Pc -> Dac, How ?

[phofman]

It is not very clear what bitrate and sample rate you can get from such cards from the i2s header.

If the card is based on Envy24HT, you can get up to 24/192 on its I2S output lines. Basically any Envy24-based card will do the job.

[francolargo]

Originally posted by Telstar


The latest ESI drivers (for julia, and some other cards) are quite good and support Vista. The ones for the older cards are a no-go for me for this same reason.

About linux world, the Envy24ht is well supported, so that's also a go.

Last but not least, there is the word clock issue. IIRC i2s contains a clock signal. I wonder if an external clock would be needed, like it is for spdif, or that can be skipped without compromising SQ too much.

It seems that the Envy 24ht might be a significant consideration. (How long until 24 bits are insufficient? ) The same chip is incorporated into ESI interfaces of any age. Even for the discontinued equipment the most recent driver supports Vista 32 and 64 and was updated only a few months ago.

http://download.esi-audio.com/?w=esi&p=30&g=1&l=en

Regarding the ESI card, there are no crystals on the rack-mount board so the only clock seems to be on the PCI card. I'm not an engineer, but I think an external clock may be generally desirable because even with the transceiver chips I observed that the length of the cable to the DACs affects sound quality. The stock cable is 3 meters. I replaced that with one that is ~80cm and improved SQ noticably (from the stock AKM DACs). I have not compared cables now that I have stuffed 3 TP Opus DACs into the little rack box. There is no space for ASRCs so I will live with whatever jitter exists.

One wonders what is the limit of interface jitter that the new ES9018 can ignore? It seems like a very different beast.

Regards,

Frank in Mpls.

[Telstar]

Originally posted by francolargo

It seems that the Envy 24ht might be a significant consideration. (How long until 24 bits are insufficient? ) The same chip is incorporated into ESI interfaces of any age. Even for the discontinued equipment the most recent driver supports Vista 32 and 64 and was updated only a few months ago.

24 "real" bits should be enough forever, unless we want a digital volume control*, but I dont care for this.
Some products are not supported in vista but others are.

Regarding the ESI card, there are no crystals on the rack-mount board so the only clock seems to be on the PCI card. I'm not an engineer, but I think an external clock may be generally desirable because even with the transceiver chips I observed that the length of the cable to the DACs affects sound quality. The stock cable is 3 meters. I replaced that with one that is ~80cm and improved SQ noticably (from the stock AKM DACs).

This concerns me a bit. Are you talking about a rca cable using the AKM dacs in their cards or something else?

One wonders what is the limit of interface jitter that the new ES9018 can ignore? It seems like a very different beast.

The ESS is a different beast for jitter. With that solution (that most people will adopt especially for cost reasons), an ultra-low jitter master clock is not needed.

For my project, which is based on several pcm1704, it is and I think I have found something suitable.

[* the ESS SAbre has 44 bits for digital volume control to be done in hardware, so for that solution is also not a problem]

[Telstar]

Originally posted by krautxy
Hi DUC995,
i use sabre DAC, Juli@ and asus Xonar PCIe. i know that Juli can be used to output I2S.

BTW, it should be possible to get i2s from the Xonar (pci-e, shielded) cards, which are a better option IMO.

[phofman]

What is the advantage of the 44-bit volume control compared to conventional 24-bits, if only the upper 24 bits are kept for the 24-bit DAC plus the 24th bit is below DAC's noise level anyways? Regulating by -6dB means loosing the MSB, in 44bit as well as 24bit formats.

[francolargo]

Originally posted by Telstar



This concerns me a bit. Are you talking about a rca cable using the AKM dacs in their cards or something else?

The cable from the PCI card to the rack box containing the ADCs and DACs, etc. is a standard DB25M/M cable. Similar to this:

http://www.cablestogo.com/product.as...=917&sku=02664

Most of the stock 3 meter cable sat coiled on the floor. Before making any other mods, I replaced it with a shorter (and better?) cable from a dead Zip drive.

IIRC, 5 of the 25 wires in the cable are unused. The PCI card has input pins for an external master clock and this is supported in software. Thus, it may not be difficult to re-clock the system from an external source through the DB25/f connector on the back plate of the PCI card. Remember also that the sample rate is selectable in software and goes as high as 192kHz. However, changing the DAC requires that it be programmed independently in coordination with the driver software.

Back to the "from the ground up" proposition for this thread, methinks that the controller chip of choice plus the software to run it are central issues in this chain of information. What would produce the highest quality source? Isn't the VIA Envy 24ht getting old and isn't there anything significantly better? Farther along, can't you engineers just 'use a bigger hammer' as it were to improve transmission and 'fidelity' of the original I2S signal ???

All the best!

Frank in Mpls.

[phofman]

Originally posted by francolargo

Back to the "from the ground up" proposition for this thread, methinks that the controller chip of choice plus the software to run it are central issues in this chain of information. What would produce the highest quality source? Isn't the VIA Envy 24ht getting old and isn't there anything significantly better? Farther along, can't you engineers just 'use a bigger hammer' as it were to improve transmission and 'fidelity' of the original I2S signal ???

I am afraid Envy24HT was the peak in high-fidelity sound card technology. It does its job - moving data from memory to I2S via DMA, clocked by separate crystal-based clocks for 44.1kHz and 48kHz families, plus simple mixer and integrated SPDIF transmitter. Complete documentation freely available, without signing an NDA. Reasonable range of supported latencies. No DSP, effects, synthesis, PLL'd clocks to spare the second crystal.

All new generation soundchips are made to save money on BOM, not to provide top sound quality. The only PCIe card with double crystals I have been able to find so far is the aforementioned http://www.esi-audio.com/products/esp1010e/ which I suspect somehow runs on the Envy24 chip too (perhaps some custom-made variant with PCIe support) - check out the board picture.

[francolargo]

Originally posted by phofman

The only PCIe card with double crystals I have been able to find so far is the aforementioned http://www.esi-audio.com/products/esp1010e/ which I suspect somehow runs on the Envy24 chip too (perhaps some custom-made variant with PCIe support) - check out the board picture.

Interesting information. Thanks!

I believe you are correct. In the picture of the PCI board I believe the Envy 24 chip has the ESI logo on the bottom right of the board. I also see that there are what look like 10 channel transceiver chips up near the main connector. Also, this main connector is changed from the older version with which I'm familiar (3 vs. 2 rows of pins).

The discussion I would hope for here is clearly not in my league , so the last thing I'll mention here about the ESI stuff is that mods within the rack box are not the simplest. The rack boxes are slim and have one large circuit board incorporating board-mount interfaces towards the front and rear. Therefore, adding significant circuitry requires either a compact board hanging downwards from the top of the case (PIA!) or a new larger case with quite a few external connectors to re-configure... I opted for simply replacing DACs and am very pleased with the bang/buck. I used DACs that needed no additional i/v conversion because there is no room for added boards...

Best wishes to all,

Frank in Mpls.

[peufeu]

I've been looking at ESI and RME products, it is interesting to see that both manufacturers share a common trend, which is to build a small PCI or PCI-Express board to put in the PC, which has several FireWire sockets, which do not use the FireWire protocol, but a proprietary one, presumably using some form of serial LVDS communication. Then they sell addons ("breakout boards") which talk to the PC using this protocol.

So it seems that high-end pro audio gear makers are perfectly aware that putting analog stuff inside a PC is wrong wrt noise (and also unapplicable to laptops) and it seems they are searching for a better way, which is exactly the point of this thread...

When I said earlier that FireWire is dead, this is exactly it : both those manufacturers developed their own protocol to solve USB / FireWire shortcomings.

FireWire is too complex, and USB is too simple...

However for living room use where larger latencies are acceptable, I believe USB will be perfectly OK for the job, and it is not going away anytime soon. This is why I chose it.

It is a pity that the protocols are closed. There is the MADI protocol, though, which looks interesting. Does anyone have a link on the PDF with the specs, that the AES wants to sell for $30 ?

[Telstar]

Originally posted by phofman


I am afraid Envy24HT was the peak in high-fidelity sound card technology. It does its job - moving data from memory to I2S via DMA, clocked by separate crystal-based clocks for 44.1kHz and 48kHz families, plus simple mixer and integrated SPDIF transmitter. Complete documentation freely available, without signing an NDA. Reasonable range of supported latencies. No DSP, effects, synthesis, PLL'd clocks to spare the second crystal.

All new generation soundchips are made to save money on BOM, not to provide top sound quality. The only PCIe card with double crystals I have been able to find so far is the aforementioned http://www.esi-audio.com/products/esp1010e/ which I suspect somehow runs on the Envy24 chip too (perhaps some custom-made variant with PCIe support) - check out the board picture.

I think this would be my best bet. I see no reason why not to use the envy24ht just for digital signal transport through i2s.

The lack of shielding *should* not be an issue, and pci-e is to be preferred since possess greater bandiwth and it is future-proof. To the one preaching the death of firewire, pci will die sooner.

About crystals, i do indeed plan to run two master clocks in my dac, one for 44.1k and one for 48k and multiplies.

More importantly, there is a pin for wordclock input?

About software, how is the sample rate selected? I know that RME drivers are transparent, in the way that they do not change arbitrarily the sample rate of the track playing.