The buffer disguised as a cable - A review of the Burson Cable+

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Odal3

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I was asked by Burson if I was interested in reviewing their product Burson cable+ and after considering it for a bit I thought it would be a fun challenge. The cable+ was provided free of charge. No affiliations.




The Burson Cable + is a bit of a confusing name because as far as I can tell it is really an audio buffer with an opamp disguised as an cable: in addition to the cable it also isolates the source from the amp (impedance matching) plus adds a 6db gain stage. Some of you may remember the Burson buffer that was sold a few years back, and to me this looks like a similar concept only that it now comes with a cable and several hundred dollars cheaper.

The cable (buffer) comes in a couple of different set-ups but the one I tried was with RCA to 3.5mm stereo jack. I wasn’t able to figure out material used for the cable or plugs, but the electronics are housed in a very nice machined aluminum enclosure. It looks really premium.  It is powered by an microusb plug by a separate power supply. The included PSU looked like an apple cell phone charger but this can easily be swapped for another psu as I did. I tried both an USB power bank as well as an ifi ipower 5V - especially the ifi helped further refine the sound.

My previous experience with testing interconnect cables has been that I could hear a positive improvement when going from a poor cable to a good cable such as when I went from an entry-level cable to a diy cable I made based on Zenwave’s Neotech wire. However, often when comparing similar style cables I find the differences are sometimes so subtle it is not even worth pointing out and other times I struggle to even reliably identify a difference. So my expectation going in to this review was that I would need to sit and A/B some cables and really strain my ears to try identify any real differences and then struggle even more to determine if I would prefer one set-up better than the other.

But then again, I didn’t really realize beforehand what a powered cable would do to the sound and I was in for a surprise. To give a clue: I liked it a lot in some set-ups.

Since I only had a cable with 3.5mm stereo jack to RCAs I was limited in my testing to the following: computer integrated audio, mobile devices and a chromecast audio.



Testing with a computer
Since I don’t use my desktop computer too often I never bothered to get a separate DAC for it so I have just been using the integrated audio on the motherboard. In other words, the audio was poor as in “flat”, not very clear and definitely not engaging. So this would be a perfect first listening experience with the cables taken straight out of the box.

So from just expecting a minor change from using the new cable, I was floored from what I heard. All of a sudden I heard a really solid stereo-image which I had never experienced before in this set-up. The muddy sound was now much clearer and my bookshelf speakers all of a sudden delivered a punchy and textured bass. Just to be clear, we are not talking about the sound quality of a high quality expensive DAC (not even close) but the improvement was so substantial it was not really a need to do any A/B comparisons. But I still did, of course, and since the Burson cable boost the volume a few db, I even adjusted the sound levels to be similar. Probably the best way to describe the sound is that it’s “cleaned up” to be able to show the max potential of the particular DAC.



Testing with mobile devices
I doubt many here on AudioCircle uses a cellphone as a DAC in their main system, so these scenarios maybe are not really applicable. But I was curious so here we go:

Using the cable with an old Samsung Galaxy S4 quickly showed the phone’s internal DAC is not very good. Didn’t matter the sound was cleaned-up and that the signal got a boost - it still didn’t sound very engaging. I also had some weird noise issues using the cable the phone - probably due to a dying battery since it didn’t happen with any of my other devices.

Using the cable with my ipad or my iphone showed some improvement and it started to sound ok. The improvements were in more detail and more refined bass. The changes were definitely noticeable, but not as dramatic of an improvement I heard from the computer - probably because they sounded better from the beginning.

Again - while the sound improved a lot it is still no match for a proper DAC.

Chromecast Audio
I have been using a chromecast audio with an old Pioneer Elite receiver in my family/TV room. The receiver is used as pre-amp plus power the surrounds and center in a HT set-up. The mains are powered by a CROWN XLS 2000 drivecore amp.

The chromecast can be connected either via spdif optical or rca. Connecting the chromecast via the optical sounds harsh and fatiguing in my system so I have always used RCAs which had the downside it made the sound a bit too dark.

Using the Burson cable and the sound is now starting to approach really good. I’m really bad explaining sound but the darkness disappeared and instead I heard increased dynamics, better defined bass and more details at the top without getting harsh. Cello, piano, guitars had more texture and air while drums and bass had some more details and punch.The no harsh part is really important to me since I’m more than sensitive to fatiguing systems and therefore don’t really enjoy too analytical/clinical systems much. Lucky for me, there was nothing at all of that.



I also tested the cable buffer between my diy Folsom amp (http://www.audiocircle.com/index.php?topic=138229.0) and the chromecast audio. Again more dynamics, soundstage and an overall improvement of the sound! The only bad thing is that the gain was borderline too much in this set-up.

If you are a chromecast audio user, adding the cable+ will definitely improve the sound quality.

Here comes the bad news...I didn’t expect that I would like this product so much and I’m now regretting that I don’t have one with RCAs on both sides so I can try it with my better DACs. If I can’t get hold of an adapter, I will cut up the cable and solder on my own.



Summing it up
So I have to admit that it was fun to review this cable, but I kind of underestimated how much time it would take - partly because it sounded good so I wanted to test it in as many set-ups as I could. This review also opened up my eyes to opamps. The cable+ uses the Burson v5i and I’m now curious to explore replacing opamps in my other set-ups.

What could be better?: I do wish that it would be possible to swap cable set-ups easier such as different length cables and connections. Perhaps a version with female RCAs would be a good option to add. Having a cable requiring a power supply also requires a little bit of planning to make sure you have an extra outlet close by.

So the conclusion so far is that if the source DAC doesn’t have good outputs, the cable+ will make a very nice impact. I do believe the level of improvement depends a lot on the output stage of the source so the benefits will be system dependent.

Hopefully I can get hold of an adapter in the near future so I can test a couple of better dacs. It may take a while but I will then update this review with a part 2. I will also add a few images.

Thanks to Burson for giving me an opportunity to enjoy the Cable+ in my systems.

Edit: added pictures
Edit 2: Added additional pictures
« Last Edit: 4 Apr 2017, 05:31 am by Odal3 »

JLM

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Thanks for the review. 

I really like the concept of buffering between components which can provide an order of magnitude greater improvement versus fiddling with interconnects.  I'm looking forward to having my turn on the iTube 2 tour to audition it, as I see it's primary function is as a buffer.

I like the price ($150 USD with a 1.2 meter cable included) but wondered if you'd care to comment about how you powered it and the convenience/cost of providing the 5 volt power supply. 

Speedskater

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in addition to the cable it also isolates the source from the amp (impedance matching)
So what does this mean?
In RCA or XLR interconnects there is no impedance matching. But there can be buffering.
Does 'isolates' mean buffering or galvanic isolation?

MarkR7

I also received a Burson+ cable last week to trial. It's their RCA/RCA version, but I am currently waiting for an iFi 5v iPower to arrive. There was no power supply included, just a micro USB cable.

I will post my impressions after the upcoming weekend, when I get a chance to put the cable thru it's paces in my pretty resolving system.

Nice review Odal; you set the bar high!

Odal3

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I like the price ($150 USD with a 1.2 meter cable included) but wondered if you'd care to comment about how you powered it and the convenience/cost of providing the 5 volt power supply.

JLM

Adding an external buffer is new to me, but the more I learn about it, the more it makes sense.

I have to admit that if you move it around to test it in different system configurations it was a bit of a pain but I would probably have felt the same or worse if I had to move around 2 sets of IC cables plus ac cord to test for example a preamp. If you are just planning to set it up once and leave it, it's no different than adding another component. The electronic portion of the cable is close to the amp end so  all of it can easily be hidden behind the amplifier.

To make it easier to move around, I tried it with a generic battery powerbank I normally use for charging USB devices. The power draw from the cable+ is very small so I didn't have to recharge the powerbank at all during the testing. My guess is the price for it was around $10. I will post a picture tonight so you can see how it looks like. Anyways, my guess is this generic powerbank is pretty noisy and other than the convenience it was not much of a difference vs the supplied smps. So if battery is preferred, I would recommend looking for better options.

Using the ifi Ipower on the other hand made it a little bit "smoother" sounding and less harsh. This is the same finding I have had when upgrading power supplies on other source components. I think the price is about $50. There are of course better options out there such as the Uptoneaudio UltraCap LPS1 but that is also 8x the price which I can't justify for a chrome cast based setup.

The ifi power supply on the other hand has a good price per performance ratio for components requiring low voltages.

A recommendation to Burson is to offer an optional power supply as I have seen other audio companies do.

Odal3

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in addition to the cable it also isolates the source from the amp (impedance matching)
So what does this mean?
In RCA or XLR interconnects there is no impedance matching. But there can be buffering.
Does 'isolates' mean buffering or galvanic isolation?

Good question. My electronics knowledge is not that deep so I may refer to it incorrectly, but I believe it is an buffer stage. As I'm sure you and many others in this forum have much much more knowledge about audio design than I have, let me know if I refer to it in an incorrect way. Always trying to learn something new. 

MarkR7 - I'm looking forward to read about your experience with it and especially how it does in a more high end system

Odal3

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Note that I added some additional pictures to the first post. These shows the cable with a chromecast audio as well as my "matching" USB power bank (battery). I also included a picture of the inside showing the v5i Opamp.

I also noticed that there are now a couple of reviews of the Burson Cable+ in the same circle. Not sure if possible or desirable but perhaps it would be good to merge them together?? What do you think?

The Moderators have also moved the review over to the cable section which is fine by me.

G Georgopoulos

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in addition to the cable it also isolates the source from the amp (impedance matching)
So what does this mean?
In RCA or XLR interconnects there is no impedance matching. But there can be buffering.
Does 'isolates' mean buffering or galvanic isolation?

I think not impedance matching but impedance isolation (hi impendance to low impedance buffer)

The reason for saying this is low impedance from buffer will feed on hi impedance (z of an amp) again

Speedskater

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Yes, if we think of it as a buffer amp with attached cables it makes sense. It isolates the load impedance and can drive a lower impedance load.