There shouldn't be any bus noise because they use opto-isolators between the USB receiver and the rest of the circuitry.

If there is a problem with the USB connection, it's probably dropouts caused by high DPC latency, etc. If you are using a notebook, try surfing the net with a wireless network connection as you listen to the DAC.

Thanks. I'll pull the ethernet cable and switch over to wireless and see how it holds up.

No problems on that front, with a dozen browser tabs all doing bandwidth-intensive things. Sorry, I'm not going to open it up but here's the answer on the internals from Charles Hansen himself.

In my experience, the analog circuitry, power supply, digital filter, and clock are all more important than the DAC chip itself. FWIW, the QB-9 uses the DSD1796. It is the "little brother" to the DSD1792 used in our C-5xe MP. There are only two differences. The first is a "less good" digital filter, which does not matter in this case as we bypass it and use our own custom digital filter. The other is the amount of output current. In theory this will reduce the ultimate S/N ratio but since we are using a new analog circuit, this does not appear to be a factor. We actually listened to both chips in this product and heard no difference.

OK, it makes fucking Duet salad.

Fuck fuck fuck fuck fuckity fuck fuck.

Okay, I'm finally drawn to the dark side. WANT. Nao.

Bastid.

Edited May 7, 200917 yr by Dusty Chalk

No problems on that front, with a dozen browser tabs all doing bandwidth-intensive things. Sorry, I'm not going to open it up but here's the answer on the internals from Charles Hansen himself.

Thanks for the info. He must really like his Burr-Brown DAC chips.

I just looked at the specs for DSD1792 and DSD1796. The DSD1792 also has better dynamic range and THD+N measurements, but maybe the digital filter is what made the difference here.

After several hours of going back and forth, I doubt my opinion is going to change much from here on out. First, a very important proviso: I have no experience with other comparable high-end sources! So this is not intended to be a qualitative review of the Ayre DAC, but rather a straight comparison with the Duet, which I know that others here have also come to rate fairly highly in its class. I ran both through the GS-1, which apart from being an admirably neutral conduit also allows for simple switching of two inputs, and roughly volume matched each individual track with an SPL meter. Material was a selection of 24/96 needledrops and Red Book, all in ALAC format. Bit rate adjustments were made in Audio Midi Setup and were consistent for both sources. ICs and Duet breakout were identical, fine Nugget Audio products.

Anyway, the first and clearest impression going to the Ayre for me was the soundstage just blowing outward. I have never thought of the Duet as closed-in, but by comparison it surely is. Not even close. Boom! (Out-of-)head shot!

Second would be detail retrieval -- there was immediately a lot more "there" there, with both hi-resolution material and standard CDs. This threw me initially, as the Duet seemed to have punchier bass, but after listening to the same upright bass lines and kick drums over and over, I came to conclusion that what I was hearing was a more one-note response making an impression over better-delineated and more-realistic impact and decay. The Ayre seems to me to do much better with transients in general and at higher frequencies it isn't even close.

Other than that, as I said, general operation is trouble free. Truly plug and play, at least with my Mac. And of course everyone loves the new new thing so take this with the requisite big pinch of salt, but I absolutely want to own one of these. It makes the Duet sound congested and slow, and if there's a front rank of Duet fanboys I believe I've been in it! Big gear sale and ritual spousal ripping of new asshole to follow shortly. Watch this space.

Awesome. Have fun with the new new thing while it still is new new.

I "heard" the QB-9 today at a local dealer who had an "open house" with John Atkinson (Stereophile EIC) and Joe Harley (AudioQuest). Amplification was done via Classe components into the B&W Signature Diamond. Atkinson demoed the QB-9 from his laptop computer using 24/88.2 files from his own recording sessions. The classical, choral, and jazz music was so boring it almost put me to sleep so there is that bias too.

So I can't offer any useful impressions other than that of the speakers, and I have to say I was underwhelmed by them. I immediately thought they needed more treble.

Atkinson did seem to enjoy the QB-9 for whatever that's worth.

Charles Hansen was there too actually, along with two other guys from Ayre, one of which I accosted to ask some questions. He confirmed the analog output stage is similar to the C-5xe's though the DACs aren't the same, but he did offer that they were Burr-Brown. He also said the QB-9 is more similar to the C-5xe than the CX-7e...

Big gear sale and ritual spousal ripping of new asshole to follow shortly. Watch this space.

Just keep working at it. I've worn my wife down so much she now just looks at me and breathes deeply and doesn't say a word when I tell her about my latest purchase.

That said she was pleased when I shipped the 4k in DACs out the other day.

ICs and Duet breakout were identical, fine Nugget Audio products.

Clearly we've found the problem here.

Someone asked for a photo of the back panel. Not all that much to see.

Ahh, that dastardly Listen/Measure switch! I demand impressions of Listen vs Measure!

USB only? I think I knew this but WTF!

Listen=linear phase filter

Measure=brick wall.

USB only? I think I knew this but WTF!

Listen=linear phase filter

Measure=brick wall.

The linear phase filter is the same as the brick wall filter. I think "listen" is the Ayre minimum phase filter.

I'm kinda glad this is USB only. Less want now.

The linear phase filter is the same as the brick wall filter. I think "listen" is the Ayre minimum phase filter.

You are correct! I meant minimum phase

I'm kinda glad this is USB only. Less want now.

Yeah, that's kind of a big ouch.

What do the other switches do?

they switch between Power A and Power B, between Disp On and Disp Off, and between Rsrv A and Rsrv B.

Duh.

What does the "USB input" do?

That won't work for me. I ball up my socks. Blast!

Is it backwards compatible with version 1.1 socks? You know, toe holes and such?

Where did you buy it? I didn't see it listed on their website.

ah! but the basket is universal, you can put your balled up socks into it, and then insert it into the DAC!

Duh.

Duh.

Duh.

How much do you bill for your imformed legal opinion?