[Napalm]

Hi All,

Now that I spent a couple of weeks with brand new BP6 + 4B SST2, here's my very short review of them and then a question.

I'm not an audiophile (the kind that "listens to cables"), so I won't talk about "airiness", "danceability" and other stuff of theirs.

For me things are much simpler, either there is some noticeable problem with the sound that bothers me continually and distracts me from listening to the music; or there isn't.

In this respect I found the BP6 + 4B SST2 to be absolutely non-objectionable. They just do what they're supposed to do without attracting any attention to them. From a music listening perspective, it's like they are not there. Which would be the supreme praise I think.

Now to the question. Today I spent some time rearranging cables and stuff. And had the curiosity to stick my ear to the tweeters to listen for hiss. Much to my surprise I found that there is a faint tone coming out of them. Not hiss, but something like a TONE (that would come from EM interference or self-oscillations). Very faint, I can hear it only with my ear at 4 inches or closer.

So I tried to find out where it comes from and it's the BP6.

The amp, without cables, with open cables or with cables connected directly to CD player is dead silent, I can't hear anything. (yeah I tried to play music directly from the CD, fortunately I was inspired enough to switch the amp gain to low and use a classic music CD recorded at low level; otherwise there would had been speaker cones all over the house).

As soon as I connect the BP6 I can hear that high pitched tone. It doesn't matter which cable I tried, which pre input is selected, or wheter the input is open, connected to CD player or shorted. It's pretty much constant.

So, any idea what this is and if it's normal or not. It doesn't bother me in any way, but since the CD player was dead quiet when connected directly to the amplifier, why would a four times more expensive preamp make more noise?

Nap. 

[gerald porzio]

I'm guessing you're hearing thermal noise - 4" is awfully close. Have you ever tried this w/ another preamp?

[Napalm]

I'm guessing you're hearing thermal noise - 4" is awfully close. Have you ever tried this w/ another preamp?

Yes I did, they had the standard hiss sound (louder than the BP6 tone). So I'm not  faulting the BP6, I guess it is within the specs, I'm just curious what it is. So far my guess is that the output stage / wires are picking some EM noise from the transformer / power circuits. The tone does not get louder when turning up the volume. However, with volume at max, there is some faint hiss that covers the tone (or the tone changes itself into a hiss). But this happens with volume close to max (that would be clipping / speaker death for sure).

I've tried different power outlets, with/ without power filter, I made sure there's no furnace or whatever running. Moved the BP6 around, held it at a distance from other components. No change.

Nap.   

[vegasdave]

This is one for James, I'd say. I do have some hiss with the phono stage in my BP6, however, when the volume is turned up all the way. Not sure if this is normal or not.

[Stu Pitt]

A couple of thoughts -

1. Move the interconnects as far away from the power cords as possible
If they have to cross, cross them at 90 degrees; don't let them run parallel.

2. Same goes for speaker cables, especially with power cords. Try to seperate the speaker cables if they have to be parallel.

3. Is your TV hooked up to the stereo, either directly or indirectly (through a cable box)?   If so, disconnect it and see what happens.

4. Try moving your components further away from each other, putting them  side by side, etc.  If you're using a turntable, try moving that further away too. 

5. Is your outlet properly grounded?  A lot of them are wired wrong. 
Thera are a lot of variables.   

[Napalm]

This is one for James, I'd say. I do have some hiss with the phono stage in my BP6, however, when the volume is turned up all the way. Not sure if this is normal or not.

Dave: I can hear a very faint hiss when I turn the volume past 4PM, on CD input. I don't have a phono stage, but in theory that would add even more noise. So I guess we're "normal".

I wouldn't have started the thread just for the (very faint) hiss as in my book it's normal, and the BP6/4B pair is the most quiet combo that has ever graced my listening room. What intrigued me was that at lower volume it sounds more like a certain frequency tone than a white noise hiss.

It's just some kind of "scientific curiosity" from my part.

Nap. 

[Napalm]

A couple of thoughts -

1. Move the interconnects as far away from the power cords as possible
If they have to cross, cross them at 90 degrees; don't let them run parallel.

2. Same goes for speaker cables, especially with power cords. Try to seperate the speaker cables if they have to be parallel.

3. Is your TV hooked up to the stereo, either directly or indirectly (through a cable box)?   If so, disconnect it and see what happens.

4. Try moving your components further away from each other, putting them  side by side, etc.  If you're using a turntable, try moving that further away too. 

5. Is your outlet properly grounded?  A lot of them are wired wrong. 
Thera are a lot of variables.   

I've checked everything, to no avail. Fortunately it's just a stereo system - no TV / receivers there to complicate things. There are 3 components - CD player, preamp and amp; and there's also a panamax surge protector, I tried with and without it. I'm pretty sure now that the noise comes from the BP6. As mentioned before, very faint, and I can definitely live with it (I actually didn't notice it at all until today). I won't loose sleep over it 

Nap.

[James Tanner]

Hi,

It could be just the 'overall gain' in the system is greater than your previous setup?

james

[vegasdave]

Dave: I can hear a very faint hiss when I turn the volume past 4PM, on CD input. I don't have a phono stage, but in theory that would add even more noise. So I guess we're "normal".

I wouldn't have started the thread just for the (very faint) hiss as in my book it's normal, and the BP6/4B pair is the most quiet combo that has ever graced my listening room. What intrigued me was that at lower volume it sounds more like a certain frequency tone than a white noise hiss.

It's just some kind of "scientific curiosity" from my part.

Nap. 

Interesting...I hear no hiss on the cd input with the volume turned up all the way.

I agree. It is the most quiet combo for me too. And I owned a very expensive Swiss-made amp and preamp by FM Acoustics. That alone is high praise for Bryston.

[Napalm]

Hi,

It could be just the 'overall gain' in the system is greater than your previous setup?

james

Hi James,

Thank you for replying. So far my explanation is that the BP6 noise has 2 components - EM interference/pickup and thermal noise. At low volume position the first one is greater and thus most prominent, and as I turn the volume up the thermal (white) noise takes precedence and is the most audible. With the volume turned past 12 o'clock you are right - the overall gain is higher.

What intrigued me was the EM (tone-like) one, audible with volume cut off. It might be that my tweeters have a peak/resonance on a multiple of power frequency (60Hz) or something like that. FWIW the speakers are Paradigm Studio 100 V5. The tweeters are known to have a resonance at 23 kHZ (although I'm sure I can't hear that frequency). Anyway, they are quite sensitive and definitely not rolled-off in the upper range so this might be the reason why I can hear it.

My local dealer has both Bryston and Paradigm so next time when I'll visit him I'll stick my ear on his speakers to see what gives.

Dave: it might be a difference in speaker / tweeter sensitivity. As I said, the hiss at max volume is very very faint, so if your speakers are something like 3 dB less sensitive than mine, you wouldn't hear it at all. What speakers do you have?

Thanks,
Nap.

[werd]

Hi

Try different inputs on your pre, also try plugging your unused inputs with rca plugs, Find the rca's with the resistors in them. Its a trial and error thing.
Power cables will change things too,

If you have a chance bring home a good power conditioner. Noise is so system/environmental dependent, people have such different results.

hope that helps and gl

[vegasdave]

What speakers do you have?

Thanks,
Nap.

JBL Studio L890s

[Napalm]

JBL Studio L890s

Intriguing, according to specs they should have about same sensitivity as my Paradigms.

Good news to report: I moved a pair of Energy RC-10 bookshelves from bedroom to family room to check with the Bryston (I guess I'm starting to be an "audiophile" now lol). The Energy's are lower sensitivity and have a slightly rolled off treble. Guess what, now I can't hear the noise. I mean with Energy's grilles off and my ear stuck to the tweeter, I'm at the point where I'm thinking "do I really hear something or is it just my imagination".

So I guess that the "tone" I was speaking of earlier was indeed some EM pickup that got obscenely amplified by a peculiarity in the Paradigm's tweeters.

BTW I took the opportunity to play some music through the bookshelves and I couldn't stop remarking how nice and smooth they sound through the Bryston (as compared to the Denon stereo receiver in the bedroom). I guess I'm in for a B60 now too lol. 

Also they beat the Paradigms in the midrange clarity and smoothness. Weee. Maybe I should have more speakers and a selector box. 

Nap. 

 

[vegasdave]

That's interesting about the bookshelves. Who knew? 

[vegasdave]

This is one for James, I'd say. I do have some hiss with the phono stage in my BP6, however, when the volume is turned up all the way. Not sure if this is normal or not.

Inspired by this thread, I tried turning the phono input up all the way...now I hear a little bit of hum coming out of the speakers...probably a wiring/ground issue I take it.

[Napalm]

Inspired by this thread, I tried turning the phono input up all the way...now I hear a little bit of hum coming out of the speakers...probably a wiring/ground issue I take it.

Ah Dave, now don't start messing with cables and so on. You'll never ever be able to listen to music with the volume knob in that position, so don't sweat over it.

Play a nice CD at regular volume and enjoy.

Nap. 

[vegasdave]

Yes, I know...I must control the ocd, haha.

Well, there's not a bit of noise at the cd input!

[Napalm]

Took the BP-6 to my local dealer today. They have a demo BP-6 so I compared them head to head.

They're about the same so there was nothing wrong with mine. The noise sound changed in character (as compared to at home) so it is definitely some EM pickup that depends on building wiring etc.

Happy Nap. 

[vegasdave]

Yeah, I bet that's the same with my unit. Because in my old place, the hiss was less.