PreBee2 Buzz/Hum

[Eddie TT]

Hello

I have a Buzz with the PreB

There is a hum the comes from the PT-9 transformer and can be heard in the room. (Turn off the bar fridge, no turn of the preamp.)

There is a Buzz like a bad earth, that sounds like a guitar amp and can be heard in quiet parts or between tracks that is loader than any other noise that is coming from the preamp.
The buzz is evenly loud on both channels and is not changed with the balance pot.

When I first powered up there was gentle crackling sound coming from the PT-9 as well as the hum.

I have checked all the solder joins.


What do I do next?

Eddie Tyrie

[Doc B.]

Is this a kit you built, or bought used? Do you have the manual?

You may have a bad connection somewhere that is causing the buzz. Also - though not nearly as likely to create noise in a BeePre2 as in an original BeePre - you may have sagging mains voltage. It would be worth checking the voltage at the wall outlet.

[Eddie TT]

 This is a kit I built.

the transformer was wired to terminal 5 on the N I have 233AC at the wall.

Yes I do have a manual.


Eddie Tyrie

[Eddie TT]

Ok this is a little embarrassing.
On U25 and U30 I thought I had a good mechanical connection, I had re-soldered it and the solder looked ok.
It was not until I rebuilt the mechanical connection at 25/30U, keeping the leads tightly packed together and not crossing over each other that the buzz has dropped to a usable level.

I have a little more tidying up to do (moving for a construction mentality to fine jeweller) to maybe get rid of the buzz altogether.

Before doing the BeeQuiet upgrade I would like to get the BeePree2 working correctly.

 Can someone please tell me will the buzz totally go away? or will it be part of the general noise floor?



Eddie Tyrie

[Paul Birkeland]

Is this transformer noise or noise coming out of the preamp itself?  You mention some resolution, so it would be good to know what's left.

[Eddie TT]

I still have nose in the room from the transformer, it is not as loud as it was.

The buzz in the signal is can be heard in the back ground still. This is more of an issue when listening to older CDs from before the noise wars.

When listening on head phones if the play back of the source is stopped and I turn up the volume beyond a normal listening level the buzz is louder than the sound of the tubes ringing when the aluminium plate is tapped between the tubes.

[Paul Birkeland]

You can try this tweak:
https://forum.bottlehead.com/index.php?topic=13332.0