Audio Alchemy DDS-PRO Transport

[Redwingnine]

I recently picked up a Audio Alchemy DIT Pro 32 and DDS 3.0 DAC. I picked this up for use in a second system. The sound from this pair is quite nice, somewhat better than I would have thought.

I'm considering looking for a DDS PRO Transport, as I wish to take advantage of the I2S output to the DTI. Using the I2S from the DTI to the DDS did provide a noticeable improvement over BNC.

So, a couple of questions: 1) Are there replacement parts for DDS PRO available, and, 2) Are there other transports that support the I2S out?

[SoNic_real_one]

Any CD/DVD with dedicated DAC will have accesible i2s lines. So it would be fairly easy to "extract" them.

[amc184]

The DDS-Pro uses a Pioneer PEA1179, as well as quite a few other Pioneer parts, as it is based on one of their players. The PEA1179 is one of the lower end members of Pioneer's 'Stable Platter' line, and is middle of the road as far as transports go. Getting replacement parts for it will probably be possible, but not cheap.

The DDS-Pro is will match your other Audio Alchemy gear and the I2S link will be ready to go, but those are really the only standout features.That said, linking other transports to your existing gear via the I2S link won't be as trivial as you might think, so those are very useful features.

Any CD/DVD with dedicated DAC will have accesible i2s lines. So it would be fairly easy to "extract" them.

I strongly disagree, most CD players don't have an accessible I2S bus, and even when a player does, you'll have to add circuitry to transmit that signal.

I2S is mainly used by Philips chipsets (they wrote the I2S standard), most chipsets from Sony, Matsushita and others used different data formats for internal transmission of digital audio. On top of that, the I2S standard defines only a data format, it doesn't define any physical layer, so each manufacturer uses different cabling and voltage levels. I've seen I2S transmitted on HDMI, Ethernet and coaxial type cables, and it looks like Audio Alchemy uses mini-DIN connectors. You'll have to find out what pinout and voltage levels are used in Audio Alchemy's version of an I2S link if you want to add an I2S output to a CD player.

[Redwingnine]

Originally Posted by amc184

The DDS-Pro uses a Pioneer PEA1179, as well as quite a few other Pioneer parts, as it is based on one of their players. The PEA1179 is one of the lower end members of Pioneer's 'Stable Platter' line, and is middle of the road as far as transports go. Getting replacement parts for it will probably be possible, but not cheap.

The DDS-Pro is will match your other Audio Alchemy gear and the I2S link will be ready to go, but those are really the only standout features.That said, linking other transports to your existing gear via the I2S link won't be as trivial as you might think, so those are very useful features.



I strongly disagree, most CD players don't have an accessible I2S bus, and even when a player does, you'll have to add circuitry to transmit that signal.

I2S is mainly used by Philips chipsets (they wrote the I2S standard), most chipsets from Sony, Matsushita and others used different data formats for internal transmission of digital audio. On top of that, the I2S standard defines only a data format, it doesn't define any physical layer, so each manufacturer uses different cabling and voltage levels. I've seen I2S transmitted on HDMI, Ethernet and coaxial type cables, and it looks like Audio Alchemy uses mini-DIN connectors. You'll have to find out what pinout and voltage levels are used in Audio Alchemy's version of an I2S link if you want to add an I2S output to a CD player.

Thanks for your response.

Your explanation regarding I2S mirrors some of my thoughts (and concerns) about getting a transport with the I2S interface available. I'm going to get the DDS PRO, as I think the I2S interface will work better with the DTI/DDE combo.

I think (but not sure) that the I2S interface from the Benchmark DAC is the same connector as the Audio Alchemy. What I fail to understand is why more transports/DACs do not use the I2S interface. It's a noticeable improvement with the DTI/DDE combination. Any ideas?

[SoNic_real_one]

Originally Posted by amc184

I strongly disagree, most CD players don't have an accessible I2S bus, and even when a player does, you'll have to add circuitry to transmit that signal.

I2S is mainly used by Philips chipsets (they wrote the I2S standard), most chipsets from Sony, Matsushita and others used different data formats for internal transmission of digital audio. On top of that, the I2S standard defines only a data format, it doesn't define any physical layer, so each manufacturer uses different cabling and voltage levels.

ANY BurrBrown (TI), AD, CS or WD DACs will have I2S line exposed. What are you talking about?
Yes, you will have to add the circuitry (digital buffers worth of 1$).

[amc184]

I think you're right in picking the DDS-Pro. I thought the Empirical Audio modified DAC-1s were using 8P8C (RJ45) connectors, but I'm not sure.

My take on the reason behind the lack of devices using an I2S interface is that there are no standards for its use as a external interface. If you manufacture a product with an I2S interface its going to incompatible with all but a few devices, and hence only a selling point to a few people. Most people won't even know what I2S is. I agree with you about the benefits though, they are significant.

ANY BurrBrown (TI), AD, CS or WD DACs will have I2S line exposed. What are you talking about?
Yes, you will have to add the circuitry (digital buffers worth of 1$).

This silly issue comes up again and again, please stop misinforming people. I2S (or Inter IC Sound) is a format for the internal communication of digital audio. It is not a generic term for an internal digital audio bus. Most input buses into DACs won't be I2S, they'll be one of the many other digital audio bus formats. Many Burr Brown and Analog Devices DACs don't accept I2S, and just because some more modern DACs can accept I2S doesn't mean that they won't be fed data in another completely different format that they also accept.

You just try capturing the 'I2S' from the input of a PCM63 or a AD1865 and feed it to a DTI Pro 32, you see what happens. Even better, get the 'I2S' from the input of a PCM54, that'll be interesting.

[stephensank]

The DDS-Pro is literally a Pioneer PD-S703, with an upgraded clock board added. Part of the AA service manual for the unit is the service info for the PD-S703, plainly labeled as such. Good transport, other than the not uncommon occurrence of the lens falling out of the laser pickup, whiich is an easy fix.

[Redwingnine]

Originally Posted by stephensank

The DDS-Pro is literally a Pioneer PD-S703, with an upgraded clock board added. Part of the AA service manual for the unit is the service info for the PD-S703, plainly labeled as such. Good transport, other than the not uncommon occurrence of the lens falling out of the laser pickup, whiich is an easy fix.

Good info, thanks for that. I just picked up a DDS PRO at a very reasonable price. I also have a I2S cable to connect it to the DTI Pro 32. Looking forward to testing this out.

I'm impressed with the Audio Alchemy DTI Pro/DDE 3.0 combo. These guys were onto something with digital. I've heard far more expensive setups that were no better, or slightly worse. The I2S cable between the two definitely improves the sound.

[SoNic_real_one]

Originally Posted by amc184

This silly issue comes up again and again, please stop misinforming people. I2S (or Inter IC Sound) is a format for the internal communication of digital audio. It is not a generic term for an internal digital audio bus. Most input buses into DACs won't be I2S, they'll be one of the many other digital audio bus formats. Many Burr Brown and Analog Devices DACs don't accept I2S, and just because some more modern DACs can accept I2S doesn't mean that they won't be fed data in another completely different format that they also accept.

You just try capturing the 'I2S' from the input of a PCM63 or a AD1865 and feed it to a DTI Pro 32, you see what happens. Even better, get the 'I2S' from the input of a PCM54, that'll be interesting.

Dude, I did say "any" like in "any in production", not 1800's DAC's. Any multibit modern DAC will have i2s lines, just look on the datasheets!
TI product line alone has 51 of them in production now and may of the old ones have it too. Wolfson has 15 of them (only the low-cost ones are missing it).

[amc184]

I'm glad you found a DDS Pro so quickly. Let us know what you think of the sound. The amount of jitter in digital to analog conversion is so critical, so I'm not surprised that you find these lower jitter combinations so good.

Any CD/DVD with dedicated DAC will have accesible i2s lines. ANY BurrBrown (TI), AD, CS or WD DACs will have I2S line exposed.

It really sounded like you said "any", not "some". Regardless, I still don't agree with what you're saying.

I looked for an example to show you what I mean, and chose the current production CD player from one of my favourite brands, the Arcam CD17. It uses a WM8741 DAC which does accept I2S. However, it's fed 16bit right justified data in this player, a format totally incompatible with I2S. It doesn't matter what formats the DAC accepts, it's all about what format the decoder / digital filter / DSP is outputting.

I could also mention all of the Sonys, Onkyos and other Japanese players, a massive segment of the market, almost all of whom don't use I2S. All up, I'd say maybe as little as 20 to 30% of modern, current production CD players use I2S. Hence, to say that all modern CD players use I2S is grossly misleading.