[rahman]

Greetings from sunny Dublin!

As someone who has spent many a late night pouring over the posts in this circle, no doubt to the chagrin of my gf, let me first say thanks to everyone for all the informative and positive discussion that goes on here. And particular kudos to James for actively sharing his knowledge and enthusiasm, being so receptive to input and even criticism, and generally setting an amazing standard of customer care.  These factors have created what I believe to be a fantastic and valuable resource and community. Keep up the good work.

I'm about to pick some MB2-p's, which represents a bit of a step up from my current FB1+, TB2+ and arcam avr280 setup, and leads me to seek your advice on, of course, "which amps???" to get the best out of these behemoths. While demoing/home testing would provide the obvious answer, unfortunately the opportunities for that here in dublin are pretty limited.    And all my digging around to-date would point to a bryston/PMC or arcam/bryston/pmc setup. So, with that in mind:
- what are people's experiences/views on passive bi or tri-amping pmc's with brystons? The views here have been somewhat mixed. Eg. a 28B would be better than a vertical 14B biamp, whereas tri-amping with a 4b and 2 3b's is better than single 7Bs. I realise it's ultimately subjective. One advantage i guess for slowly going the multi-amp route is that it allows for a gradual progression of acquisitions and improvements than a big one-off hit on the wallet (and from the gf!).  Eg 1 8B for stereo duty initially then another down the track for triamping (though not sure if bridging the 8B for stereo on MB2's is really feasible - thoughts?). I guess I need to know how much headroom I should have for each driver to really make em shine and how that differs from the headroom needed for same by single-amping;
- if passive tri-amp, how would this work? A Y+1 IC or splitter box etc;
- if single, I'm guessing I should probably go 7B's and up?; and
- anyone out my way got some brystons gathering dust they feel like setting free?  The 2nd hand market in the UK looks a bit dry atm.

I'll definitely try to demo, but any advice would be mucho appreciated.

Apols for rambling and a big thumbs-up to those have perservered.

Cheers
Adrian

[Viajero5000]

Hi Adrian,

Welcome to the forum; if set up properly, I'm sure you'll find the MB2s to be very nice speakers.

Firstly, for a single-amp situtation, the bigger (7/14/28SST) Bryston amps are needed for p MB2s. Anything less (eg a 4B) doesn't have what it takes to make these speakers work properly. I've never tried a 28B in my system; James has, and he suggests using this as opposed to a lower in the line bi-amp. Like you said, due to financial considerations, it may be easier to start off with a cheaper amp and build up. In that case, you can get a used 7/14B-SST for a decent price to start off... i recommend SST (not ST) series amps... much improved mids/highs to my ears. Secondly, when you have the cash, add a second amp to bi-amp... it'll make your speakers sound cleaner, natural, more dynamic. If you dont have enough cash, perhaps an ST amp on the bass, and an SST on the mids/highs may be a low-budget solution.

[rahman]

Gday Viajero

Many thanks for your reply.

I'll see if i can't lock down a demo with some 7Bs, 14Bs (and, wishful thinking, 28B's). Will look into bi/tri-amping down the road.

Cheers
Adrian

[Viajero5000]

i guess in theory one of the best ways to eat your cake and have it would be to buy a pair of 6B-STs and put one on each speaker. This will give you an SST tri-amp (the 6B-ST was the first of the SST designs), with power aplenty for each driver, without breaking the bank. You can even consider changing the x-over to an active one without the need to change amps and really enjoy the full potential of this set-up. The catch of course is being able to simultaneously find a pair of 6B-ST's on the used market!

[rahman]

i guess that was what i had in mind originally - 2*8Bst's in a passive tri-amp with a view to eventually going active. that's what pmc originally did with active mb2's - though i think they're now 2*7b's and 2*4b's.

in any event, tracking down 2*8B-st's in good nick is probably as hard, if not harder, than finding 2*6B's, based on what i've seen so far - so I might start with some 7B's for single amp then grab either 2*3bs or 4bs down the track.

of course, it might just be worth waiting a little bit to see how the 28b improvements work their way down the line...

final qn - would it be possible to passively tri-amp with, say, an sp2 by using a Y-XLR for tweet and mid and the rca for woofer?

cheers for the input
adrian

[mclsound]

hi adrian,i had a 4bsst and have a 14bsst and a 10bLR,i would find a good pair of 7bst,not sst,for your LOW only and a 14 for mid/hi,i found the 14 much better than the 4bsst on mid/hi.
the 7bst on low is no different than the sst and you can use the extra money towards the 14.
I loved my IB1's,and only could dream about MB2's, i like solid deep bass and soft mid/high at rather high spl at times.
i found the 4bsst awsome at low to mid volumes BUT a little to metallic at high volume.
now this was on my DIY  WWMTTM,2-12"Volt(3143), 2-ATC mids(75/150) and Scanspeak 9700 tweeter, which was much louder and brighter than the IB1's.
the 14 has more control for sure.
my sound tastes only
john

[jethro]

Adrian:

From my past experience with 8B-ST, 3B-ST, 4B-ST, and 4B-SST amps with
my IB1's, I would suggest that you would get the best sound quality for your dollar by buying the
best SST-series amp (or 2 monoblocks) that you can afford. I would avoid
bi-amping, and tri-amping until you get a working system with a single amplifier
channel per speaker. In my opinion, the 4B-SST is much better than the
3B-ST, 8B-ST, and 4B-ST amps, and by bi-amping or tri-amping with the
ST series you are going to lose quality in the midrange and the treble,
and also probably lose bass authority. My non-expert ears tell me that the
4B-SST adds some fullness to voices and guitars which makes a big difference
with some poor recordings. To me and a couple of my friends it was like night and day
when I switched to the 4B-SST.

HTH, Steve

[Viajero5000]

I agree the experiences above; dont get an ST amp for the mid/tweet (though it's reasonably ok for driving the bass, perhaps a tad 'drier' and boomier though, but can't say for sure since i havent done comparisons in the same room). Also agree that 14b is way more enjoyable to listen to than the 3/4b.  Hence the suggestions for the 14BST as single, or 6BST pair as tri-amp; both are SST designs but sell for slightly less than the branded SST amps in the used market, for those who dont have the budget to buy brand new.

[rahman]

Gday guys

Many thanks for all your thoughts - you certainly have provided some good food for thought.

I'll keep ya posted.

Best
Adrian

[guest2521]

I went from triamped mb2 to active mb2-xbd

triamping works MUCH better than monoblocks, 2 pairs of 3b-st and a 4b-st would work wonders - much better than a pair of 7b-st. I tried all the combinations. I eventually settled on two 4b-st and a 7b-st pair.

[Viajero5000]

Hi Nick, which front ends (pre and cdp's) have you found to work well with your system?

[guest2521]

I am using a ps audio gcph phono stage and pink triangle dacapo II cdp - both have inbuilt volume control and are connected to a balanced switch to the active crossovers, so I dont have a preamp - which makes a huge difference.

[Daniel Datchev]

Hi All,
as to multi-amplifying speakers, there was a post by Mr.Tanner that prior to
go in this direction the manufacturer of the speakers have to create them for this purpose.
If you take a look at  PMC MB2 and MB2A are using different tweeters.
I think it is possible to match the levels of different cones using sound generator, mic with sound analyser and pressure meter and get reasonable results.
But passive multi amplifying I think is No sense!
Daniel