chord qutest owners question

[windhoek]

We typically keep our CHORD QUTEST powered-up 24/7 - unless a typhoon is in the area.

Importantly, the very best sound quality we have achieved is by powering the QUTEST on a garden variety CELLPHONE CHARGER BATTERY - they type that you might take with you to recharge your cellphone, in the event that you might be away from mains power for a spell.

The sonic improvement is quite noticeable.

I hooked up my Qutest and to a garden variety power bank last night to see how it would work out. Not only that, I went one stage further and connected my Android media player (an Android phone without a SIM card) to my Qutest via a USB-C to USB-B cable, and using USB Audio Player Pro in bit-perfect mode. In short, the source and DAC were battery-powered, while my amp was the only mains-powered piece of kit in the chain.

It sounded great!

It just so happens my DAC has been switched off for the last few months as I've been playing records most of the time (my living room gets too hot to sit and enjoy music during summer so I pretty much migrated into my bedroom to find somewhere cooler to live and enjoy music). All of which is to say I can't say for sure it sounds better, but my intuition tells me it does and by quite a bit.

When I was listening to Nice Work by Carol Kidd I remember thinking so this is why people buy Tannoys, as the piano playing sounded like nothing I've ever heard before; I don't mean the performance only, I mean the timbre as well. And wow, can that lady carry a tune. Suffice to say I was well and truly captivated.

Before that, I listened to Digital Rain by Johnny Jewel and that album sounded incredible. In fairness, it always sounds incredible, but I think it was extra incrediable last night.

Finally, I played Rumours by Fleetwood Mac. Unfortunately it was getting late and so having played two albums at boogie volume already, it was time to turn out it down a bit. Despite the drop in volume, the same richness of sound was there to be heard as well.

Next time I play some digital music I'll use my Bluesound Node 2i as the source, which is mains powered, and see how things sound while the Qutest continues to be powered by a batty bank. Fwiw, three albums barely made a dent in terms of power depletion so charging might be a once a week affair or something like that. In contrast, I reckon I can go from full power to zero in four albums using my Android media player in USB out mode. In saying that, all the albums I played last night were 24-bit so maybe I could play more albums at 16/44.1, we'll see.

Anyway, doubling up on battery power in this way resulted in a great night's listening!

 

[SONDEKNZ]

@windhoek

We have very similar taste in music. I rate Carol Kidd’s eponymous debut album as one of my finest jazz albums - and quite possibly the very best recorded.

I’m glad you tried the power bank for your Qutest. Although you can’t yet say for certain that there is a dramatic sound quality improvement, you will know in an instant - for certain - the moment you switch back to mains power for the Qutest.
(Please report, if you try it…)

Allow me to share another digital playback tip - one which delivers an equally big bang for the buck…

For digital source, use the device that has the latest and fastest processor. Typically, this will be a laptop. Whether it be a Mac or a PC, the faster the processor, the better the sound.

This applies equally to online streaming and playback of digital files.

With a high-speed device, even playback using good old Windows Media Player (with lossless files) sounds stunning - let alone some of the other more highly regarded music players.

The faster the processor, the better it sounds!

It goes without saying that the device in question needs to be running on battery power, for best results.

Try it… you’ll like it!

 

[windhoek]

@windhoek

We have very similar taste in music. I rate Carol Kidd’s eponymous debut album as one of my finest jazz albums - and quite possibly the very best recorded.

I’m glad you tried the power bank for your Qutest. Although you can’t yet say for certain that there is a dramatic sound quality improvement, you will know in an instant - for certain - the moment you switch back to mains power for the Qutest.
(Please report, if you try it…)

Allow me to share another digital playback tip - one which delivers an equally big bang for the buck…

For digital source, use the device that has the latest and fastest processor. Typically, this will be a laptop. Whether it be a Mac or a PC, the faster the processor, the better the sound.

This applies equally to online streaming and playback of digital files.

With a high-speed device, even playback using good old Windows Media Player (with lossless files) sounds stunning - let alone some of the other more highly regarded music players.

The faster the processor, the better it sounds!

It goes without saying that the device in question needs to be running on battery power, for best results.

Try it… you’ll like it!

The digital media player I mentioned, which I use for listening to music away from home and stuff like that, is an Axon 7 Mini, and it's probably around five years old. If it turns out that using a mains-powered Bluesound Node 2i (which I only use to play music from an attached SSD) + battery-powered Qutest is nowhere near as good as the battery-powered media player + battery-powered Qutest combo I tried last night, then I just might have to buy a tablet to use as the digital source in my main system. I'm guessing a new tablet will have a much better processor and a much better battery as well so that might improve things even more as you suggest.

Either way, I've got some battery-powered playback experiments to do

EDIT: The only downside about using a battery-powered digital media player + battery-powered Qutest combo like I did last night is that the media player would be hardwired to the Qutest via USB, and so when it comes to navigating and selecting music to play, I'd have to get off the couch and walk over to the media player. Having been using Bluesound Node 2i for the last year or so and being able to navigate and select music from the comfort of my couch, having to walk over to my hi-fi rack to play music seems like a step backwards.

Sure, I have to do that when it comes to playing records, but being able to control media from your couch was one of the great benefits of the modern age and home networking. Still, if it's the best way to go for enjoyment and sound quality, then that's probably how it's going to have to be... unless there's a way to control one Android device from another.

 

[SONDEKNZ]

@windhoek

We also have iPhone 13 Pros and an iPad Pro, but the laptops still sound best. I figure it is the faster processors.

I look forward to reading about your further findings… Appreciated.

 

[windhoek]

@windhoek

We also have iPhone 13 Pros and an iPad Pro, but the laptops still sound best. I figure it is the faster processors.

I look forward to reading about your further findings… Appreciated.

What is your playback chain from source to Qutest, and how is it all connected?

I've got a 2014 Macbook Air, which might well have the fasted process of the devices I have.

 

[SONDEKNZ]

What is your playback chain from source to Qutest, and how is it all connected?

Most of our components are detailed under my profile signature.

Interconnects are almost all DNM, with the exception of the shielded cable carrying our phono signal from SUT to Phono Preamp. Nothing we’ve tried matches DNM, for honesty, dynamics, extension and bang for the buck.

Our speaker cables are old AudioQuest Crystal II and have been with us since our hi-fi journey began in the early 1980s. Ironically, we have brand new DNM cables in the cupboard, but haven’t found the time to terminate them properly yet. So, potential change/improvements are just ahead.

I’m pretty sure your MacBook Air will win the day as your digital source, if it is your fastest processor.

Our 2018 MacBook Pro is a killer source and betters our iPad Pro quite convincingly. Apple Music (iTunes) for ripped lossless files or QQMusic (China’s TIDAL) for online streaming - its all superb!

 

[SONDEKNZ]

Correction! I see I have not listed our components yet. Will get that done a bit later…

 

[windhoek]

I'm now playing Nice Work again but this time through my Bluesound Node 2i to my Qutest via digital coax, and I'm pleased to say it sounds thoroughly stupendous!

I guess that means I don't need to get a better digital source as the mains-powered Bluesound + battery-powered Qutest combo sounds, for all intents and purposes, just as good as my battery-powered digital media player + battery=powered Qutest combo.

Whether and to what extent this improves upon the mains-powered Bluesound + mains-powered Qutest remains to be seen. Regardless, the mains-powered + battery-powered Qutest combo sounds amazing as it is

 

[SONDEKNZ]

The best outcome! Nice.

 

[cb01]

As an aside...

The QUTEST also offers three different levels of VOLTAGE OUTPUT: 1V, 2V or 3V.

Whilst this goes some way towards matching volume levels with other digital sources - of various voltage outputs - in our system, the 3V sounds clearly superior.
(Even if 1V actually matches our VINYL LP source better than 3V...)

I assume the 3V sounds better because the 1V and 2V output options are simply padded-down with added resistance - amounting to "lost gain". Happy to be corrected on this point.

What have others found?

Rob Watts says that the volume adjustment is actually made completely inside the FPGA.

Difference is likely attributable to the interaction between the Qutest's discrete output stage and the input stage of your preamp.

 

[SONDEKNZ]

Rob Watts says that the volume adjustment is actually made completely inside the FPGA.

Difference is likely attributable to the interaction between the Qutest's discrete output stage and the input stage of your preamp.

Very good info, thanks.

This makes good sense and perhaps explains why we prefer the Qutest 3V output, with our current “passive preamp” arrangement.

The good news is that the Qutest output can be varied in a heartbeat, in the event that our system needs change - and there appears to be no padding-down of gain. A very good thing IMHO.

Such a well sorted piece of kit.

 

[cb01]

Very good info, thanks.

This makes good sense and perhaps explains why we prefer the Qutest 3V output, with our current “passive preamp” arrangement.

The good news is that the Qutest output can be varied in a heartbeat, in the event that our system needs change - and there appears to be no padding-down of gain. A very good thing IMHO.

Such a well sorted piece of kit.

It's really well implemented. The FPGA is doing borderline theoretical calculations down to -300dB and Is then decimating/truncating to a -150dB/-180dB scale IIRC upon output of the FPGA into the pulse array. This means that as for the actual math of the DAC function, including volume control, the only limit is the linearity/performance of the discrete output stage. Which is a mighty little thing in and of itself. Going from -300dB dynamic range inside the FPGA to -297dB or -294dB is functionally meaningless, as it's being normalized in the FPGA prior to output.

My SN3 sounds different at all 3 output gain levels (1v/2v/3v RMS). For me as well, this is attributable to differences in the class-A preamp interactions with the Qutest discrete output stage at those three levels. Actually a handy way to tune the system in subtle ways.

For me, background noise (ear to tweeter) changes not at all between the three output levels.

 

[windhoek]

I'm now playing Nice Work again but this time through my Bluesound Node 2i to my Qutest via digital coax, and I'm pleased to say it sounds thoroughly stupendous!

I guess that means I don't need to get a better digital source as the mains-powered Bluesound + battery-powered Qutest combo sounds, for all intents and purposes, just as good as my battery-powered digital media player + battery=powered Qutest combo.

Whether and to what extent this improves upon the mains-powered Bluesound + mains-powered Qutest remains to be seen. Regardless, the mains-powered + battery-powered Qutest combo sounds amazing as it is

And the results are in... battery-powered Qutest sounds better than mains-powered Qutest.

I played Nice Work again last night via mains-powered Bluesound Node 2i + mains-powered Qutest and it didn't take long before I felt sure that battery-powered Qutest sounded better. I switched over while the album was still playing and sure enough, it sounded better. Everything is just more

 

[mjw]

a garden variety power bank

Is this one of those weighty jobs for charging a phone on the go - iPhone sized but deceptively heavy?

 

[SONDEKNZ]

Is this one of those weighty jobs for charging a phone on the go - iPhone sized but deceptively heavy?

Yup. That’s the one!

 

[windhoek]

The one I'm using was a fiver from Currys a couple of years ago. I actually bought it to power my Chromecast Audio via battery following a pink fish recommendation, but I'm pleased to say it's more than up to the job of powering my Qutest.

 

[windhoek]

I just realised that powering my Qutest via battery is like powering my Qutest via its own radial from the consumer board: it gets the Qutest off the noisy ring main. I'm a tenant so I'm pretty much stuck with a ring mains setup throughout the house but at least using a battery takes the Qutest off the ring mains. I've no idea whether a dedicated radial would produce better results than using a battery, but either way, battery is so much better than ring mains when it comes to powering my Qutest.

Mmm, I wonder what else I could power by a battery and so take more devices off the ring mains supply. Mmm...

 

[MarkW]

Given how little Watts knows about good accessible competent design as opposed to his Fisher Price aesthetic I struggle to take anything he says too seriously.

I'm not a fan of the Chord aesthetic but it's not really Rob's fault. John Franks is the one with the crayons.

The battery thing is interesting because all these 5v batteries are using dc-dc (switching) circuits (there are no "5v" cells available and cell voltage varies with charge state). So it's probably not an especially low noise way to power your dac, and yet it does sound "better" than off the mains. The isolation from mains-born rf is probably the real hero in this scenario and it is probably as true for the Qutest as it is for the Dave that these dacs are very sensitive to noise.

Maybe a battery, a 5v linear reg and a nicely shielded cable are the ultimate power approach for the Qutest.

 

[SONDEKNZ]

Mmm, I wonder what else I could power by a battery and so take more devices off the ring mains supply. Mmm...

Our LP12 turntable is next on my list.

With its ORIGIN LIVE DC MOTOR, it is a prime candidate for battery supply.

I will get to it.