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#313480 - 07/06/10 12:08 PM audio impedance buffers
sauniq Offline
buff

Registered: 01/13/10
Posts: 43
Loc: winnipeg manitoba canada
I have read that audio buffers such as ones made by Burson can substantially lower output impedance of components, the Burson Audio Buffer claims to remarkably increase perceived dynamics, detail and bass power.

Does anyone have any experience with this type of equipment and can share their opinion. Any other manufactures beside Burson?

thanks
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#313528 - 07/06/10 09:59 PM Re: audio impedance buffers [Re: sauniq]
JohnK Offline
shareholder in the making

Registered: 05/11/02
Posts: 10631
David, I took a look at the Burson site and was immersed in a pool of pure drivel. The discussion of their buffer appears designed to mislead or even frighten those not familiar with the technology involved. Components such as players have an output impedance. Amplifying equipment has an input impedance. The two units are connected in series, and impedances connected in series form a "voltage divider", which means that the units use the voltage in proportion to the ratio of their impedance to the total impedance of the two units. For example, if a player having an output impedance of 1000 ohms was connected to a pre-amplifier or amplifier having an input impedance also of 1000 ohms, the two units would each consume half of the input voltage(1000/{1000+1000}), a significant loss of voltage input to the amplifier.

The most common suggestion is that the input impedance of the amplifier should be at least 10 times the output impedance of the player or other sending unit, so that the amplifier receives nearly all the voltage. Players vary from about 20 ohms to 1000 ohms(this wide variance indicating that the number isn't crucial when connected to an amplifier with typical input impedance). Competently designed amplifiers have input impedances in the tens of thousands of ohms, a common number being 47KOhms. No significant signal loss(the only problem which can arise out of inappropriate impedance combinations)occurs and no additional "buffer" is needed.

Obviously, inserting a device which adds further amplification,(as the Burson item does)will make the sound slightly louder if the settings aren't adjusted to compensate for the added gain, and the louder sound will be "better", a result which would also occur from setting the volume control slightly higher. The Burson item is a ripoff.
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#313553 - 07/07/10 12:45 AM Re: audio impedance buffers [Re: JohnK]
sauniq Offline
buff

Registered: 01/13/10
Posts: 43
Loc: winnipeg manitoba canada
Thank you for the great reply! I have been listening to alot of LP's and older recordings using a new amplifier. The sound is so amazing, recordings back 20 years ago IMO are so tasteful in dynamic range, and microdynamics and are an important part of the art and enjoyment of music.

Last night I listend to Joe Jackson's album-Body and Soul. I first listened using a flac file I stored on my laptop, and was so blown away I wanted to hear the difference if I played the original...long story short, I actually loved the computer file as much as I did the LP. So I am really curious now about the benefits of Audio buffers and DA converters.

once again....thanks for your reply
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#313588 - 07/07/10 10:20 AM Re: audio impedance buffers [Re: JohnK]
alan Offline

connoisseur

Registered: 01/29/02
Posts: 3265
Loc: Toronto/New York/parry Sound
Thanks, JohnK, for saying what I wanted to say! When I skimmed the Burson site, I thought to myself, ah, more smoke and mirrors. (The tweak market will love this stuff.) I did recall the output/input impedance "ten times" rule and 50,000 ohms input impedance for the receiving device was still lodged in my brain from bench testing years ago.

Thanks for confirming that with the 47 kOhm figure.

Regards,

Alan
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#313592 - 07/07/10 10:30 AM Re: audio impedance buffers [Re: sauniq]
alan Offline

connoisseur

Registered: 01/29/02
Posts: 3265
Loc: Toronto/New York/parry Sound
Hi sauniq,

To add to JohnK's excellent post, I would point out to you that DAC (converter) technology is quite mature, and that there are no benefits to stand-alone DAC units over the internal DACs contained in AV receivers and other such devices.

I've made this post many times previously and I'm sure JohnK will concur in my views.

If anyone claims that stand-alone outboard DAC's are superior, ask them for comparative data performed with double-blind listening tests to musical source material. I did such comparisons with duplicate CDs perfectly synchronized running through a $30,000 outboard DAC vs.the internal DAC from a Sony CD player, and there were no audible differences so long as the playback levels were perfectly equal.

Regards,
Alan

Such tests were also done by two University of Waterloo PhDs, Stanley Lipschitz and John Vanderkooey, who published their paper in the Audio Engineering Society journal.
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#313701 - 07/07/10 10:18 PM Re: audio impedance buffers [Re: sauniq]
JohnK Offline
shareholder in the making

Registered: 05/11/02
Posts: 10631
David, what Alan points out relating to buying a separate DAC is certainly supported by hard evidence, rather than fanciful illusions. In addition to controlled blind listening tests, measurements of units taken(including their internal DACs)are pretty uniform in demonstrating audibly flat frequency response with inaudibly low noise and distortion.

Despite this, the urge to tweak the untweakable persists, and of course there are sellers only too happy to profit handsomely by satisfying the urge.
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#313704 - 07/07/10 10:37 PM Re: audio impedance buffers [Re: JohnK]
sauniq Offline
buff

Registered: 01/13/10
Posts: 43
Loc: winnipeg manitoba canada
Did either of you notice the picture of the Axiom Audiobyets

http://bursonaudio.com/burson_buffer_160.htm

Today I listened to a Simaudio DAC in a blind test and could tell when the DAC was being used, It was very uncomfortable to hear!

I apprecaite the reference material and the replies. I will stop tweaking smile more money save to use on buying great recordings.
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MoonW5.3's
MoonP7 Pre
Moon300D DAC
Marantz AV8003
HSUVTF3 MK3 Sub
Axiom LFR 1100
AxiomVP180

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#313705 - 07/07/10 10:40 PM Re: audio impedance buffers [Re: sauniq]
JohnK Offline
shareholder in the making

Registered: 05/11/02
Posts: 10631
Yep; that was the only good thing I saw on the site.
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