Bryston BP17 Cubed preamplifier

vklyushnikov · « **Reply #181 on:** 4 Oct 2018, 05:10 pm »

Hi James

I just installed BP17 Cubed with 4B Cubed in my system and have some questions:

Is it normal for preamp to have slight transformer noise - even in standby mode? 4B3 also has it but it is quiet after turning off
Which gain setting on 4B3 is correct for XLR output of preamp? I chose 23 db, but surprised how much should I turn volume knob compared to my old BP25/4BSST combo

Regards,
Vladimir

James Tanner · « **Reply #182 on:** 4 Oct 2018, 05:27 pm »

HI Vladimir

1. The BP-17 always has some power as it needs it to allow for remote turn-on. The noise should not be excessive and a lot will depend on the line frequency in your area.

2. I would use the 29dB setting as the volume control is different than the BP25.

james

vklyushnikov · « **Reply #183 on:** 4 Oct 2018, 08:52 pm »

James, thank you very much for reply. Looks like new volume works great for me - as my listening room is relatively small. Am I correctly understand that 23 db is also fine - as long as I don't need too much loudness? And which type is BP173 XLR output - actively balanced or transformer coupled balanced?

James Tanner · « **Reply #184 on:** 4 Oct 2018, 09:32 pm »

Quote from: vklyushnikov on 4 Oct 2018, 08:52 pm

James, thank you very much for reply. Looks like new volume works great for me - as my listening room is relatively small. Am I correctly understand that 23 db is also fine - as long as I don't need too much loudness? And which type is BP173 XLR output - actively balanced or transformer coupled balanced?

Hi

Yes 23 is fine as well.

Actively Balanced using discrete components.

james

alexone · « **Reply #185 on:** 10 Oct 2018, 12:41 pm »

James,

the preamp section of the B 135³ is basically the same as the BP 17³ ,(i guess)....

now the B 135³ has a 'clip' function whereas the the BP 17³ has a 'bypass' function.

why?

al.

James Tanner · « **Reply #186 on:** 15 Oct 2018, 06:02 pm »

Hi James,

Although a preamp can clip at the outputs, a "CLIPPING" indicator is usually associated with power amps.
When the BP17 preamp which uses the same dress panel as the B135) was designed, an LED indicating clipping became redundant.
The LED needed to be used for something, so it was decided to indicate the "BYPASS" function.
On the B135 Amplifier, bypass is indicated by both "BALANCE" LEDs turning red when the bypassed input is selected.

I hope this helps.

David

Stefan_DR3 · « **Reply #187 on:** 14 Dec 2018, 07:24 am »

Quote from: James Tanner on 24 May 2018, 09:31 pm

Full Stereophile review:

http://bryston.com/PDF/reviews/2018_05_Stereophile_BP_17.pdf

JA found some 60 Hz power related noise in the LEFT channel, although below human audible levels:

https://www.stereophile.com/content/bryston-bp-173-line-preamplifier-measurements

In fact a lot has been written of the Cubed series’ low-noise circuits, however I am getting some unexpected noises out of the preamp. Given the great specs, baseline noise level (with volume turned all the way down) is a bit higher than I would expect for a solid-state preamp. Fortunately this white noise, which can be heard standing close to the speakers, does not increase as volume is turned up.

There is also a transient "pop" every time the output is muted or un-muted. This pop is about 5 times louder in the LEFT channel on my unit. If you watch the speakers you can see the woofers move a bit when muting and un-muting. This prompted me to put a voltmeter on the pre-outs, with no source signal and volume at zero. I don’t know if this relates to JA’s measurements, but there does seem to be something odd happening in the LEFT channel on my unit. Without muting I measured 12 mV DC on the right RCA output; 32 mV DC on the left. When muting it spikes off the scale, so at least an order of magnitude higher.

This is my first Bryston preamp. Are others' like this?

CanadianMaestro · « **Reply #188 on:** 14 Dec 2018, 03:08 pm »

To Bryston: I used to have the old version of BP17 (non-cubed), and I heard no clicks/pops when muting off balanced. As the cubed amp innovation deals exclusively with the input stage, I'm puzzled as to why an output would have this issue. It should be dead silent, no?

cheers

PierreB · « **Reply #189 on:** 14 Dec 2018, 03:28 pm »

Hi Stefan,
I used to have a BP-25 and it makes the same noise as yours when I press the mute button. And it’s louder in the left channel than in the right. It’s only when I use XLR cables. With the RCA connection between the BP-25 and 2B SST, no more noise. I try different XLR cables with no succes.
I return my 2 Bryston for a complet check but they find nothing wrong. So I only use RCA connection.

CanadianMaestro · « **Reply #190 on:** 14 Dec 2018, 03:35 pm »

Quote from: PierreB on 14 Dec 2018, 03:28 pm

Hi Stefan,
I used to have a BP-25 and it makes the same noise as yours when I press the mute button. And it’s louder in the left channel than in the right. It’s only when I use XLR cables. With the RCA connection between the BP-25 and 2B SST, no more noise. I try different XLR cables with no succes.
I return my 2 Bryston for a complet check but they find nothing wrong. So I only use RCA connection.

You don't hear any noise when music is playing, right?
I think that's what's crucial here.
But yes, it's unsettling that noise is there in bal mode when muted.

cheers

PierreB · « **Reply #191 on:** 14 Dec 2018, 04:20 pm »

Quote from: CanadianMaestro on 14 Dec 2018, 03:35 pm

You don't hear any noise when music is playing, right?
I think that's what's crucial here.
But yes, it's unsettling that noise is there in bal mode when muted.

cheers

No, I don’t hear any noise. Only when I press the mute button, I heard a single loud pop. No more.
They always be extremely silent.

gberger · « **Reply #192 on:** 14 Dec 2018, 06:58 pm »

Since I find my BR2 difficult to use with my macular degeneration, I use it as a doorstop.

CanadianMaestro · « **Reply #193 on:** 14 Dec 2018, 07:15 pm »

Quote from: gberger on 14 Dec 2018, 06:58 pm

Since I find my BR2 difficult to use with my macular degeneration, I use it as a doorstop.

I use it to silence my neighbor's cat when I want absolute silence for my listening pleasure.

Stefan_DR3 · « **Reply #194 on:** 14 Dec 2018, 07:47 pm »

Quote from: PierreB on 14 Dec 2018, 03:28 pm

Hi Stefan,
I used to have a BP-25 and it makes the same noise as yours when I press the mute button. And it’s louder in the left channel than in the right. It’s only when I use XLR cables. With the RCA connection between the BP-25 and 2B SST, no more noise. I try different XLR cables with no succes.
I return my 2 Bryston for a complet check but they find nothing wrong. So I only use RCA connection.

Thanks Pierre, this is good information. I didn't realize the issue was particular to their balanced outputs. I will probably continue to use XLR despite the muting pop.
Bryston just re-tested my preamp so I have to assume it is characteristic (a minor annoyance).

Being premium products and a long-standing issue, I'm disappointed none of the professional reviewers have mentioned it though.

john1970 · « **Reply #195 on:** 14 Dec 2018, 10:37 pm »

Quote from: Stefan_DR3 on 14 Dec 2018, 07:24 am

JA found some 60 Hz power related noise in the LEFT channel, although below human audible levels:

https://www.stereophile.com/content/bryston-bp-173-line-preamplifier-measurements

In fact a lot has been written of the Cubed series’ low-noise circuits, however I am getting some unexpected noises out of the preamp. Given the great specs, baseline noise level (with volume turned all the way down) is a bit higher than I would expect for a solid-state preamp. Fortunately this white noise, which can be heard standing close to the speakers, does not increase as volume is turned up.

There is also a transient "pop" every time the output is muted or un-muted. This pop is about 5 times louder in the LEFT channel on my unit. If you watch the speakers you can see the woofers move a bit when muting and un-muting. This prompted me to put a voltmeter on the pre-outs, with no source signal and volume at zero. I don’t know if this relates to JA’s measurements, but there does seem to be something odd happening in the LEFT channel on my unit. Without muting I measured 12 mV DC on the right RCA output; 32 mV DC on the left. When muting it spikes off the scale, so at least an order of magnitude higher.

This is my first Bryston preamp. Are others' like this?

I had the exact same issue(s) with a new BP17 cubed I purchased about a year ago. At that time I had a BP26 converted from a BP25 and MPS2 which was significantly less noisy. Since then I moved onto a SimAudio 740P preamp and have the very precise volume control which I desired along with absolute silence.

Good luck,

John

TJ-Sully · « **Reply #196 on:** 15 Dec 2018, 12:35 am »

Hi Stefan, I've used a Bryston BP20 for about 5 or 6 years - and it was dead quiet. Not a hop hiss or buzz.
The only issue i had was with my own room - in the winters, it's super dry in my house, and prone to static shocks. Sometimes I'd get a shock on almost anything i touch - even the preamp. This would sometimes cause the unit to lose power.
But as for noise - absolutely zero.
hope you can figure it out.
cheers, TJ.

gberger · « **Reply #197 on:** 15 Dec 2018, 08:20 pm »

Plaintive Cry in the Wilderness for a simple "Volume Up - Volume Down" remote for my BP17c.

Kusot · « **Reply #198 on:** 26 Dec 2018, 11:10 am »

I believe the last few posts are regarding grounding. DC voltage on output and pops sounds like ground loops. Difference between RCA and xlr sounds like ground loops. Difference in dry and humid conditions sounds like groundloop. Are all components connected to a same circuit? I have bp16p, bp173p, BDA3 and bdp3. I have heard pops and noice, but it has always been related to grounding. Right now I connect all components to socket with common ground, BUT the common ground is not grounded. I use xlr between bdp3 and bp173 and RCA to amps.

Stefan_DR3 · « **Reply #199 on:** 1 Jan 2019, 09:06 pm »

Quote from: john1970 on 14 Dec 2018, 10:37 pm

I had the exact same issue(s) with a new BP17 cubed I purchased about a year ago. At that time I had a BP26 converted from a BP25 and MPS2 which was significantly less noisy. Since then I moved onto a SimAudio 740P preamp and have the very precise volume control which I desired along with absolute silence.

Good luck,

John

Thanks John. I did wonder if I should have gone with the BP26 instead