Bryston Launches BP-17³ Cubed Preamplifier

[Stefan_DR3]

How sensitive are your speakers? I found my 17 Cubed to be noisier than expected, especially for a solid state preamp, but only when no music is playing. Given the big deal that was made about the new circuits I was disappointed and began wondering if I should have gone for the 26.

Having said that the sound quality of the music it makes is certainly not inferior to any preamp I’ve ever heard. The features are also very useful, it’s relatively compact and the price was reasonable.

However if you have high sensitivity speakers and you are the type of person that is going to obsess over minor annoyances, like noises that do not affect playback of actual music, you may be disappointed.

[clpetersen]

Originally Posted by Stefan_DR3

How sensitive are your speakers? I found my 17 Cubed to be noisier than expected, especially for a solid state preamp, but only when no music is playing. Given the big deal that was made about the new circuits I was disappointed and began wondering if I should have gone for the 26.

Having said that the sound quality of the music it makes is certainly not inferior to any preamp I’ve ever heard. The features are also very useful, it’s relatively compact and the price was reasonable.

However if you have high sensitivity speakers and you are the type of person that is going to obsess over minor annoyances, like noises that do not affect playback of actual music, you may be disappointed.

Thanks for the information. That is interesting, as the 17-cubed is supposed to have an extremely low noise floor. Will keep in mind.

[James Tanner - Bryston]

Hi Stefan

Yes I am surprised to hear that you have excessive noise in the system?

here is the link to the Stereophile Magazines measurements which shows superb noise specs.

https://www.stereophile.com/content/...r-measurements

[Stefan_DR3]

Hi James,
I read all the professional reviews but was disappointed that they did not measure the baseline noise or mention the pop when muting. They measure the signal to noise ratio (SNR) with volume at max gain, which is excellent of course. Under those conditions nobody will hear any noise. However with the volume at zero there is a white noise that can be heard 2m from the speakers (90dBm Thiels). I have the amps on the low gain setting. The good news is this noise does not increase as the volume is increased.

Here is my reply to the Stereophile article and my own measurements:
https://www.audiocircle.com/index.ph...028#msg1719028

[Stefan_DR3]

On second look, one can calculate the noise floor that Stereophile likely measured, based on this sentence:

"The actual distortion doesn't rise above the noise floor until the output reaches 15V, when it is just 0.0005%, but rises rapidly above that level."

15 V x 0.0005/100 = 0.075 mV which is -106dB, not far off the Bryston spec.

I am measuring 100 times that (7.5 mV) and a DC offset of -13 mV (R) and +37 mV (L) on the RCA outputs. The XLR outputs have no DC.

[Formerly YB-2]

Originally Posted by Stefan_DR3

How sensitive are your speakers? I found my 17 Cubed to be noisier than expected, especially for a solid state preamp, but only when no music is playing.

Interesting. When I had one I used with 88db sensitivity speakers and never noticed any noise between tracks, etc. Thought it was an excellent, very flexible preamp and would likely still have if I had not moved back to tubes.

[Stefan_DR3]

Originally Posted by clpetersen

Thanks for the information. That is interesting, as the 17-cubed is supposed to have an extremely low noise floor. Will keep in mind.

You should be OK. I think Stereophile’s unit measured better than mine. According to their graph it would be 0.0009 % noise at 8V output (12dB gain).



I selected that point because it matches the conditions of the Bryston factory test. The spec sheet (test report) that came with my unit, serial 000007, says it scored 0.0018 % which is double the noise.

I am curious what the specs would be for that BP26 though.

[urbanluthier]

.

[urbanluthier]

.

[urbanluthier]

.