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Chord Electronics Qutest ------- SBooster PSU

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Here is Martin V's (Mr Underhill) review of the SBooster and Zero Zero LPSUs for the Chord Electronics Qutest. These items are his personal property and he is aware of Chord Electronic's views on add on LPSUs. .

Over the last few years my system has undergone some radical changes, in part due to some pesky felines and in part due to my 'friend' George.

There were aspects of my system that dissatisfied me and so I went on a DAC hunting exercise, which resulted in my buying a Border Patrol DAC with which I was very satisfied, until my 'friend' brought over his Audio Note DAC 2.1. I shortly thereafter sold the BP DAC and became the owner of an AN 2.1, somewhat upgraded.

A few weeks ago I had what proved to be a wallet threatening conversation with my ‘friend’ about the Chord Qutest. Now I had always had an itch to try the Chord M-Scaler, and to cut a long story short I sold my EAR868PL, had a negotiation with my dealer, Signals – excellent chaps, and bought the Qutest & M-Scaler with the usual legal protections. Two days later the Qutest arrived.

My initial thoughts on the Qutest were very positive, but from the Head-fi threads, which go on and onnnnnnn, I knew that most people advocated trying a good quality LPSU, and I happened to have two to hand; prices and specs are at the end of this review.

I have found that good digital audio requires the removal of noise, which has a number of sources. In particular I have had good results from:

Improving DC with Linear Power Supplies;

Removing poor power supplies, linear or switch mode;

Giving my equipment a common route to ground;

Use of LT3045s to increase PSRR and reduce noise; and

l Having a dedicated electrical ring for my HiFi equipment.

PSRR is Power Supply Rejection Ratio, and LT3045 raise this significantly, as well as dropping RMS Noise. I bought the small cards and fitted them inside project boxes:


Here are my music file USB sticks powered by the ZeroZone LPSU via a brace of LT3045 housed in the plastic boxes.

In judging digital audio there are two areas to which I pay particular attention:

Bass. This I find quickly tells you whether a change is just different or better; and

Detail. The issue here is that noise can act like spice, heightening the detail and making some music sound better. Generally, I find this is noise that reduces relaxation, that is mine!

With ALLLL that said I won’t repeat George’s review, with which I heartily concur. The Qutest required a 5v power supply. Readily available I had:

1.    A Zero Zone R-Core 8v 6A LPSU; and

2.    An SBooster Mk I, 5-6v 3A LPSU.

These I pitted head to head using:

Prestige II server, files on 4x512GB USB. Both powered by LPSU. Minimserver.

Meridian 210

Townshend Allegri

Naim 300DR

Avondale PXO

Naim SBL

Zero Zone R-Core 8v 6A LPSU



8V R-Core low noise LPSU
I fed the output DC into two 7V LT3045 in parallel, one 2A the other 1A >> three 5V 1A LT3045 >> Chord Qutest.

For these initial tests I place the Qutest on some loudspeaker pucks with some absorbent rubber beneath, something rather more bespoke is now in place.

One thing did concern me, the positioning of the LPSU which I put on the floor.

The only usable output in a non-Merdian system using my Meridian 210 is SPDIF, and not BNC. I use a very pure silver ribbon cable which I connected to the Qutest BNC 1 using a BNC adapter.

Sound Quality

I initially started my listening using the incisive filter. I was immediately struck by the increased sound field. Not just left to right but by the depth, this was something new …and with SBLs. With highly produced music, rock et al, the overall size of the sound field was generally of the same order as the Audio Note, however with classical music in a natural acoustic it was as though the music was no longer tied to the speakers.

Familiar music had new detail, this is something I had previously heard with the Schitt Yggdrasil, but with that box I ultimately felt I was at a musical autopsy, here the detail was part of a cogent whole.







I arranged the SBooster so that it was running at 5.5v into the three 5v 1A LT3045 >> Chord Qutest.

Sound Quality 2
This was even better. The positives remained, the sound was even more relaxed and so was I. The sound field was VERY large and powerful.

Comparing the Qutest (QT) to my upgraded Audio Note 2.1 (AN), this is NOT at the 2.1 reference level as the PSU is not valve rectified, but is a definite step up on a standard 2.1.

Sting, Mercury Falling, I Hung My Head - NAS
There is some complex percussion in the track. On the AN I always felt that the music was almost tripping over itself, that the percussionists were struggling. Not so with the QT. The sound field is more open and the noise floor is lower, so that not only is more detail revealed but is placed in a wider, deeper and more airy space.

Led Zepplin, Mothership, Immigrant Song - NAS
The comment about the QT detail resolution and sound field are consistent. The one place where the AN can perhaps compete is in the slight added weight it brings to vocals, which could also be described as thickening, or 2nd order harmonics?

Leonard Cohen, You Want it Darker, You Want it Darker - Qobuz
Great track, but through the QT is became something breath taking with the male backing singers rendered wonderfully.

ELP, Pictures at an Exhibition - Qobuz
Not the best recorded live session. Through the AN this was OK, through the QT my attention was held.

Dead Can Dance, Toward the Within, Rakim - Qobuz
This is a superb live album. It is very good through the AN. It is even better through the QT.

Lorne Balfe, Musical Anthology of His Dark Materials, His Dark Materials - Qobuz
This is a highly produced piece of music with added distortion. I thought the AN’s more concentrated sound field might work in this music’s favour but the QT doesn’t lack any weight or drama. QT wins again.

Where I feel the AN can shade things is by being kinder to less well produced music & I feel with the slight mid-range weight that aids vocals. However, the QT is a cleaner window, while NOT being brutally honest. Its adds to this through the size, precision and power of its sound field.

But WAIT, There is More

I read this:


I felt I HAD to have a listen and so ordered an SBooster Ultra Mk II, to be frank my thinking was that my LT3045s would be doing everything that the Ultra would bring to the table; I was wrong.


The SBooster Ultra MkII is an add on box that linked onto the end of my SBooster 5v MkI; and what an excellent uptick in performance it gave. The result is a more relaxed, more dynamic and even more detailed sound stage.

But WAIT, There is EVEN More

Let me tell you about the M-Scaler ........Stop that (ed).


I should mention that in some applications I have been as happy with the ZeroZone as with the SBooster, but with the Chord Qutest I would pick the SBooster; and adding the SBooster + Ultra to the Chord Qutest takes an excellent DAC and significantly boosts its performance. A value for money SHOULD do.

Brief Specifications


SBooster MkI

8V, lowered to 5V by LT3045 for review

5-6V, run at 5.5V when using LT3045 > 5V









Via eBay, circa £140 negotiable, add taxes

Mk II = £330 inc VAT


Edited by George 47
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