Preamp for Burmester power amp


Hi all, I am new to here. Currently I am using JRDG Capri with Burmester 956 Mk II power amp, to drive ATC SCM40 V2. 

I intend to to upgrade the preamp (as I think it’s the weakest part), among Pass Labs XP12, Ayre KX5 Twenty and Bryston BP 17 Cubed, which one u think is a better match with my Burmester?
nibongese
There are some technical factors that should be taken into consideration in making this choice:

1)The Bryston has very low input impedances of 6.5K unbalanced/4.5K balanced. Those values are low enough to be a problem for most tube-based source components, and some solid state source components. Even if those values aren’t a problem for the source components you presently have, they may significantly constrain future upgrade possibilities.

2)According to Stereophile’s measurements the Ayre provides essentially zero gain from any of its inputs to its balanced outputs (which are the outputs that would presumably be best to use with your fully balanced amp). Since the efficiency of your speakers is somewhat low (specified as 85 db/1W/1m, with the identically specified earlier version of the speaker measured as only 81 db at http://www.avmentor.net/reviews/2014/atc_scm40_2.shtml), that lack of gain may be an issue if you are using vinyl or other analog sources. With some analog sources you could conceivably even find yourself wanting to turn the volume control up higher than it can go, especially if you listen to material having wide dynamic range such as a lot of classical symphonic music.

3)The balanced inputs of your amp have an **extremely** low input impedance of 1.88K. I suspect that the Pass and Ayre preamps would be able to drive such a low impedance with good results, but it would probably be a good idea to check with the manufacturers to be sure.

Good luck. Regards,
-- Al
Hi Almarg, thanks for your prompt reply. It seems like Ayre & Pass Labs preamp are better match with Burmester power amp.

Have u ever listened Pass Labs + ATC/PMC speakers?
Have u ever listened Pass Labs + ATC/PMC speakers?
No, I have no experience with ATC or PMC speakers. Or for that matter with the three preamp models you are considering.

Good luck, however you decide to proceed. Regards,

-- Al
Hi Almarg,

How about Mark Levinson 326s or 523 preamp? Do u think they are good match?

thanks
Burmester Preamp for Burmester power amp :)
nibongese


With the Burmester 956 Mk II with an input impedance this low.
Input Impedance XLR/RCA, 1.88 kΩ / 13.6 kΩ on both xlr and rca.
http://www.rutherfordaudio.com/products/burmester-956-mk2-power-amplifier/

Make sure you have a solid state preamp with nice low output impedance, passives and most tubes preamps need not apply, unless the tube pre has a "paralleled cathode follower" for an output stage, to get the output impedance down to solid state territory, then the tube nutz say they don’t sound to good, but muso’s love them so wt*.

Gain of the 956 is quite high at 31.5db (.8v in for full watts out) so you really don’t need any more preamp gain, all you’ll need is a active pre with unity gain buffer, this way you be able to use a good range on the volume control.
Where with a active preamp with gain you could be at 9 o’clock on the volume for loud listening.
What is your source output level?

Cheers George
My source is Burmester DAC 113 and Blacknote DAC 30
From what I found the 113 dac gives out 4V!
and the Dac30 is 2.5v

As you can see your 956 only needs .8v into it for full wattage output, so the preamp should be (unity) no gain to get good volume range on the volume control.

Cheers George
Hi George,

thanks for for the advice. So what do u mean is I just need a DAC with volume control ?
nibongese OP
 So what do u mean is I just need a DAC with volume control ?


Oh yes!!, but your the one who said it, now watch the pro preamp brigade chuck a mental, and put a hex on your first born.

If they have volume controls: If not you’ll need that buffered preamp.
The 113dac is 130ohms output impedance so a fine match direct into the 956.
The Blacknote even though it’s tube has an output transformer which is a nice low 75ohm output impedance so it’s fine also into the 956.

Hopefully you can use their digital domain volume controls at 75% or higher and it’s not too loud, below 75% you’ll start to run the risk of "bit stripping" 16bit 14bit 12bit 10bit ect the lower you go on the volume.

Cheers George


Hi, nibongese,

A few years ago I played around with your amp (or was it a previous model?) driving a pair of ATC scm50 (not my spkrs)—coincidence, eh!
With the owner, we tried the following pres on loan from shop & friends. Cables were from Nordost. The cd source from Burmester, Ayazi dac (modded; 1st I'd heard of that). We listened to classical, chamber and orchestral music:
  • *Burmester 099-- excellent result, music had a sense of urgency/dynamics, low-level detail was OK, hi frequencies OK and pleasant rather than super-detailed, low-frequency extension very good 
  • *Burmester something else (cheaper than 099): pronounced midrange, recessed hi & low frequencies, somewhat pronounced mid-bass; not bad result, but pale compared to its big brother.
  • *Cat Ultimate (yes that's tubes): similar to 099 but with less pronounced highs; I remember that low frequencies were unusually good, however.
  • *Dartzeel "NHB-something": outstanding result. Extension at both ends fantastic, details, no edges, no screeching, good sense of air around the instruments and good dynamics. The amp seemed to have been inspired to boost its dynamics!
  • *FM acoustics FM122 single-ended with FM IC: outstanding (- I rarely use superlatives). I remember being so enthusiastic, we switched to a blues & similar (JL Hooker, Clapton, B Guy) just for the sheer joy of it and spent some time drinking and listening and not auditioning!
  • *The big Ayre of the moment (XK5?): excellent result overall: no frequency group was pronounced, nice flow to the music ("liquid")-- but lacking in dynamics & extension vs compared to FM & Dart.

(Ultimately, the choice was to trade in the Burmester & buy a used FM pre/power combo... )

Good luck, the fun is in the journey as well as the destination!
3)The balanced inputs of your amp have an **extremely** low input impedance of 1.88K. I suspect that the Pass and Ayre preamps would be able to drive such a low impedance with good results, but it would probably be a good idea to check with the manufacturers to be sure.
I know of a few tube preamps that can drive low impedances like this no sweat, and balanced as well.
Why would anyone design an amplifier with only an 1,880ohm input impedance? It makes very little sense unless they want to force the buyer to (also) purchase their supposedly matching preamp. Just curious.
I know of a few tube preamps that can drive low impedances like this no sweat, and balanced as well.

I know of some too. I hear they are quite good!

Best regards,
-- Al   :-)
Hi Almarg,

How about Mark Levinson 326s or 523 preamp? Do u think they are good match?

After looking at their specs and at Stereophile’s measurements of the 326s and the 526 (which is spec’d similarly to the 523), I don’t see any technical or compatibility issues. I have no knowledge of their sonics, though.

With either of those models, btw, you would want to avoid the higher of the various gain settings they provide, certainly in the case of the 326s. The specified input overload voltages for that model are very low for its 12 db and 18 db gain settings.

Regards,
-- Al
kalali1,378 posts08-10-2018 3:09amWhy would anyone design an amplifier with only an 1,880ohm input impedance? It makes very little sense unless they want to force the buyer to (also) purchase their supposedly matching preamp. Just curious.
This is a classic con job, it happened with a hiend English company who designed their full range speaker to be way overdamped. Which worked perfectly with their sister companies well underdamped amplifiers.

The amp manufacture then did A/B's at hifi shows here in Australia using of all things a Krell amp to show how much better the bass was on their own amp, because the Krell believe it or not into these speakers had no bass, if very thin at all.

The only advantage to having input impedance's on amps this low, is that it's a great equalizer for different interconnects. They all sound similar, filtering effects are reduced. 

Cheers George      
nibongese OP
This would be a good one to try nibongese, if your dacs don’t have volume controls to go direct with, it has 3 different modes of operation, all with zero or minimum gain.

It’s all remote controlled with probably the best mechanical volume control available.
You got xlr or se 5 x inputs, and 3 x outputs.
A choice of 2 different low impedance active output buffers, tube, j-fet solid state and a passive which wouldn’t suit.

It’s designed by Mike Moffat of Theta fame so he really know his stuff, and you can return it if not happy.

http://www.schiit.com/products/freya

Cheers George


 kalali1,378 posts08-10-2018 3:09amWhy would anyone design an amplifier with only an 1,880ohm input impedance? It makes very little sense unless they want to force the buyer to (also) purchase their supposedly matching preamp. Just curious.
This is a classic con job, it happened with a hiend English company who designed their full range speaker to be way overdamped. Which worked perfectly with their sister companies well underdamped amplifiers.
Its more likely that they built the balanced inputs to support the balanced standard, which expects fairly low input impedances. Any source with an XLR output should be able to drive this no worries, but sadly, this practice is rare in high end audio.
@georgehifi who is this hi end English company that overdampened their speakers?
They were Linn Isobarics a very over damped design, back in the 70-80’s. When the Linn/Naim retailer Riverina HiFi demo’ed a KSA Krell on them they had very little bass weight!!!!!, yet with the first early Naim 250’s they had had all the bass weight in the world with the Isobarics.
The Naim was said to have a damping factor of only 8. Over damped speaker under damped amp makes for synergy.
Needless to say that Linn/Naim reatier sold many of those combinations, especially when he demo’d Krell!! couldn’t do bass into them!!

Cheers George