finally opened this unit up after having it for the better part of a year. not much to note other than the small daughter board at the right-front side of the main board. i was told that this was a factory upgrade that is the equivalent of a DSP 1000 MKIII.

side view

Scott,

What's the specs on this again? Oversampling? Bit-count?

I've bought the DSP 7000 yesterday. It sounds pretty good, but I don't seem to be able to find that much information about it. Can someone tell me more about the EAD DAC's. I've bought it for the first owner who was very carefull with it, so it looks like new and comes with the original box, manual and he even had some prospects as well. Anyway, I think I've bought it for a good price, but I am jot entirely sure because I was not able to find much information on the internet.

Sonik

They are extreme beautiful and from what i know, with outstanding transparecy. Whitch lead us to one important aspect:
They are very sensitive to what kind of cables and even power cables you guys are using.

These are not an upsampling or oversampling DACs, they are DTS bitstream driving by Crystal CS8412 receiver, the first outboard digital-to-analog converter to incorporate EAD's award-winning AccuLinear analog circuitry, witch ensures that input circuitry is never driven beyond its linear operating range even with full amplitude signals at the highest possible audio frequencies. Even their la-*test*-('")s produts still uses that "old" technology : http://www.tricell-ent.com/EAD.htm


A little info to understand the "magic" about over sampling:

When a sampled signal, any sampled signal, is replayed over a DAC, the resulting analogue-domain signal spectrally contains the original information, say the band from 20Hz up to 20kHz, as well as an infinite series of copies - images - of that information, shifted up in the spectrum around half the sampling frequency fs and its integer multiples. With CD, and its 44.1kHz sampling rate, this means that there is music up to 20kHz, then a gap, then garbage from 24.1kHz to 64.1kHz, a gap, garbage from 68.2kHz to 108.2kHz, and so on...

Assuming that we can't hear above 20kHz, it is just fine to listen to such a raw output of a DAC. But, our amplifiers don't like the spectral images above 20kHz. These can cause nasty intermodulation distortion which folds down into the audible band. And even if they didn't, it still would be an absolute waste of power trying to amplify the images.

Neither do our speaker's tweeters like that images. Tweeters are made to withstand power levels in the order of 5 to 10 Watts. This is fine, even with high-power amps, as the spectral contents of actual music are mostly lumped into the lower frequencies only. But if you confront a tweeter with a digital image, you hit it with all of the bass power of the original signal, magically up-transformed to a higher frequency. And it is not only the first image that hits, but also the second, the third, and so on. R.I.P. Tweeter.

So we really really have to filter the raw output of an audio digital-to-analogue convertor, not so much for sound quality's sake, as for the safety of our gear.

The first Japanese CD-players back in 1980 used sharp high-order analogue filter sections right after the DAC chips. Now it is a very tough job to make a high-order filter with analogue components, keeping an eye on overall cost, and hoping for a decent sonic transparency.

Philips, at the time not able or not willing to make a true 16 bit DAC chip, did things differently. Using oversampling, digital filtering, and noise-shaping they traded DAC resolution against time and hence avoided the need for a 16 bit part and for a steep analogue filter. The Philips machines - and the ones they spawned, notably the first Meridians and Missions - sounded better and the rest is history: quickly everyone adopted upsampling and digital filtering, inserting 1, or 3, or 7 interpolated values inbetween each pair of original samples.

But how does this all work?
Say that you use 4-times oversampling. This raises the original sampling frequency from 44.1kHz (CD) to 176.4kHz. If you combine this with a sharp digital filter cutting above 20kHz, you can clean the whole band from 20kHz to 176.4kHz-20kHz or 156kHz from all nasties. All that is required after DA conversion would be a gentle analogue filter reducing the remaining components above 156kHz.

And everybody was happy for a while. The engineers because they had a seemingly simple solution to a real problem, and the salespeople because now they had a distinguishing specification in what so far had been a market of rather homogeneous products: the race of oversampling figures could begin. Philips with 4x and a true 16 bit DAC, Japan Inc. with 2x, UK-based Cambridge with 16x, Japan Inc. with 8x, then Belgian outfit Audio Discovery with a shocking 32x (8 TDA-1541 convertors in a massive 4-box CD-player), Wadia and Krell following later, and so on.

But wait a moment: all that oversampling and obscenely-high-order filtering is signal processing. And whenever you process a signal, you change it. Not necessarily for the better ...

Sorry for the bla, bla bla...i'm going to dinner.

outstanding post Alvaro, i think i actually somewhat understand the process now.

i finally found the manual for my DSP 1000, heres what it says on the spec's of the unit:

EAD's proprietary AccuLinear design (whatever that is)
guaranteed THD and noise level below -96 dB
199-tap digital filter (whatever that means)
semi-toroidal power transformers (one each for digital and analog)

Frequency Response: 0-20 kHz ± 0.1 dB
Signal to Noise Ratio: >113 dB (minimum) 119 dB (typical)
Oversampling: 4x
20-bit DAC's: hand matched, select grade
jitter: <100 picosecond rms

Hey Scott,
can you do me (us) a favor and tell me what are the chip dac references in your unit? The ones started with AD....

I think maybe i'm wrong about what i said before...I mean with a Bitstream dac...

Could it be, AD1862N-J from Analog Devices ? and with dital filter NPC SM5813ATT ?

Tanx.

i dont know .... its not listed in the manual.

I was posting almost the same time as you...
Ok, that's not a bitstream device!

That is indeed a multibit with the state of the art AD1862N-J from Analog Devices, dital filter NPC SM5813ATT and as i said before with Crystal CS8412 receiver.

IT is an awesome device.
Tanx for sharing.

Very good posts here. Thanks guys. I've been doing some short listening sessions with the EAD and I am very happy I bought it. I still have to do some comparrisons with my other dacs. I will post the result here fot who is interested in them.

Sonik,

I see them selling for a very rough average of $250and up- usually "up", esp. for the 7000. If you got it for $400 or so, you did at least average, in my opinion, if not better.

Scott, I finally pinned some info on the PS Audio products myself. The PS Audio Superlinks are an 18-bit, while the PS Audio Ultralinks are a 20-bit unit. The newest offerings are 24 bit.

The Ultralinks are closer to the EAD 1000s than the Superlinks- the superlinks still being very good, but the EAD should surpass it. The Ultralink gives it more competition- it's that model some folk claim is equal/slightly nicer than the EAD 1000.

Of course, this is opinion only, and I'd love to hear the EAD 1000 vs. a PS Audio Ultralink- more equally-footed competitors than the PS Audio Superlink.

At the end of the day either one is going to be a stellar performer and worthy to take home and I feel comfortable that it would come down to splitting hairs.

Indeed, both companies made some fantastic DACs.

Following eBay and Audiogon for the last 6 months or so, I find the average price of an EAD DSP-7000 to be about $400. I have seen them go as high as $456, and one went on eBay for $134 The DSP-7000 mk III usually gets you a premium of $50 over the DSP-7000.

I agree, a comparison would be great. Perhaps when I get the listening room finished in the new year (I guess I need to provide an update on that) a DAC shootout is in order. I have a PS Audio Ultralink Two (the "Two" is supposed to be superior to the original Ultralink) and Adcom GDA-600 (once considered "one of the best values in high-end audio") that can be -*test*-('")ed. I also have an Adcom GCD-750 CD player and Sony DTC-75ES DAT player, both of which have digital inputs that allow them to be used as DACs. My Adcom GCD-575 CD Player (also highly regarded in its time) can serve as the baseline and transport. So who has a DAC and is willing to bring it to Northwest Atlanta and serve as a judge?

Better yet, bring 'em my way- we'll try the PS Audio Superlink II I have, the Entech 205.2 I have, the sony DAT E75ES like yours I have, and my recently scored for a bargain Audio Alchemy DTI unit. All against your gear. And don't you want to see a white christmas in New England anyway?

I may wrestle you for your Ultralink II however.

And I have a mean headlock up my sleeve...

Thanks guys. I paid about 275 dollars for it. The unit is in "like new" condition and comes with manual and original box. I did not realy have much to go on, but I thought the price was reasonable given the state and completeness of the dac.