Burson Audio HDAM Buffer

NewBuyer · « **on:** 6 Oct 2006, 03:03 am »

I have been spending some time with one of these Buffer units, and just wanted to share with readers here that it is truly one of the best and most fortunate purchases I've ever made in audio. Looking back on my past experiences in this hobby, I feel this is really saying something.

This is one of the very few times that I've ever been truly surprised by an audio component. The sonic benefits are not placebo. I've tried this Buffer now in several different system configurations and the improvements reproduce each and every time. Extremely pleasant improvements too, the kind that make me wish I'd found this item a long time ago.

Great service from Burson as well.

What a great audio find - I'm very happy about this.

I wonder if many others around here have also discovered this little audio gem.

GHM · « **Reply #1 on:** 6 Oct 2006, 03:16 am »

New Buyer..man we must think alike. I use the same buffer!!!

Your comments are on the money. It is a permanent part of my little system.
I've been using one for a couple of months now. I had no idea you had the same unit!

NewBuyer · « **Reply #2 on:** 12 Oct 2006, 09:38 am »

Quote from: GHM on 6 Oct 2006, 03:16 am

New Buyer..man we must think alike. I use the same buffer!!!
Your comments are on the money. It is a permanent part of my little system.
I've been using one for a couple of months now. I had no idea you had the same unit!

GHM, where in your system do you use your buffer - before the preamp, or after?

GHM · « **Reply #3 on:** 12 Oct 2006, 11:47 am »

Newbuyer,
I use the buffer before the preamp and after the Dac.

NewBuyer · « **Reply #4 on:** 13 Oct 2006, 04:17 am »

Same here.

Burson advises that either Buffer position (i.e. before preamp, or after preamp) is appropriate, and recommends that both positions be tried in an individual system to see what sounds best. When I get a chance I am going to try each position out and see. Would you want to try both in your system too, and post your impressions?

Rocket · « **Reply #5 on:** 13 Oct 2006, 09:19 am »

Hi,

What does the HDAM buffer do? Why does it make the sound better?

Sorry for being an ignoramous but i don't know anything about this technology.

Regards

Rod

Gordy · « **Reply #6 on:** 13 Oct 2006, 09:58 am »

Hi Rod,

The buffer lowers output impedence to a claimed 10-30. Here's the Burson write up:

http://www.bursonaudio.com/Burson%20HDAM%20Buffer.htm

and a TNT review:

http://www.tnt-audio.com/accessories/hdams_e.html

GHM · « **Reply #7 on:** 13 Oct 2006, 11:22 am »

Quote from: NewBuyer on 13 Oct 2006, 04:17 am

Same here.

Burson advises that either Buffer position (i.e. before preamp, or after preamp) is appropriate, and recommends that both positions be tried in an individual system to see what sounds best. When I get a chance I am going to try each position out and see. Would you want to try both in your system too, and post your impressions?

Newbuyer,

Well since the output impedance is fairly high on my Dac(no op amps) for a TVC. I would probably need a second one to go after the TVC to hear a difference for the better(if there was a difference). Without the buffer between the Dac and the TVC my sound would degrade considerable.

I sent my buffer to another AC member that used the same Dac and another brand of TVC. Before the addition of the buffer he got rolled off highs, congested and small soundstage. From his words...with the buffer... highs opened up and became more extended, the music became more emotionally involving with presence. Everything was better defined in the soundstage.

So using it after my preamp would most likely just make things worse. Than not having it in the chain at all... I would think?

woodsyi · « **Reply #8 on:** 13 Oct 2006, 12:26 pm »

I guess we can call this an audio gear "Synergizer."

ryno · « **Reply #9 on:** 13 Oct 2006, 01:53 pm »

GHM
What do you consider high for a DAC output impedance?
My CIaudio is 750 ohms I think. Higher than 10-30, but is it high enough that it might cause problems with a TVC?
Ryan

chadh · « **Reply #10 on:** 13 Oct 2006, 02:03 pm »

There are a bunch of these sorts of things around. For example, this one from Decware: http://www.decware.com/newsite/zbox.htm (it also seems to have a volume control, so I don't know why it's not a single source line-stage - but the point is it's really marketed as a buffer); Musical Fidelity has had one for a long time; and Albert at Space-Tech-Labs (he made my pre-amp) also makes buffers. Of course, these are all tubed units, and always give the impression that they are a convenient way to incorporate some "tubey-ness" into your system without messing with your source or amplification.

My question is this: Suppose I have a modified source (e.g squeezebox, olive etc). The first thing that any of the modifiers do is to take out the op-amp output stage. Space permitting, the modifiers could always add in a reasonable output stage that would do the sorts of things that these buffers do. But they don't. Why? Or, to take a more specific example, Peter Daniel's Non OS DAC used by Gymane doesn't include an output stage at all. Why not, if it makes things sound so much better?

When I read the Decware information, for example, it suggests the buffer is like a magic black box for curing digital nastiness. But what if the digital source has no nastiness? It just seems to me that if impedence matching were such a big deal, then the audio sector dac, my modded squeezebox 2 and all of those red wine modded olive units etc. would have brand new output stages rather than none at all.

There's obviously something I'm missing here. Is this only an issue if you want to use a passive line-stage?

If this is the case, why would I think that things should be better using a passive line-stage and a buffer than just using an active pre-amp? Certainly when I talked to Albert about the possibility of using a buffer between my source (which has a volume control) and amps, he encouraged me to use an active pre-amp instead. (Then again, he had a financial interest in my decision!) The first iteration of the Superphon Revelation III, for example, is an active, zero-gain preamp. Should I be thinking of this in the same way, but with a much higher cost than the Burson buffer plus the Prometheus TVC?

Whatever the case, I'm glad to hear that you guys are enjoying the sound of your systems so much.

Chad

GHM · « **Reply #11 on:** 13 Oct 2006, 03:38 pm »

Quote from: ryno on 13 Oct 2006, 01:53 pm

GHM
What do you consider high for a DAC output impedance?
My CIaudio is 750 ohms I think. Higher than 10-30, but is it high enough that it might cause problems with a TVC?
Ryan

Hi Ryan.. 750 is a long way from 2700 ohms

. That is the output impedance of my Dac. The Dac chip itself is what drives the output. Some Dac chips aren't voltage output designs. So you need an op amp or some form of buffer device. I think the CIA uses a discrete output transistor of some kind? not sure though. Ryan I'm thinking you should be fine below 1000 ohms. You're driving a passive now. The input impedance is 33.2K ohms. Without the active buffer employed your amplifiers see 8,300 ohms on the input. With the TVC your amplifiers will see more like 187 ohms to 750 ohms in theory. All of this without the noise of an additional power supply.

ChadH, you have some very good questions as well. I'm no audio gear designer by any means, but from all I've read and experienced with this type of stuff.

Results will vary depending on the source output to begin with. By the way the Burson doesn't use tubes to smooth over digital nastys..if they're there you'll hear them..no doubt. That's the difference between this unit and the MF or Decware. It isn't there to add tubiness or any sort of coloration..and it doesn't either.

It's probably the most transparent piece of gear I've owned. There are cables that have more coloration than this unit. Another thing you'll notice when your output drops this low are the differences in cables. Cables become less of an issue..as they start to sound more a like. In theory this is why cables sound different. It's their reactance and capacitance that alter the frequencies you hear at the end of the chain.

As far as the buffer/TVC verses linestage. Well that's a tough one. I'm guessing it depends more on the gain of the linestage. If you have a high gain linestage, there's more of a chance of having noise that you won't have with the Burson/TVC. The active preamp with no gain is what I consider a Passive linestage with an active buffer. It's basically the Burson/TVC combo in one chassis so to speak. This also depends on what type of passive, as there are several different approaches. Ryan's IRC preamp for example fits in this mold.

IMHO having the power supplies separate have advantages. Much lower noise floor generally speaking. The negatives for some are the added cable expense. I think it's a give and take with either way you go..ultimately whatever sounds best too you.

I think we've all experienced the outputs of some low budget players and some higher budget. The Op amps used in some cases are what cause the problems we hear. For example grainy, hard and splashy cymbals. A good output stage or buffer does away with this. You get pristine steely guitar plucks and strums. Cymbals also have a shimmer instead of that throwing sand over glass sound

.It sure makes it easy to know if the equipment is the problem or the CD. As some recordings are grainy..nothing can be done about that.

If you take a look at what modders concentrate on like Wayne of Bolder cable. You can see this is one of their main concerns..analog output. Having no op amps does away with the concern..but you then have other problems .Like driving passives..it is always a give and take.

Good listening

GHM · « **Reply #12 on:** 16 Oct 2006, 08:12 pm »

6moons just posted a review of the Burson Buffer.

Too bad he didn't have a passive preamp to try out in the chain as the improvements would have been more noticeable.

There's even a review of my Dac. The Audio Zone Dac 1 aka Audio Sector Premium Dac. The reviewer bought the review sample to replace the EE minimax cd player. I think once Paul Candy hears that Dac with the Jitter buster..he'll be really groovin!!

NewBuyer · « **Reply #13 on:** 17 Oct 2006, 11:54 pm »

Thanks for the link GHM!

teiki arii · « **Reply #14 on:** 18 Jan 2007, 06:10 pm »

I have bought a XLR/RCA Burson Audio Buffer three months ago and I am very pleased with that "gem". I use it to plug my XLR Cayin CDT-17A to any RCA preamp. And it works so well compared to my RCA single-ended Cayin CDT-17A outputs. Since I was not convinced by impedance explanations I was a little frightened by the results. I still do not understand how it works but I'm very impressed and glad of its skills! A friend of mine tried to use it from RCA CDP with XLR/RCA adpatators and was overjoyed as well...

I also replace IC-OPA in "differential section" by Burson Discret OPA nine months ago. The quality of the sound is phenomenal! I have tried OP275, adaptated AD825, OPA627AP, OPA627BP, AD843JNZ, AD845, AD847JNZ, AD8065, AD8610, OPA134AP, OPA604AP... Here is an excerpt of a review I made about it:
"After replacing my OPA627BP/AD843JNZ by Burson Discret OPA on that section, I understood at a glance I was finding what I have searched for months and months. The difference was so amazing that I couldn’t believe I had the same CDP in front of me : The soundstage became exceptionnal in « wide » , « high » and « deep » aspects. I could almost see the stage with protagonists on it ! The music instruments and voices’ 3D positions are accurate and precise. The piano sounds like a piano! Actually, the piano is a very difficult music instrument to be reproduced. With Burson Discret OPA in « differential section » the played notes get body impacts and feel « full ». With OPA627BP, the sounstage is very nice more deep than wide but the notes feel « half » played and the bass, where have the bass gone ? With OPA134AP/OPA604AP, the music feels « slow », not precise while soundstage is very « musical ». With AD843JNZ, the performance is acurate but the « remanence » disappears and the « musical » effects and atmosphere with it. Besides, the midrange and sounstage are not so good.
But do make no mistake : Burson Discret OPA are by very far better than IC-OPA in any ways ! I am very impressed by the natural, unfatiguing skills of my new "burson Cayin CDT-17A" which make the musical performances alive. The first class State-of-the-Art modules are « quick » and the attacks of the notes make feel the music instantaneous, like a snapshot. It perfectly looks like transparent, neutral and realistic. You can feel physically the piano, it comes true. The tones and snares are marvellous because they seems to be as if the instruments were in front of me. Dynamic is exceptionnal : the high are « aerial » and « clarified » without becoming « harsh » neither agressive, the bass are « decent » and « honest » without being « boomies », the midrange is « warm » without being « caricatured » nor « grotesque ». Details contribute to catch the mood of the audience around so well that I can clearly listen to the record machine’s motor on some CD!../..
Now, I still have to compare, in « I/V conversion » section, Burson Dual Discret OPA to OPA2134AP, NE5532, AD827, Double OPA627, LM4562, AD826, AD823, AD8066, AD8620, THS4032, LM6172, OPA2111, OPA2107… that’s another story –of tests-…
NB : to profit fully of the Burson Parts, I recommend over hundred hours of « burn-in »…"

best regards.
teiki arii.