[esklar0723]

Hi Everyone

My first post here. I have a buzz coming from my 4 SST2 when I first power it up and then reoccurs during it's use. I recently added a BIT 15 to see if that would solve the issue, no luck. Also I do use a dedicated AC line from my fuse box in the house and I am using the supplied power cord from the 4b.

Any thoughts?

[avahifi]

Is the buzz/ hum coming from the speakers or from the amplifier chassis itself?

You need to isolate the problem.  The easy way to do this is to simplify the system.

First, turn the system off, wait unit the amp is really shut down.  Then disconnect the input cables at the amplifier, so it is connected to the speakers only.

Then turn amp back on.  No music of course now, but does the buzz/hum reappear?  If so it is an amplifier issue.  If not then you need to look earlier in the chain.

I guess I need to write a whole new system troubleshooting guide here at AC.

Meanwhile, download this:

http://avahifi.com/index.php?option=com_content&view=article&id=88&Itemid=184

Regards,

Frank Van Alstine

[James Tanner]

Is the buzz/ hum coming from the speakers or from the amplifier chassis itself?

You need to isolate the problem.  The easy way to do this is to simplify the system.

First, turn the system off, wait unit the amp is really shut down.  Then disconnect the input cables at the amplifier, so it is connected to the speakers only.

Then turn amp back on.  No music of course now, but does the buzz/hum reappear?  If so it is an amplifier issue.  If not then you need to look earlier in the chain.

I guess I need to write a whole new system troubleshooting guide here at AC.

Meanwhile, download this:

http://avahifi.com/index.php?option=com_content&view=article&id=88&Itemid=184

Regards,

Frank Van Alstine

Thanks Frank.

james

[esklar0723]

Thanks Frank,

After doing some trouble shooting, I discovered that the hum actually seems to come from the BIT 15,which is on a shelf below the 4b, when I have the 4b plugged and up and running. I plugged the 4b into the wall socket and get no hum so I hope it is fine.So now I have only the 4b turned on and I get slight hum from the BIT 15. Nothing else is turned on in the system.

 So here is run down on what is plugged into the BIT 15:

4b sst2
Bp-26/MPS-2
Bcd-1
Simaudio Lp 5.3
REL T5 subwoofer.

I don't think I am straining the BIT 15 during use but comments would be appreciated.

[avahifi]

Pardon my ignorance, but what is a "BIT 15"?

Frank

[Elizabeth]

Here is an advert for a BIT 15
http://www.audioadvisor.com/Bryston-BIT-15-Isolation-Transformer-Surge-Protection/productinfo/BYBIT15/

[James Tanner]

Thanks Frank,

After doing some trouble shooting, I discovered that the hum actually seems to come from the BIT 15,which is on a shelf below the 4b, when I have the 4b plugged and up and running. I plugged the 4b into the wall socket and get no hum so I hope it is fine.So now I have only the 4b turned on and I get slight hum from the BIT 15. Nothing else is turned on in the system.

 So here is run down on what is plugged into the BIT 15:

4b sst2
Bp-26/MPS-2
Bcd-1
Simaudio Lp 5.3
REL T5 subwoofer.

I don't think I am straining the BIT 15 during use but comments would be appreciated.

Hi

I would recommend plugging the 4B directly into the wall and only your sources into the BIT 15

james

[esklar0723]

Thanks James,

I did try the 4b into the wall socket and it does eliminate the hum.

I thought the BIT 15 would be able to handle the load of everything I listed.

Any ideas as to what is happening here?

 If I want to provide filtering and protection for the 4b, do I need to look into a BIT 20?

I thought I had read on this circle that the BIT 15 is capable of handling amps like the 4b?

[Speedskater]

I like that AVA Troubleshooting Flow Chart.

For hum and buzz problems, Bill Whitlock has an excellent troubleshooting section in:

An Overview of Audio System Grounding and Interfacing
by
Bill Whitlock, President
Jensen Transformers, Inc.
Life Fellow, Audio Engineering Society
Life Senior Member, Institute of Electrical & Electronic Engineers

http://centralindianaaes.files.wordpress.com/2012/09/indy-aes-2012-seminar-w-notes-v1-0.pdf

[brucek]

........ If I want to provide filtering and protection for the 4b, do I need to look into a BIT 20?

The notion that there is something fundamentally wrong with the power that is available at a wall receptacle is nonsense. Is the 4B's power supply so poorly designed that it can't tolerate some noise and harmonic distortion on its AC power source? In fact it's designed to take care of that problem quite nicely. It's proven that ability to you by eliminating the hum when you plug directly into your power receptacle. Why do you feel you require another device between your power amp and the wall?

brucek

[PRELUDE]

The notion that there is something fundamentally wrong with the power that is available at a wall receptacle is nonsense. Is the 4B's power supply so poorly designed that it can't tolerate some noise and harmonic distortion on its AC power source? In fact it's designed to take care of that problem quite nicely. It's proven that ability to you by eliminating the hum when you plug directly into your power receptacle. Why do you feel you require another device between your power amp and the wall?

brucek

+1
This is what exactly I was thinking.

[mav52]

The notion that there is something fundamentally wrong with the power that is available at a wall receptacle is nonsense. Is the 4B's power supply so poorly designed that it can't tolerate some noise and harmonic distortion on its AC power source? In fact it's designed to take care of that problem quite nicely. It's proven that ability to you by eliminating the hum when you plug directly into your power receptacle. Why do you feel you require another device between your power amp and the wall?

brucek

Agree with the above

forget the Bit 15 and enjoy your music

[esklar0723]

Point taken.

However my main requirement for using some sort of conditioner is protection. In that regard the BIT 15 is well designed for that purpose. My area experiences a lot of voltage spikes and dips that have destroyed some clocks etc in the house. I was looking to mitigate that with my audio equipment much like I do for my home computers.

Robert

[PRELUDE]

Point taken.

However my main requirement for using some sort of conditioner is protection. In that regard the BIT 15 is well designed for that purpose. My area experiences a lot of voltage spikes and dips that have destroyed some clocks etc in the house. I was looking to mitigate that with my audio equipment much like I do for my home computers.

Robert

Then the best bet for you would be to get the whole house surge protection at your main AC panel.

[drummermitchell]

perhaps these might do the trick from Environmental Potentials:EP-2050+2775 ground filter connect to mains panel

[Diamond Dog]

After doing some trouble shooting, I discovered that the hum actually seems to come from the BIT 15,which is on a shelf below the 4b, when I have the 4b plugged and up and running. I plugged the 4b into the wall socket and get no hum so I hope it is fine.So now I have only the 4b turned on and I get slight hum from the BIT 15. Nothing else is turned on in the system.

 So here is run down on what is plugged into the BIT 15:

4b sst2
Bp-26/MPS-2
Bcd-1
Simaudio Lp 5.3
REL T5 subwoofer.

I don't think I am straining the BIT 15 during use but comments would be appreciated.

Hi :  I had a BIT 15 in my system which at the time had a BCD-1, a preamp and a pair of 7BSST-2's plugged into it and it buzzed like an apiary. Sent it back to Bryston, they sent it away to Torus, it was there for a while and then they sent it back to me. It was quieter...but not quiet. Replaced it with a BIT 20 - problem solved. Draw whatever conclusions you like from that.

D.D.

[drummermitchell]

I have a 20a Torus 240v (no buzz or hum)my 60a(240v)slight hum,course it has a huge transformer in there.
Can't hear it  when playing track or movies and it's up near the front of the room.
As I posted the Environmental 2050 I will put on my two 30a breakers which feeds the 60a Torus just to see.
Or maybe she'll go on the mains panel to take care of whole house,they should be here in a week.
Acoustic frontiers sells them plus Torus,Surgex and a few other pieces.

[runs10k]

I also have the 4B sst2 and it is plugged into a Torus 20. Quiet as a mouse.

[James Tanner]

Point taken.

However my main requirement for using some sort of conditioner is protection. In that regard the BIT 15 is well designed for that purpose. My area experiences a lot of voltage spikes and dips that have destroyed some clocks etc in the house. I was looking to mitigate that with my audio equipment much like I do for my home computers.

Robert

Hi Robert

Yes I usually recommend the BIT 15 for systems that do not have large amplifiers like the 4B SST as large amplifiers can cause the smaller transformer in the 15 amp to overload sometimes.  Also digital source gear like DAC's, Processors, etc. can be easily upset by crap on the line.  I would recommend the 20 Amp BIT if you are plugging in the 4B.  Generally speaking though from a 'rejection of noise' perspective quality amplifiers like the 4B do not really require an isolation transform for that reason as it has an excellent power supply as it is. 

Where the BIT is helpful is in the protection from spikes and and total 'ISOLATION' from the rest of the power grid in your home.  The other main advantage is the very low output impedance provided to the amplifier.

Here is a memo I did on the subject that may help:

Benefits of Bryston BIT Power Isolation Units:

Benefit #1: Very low source impedance and high current for your power amplifier

BRYSTON power isolation units present very, very low impedance to any electronic device that is connected to them. A Single 20 amp BIT Isolation Transformer has an output impedance of 0.2 ohms and can deliver 400 amp peaks (instantaneous current).

Although every amplifier has energy storage in its power-supply, more energy storage will almost always improve dynamics and focus in the amplifier.  The BIT stores energy in the form of the magnetic field between its transformers primary and secondary windings.  That means the current the BIT draws from the wall is more of an 'average value' from the wall, instead of the 'high peaks' the amplifier may demand. 

It's true that a smaller amplifier can be expected to draw less current than a larger one, but even a 150Wpc amplifier can demand instantaneous current above 15 Amperes from the line.  The 7B SST2 can demand up to 15-18 Amps peak per channel when driving 4 Ohms. The 14B SST2 can of course demand twice as much, up to over 35 Amperes for both channels into 4 Ohms. 

A typical 200 watt audio power amplifier demands 10 amps RMS current from a 120 volt line (1200VA) but may demand up to 50 amp instantaneous peaks. The standard residential wall receptacle can't supply the 50 amp peaks because they typically have higher nominal impedance. A Bryston BIT Isolation Transformer 20 amp PIU plugged into the same wall plug can supply these peak current requirements quite easily.

James Tanner

[esklar0723]

thanks James

...and everyone else for that matter for your input. I think for now I will run the 4bSST out of the wall socket and that solves the problem.

I may look into a BIT 20 down the road though.

Happy Holidays everyone and happy boxing day to james!

Robert