how to prevent hiss from speakers

Marius · « **Reply #20 on:** 14 Sep 2015, 06:17 pm »

Thank you so much Mike, i will try and report back. Nothing i can damage i hope...

Indeed the hiss is only present with the bp26 turned on. The BP26 volume has no influence. All the way down or up, it is there and stays the same. Playing music masks it of course.
Ill try to reduce gain on the 10bsub. There's no way i can do that on the BP26? Or through some extra resistance in the cabling? My dealer did install something like that on my sub , maybe the speakers need that too?

Cheers, and thanks again,
Marius

Quote from: Mike Pickett on 14 Sep 2015, 04:28 pm

Hi Marius;

I've sent you a picture via e-mail showing the locations of the jumpers in question.

That fact that the noise disappears with the BP26 turned off indicates that the 10B is likely not causing the issue, but reducing the gain may help nonetheless...

If the noise is present even with the volume turned all the way down on the BP26, reducing the gain at the 10B should reduce the level of the hiss. If the hiss goes away with the volume down, and increases with increased volume, it's likely originating before the BP26, and reducing the gain at the 10B may not be useful.

Thanks,

Mike

Mike Pickett · « **Reply #21 on:** 14 Sep 2015, 08:14 pm »

Hi Marius;

No risk of damage, as these are mechanical jumpers with no soldering involved.

It is possible to reduce the gain in the output stage of the BP26, but this not something that can be done in the field...

I don't recommend cable based attenuators, as this can interfere with impedance matching, especially if done in the speaker cables.

Thanks,

Mike

Marius · « **Reply #22 on:** 14 Sep 2015, 08:19 pm »

Great,thanks.
I'm on my way, and be back to you.

Appreciated,
Marius

Quote from: Mike Pickett on 14 Sep 2015, 08:14 pm

Hi Marius;

No risk of damage, as these are mechanical jumpers with no soldering involved.

It is possible to reduce the gain in the output stage of the BP26, but this not something that can be done in the field...

I don't recommend cable based attenuators, as this can interfere with impedance matching, especially if done in the speaker cables.

Thanks,

Mike

Marius · « **Reply #23 on:** 15 Sep 2015, 11:11 am »

HI,

For starters i took out the 10bsub and connected pre-amp directly to the 28b's. Hiss is no less, if not worse..

I must say there's much more crosstalk than i previously noticed. several sources are all audible on non playing inputs, and i don't even have to turn the volume all the way up. on the Disc input a small hum is added, even though there's no record player hooked up to my BP1.5 at the moment.

Im off for a right screwdriver to lift the top of the 10bsub, but am wondering if it is needed thing to do. Mike, should I send in the BP26 for servicing?

The thing is, with unbalanced inputs, i don't have the issue of being unable to turn up the volume higher than 8 or 9 o'clock. Thats only incase of balanced connections (my BDA and BCD1).

cheers,
Marius

Marius · « **Reply #24 on:** 15 Sep 2015, 11:31 am »

HI Mike,

Jumpers are installed, indicating it is already -6 db and the 10bsub can't be reduced any further?

full

left channel

right channel

cheers,
Marius

btw, on the board a date of oct 96 is printed. i bought it somewhere in 2008, which seems reflected on the serialnr plate: date 08 46. No worries there i suppose ?

Quote from: Mike Pickett on 14 Sep 2015, 04:28 pm

Hi Marius;

I've sent you a picture via e-mail showing the locations of the jumpers in question.

That fact that the noise disappears with the BP26 turned off indicates that the 10B is likely not causing the issue, but reducing the gain may help nonetheless...

If the noise is present even with the volume turned all the way down on the BP26, reducing the gain at the 10B should reduce the level of the hiss. If the hiss goes away with the volume down, and increases with increased volume, it's likely originating before the BP26, and reducing the gain at the 10B may not be useful.

Thanks,

Mike

Mike Pickett · « **Reply #25 on:** 17 Sep 2015, 01:42 pm »

Hi Marius;

Given that the jumpers are already in place, and that removing it from the system doesn't help, I don't think it's the source of the issue.

I think that having a technician check the noise floor on the BP26 is a reasonable next step...

Thanks,

Mike

Marius · « **Reply #26 on:** 17 Sep 2015, 05:17 pm »

Ok Mike
How do I proceed ? Do i send the bp26 to Canada? I wouldn't want a non Bryston technician check its innards.

Have less than optimal experience with that to be honest.

Cheers Marius

Marius · « **Reply #27 on:** 27 Sep 2015, 05:29 pm »

Hi Mike, James,

Mike didn't come back to this thread yet, but instead of opening the BP26, and having to send it all the way over to Canada, could this level control http://www.goldpt.com/sa1x.html or the likes of it be recommended by Bryston? Or do you make anything like this yourselves?

Not sure what to look for or watch out for in these boxes, and what determines their audiophile/professional quality.

Marius

Marius · « **Reply #28 on:** 13 Jun 2016, 08:48 am »

James,

Now I've auditioned the Model T's, I've positively established that the hiss is not to do with the 10bsub (I've taken it out of the system for the T's sake).
There's a hiss coming out of (both of) the T's tweeters. On both gain settings, a bit less in the 2v gain setting. (which is beyond me, how would a 2v gain be more silent than the 1v gain...?)

Mike suggested a noise floor check of the BP26. Would that still be your advice? And if so, who can do that, should i take the BP26 to Mafico? Or can i adjust anything myself in the BP26. Might of course also be something in the 28b's? I can not test that, since both have to be on to hear the hiss.

(or does a powered 28b, with an unpowered bp26 mean it isn't the 28b causing the hiss?)

Before i begin that journey, id like to hear from you and of course others on this board, if there should be a dead silent speaker, or if a hiss is to be expected. I wouldn't think so, especially in an all Bryston setup.

Would the update to the cubed input section be of any help here?

Cheers,
Marius

James Tanner · « **Reply #29 on:** 13 Jun 2016, 10:43 am »

Quote from: Marius on 13 Jun 2016, 08:48 am

James,

Now I've auditioned the Model T's, I've positively established that the hiss is not to do with the 10bsub (I've taken it out of the system for the T's sake).
There's a hiss coming out of (both of) the T's tweeters. On both gain settings, a bit less in the 2v gain setting. (which is beyond me, how would a 2v gain be more silent than the 1v gain...?)

Mike suggested a noise floor check of the BP26. Would that still be your advice? And if so, who can do that, should i take the BP26 to Mafico? Or can i adjust anything myself in the BP26. Might of course also be something in the 28b's? I can not test that, since both have to be on to hear the hiss.

(or does a powered 28b, with an unpowered bp26 mean it isn't the 28b causing the hiss?)

Before i begin that journey, id like to hear from you and of course others on this board, if there should be a dead silent speaker, or if a hiss is to be expected. I wouldn't think so, especially in an all Bryston setup.

Would the update to the cubed input section be of any help here?

Cheers,
Marius

Hi marius

Hiss is usually transistor or component capacitor noise. It could also be RF.

If you do not have the preamp plugged in and the the amp on with no hiss then it is not the amplifier. So that leaves the preamp or a source component. So I would remove all the sources and plug in the preamp and see if you hear hiss. Then add each source one at a time and see if one of them adds the hiss.

james

Marius · « **Reply #30 on:** 13 Jun 2016, 11:00 am »

Quote from: James Tanner on 13 Jun 2016, 10:43 am

Hi marius

Hiss is usually transistor or component capacitor noise. It could also be RF.

If you do not have the preamp plugged in and the the amp on with no hiss then it is not the amplifier.

Check, that is the case.

Quote from: James Tanner on 13 Jun 2016, 10:43 am

So that leaves the preamp or a source component. So I would remove all the sources and plug in the preamp and see if you hear hiss. Then add each source one at a time and see if one of them adds the hiss.

james

Before plugging out everything: i have volume all the way down, and the hiss remains. turning the volume up without anything playing doesn't change the hiss. It doesn't get louder, and no crosstalk is audible.

Seems to be the pre amp?, or still remove all sources...

Marius

werd · « **Reply #31 on:** 13 Jun 2016, 03:25 pm »

You are overpowering a pair of high sensitivity bookshelves. You are going to get hiss. You should try running a decent passive preamp or upgrade the crossovers in the speakers because of age. The passive will reduce the system gain for sure. The speakers may be aging hard to say.

Get rid of gain in your system. Think of system gain and speaker sensitivity as two different contributing aspects of noise. You are full speed ahead on both. Don't do that if you are trying to get rid of a hiss.

I like the bookshelf sub-thing but those speakers are not meant for what you are trying to do. Which is ok but
You are going to run into too much gain and hiss. Get a pair mini Model Ts or low sensitivity book shelves is the best solution.

Marius · « **Reply #32 on:** 13 Jun 2016, 03:34 pm »

Quote from: werd on 13 Jun 2016, 03:25 pm

You are overpowering a pair of high sensitivity bookshelves. You are going to get hiss. You should try running a decent passive preamp or upgrade the crossovers in the speakers because of age. The passive will reduce the system gain for sure. The speakers may be aging hard to say.

Hi Werd,

I am powering the Model T's.... hardly aged bookshelves

My preamp is the BP26, which i would have though is a decent one?

btw, this thread started using my ELS63's which though sensitive enough, are less sensitive than the Model T's i believe, have to turn the volume a little bit up compared to the Els's. Not sure though, could be other aspect i don't know of of course.

Cheers,
Marius

werd · « **Reply #33 on:** 13 Jun 2016, 03:43 pm »

Quote from: Marius on 13 Jun 2016, 03:34 pm

Hi Werd,

I am powering the Model T's.... hardly aged bookshelves
My preamp is the BP26, which i would have though is a decent one?

Cheers,
Marius

What about the 102s?

The 26 preamp is quiet. Usually added noise is around the volume control. Which is easy to hear because it fluctuates with volume. If it's not there then try blowing compressed air or using a Deoxit Gold in the connections. That will help. Make sure the ground screws are tight. Is this worse on vinyl?

James Tanner · « **Reply #34 on:** 13 Jun 2016, 04:01 pm »

Hi Marius

I did some more investigating and the hiss would have to come from the output section of the preamp. The volume control is after the source input stage on the BP-26 so it is not likely a source issue.

I think it is simply the overall gain in the system and the higher efficiency of the Model T's over the Quads.

The hiss getting louder though with the 2 Volt setting vs the 1 Volt setting does not make sense ?

james

Marius · « **Reply #35 on:** 14 Jun 2016, 05:42 am »

Hi James,

So the output section of the BP-26 is too strong for the 28B

Or at least not optimally matched, since there's a hiss in all 3 setups, Esl, 102 Kef, and now the Model T's.
Need some adjusting to the section then? Mike suggested along those lines earlier. How to proceed now? Need shipping back to Bryston technicians?

Would be a good moment to also check the source selector (on the above mentioned cross-talk) to be up to specification.
Marius

Wim J · « **Reply #36 on:** 14 Jun 2016, 08:07 am »

Marius,

Did you already try to put the MPS-2 power supply on TOP of the BP-26. This is the better position when you have a noise problem. You could also try another output on the MPS-2 ,.... ( 4 available )

Marius · « **Reply #37 on:** 14 Jun 2016, 08:10 am »

HI Wim,

Really? No i haven't, will do so quickly, thanks for the tip.
How come this could be significant?

Marius

Quote from: Wim J on 14 Jun 2016, 08:07 am

Marius,

Did you already try to put the MPS-2 power supply on TOP of the BP-26. This is the better position when you have a noise problem. You could also try another output on the MPS-2 ,.... ( 4 available )

James Tanner · « **Reply #38 on:** 14 Jun 2016, 09:22 am »

Quote from: Marius on 14 Jun 2016, 05:42 am

Hi James,

So the output section of the BP-26 is too strong for the 28B

Or at least not optimally matched, since there's a hiss in all 3 setups, Esl, 102 Kef, and now the Model T's.
Need some adjusting to the section then? Mike suggested along those lines earlier. How to proceed now? Need shipping back to Bryston technicians?

Would be a good moment to also check the source selector (on the above mentioned cross-talk) to be up to specification.
Marius

Hi Marius

No the BP-26 matches the 28B's very well. I have 3 setups in my home and they are dead quiet. I guess on some systems you might hear some hiss if you put your ear to the tweeter.

james

Wim J · « **Reply #39 on:** 14 Jun 2016, 11:15 am »

Quote from: Marius on 14 Jun 2016, 08:10 am

HI Wim,

Really? No i haven't, will do so quickly, thanks for the tip.
How come this could be significant?

Marius

In an other post (can't find it right now) James or Mike explained there is difference in noise floor of a few dB between the two positions. Maybe a few dB can make a difference in your case? Since the MPS-2 is the power supply for the BP26 it can also introduce noise on the BP26 circuits. This would also be volume independent. Try another output on the MPS-2 as well. There are 4 identical circuits inside the MPS2. Also make sure the connecting DC-power cable between the units is not damaged and/or is not next to mains-, sat-, USB or network cable. It shouldn't matter, but sometimes it just does!