-pin DIL package and looking like an op amp, there are just two transistors inside.

I also love the now defunct OP275 (dual) and OP176 (single) op amps, but these have been withdrawn and are replaced with far more mundane products.

Cheers,
DVV

[starlet]

In my norh cd-1, I replaced the NE5532P op amp with the OPA2604 which, IMO produce a more life like sound. I have also  changed the TLO71 with the OPA627. The 627 is very rich sounding at first but after some breakin, it has cool down a little.

As for DC servo applications, the LM741 was swap with the AD711.

Over all, the sound now is much warmer, bigger and more real than before. I like it!

[tmd]

Starlet,
How difficult was it to replace the chips in the CD-1? I have a buddy who has one and has been bitten by the tweak bug and will tell him about your experiences. Did you do anything else to the CD-1 like a superclock or PSU upgrades?
General question;
What is a DC servo application? Where in the CD player is this chip and what does it do?
Thanks, Neil.

[starlet]

Neil,

I actually know nothing about all this. What I did was a searched on AA, asked a few questions, get a friend to pluck them in and I just pray that it works. I am glad that I did that.

From what I know, it is quite difficult to replace the clock as it is sitting under the transport. I didn't dare mess with it.

Other things that I did was swap out15 1N4007 diodes in this player and replaced them with Harris RHR D460. The current is 4 time that of the 1n4007. Oh boy… the improvements were very obvious. It did not change the characteristic of the player but as if a pillow has been removed from my speakers.

I have also place a piece of blu tack on the Crystal's receiver which improved the clarity of the sound. Dare not do the same to the DAC as it runs pretty hot while playing.

Do it one step at a time so that you can hear the benefit that each tweak has brought about.

[tmd]

Thanks Starlet. I will pass on your findings. How I love to hear about tweaking. For some reason, it really appeals to me to be able to make a consumer product perform better than when it left the factory.
Neil.