USB Lead Help Please.

Hi Guys,
Having just been bowled over by the benefits of Mike Homar's new cable it raised a question in my mind. The music stream was CDP to StanDAC to amp to speakers. This stream is not my main way of listening to music as the CDP is normally replaced by the PC as the source. Given that replacing the interconnect between CDP and StanDAC produced such a major improvement, this raises the question that, all other bits of the music stream being the same, would it be possible to get a similar level of improvement by replacing the interconnect between PC and StanDAC? This interconnect is a USB A to B lead. So, ...... is it possible to obtain high quality USB leads more suited to audiophile applications than bog standard PC data transmission and, if so, from where?
Any ideas or comments on the flawed logic out there?
Look forward to hearing from you.
Cheers,

Just use decent quality USB leads.

The interface is very different to the S/PDIF you have used to connect CDP to DAC and the same logic does not apply.

Chris:)

The most you need is something like Belkin

Most DACs don't even use USB 2.0 (The Beresford USB is 1.1) so even a bog standard USB 2.0 cable is 'overkill'.

Thanks Chris and Chebby.

Quote:

---

Originally Posted by chebby

The most you need is something like Belkin

Most DACs don't even use USB 2.0 (The Beresford USB is 1.1) so even a bog standard USB 2.0 cable is 'overkill'.

---

You sure? The PCM2902 stock sheet I have from TI says it is USB2.0. I better take this up with TI.

i have had some trouble with wiring the beresord throught a cheapy usb hub.. the sound goes to crap, pops and crackles etc... i am lead to belve that this is due to the voltage being spilt between the ports? i know that this situation is because of the hub but if that can effect the signal, could a crap usb cable not do the same?

Has anyone noticed digital hashing noise when using the USB connection with a Windows Laptop? I have two fairly new Vista Laptops in the house. Both inject noise when the mains is plugged in, but are silent and perform most excellently when running on batteries.

The more expensive Samsung Q210 is worse than the Dell Inspiration.

I have not tied a different USB lead.

Perhaps I have very noisy mains?

The Samsung runs Squeezecentre and the Squeezebox does not have any problems, but of course there is no wired connection.

What experiences have others?

Any views Stan?

Hi Dave I bought This Belkin one - gold plated connectors which won't tarnish, looks well made - just be aware it has a blue LED in each plug, which I don't mind, but might bug some people (both light pollution and sonically?) Can't say I can tell any difference between the cheapo one I used to start with, though... (It's gone up 50p since I bought mine though!)

You should always wire a USB cable between a PC port and a DAC. Don't route it trough a USB hub. The USB hub polls each or its port in serial mode, which results in an interruption of the data on a 1/n time span, where 'n' is the number of ports on the uSB hub.

Quote:

---

Originally Posted by Sensimilia

You sure? The PCM2902 stock sheet I have from TI says it is USB2.0. I better take this up with TI.

---

The second line of this TI PCM2902 page says USB 1.1...

http://focus.ti.com/docs/prod/folder...t/pcm2902.html

Quote:

---

Originally Posted by Labarum

What experiences have others?

---

Very old IBM ThinkPad on docking station, purely being used as a "client" on the network for itunes sharing, and spotify/internet radio running XP - connected to Caiman via aforementioned Belkin premium lead (direct to the docking station) - both DAC and laptop plugged into Tacima mains conditioner - no problems at all.

HOWEVER - the standard PSU on my Roku Soundbridge was introducing some noise into the system previously (including on the monitor screen) so entirely possible a laptop PSU could be doing the same - I bought a cheapo ebay replacement which cured the issue! (this was before I was converted to the benefits of mains conditioners! ;) )

Quote:

---

Originally Posted by chebby

The second line of this TI PCM2902 page says USB 1.1...

http://focus.ti.com/docs/prod/folder...t/pcm2902.html

---

I better look for a better solution then...

about which one is discussion - pcm2902 or pcm2902b ?

I have referenced this tremendously long thread before

http://www.computeraudiophile.com/co...04-mini-review

It seems it is possible to achieve higher than 24/96 with USB 2 using custom drivers and providing the USB socket is correctly implemented - apparently many are not.

I don't understand all the technical bits, and I do understand that a Standac is not aiming higher than 24/96 - but parts of the thread may be worth reading.

And where this essay gets us, I don't know.

http://www.computeraudiophile.com/co...B-Audio-Primer

pcm2902b (usb2) has:
16-Bit Delta-Sigma ADC and DAC
Sampling Rate:
DAC: 32, 44.1, 48 kHz
ADC: 8, 11.025, 16, 22.05, 32, 44.1, 48 kHz

I do not think that 24/96 will be possible from USB connection.

Quote:

---

Originally Posted by Gints

about which one is discussion - pcm2902 or pcm2902b ?

---

PCM2902B

Quote:

---

Originally Posted by Gints

I do not think that 24/96 will be possible from USB connection.

---

It has already been achieved, and bettered. See my last post.

but that was other chip and solution.

This is from link in your post

---
Most USB capable DACs today use adaptive mode USB. This is commonly done using a PCM270x chip from TI and to a lessor extent the PCM290x or CMedia parts. The big plus for DAC Manufacturers when using this chip is that no programming is required. The chip can be "popped" into place without extensive R&D, USB audio programming skills, a lengthy time to market, and a substantial amount of money. Big drawbacks to this method are very limited sample rate support (32, 44.1 & 48k), maximum of 16 bit audio, and sound quality.



Another less common adaptive USB implementation is done using a TAS1020 chip. Manufacturers then have a choice of implementing the chip exactly like the PCM270x without additional programming or possibly using the example code provided by TI, or the manufacturer can purchase code from CEntrance, Inc. to use with the TAS1020. Popular devices using the CEntrance code are the Benchmark DAC1 variants, Bel Canto USB Link, and the PS Audio Perfect Wave DAC. Using the TAS1020 and CEntrance code greatly enhances the USB interface and allows native 24/96 playback without the need for additional device drivers or special software
---

TAS1020 is discontinued

yes, I saw that. But it is about chips with manufacturer fixed settings and chips which are programmable by designer.

Just received my 7520 from dac chip replacement and I opened it to see how it looks (Tirna did a good job), and I also checked usb chip. Stan, I have PCM2902E chip and when I tried to find data sheet the only one I found referred to PCM2902, not to PCM2902B. Do not care about 1.1 or 2.0 usb standard (there should be no difference for stereo) but the dac sections of usb chips have some differences. Can they to affect a sound quality? Or maybe that section is not involved in your design because it is only usb-spdif convertor?
I have my 7520 from first batch, I think, and, if in current production pcm2902b is used, is there any other parts, who is replaced?

I don't see that USB 1.1 in and of itself is a problem, especially given that even the £1100 Benchmark DAC1 USB uses a USB1.1 input.

I quote from a review....

"As its name suggests, the new DAC1 adds a USB port to take digital audio data directly from a computer at sample rates up to 96kHz and bit depths up to 24. Benchmark chose to use a USB 1.1 port rather than the more modern and much faster USB 2.0 (which is backward-compatible with USB 1.1), because then the D/A could be used without the host computer having to run a custom driver program, and Benchmark could thus control communication to allow the transmission of bit-transparent high-resolution data. (The code to do this was developed for Benchmark by Centrance, Inc..) USB 1.1 has a maximum transmission rate of 12Mbps, which is sufficient for two channels of 24/96 data."

So even a Benchmark DAC running at 24/96 over USB is not going to put any undue stress on a USB2.0 rated cable given that the maximum data rate of USB1.1 is only 12Mbps.

Quote:

---

Originally Posted by Gints

Stan, I have PCM2902E chip

---

You are right. My mistake. I built the prototype with the PCM2902B, but TI has been supplying me with the latest improved version, which is the PCM2902E.

Both Wolfson and TI have given me access to their latest revision chip sets, for which I am most grateful to them. As far as I am aware, other manufacturers are still developing and using the older TI PCM2702. That leaves the TC-7520 and 7520SE as the only affordable hi-fi spec. USB audio DACs on the market.

Quote:

---

Originally Posted by Sensimilia

That leaves the TC-7520 and 7520SE as the only affordable hi-fi spec. USB audio DACs on the market.

---

???

EMU 404 USB ~£150

http://www.dolphinmusic.co.uk/produc...-0404-usb.html

http://www.emu.com/products/product.asp?product=15185

http://www.computeraudiophile.com/co...04-mini-review

I mentioned hi-fi spec. ;). Not every audio device is a hi-fi product:).

Quote:

---

Originally Posted by Sensimilia

I mentioned hi-fi spec. ;). Not every audio device is a hi-fi product:).

---

Did you read the spec of said box?

And see the DAC chip it uses?

Some pretty demanding audiophiles on the other forum believe it to be incredible at the price, and I am tempted to give it punt as I may need another DAC.

They say with has a phone amp that will drive the more demanding phones, which is an issue for me.

The plastic case is pretty tacky though, and a Standac sits more easily with a Cable or Sat TV Box and a Squeezebox.

Quote:

---

Originally Posted by Sensimilia

That leaves the TC-7520 and 7520SE as the only affordable hi-fi spec. USB audio DACs on the market.

---

Roland UA-25EX £180

http://www.rolandus.com/products/pro...0&ParentId=114

http://www.soundware.co.uk/sc/products/Edirol%20UA-25EX

Come on Stan, your DAC is excellent, but it's not the only show on the road!

:)

As I mentioned Brian HI-FI SPEC..

Quote:

---

Originally Posted by Sensimilia

As I mentioned Brian HI-FI SPEC..

---

Ah, you mean HiFi specific, not to HiFi specifications.

We are agreed then. Yours is the only high performance box in the price bracket that sits comfortably in a HiFi stack, because its case is made for the lounge rather than the music studio. That's why I bought it rather than one of the others. And very nice it is too.

I meant hi-fi specification. However, you are absolutely correct. There are even cheaper USB equipped DACs on the market than those of mine. Now that the Caiman is sold out and withdrawn from my site anyone after a USB DAC may well be interested in the links and details of suitable alternatives to mine. Especially when savings can be made in the purchase price for a hifi product.

Stan

Quote:

---

Originally Posted by Sensimilia

Now that the Caiman is sold out and withdrawn from my site anyone after a USB DAC may well be interested in the links and details of suitable alternatives to mine.
Stan

---

After the extremely rapid sale of the Caimans are you not tempted to make it your standard premium DAC offering and 'disappear' the TC-7520 ?

The name change alone would at least save HFW reviewers from the arduous task of differentiating between two products with a one digit difference in name. (This month's HFW photographed and reviewed the TC-7520 but insisted on calling it the TC-7510 throughout!)

They are not alone either. Numerous times I have come across people on various forums who confuse the two DACs (innocently or otherwise).

Quote:

---

Originally Posted by chebby

After the extremely rapid sale of the Caimans are you not tempted to make it your standard premium DAC offering and 'disappear' the TC-7520 ?

---

I am more likely to withdraw the TC-7510 seeing that I have had it in production for several years and demand has dropped since HFW got the price wrong....

The TC-7520 is more flexible than the Caiman. You can do a lot of mods on it, including removing the USB input and fitting another TOSLINK input in its place. And you can even convert it into a Caiman for just an extra £20 or less if you are skilled in soldering.

My personal bedside DAC is a TC-7520 with WM8716 and LM4562HA. And soon I hope to be experimenting with some power supply tweaks:eyebrows:. I would never dream of butchering a Caiman with those experimental mod. One day a unmodded Caiman may well be a very high priced collector's item on eBay, going for a fortune ;).

'What Hifi?' are reviewing a Caiman soon. (Just in time for the WHF awards deadline apparently.) http://community.whathifi.com/forums/t/292926.aspx

So, if it does really well, you could have a whole new bunch of potential customers (who have little interest in soldering irons or doing mods) asking where to get a 5 star product that is no longer available according to your earlier update.....

Quote:

---

Originally Posted by Sensimilia

Now that the Caiman is sold out and withdrawn from my site ...

---

I must admit I am confused. Is the withdrawal a temporary state of affairs or is that it, no more Caimans?

Quote:

---

Originally Posted by chebby

'What Hifi?' are reviewing a Caiman soon. (Just in time for the WHF awards deadline apparently.) http://community.whathifi.com/forums/t/292926.aspx

So, if it does really well, you could have a whole new bunch of potential customers (who have little interest in soldering irons or doing mods) asking where to get a 5 star product that is no longer available according to your earlier update.....

I must admit I am confused. Is the withdrawal a temporary state of affairs or is that it, no more Caimans?

---

You are late to the Caiman discussion, so I am not surprised that you are confused. To recap one last time: the Caiman was a limited run for AoS members who are not skilled enough to modify a TC-7520 with a WM8716.

As it turns out, the product is a success outside of AoS, and there is a demand for more. So I am looking at making an additional quantity. But to do that takes time. First I have to order the parts, and then wait for them to arrive before I can solder them onto the PCB.

The Caiman is currently not available. That is not the same as writing that it is no longer available. So don't confuse people by turning 1 + 1 into 5.

Stan

Ok fair enough. This is why I needed to ask the questions.

(a) I am a potential Caiman customer and an existing TC-7520 customer.

(b) I want to see the Caiman do well and wish the best for Beresford in the forthcoming WHF review.

and it is a def caiman that whathifi have not a 7510 or 7520? id be interested to here what they make of it!

Quote:

---

Originally Posted by hamish_gill

and it is a def caiman that whathifi have not a 7510 or 7520? id be interested to here what they make of it!

---

If I can see the list of the other DACs under review, the likely winner is probably going to be a mainstream brand name. I trend to just make up the numbers...
My DAC is far too clinical and revealing. Most reviewers are into titillation, rather than full nudity. Or to put it in a different way: they like to imagine listening to a guitar player stroking a guitar, rather than actually hearing it loud and clear:mental:.

Quote:

---

Originally Posted by Sensimilia

One day a unmodded Caiman may well be a very high priced collector's item on eBay, going for a fortune ;).

---

Do you know what Stan, I seriously wouldn't bet against it! This little box has all the hallmarks of becoming a legend, IMO.

Quote:

---

Originally Posted by Sensimilia

You are late to the Caiman discussion, so I am not surprised that you are confused. To recap one last time: the Caiman was a limited run for AoS members who are not skilled enough to modify a TC-7520 with a WM8716.

As it turns out, the product is a success outside of AoS, and there is a demand for more. So I am looking at making an additional quantity. But to do that takes time. First I have to order the parts, and then wait for them to arrive before I can solder them onto the PCB.

The Caiman is currently not available. That is not the same as writing that it is no longer available. So don't confuse people by turning 1 + 1 into 5.

Stan

---

Hi Stan,

It's been a while since I visit AoS and there you go - I've missed all the brouhaha on Caiman, only to discover it when it's already out of stock.

I am currently using the 7510 6/4 and really looking forward to upgrade to Caiman. Hope that you won't pull the brake in producing Caiman..

Getting back to the thread.

From my own experience, crappy free USB cables do sound well..crap.

Lossless files which are saved inside the Mac sound much better than the ones which are stored in the External Hard Disk (connected via USB)

I can't comment on the differences of USB cables as I only own freebies.
Can someone please recommend a decent USB cable for me to try?

The Caiman is not dead, just resting:). The next production should be ready end of this month.