ARCHIVED FORUM -- March 2012 to February 2022READ ONLY FORUM
This is the second Archived Forum which was active between 1st March 2012 and 23rd February 2022
Peter called yesterday......
What a charming man, he has kindly loaned me some of his amazing equipment. I couldn't resist posting a picture of his fabled 4401!
I have of course powered it up and had a listen......I have to say it crackles when the sliders are adjusted, particularly volume and balance, the linear pots probably need a clean.....however the clarity of sound does not dissapoint
I am afraid that in common with all the nonsense that I dropped off, it has seen very little action for some time! It was a pleasure meeting you and I do hope you give the 4401 some exercise!
Wife is delighted to see the back of some of the bits lying around - some were, it has to be said, very dusty!
Peter
Very nice to see them side by side. Both are great looking receivers. Yes, idle time is not good for audio equipment. You need to take them for a spin once in a while.
-sonavor
The only thing that I use really is the Beolab 5000 system - and the radio on the BC2!
Things have taken a turn for the worse with Peters 4401 when I turned it on a few days ago it emitted a curious buzzing from each speaker, this noise persists even with nothing connected to the inputs and is clearly affecting both channels. Previous posts in the forums (Martins of course) suggest the rectifier circuit may be the cause.....now that I have completed Peters hybrid Beogram, and having consulted Peter, I will have a look inside and see if anything untoward has gone on........I will post pictures and no doubt seek advice as this develops.
Removal of the top reveals no obvious issues, interestingly not all of the electrolytic capacitors and skeleton trimmers where replaced during this units last restoration in 2009. As I have a fully functioning 4400 I will be able to do some comparison's between the two with my scope and hopefully identify the source of the noise that's being picked up
This big 2200uf cap looks suspect.........
I have chased this down for a week now......the suspect cap turned out to be fine. I have been taking readings from my fully functioning 4400 and comparing the results with the same readings from Peters 4401....and finding nothing different. there are quite a few differences between both circuits however.....not sure if these are repairs carried out by Frede or work done in the B&O factory, they are very neat. None the less today following further fruitless tests and with the 4401 still purring away with no inputs connected (it was almost like a low frequency switching which was not affected by the volume controls and was present in both channels) I turned on my standard lamp, as the room was darkening, and the purring immediately dropped in volume! mains related I thought right away.....tucked away in a power socket in the corner of the room lies a TP Link connected via ethernet cable to my modem, another TP Link is plugged into the sitting room and connected to my sky box also via a Ethernet cable,disconnecting this TP Link from the socket silenced the irritating purring noise immediately. Odd that my 4400 doesn't pick up any noise from this. I suppose the mystery is now solved......but it was so annoying that I only stumbled across the solution because it was getting dark.............the important thing is that nothing is wrong with Peters 4401 ;¬)
Part of growing up I suppose
I imagine that it is quite an early model and I wonder if they improved the shielding in yours. The 4401 is a prototype so may not be quite as good as yours - but don't tell anyone!