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Thursday, December 24, 2015

Beomaster 4000 (2406): A New Arrival from Italy

A Beomaster 4000 (2406) just arrived from Italy. It needs a bit of TLC before it is fit to amplify the Beogram 4000 that I just restored. The main complaint is a strong mechanical hum coming from the unit once it warms up. Unfortunately, this is a common complaint with classic audio. Old transformers have a tendency to do this since their insulation slowly decays and the windings and laminated cores get a bit loose in that process. Add 50 or 60 Hz magnetic field changes and a n annoying mechanical hum can develop. Otherwise this unit is in a fairly pristine condition. Here are a few impressions. It even came with the FM preset cover, which is often lost.

The outside is almost pristine and the sliders are clear and solid. Also the switches seem to be good, which is very important in these units if they are considered for restoration, since they can not be fixed with any reasonable amount of effort.
This shows the interior from the top after taking the wood enclosure off:
and from the bottom:
A very similar construction like the Beomaster 4400.
One of the screws that hold the enclosure to the frame was missing,
and it came with an old Italian style line plug. 
I had to take the plug off and put on a US plug to be able to run it over here. None of my travel adapters were able to take the center pin of the original plug:

After finally plugging it in it started right up and it sounds very good, and the heat sinks stay cool. I did not try out all the inputs, but I expect little trouble since the FM tuner works very well. Unfortunately the loud hum indeed manifested itself after about 10 min, which is not acceptable. It is really pretty loud! In summary, except for the noisy transformer this unit is in a very nice condition, and it would be a shame to abandon it. So I will have to look into alternatives to the original transformer. There is nothing one can do about it except exchanging it with a quiet one.







2 comments:

  1. Did you ever try "Plastik Spray" for the noisy transformers?
    I used that sucessfully several times on Thorens transformers...
    http://de.farnell.com/kontakt-chemie/plastik-70-400ml/schutzlack-plastik-70-400ml/dp/800971?CMP=KNC-GDE-FDE-GEN-KWL-KONTAKT_CHEMIE&mckv=_dc|pcrid|88803642667|&gclid=CJPmrdP498kCFRThGwodz-8L9A

    Even it is not 100% intended for that purpose I think it would be worth trying.

    Regards
    Markus

    ReplyDelete
    Replies
    1. Interesting...how exactly did you do it? Do you have some pictures to share?

      Delete

Comments and suggestions are welcome!