[Eric]

My 2.5 buzzes louder the more I plug into it. It sees limited use in my system because of it

[satfrat]

My 2.5 buzzes louder the more I plug into it. It sees limited use in my system because of it

                         Eric, d you have the older model 2.5 or is it the Ultra with the NoLo transformer? Do you have the conditioner on a dedicated circuit or is it just plugged into a wall socket that might have dimmers connected to it? Regards, Robin

[Eric]

I have the older model 2.5

[Mad DOg]

I have the older model 2.5

yeah, the transformer in older models hum...and i believe you can upgrade it to the lo-no version for $275 + shipping...

[Beezer]

I have a 3.5 with the lo-no transformer and it hums, so lo-no doesn't mean no noise.  Given the messages here, I need to talk with Chris again about whether or not the hum can be eliminated.

Beez

[satfrat]

I have a 3.5 with the lo-no transformer and it hums, so lo-no doesn't mean no noise.  

Beez

Right Beez,,,, LoNo means low noise. But for the most part, it might as well mean no noise, especialy if your tied into a dedicated circuit. The LoNo transformer will combat nearby florescent lamps & dimmers but it's not bulletproof. That said, I have my BP2.5 onto a dedicated circuit but have both dimmers and florescent lighting in the same room without so much as a purr. Regards, Robin

[rkapadia@ROOP]

The BPT units should not hum at all.  In the rare occurance this happens, I'd suggest contacting whoever you purchased your amplifier for to coordinate service from the factory.  When ideally operating, there is absolutely no hum from a BPT transformer - zero.  If anybody experiencing this problem has ordered a unit through me, please drop me an email and we'll take care of the issue promptly.

Regards,

[BikeWNC]

I took some time this afternoon to go through the issues I have been having with my 3.5.  

First, as I noted before there is a hum that increases in volume as more gear is added to the unit.  With a few low power components plugged in there is no or almost no hum.  Add the amps and it is quite noticable.

Second, I have a ground loop hum, which comes through the speakers.  When I remove everthing from the 3.5 and put it on a powerbar into the wall, the hum is barely audible with the volume turned to 3/4 max.  I've had to put a cheater plug on my preamp, but I use this configuration on both the 3.5 and the powerbar.  Why does the 3.5 make the hum much worse?  I have tried every possible cheater plug combination to no avail.

I've checked my AC for correct polarity using one of those 3 light tools bought at rat shack and it is OK.  

Any thoughts?

[Marbles]

Are you sure it is a ground loop?  Could it be that it is the noise level of your compnents?

Also do you have a cable TV hookup anywhere in the system?

Third, have you (starting at the amp) unhooked IC's until the buzz goes away...ie identified what is causing the ground loop?

[satfrat]

I don't understand why you HAVE to use a cheater plug on your preamp, please explain for the simple minded? Regards, Robin

[BikeWNC]

There is no cable hookup on this system.  The hum on the powerbar to the wall connection is pretty low.  I wish it wasn't there, but I could live with it if I had to.  The hum with the 3.5 is very loud even with the volume at minimun.  I have taken everthing off the system but the preamp and the amps and the hum is still there.  If I put a cheater plug on the preamp the hum becomes much lower.  But only on the powerbar, not the 3.5.  I don't know why the cheater plug helps on the preamp, but I have read that this often works from discussions over on AA.  I'm going to do a few more configurations, starting at a basic CDP --> Preamp --> single amp.  Heck I may take the pre out and just go CDP to amp and see what happens.  I have a call into Klaus at Odyssey for help since the preamp is Symphonic Line and the amps are Odyssey Extremes.  I don't think it is the amps though as I have the same hum with a Bryston amp.

One other thought I had was that the tubes in the preamp are picking up the hum from the BPT unit and adding it to the signal.  The preamp is one shelf above the 3.5.  That would account for the difference between the wall and BPT connections.  Perhaps I should try to move them so that the two units are as far apart as possible.

Andy

[Marbles]

Having the pre right above the BPT might do it.  

Torodial transformers put out a lot of EMI right above and below them.

[satfrat]

Do you have an after market power cord on the Symphonic? And if so, is there a ground connection on the IEC terminal or is it just a 2 prong IEC? In my Sunfire, there wa only a 2 prong IEC and I got a VenHaus flavor 3 PC that has the ground connected at the AC plug but disconnected at the processor. I'm just throwing up thoughts here,,,, Regards, Robin

[BikeWNC]

I took the whole rack apart and spread everything on the floor away from the BPT and preamp power supply.  I left the dac and TacT out and turned on the system - quiet!  There is still the low level buzz from the BPT 3.5 itself but all of the speaker hum, except for a very very low buzz at full volume, is gone.  No cheater plugs were used.  Essentially the main problem is fixed, unless it reappears as I add in the other gear.  The new problem is a WAF issue as I'll never be allowed to keep components all over the floor.  What is the minimum distance from the BPT I need to avoid problems?  Is it only a vertical RFI issue or do I need to worry about horizontal proximity?  Thanks Marbles, for your help.

Andy

[bubba966]

Andy,

Do you have any ERS applied in the BPT? That might take care of your EMI problems if you installed ERS both above & below the tranny in the BPT.

[BikeWNC]

Satfrat,

I'm using the stock cord, though I have a Zu Mother PC that I usually use on the Preamp.  The problem as I mentioned in the above post was as Marbles guessed, a RFI issue from the preamp being over the BPT.  Now I need to figure out how to put it all back together without reintroducing the problem.  

I really like the BPT 3.5.  But I will contact Walter at Underwood HiFi about the transformer hum.  I will probably go for the signature upgrade if I send it back.

Andy

[BikeWNC]

Bubba,

My 3.5 was ordered with ERS, though I'm not sure how it was applied.  It also has 2 pairs of Bybees.  I understand the signature mod does not use Bybees.  I wonder if Chris would remove them or leave them in?

Andy

[Marbles]

If you picture a big donut lying flat in the BPT, it will shoot EMI strait up and strait down from this donut.  You should be able to put equipment right beside the BPT, but I would not put a pre right above or below it.

You might have better luck if you put an amp right above it.

That BPT has to weigh a ton, so I would put it on the lowest rack, then I would try an amp above it, then a source above that, finally I would try the pre above that.

If that doesn't work, set the BPT beside the rack.

Good luck.

[satfrat]

Bubba,

My 3.5 was ordered with ERS, though I'm not sure how it was applied.  It also has 2 pairs of Bybees.  I understand the signature mod does not use Bybees.  I wonder if Chris would remove them or leave them in?

Andy

The Bybee's have been replaced by the Z-sleeve, an ERS product that has 10 times the effect of ERS. This little baby really clears up the highs and resolution. The Bybee's are still an option tho. Regards, Robin

[Marbles]

Andy did you have any luck with putting the equipment back in the rack?