James Tanner - Bryston
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MEMO: To All Bryston Customers
SUBJECT: Bryston 28B Amplifier Power Ratings Explained
July, 2014
Hi Folks,
We continually get asked about why we do not rate the Bryston 28B SST2 amplifier into lower impedance loads in our literature when reviews * constantly point out how well the 28B SST2 drives low impedance speakers.
The reason the Bryston 28B SST2 is rated at ‘only’ 900 Watts into 4 Ohms has to do with circuit-breaker ratings. CDN regulations only allow a 12-Amp rating on the circuit-breaker, (80% of the 15-Amp cord rating). When run at 2000 Watts, the breaker would open in only 30 seconds to a minute. This does not have any effect on musical performance, but for continuous power testing we felt it prudent to rate the amp at a power it could sustain without opening the breaker. Similarly, when the amplifier is run on a 2-Ohm load, the breaker would open at lower power levels. In addition, the amplifier’s thermal breakers could open in a short time at 2 Ohms continuous. Again, for speakers with impedance dips into the 2-Ohm range this has no effect. The amplifier will play musical material into the most ‘difficult’ speaker loads with perfect fidelity.
In fact the reason the amplifier tested at ‘only’ 1000 Watts continuous into 2 Ohms is because the steady-state current limit is reached when testing this way. However, the current is not limited on musical crescendos or transients, so peaks of at least 4KW can be reached on speakers with impedance dips down to the 2-Ohm range!
In fact, as the article pointed out, the 28B SST2 has two salient characteristics: One, it is completely untroubled and undisturbed by low impedances and so-called difficult speaker loading. Two, it is extremely transparent at low volume levels and also completely open and musical when the music starts demanding great power and heavy current reserves at realistic volume levels. In these and any other musical respect we will happily compare the 28B SST2 against any other amplifier made.
cwr
*ftp://ftp.bryston.com/pub/reviews/Aust_HiFi_July_Bryston_2014.pdf
SUBJECT: Bryston 28B Amplifier Power Ratings Explained
July, 2014
Hi Folks,
We continually get asked about why we do not rate the Bryston 28B SST2 amplifier into lower impedance loads in our literature when reviews * constantly point out how well the 28B SST2 drives low impedance speakers.
The reason the Bryston 28B SST2 is rated at ‘only’ 900 Watts into 4 Ohms has to do with circuit-breaker ratings. CDN regulations only allow a 12-Amp rating on the circuit-breaker, (80% of the 15-Amp cord rating). When run at 2000 Watts, the breaker would open in only 30 seconds to a minute. This does not have any effect on musical performance, but for continuous power testing we felt it prudent to rate the amp at a power it could sustain without opening the breaker. Similarly, when the amplifier is run on a 2-Ohm load, the breaker would open at lower power levels. In addition, the amplifier’s thermal breakers could open in a short time at 2 Ohms continuous. Again, for speakers with impedance dips into the 2-Ohm range this has no effect. The amplifier will play musical material into the most ‘difficult’ speaker loads with perfect fidelity.
In fact the reason the amplifier tested at ‘only’ 1000 Watts continuous into 2 Ohms is because the steady-state current limit is reached when testing this way. However, the current is not limited on musical crescendos or transients, so peaks of at least 4KW can be reached on speakers with impedance dips down to the 2-Ohm range!
In fact, as the article pointed out, the 28B SST2 has two salient characteristics: One, it is completely untroubled and undisturbed by low impedances and so-called difficult speaker loading. Two, it is extremely transparent at low volume levels and also completely open and musical when the music starts demanding great power and heavy current reserves at realistic volume levels. In these and any other musical respect we will happily compare the 28B SST2 against any other amplifier made.
cwr
*ftp://ftp.bryston.com/pub/reviews/Aust_HiFi_July_Bryston_2014.pdf
