Beresford Bushmaster DAC Reviews

[allsorts]

I'm running the BM off a li-po battery. Was so impressed by the immediate SQ improvement that I went and bought a second battery so I always have one ready to go. The SBooster from Mark Grant, which I had attached prior to the battery upgrade, had less/little effect - to my ears. The battery powered improvement has now got me thinking, whether my Macbook running off its battery would improve on my current mac mini mains powered source?

[NRG]

I agree with the above about the sBooster, if there is an improvement it's minimal at best to my ears...it does cut the SMPS noise down by about 45db though so its effective in that respect.

Can't agree about the battery though, found it reduced HF detail and clarity. A step backwards IME. The output impedance of a battery gets a lot worse as frequency rises and I wonder if this effect is directly responsible.

[Clive]

Can't agree about the battery though, found it reduced HF detail and clarity. A step backwards IME. The output impedance of a battery gets a lot worse as frequency rises and I wonder if this effect is directly responsible.

I found the same when running a T-amp from a battery, the sound was "nice" but lost detail.

[StanleyB]

The BM has a noise filter built into the internal power supply as well, but its main purpose is to reduce the noise on the power rails to the digital and analogue circuit. The filtering effect of the internal filter is not very steep so that the power rail impedance is not increased.
I have been playing around with a couple of inexpensive and simple mods to see if I can get more out of the PSU circuit. But the Olympics have come in the way so the project is on ice for a week or two for now.

[DaveK]

I found the same when running a T-amp from a battery, the sound was "nice" but lost detail.

I'm running a pair of Mini-T amps bi-amped from a single LiPo battery and can't say I've noticed any lack of detail. Not saying it doesn't happen, just that I don't notice it with my kit and my ears . I'll try and take special notice next few times I listen, maybe even A to B test 'cos I've still got my linear supply through JLH Ripple Eaters 'plumbed in'.
I had thought about putting the Ripple Eaters between battery and Mini-Ts but was advised against it because of initial current draw IIRC - anybody got any thoughts on that?
Cheers,
Dave.

[MartinT]

There's no ripple to eat from a battery, Dave. Only mains PSUs have ripple.

[DaveK]

There's no ripple to eat from a battery, Dave. Only mains PSUs have ripple.

Martin,
Thanks for your response. What little logic I have regarding electricity led me to think the same but to be safe I asked the question on another audio forum - see here: -

http://rockgrotto.proboards.com/inde...ad=8368&page=1

Given the inconclusive nature of the responses I thought I would risk posing the same question on here.
I interpret the other replies as being possibly not in total agreement with your thoughts. As I said, I know nowt, so I'm not pitching A against B, I'm just interested in seeing if I can raise the SQ any, given that I already have the Ripple Eaters, but not wanting to see any smoke if I tried to .
Cheers,
Dave.

[MartinT]

Well, ripple is strictly speaking the residue from imperfect rectification and smoothing of a sinewave (transformed mains, in this case). Yes, the battery may exhibit 'sag' and it's just possible that the 'ripple eater' may help to compensate, but in a battery there is no ripple.

[DaveK]

Thanks Martin,
I'm beginning to wonder if there are any 'absolutes' in audio electronics, or indeed in anything 'audio' .
Cheers,
Dave.

[MartinT]

Absolutes are for religion, inquiry is for science.