[bhobba]

Hi Hugh And All

I recently came across the following article:
http://www.chordelectronics.co.uk/products_detail.asp?id=33

That sampling rates up to 1Mhz sound better than lower sampling rates is a rather interesting finding.  I know Hugh has commented he does not think digital can sound as good as analogue until they operate at sampling rates that high.  It also may help explain why his extremely 'quick' hologram power supply sounds so good - it is letting that timing information through. 

Another interesting product along similar lines is the Anagram up-samplers to 384K implemented on the new Cambridge Audio's CDP's:
http://www.cambridgeaudio.com/product_reviews.php?PID=272&Title=Press+reviews

They evidently kill anything near its price point.  I have got 'itchy' fingers to get one of these and have mods done on it.  I understand why high quality caps etc like BG's are not used in a product like this, but why they have these complex output stages with a number of medium quality op-amps and associated circuitry is beyond me.  For voltage output DAC's direct coupling using a high quality cap would seem ideal.  For current output DAC's a simple transistor or FET class A I/V converter looks the goods. 

Interested to hear what others think.

Thanks
Bill

[rabbitz]

Another interesting product along similar lines is the Anagram up-samplers to 384K implemented on the new Cambridge Audio's CDP's:
http://www.cambridgeaudio.com/product_reviews.php?PID=272&Title=Press+reviews

I have a Cambridge 840C and it's ripper. Like a LF55 the sound quality sneaks up and you have to live with it for a while to appreciate it. If you want to be wowed and impress your mates, forget about it as it's a music maker pure and simple.... doesn't tart up the sound or add the warm fuzzies. This player is a winner on all counts and has a bonus of being a DAC for 2 other devices.... bargain of the year.

Caps are not an issue with this player as there are none in the signal path. I'm not going to argue about the quantity of OPA2134 op amps in there (there are a few) but the output has a very low impedance (<50R) which can only be achieved by a good buffer on the output AFAIK. They have Doug Self on board so I imagine it's all done for a reason.

I thought the output impedance would be low enough for a passive pre but still sounded better using a Burson Buffer.... great gadget.

CD tracking is very good considering it uses a crappy Sanyo drive and laser. Doesn't go through my torture CD like the Sony CDP-X55ES with the great KSS-270A laser and linear drive but does 75% of the tracks which is admirable. Most CD players only do 20% of the tracks.   

[bhobba]

I have a Cambridge 840C and it's ripper.

Great to know.

I thought the output impedance would be low enough for a passive pre but still sounded better using a Burson Buffer.... great gadget.

I am thnking about going the whole hog and getting the Burson pre.

CD tracking is very good considering it uses a crappy Sanyo drive and laser. Doesn't go through my torture CD like the Sony CDP-X55ES with the great KSS-270A laser and linear drive but does 75% of the tracks which is admirable. Most CD players only do 20% of the tracks.   

To me the CD player is just a bonus.  I was gong to feed it from a Squeezebox anyway.

I was thinking of the 740C.  Do you know anything about its output?  I was thinking of getting its clock and power supply modded but ripping the output buffer out and replacing it with a simple cap (the DAC in the 740C is a voltage out DAC).  The other option is a Burson discrete op-amp.  Any thoughts?

[andyr]

Hehe ... I guess that's why vinyl sounds so good, musically speaking (although some grouches have issues with "pops & clicks")!!    I guess you could say analogue is "sampled" in the GHz?   

Regards,

Andy

[SamL]

Hi bhobba,
Have a look at the TDA1541a DAC SE DAC (v4) from Thomas, aka Tube-lover from diyaudio.com. It is a populated kitset and provide various feature that are not found on other DAC. It can be NOS (non oversampling), 4xOS, reclock, no reclock. You can use the provided 2 channel opamp I/V, 2x 2 channel opamp I/V, tube buffers I/V(extra) or the new release nano pulse transformer I/V (extra). It has true balance output (extra) and multiple input with USB are there with extra pcb.  If you love mod, you will love this DAC and schematic are available.
The sound of the DAC is superb. High, mid and bass are all there with details and emotion. You don't need to mod the player to enjoy it.  Before this DAC, I got myself the Beresford 7510 MK5, a very talk about DAC on some forum. Well, it is a good DAC for the money but is only comparable to my mod Pioneer DV667 DVD player. Maybe it is my system but this is what I found. Each has its own quality but overall it is only comparable. So it is not much of an upgrade to me.
The TDA1541a DAC SE DAC (v4) on the other hand is a leap above. I can hear improvement before the DAC is fully burn in.  Unlike others, I don’t do critical listening. If I can’t hear the improvement with leisure listening, I don’t think it is worth keeping.  I am keeping the TDA1541a DAC SE.
Like most seller over diyaudio.com, Thomas is doing this part time and only charge penny for the DAC. The down side of this is he is always busy and the unorganised part of him is making things difficult for those who deal with him. It took me 6 weeks after payment to get my DAC and 3 months now I am still waiting for the source selector with USB input. Well, like many others who still missing some bits, I am happy to part more money for the next upgrade that he will be releasing. His is a honest person but just not well organise. After enjoying our music thought his DAC, most tent to forgive & forget the imperfect part of him.

http://www.diyaudio.com/forums/showthread.php?s=&threadid=79850&perpage=25&pagenumber=51
http://www.diyaudio.com/forums/showthread.php?s=&threadid=110685&pagenumber=1

For those who wonder how the NOS/OS/clock/reclock work, it is done through jumper and switch.
http://www.diyaudio.com/forums/showthread.php?postid=1342664#post1342664

Have fun

[rabbitz]

To me the CD player is just a bonus.  I was gong to feed it from a Squeezebox anyway.

I was thinking of the 740C.  Do you know anything about its output?  I was thinking of getting its clock and power supply modded but ripping the output buffer out and replacing it with a simple cap (the DAC in the 740C is a voltage out DAC).  The other option is a Burson discrete op-amp.  Any thoughts?

I thought the outputs would be very similar. Discrete op amp might be an issue as it's all SMD's in there and from experience the Burson op amps need higher voltages to be at their best..... 18V - 24V. Just adding the external buffer yields better results IMO.

Before thinking about modding, have a look at the inside as it's SMD city. The power supply is quite good as there are over 18 supplies in there. May be better off with a dedicated DAC.



On vinyl... I'm building a retro (late 1970's) system and have added a turntable. It's only a modest Ariston / Ortofon setup but enough to show me why I gave up vinyl in the late 1980's and what a PITA to use. Sure there are some endearing parts to the sound but all the CDP's I have here sound far better overall.

I do know how to set up a turntable, have had vast experience and played the $$$ game on cartridges / turntables all those years ago. CD may not be ppppeerrfect but it's quite good and doesn't lack too much.

Just a comment and not the start of a fight or flaming session.
  

[bhobba]

I thought the outputs would be very similar. Discrete op amp might be an issue as it's all SMD's in there and from experience the Burson op amps need higher voltages to be at their best..... 18V - 24V. Just adding the external buffer yields better results IMO.

The other option some modders use is an output transformer.

On vinyl... I'm building a retro (late 1970's) system and have added a turntable. It's only a modest Ariston / Ortofon setup but enough to show me why I gave up vinyl in the late 1980's and what a PITA to use. Sure there are some endearing parts to the sound but all the CDP's I have here sound far better overall. I do know how to set up a turntable, have had vast experience and played the $$$ game on cartridges / turntables all those years ago. CD may not be ppppeerrfect but it's quite good and doesn't lack too much. Just a comment and not the start of a fight or flaming session.

I agree.  You time and effort in posting the info is very much appreciated.

Thanks
Bill

[bhobba]

Have fun

I always do.

Such a lot of very interesting info - thanks for posting it.  Trouble is I ma not that into modding.  I am just damn interested in that Anagram stuff - it really has me hooked.

Thanks
Bill