Which Bryston Amp to drive a 4 ohm load?

[MASSIVE Master]

As nice as the 2BLP is for bookshelf speakers, it doesn't have nearly the power necessary to drive what you're driving -- Not at "thumb-snapping" volume anyway...

Maybe a 4B...?

Long story short, you're running 60 watts (if I recall) per channel. You should be running 4x that for those speakers at the minimum if you're looking for some "oomph" factor.

On the bright side, you know your thermal protection is working.

[modmark]

Thanks I just got swallowed up in the Hypex thread as well so there is always that. I should be never logged on

[silverking]

The Bryston 2BLP loves a 4 ohm load.....just not the 4 ohm load you're presenting it with

[modmark]

Originally Posted by silverking

The Bryston 2BLP loves a 4 ohm load.....just not the 4 ohm load you're presenting it with

:P

[cathode]

Originally Posted by silverking

The Bryston 2BLP loves a 4 ohm load.....just not the 4 ohm load you're presenting it with

On what basis ?
The 2B-lp employs a common emitter output stage, hardly ideal for very low impedance loads.
Furthermore, the 2B-lp not only lacks the text-book standard Zobel network (refer to D.Self, R. Sloan, and R. Elliott), and places an output capacitor AFTER the series inductor, making stabilisation issues WORSE.
As I've mentioned in other threads, good as a boat anchor.

[silverking]

You don't like Bryston designs.....I've seen some of your other posts where you say the same thing.

No problem mate, use whatever works for you.

[Thomas W. Bethe]

I would suggest a Bryston 4BST. Our 3BST works great but the extra power of the 4BST would be nice with the Martin Logans. If I remember correctly the MLs have a somewhat non linear impedance curve and 4 ohms is only the "reference" impedance.

Best of luck!

As to the nay sayers. Your money - your choice.

[tpad]

Well known problem with trying to drive electrostatics. Back in hi-fi days of old, KLH-9 owners found this out very quickly!

ES speakers employ a step-up transformer to develop the necessary HV drive to the panels. So, what the amplifier sees is the capacitance of the panels reflected back through the xfmr. At very low frequencies (as you approach dc), the xfmr reactance decreases, and this additional inductive reactive load is added on. So the amplifier winds up trying to drive a highly reactive complex load, which is not a trivial situation.

What you need is a lot of drive current. Probably, an amplifier with a power rating at least twice what you would normally think you would need.

[Axiom05]

The ML Ascents have a built in powered woofer so they are easier to drive than a full range ES. That being said, 60 watts is probably insufficient to drive these speakers to loud levels. A 4BST is probably a good choice if you like Bryston. If you can find a pair of 7BST's at a good price, you will definitely not be disappointed.

[dcollins]

Originally Posted by cathode

Furthermore, the 2B-lp not only lacks the text-book standard Zobel network (refer to D.Self, R. Sloan, and R. Elliott), and places an output capacitor AFTER the series inductor, making stabilisation issues WORSE.

That's odd. I wonder what their reasoning is?

As I've mentioned in other threads, good as a boat anchor.

At 20lbs, that is arguable.


DC

[nosebleedaudio]

Originally Posted by cathode

On what basis ?
The 2B-lp employs a common emitter output stage, hardly ideal for very low impedance loads.
Furthermore, the 2B-lp not only lacks the text-book standard Zobel network (refer to D.Self, R. Sloan, and R. Elliott), and places an output capacitor AFTER the series inductor, making stabilisation issues WORSE.
As I've mentioned in other threads, good as a boat anchor.

Wow, I disagree 100%...
Specs show a damping factor >500 @ 8ohms...REALLY Good, find a better 60 watt amp....
I used a 2B to drive a pair of PMC IB1's, everyone was shocked when they found out they were driven by a 60 watt amp...
Love Bryston's...

[cathode]

Originally Posted by nosebleedaudio

Wow, I disagree 100%...
Specs show a damping factor >500 @ 8ohms...REALLY Good, find a better 60 watt amp....
I used a 2B to drive a pair of PMC IB1's, everyone was shocked when they found out they were driven by a 60 watt amp...
Love Bryston's...

What do you disagree with ? The fact that the output stage is common emitter.
Rather than believing some tech writer's specs, have you measured the output impedance?
There are tech shops in studios that have a pile of Brystons, too nice to throw away but sonics too substandard to use, even on NS-10m's.

[nosebleedaudio]

Originally Posted by cathode

What do you disagree with ? The fact that the output stage is common emitter.
Rather than believing some tech writer's specs, have you measured the output impedance?
There are tech shops in studios that have a pile of Brystons, too nice to throw away but sonics too substandard to use, even on NS-10m's.

Let me say this, I would believe Bryston's specs MORE than your comments...
I could measure it...

[cathode]

Originally Posted by dcollins

That's odd. I wonder what their reasoning is?



At 20lbs, that is arguable.


DC

Dave, there are plenty of boat anchors at marine shops that weigh less than 10 pounds.

[dcollins]

Originally Posted by cathode

Dave, there are plenty of boat anchors at marine shops that weigh less than 10 pounds.

I stand corrected.


DC

[nosebleedaudio]

Originally Posted by cathode

On what basis ?
The 2B-lp employs a common emitter output stage, hardly ideal for very low impedance loads.
Furthermore, the 2B-lp not only lacks the text-book standard Zobel network (refer to D.Self, R. Sloan, and R. Elliott), and places an output capacitor AFTER the series inductor, making stabilisation issues WORSE.
As I've mentioned in other threads, good as a boat anchor.

So I guess you NEVER looked at the schematic??
I JUST double checked, the Zobel IS there, so I guess YOU listen to others BS...
So much for you WRONG statement...

[modmark]

yay! I succeeded in starting a thread that got everyones undies in a bunch! thanks sooo much for the comments. The 4bst is a great recommendation and I do like Bryston very much. however even at 2.7k used it is more than I can move on at this point (more than 1k more than the MLs cost) Bryston users: is a 4b worth considering as a step up on my way to the 4bst at this point? thx
-m

[nosebleedaudio]

Originally Posted by modmark

yay! I succeeded in starting a thread that got everyones undies in a bunch! thanks sooo much for the comments. The 4bst is a great recommendation and I do like Bryston very much. however even at 2.7k used it is more than I can move on at this point (more than 1k more than the MLs cost) Bryston users: is a 4b worth considering as a step up on my way to the 4bst at this point? thx
-m

get a ST..

[Axiom05]

The 4B, while not as good as the ST series, is a very good amp. I bought one back in 1987 which I used with a pair of B&W Matrix 801 series 2 speakers, then a pair of Thiel CS5i speakers, both of which like power (and the Thiels were a demanding load). I replaced the 4B with a pair of 7BST's. The 4B is still cranking out the juice in my father's stereo system.

[bassfuzz]

If your considering a 4B pricepoint you may want to check out Emotiva amps, priced well and handle low ohms without issue.