Help with digital front end improvements w/DEQX

[Rob S.]

Hey everyone,
       I've just begun Tri amping my speakers using the DEQX 3.0 as processor.  I've been enjoying the best sound yet out of my speakers to date ( also thanks to Richie for his speaker placement help months ago, I keep coming back to his marks on my carpet.      Every aspect of the sound has improved.

My nervosa is creeping back with regards to my digital front end.  I'm using the DEQX as preamp/ crossover/DAC. I'm now looking at ways to improve the "transport" side.   Whether it be SB3 connected to the digital input, or my very basic Cambridge 540 DVD/cd player.   Due to my DEQX input capabilities, I have one standard rca digital input, which can be used for either my cdp or SB3.  I have several balanced inputs I need to take advantage of.   Also, my lone rca analog input is being used by my TT, What can be done to help my front end.?

Thanks for reading and any advice is welcomed....

Rob S.

[richidoo]

Congrats on the new toy Rob!!

Here's a picture of the back of the DEQX:
http://www.moon-audio.com/DEQX/HDP-3_rear_2.jpg

It would nice to have a disc player on one digital input, and a streamer on the other. You'll probably need to convert a consumer (.5V) SPDIF output to professional (5V) AES/EBU. Info on conversion: http://www.rane.com/note149.html     A transformer can do it, or an active amp. There are a lot of choices.

Then you could put your phono preamp into the single ended analog inputs.  I bet you already thought of that...   

[Rob S.]

Rich,
    You think a simple RCA-balanced adaptor would be much of a compromise sonically, if I use it on digital cable going into the DEQX?

Which Cdp's have XLR outputs?

Rob

[richidoo]

The two digital transmission formats have different voltages. So the balanced digital input is lookin for +/-5V square waves. If it only gets .5V it will not perform well, or not at all. So you need something to bump up the voltage.  No! not another AMPLIFIER!    According to the Rane note I posted above, most digital transceivers can tolerate either standard, so it's worth a try. The temporary contacts of the adapter will not be 75 or 110ohm, so you can expect jitter to be increased by using the adapter. Maybe DEQX reclocks well enough so that doesn't matter. Their balanced output version comes with a clock-in jack so at least they are aware of the issue.

Here's a cheap opamp based adapter from Hosa. Limited to 96kHz sample rate.
http://www.sweetwater.com/store/detail/CDL313/
M-Audio Midiman CO3 also does this, also limited to 96kHz, but I think it's discontinued.

A transformer will allow 192kHz if it's designed to. See figure 4 in the Rane note for the circuit. Sol made a converter to adapt Shane's Buffalo SPDIF input to his Lynx PC card's AES 5V output. Lundahl 1574 is $25. Sol can recommend the best part for your app.

ARC CD5 and Oracle CD Transport have balanced digital outs. 
You really only need a transport, with no analog stage, or at least not expensive one. But stand alone transports mean high end audio so watch out for the big rip. It would be nice to have a transport with clock input, so you could sync your transport to the DAC in the DEQX via an external clock.
This looks cool if it's real:
http://www.psaudio.com/store/products.php?product=Classe-CDT%252d1-CD-Transport
Check the 'goner for "balanced digital" or similar

[bpape]

Or you can pick up a used CAL Delta transport.  Those have AES/EBU outputs so you wouldn't use either the standard XLR or standard RCA.  They can be had for a resonable price these days.  I think I saw one on AC in the mid $300's IIRC.

Bryan

[Face]

Is it me, or those look straight out of a car dashboard? 

[richidoo]

Yup, it does...

They are out of biz... 

http://www.californiaaudiolabs.net/

[bpape]

Oops.  I was wrong.  No AES/EBU, just balanced outs

http://www.audiocircle.com/index.php?topic=83883.0

Lots of mods can be done to this unit to raise the bar from already very good performance.


Bryan

[richidoo]

That's cool, no analog jacks!

Variants of AES standard can be balanced, but the EBU standard requires a transformer.

[RichardS]

Another option to consider:
Get a jitter box that has multiple inputs and use the digital RCA or AES/EBU output into same on your DEQX. I use a Genesis Lens that's connected to a BNC source (with a RCA-BNC cable), RCA source and AES/EBU source, all with one output to my Tact. Sonic Frontiers (Assemblage) Monarchy and Perpetual Tech make reasonably priced jitter boxes that you can find used, but you'll have to check their input options. The added benefit of jitter reduction will likely help the sound too, esp. with your less expensive sources.
Then again, maybe these are more than you want to spend.

[Rob S.]

Thanks guys for the suggestions.

if I go stand alone player or transport I like this one ( especially for the product description) http://www.audiogon.com/cgi-bin/cls.pl?dgtlplay&1286719479&/Audio-Research-Corp-CD-1-very-
no remote so forget that...
another nice faceplate on a cd transport:  http://www.audiogon.com/cgi-bin/cls.pl?dgtltran&1284332131&/Audio-research-CDT-1-digital-c   anybody know how old this model is?

yeah, I like the price on the CAL unit....  Will a transport really make much sense here as far as improved sound goes, isn't the DAC/preamp and so on going to have more bang for my buck?

Rob

[richidoo]

AR CDT-1 was made in 1995. 1996 came the CD2. But CD1 got good reviews and supposedly very low jitter. You know you can get it fixed if the need arises. Seems like a good price, but I don't know the cons, or why it was only made for one year, Could be that the parts were too expensive, hence the good reviews.  

http://www.arcdb.ws/CD1/CD1.html

As far as sound goes, the sound begins at the DAC in the DEQX. Transport is a data source. If DEQX does nothing about jitter reduction, then the transport and digital cable will have a big effect. Find out what DEQX is doing about jitter.

A feature that I look for in transport/CDP is the ability to rewind through the track break to be able to play only the end of a song. And the ease of FF and REW.

A really cool transport is the one in the PerfectWave system from PS Audio. I didn't get to play with the transport controls yet, but it's a memory player so it gives a very low jitter output, with the song buffered to memory and sorted before playing with very low jitter. It lists for $3k. Black Sand Audio and Hometheaterdoc are dealers.

[JLM]

I'm not aware of any upgrades to the crossover or EQ portions of the DEQX.

I had Scott Endler mod the DAC in my DEQ2496 (I run single driver speakers).  Unfortunately I didn't have XLR cables for the analog outupt from the 2496 until I had Scott supply them with the modded unit, so I can't say how much good the mods did.  But it's got to be a lot cheaper than a new DAC.  Current favorites are the Easter Electric tubed DAC, the dB Audio Tranquility, and the Wired 4 Sound DAC II.

Another upgrade consideration is in the digital cabling.  (I'm no fan of expensive cables, but some swear by them.)