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Forum 141

[Closed] Restoring a Beau Decca Mirror-Lid TV and remaking the PSU

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neil1974
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The beauty of the new chassis is that it looks like it's always been there :aad .

Cheers
Neil.

 
Posted : 29/03/2014 12:41 am
Refugee
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Is it possible that tape head equalisation is also offered?
That would account for the extra settings.

 
Posted : 29/03/2014 12:22 pm
Brian Cuff
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The set was released in 1948 so I think that it is fairly unlikely to cater for tape - I may be wrong but I don't think so, Ref.

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Posted : 29/03/2014 2:11 pm
Cathovisor
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Most likely EQ settings - if that's what indeed they are, and not just top-cut settings - are for NAB, Decca and EMI 78s. The latter two sound very different to each other; HMV discs are quite bass-heavy, whilst Decca FFRR recordings are pretty bright by comparison.

 
Posted : 29/03/2014 2:27 pm
Refugee
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Perhaps a circuit snippet of the switching will help us work out what the EQ is for.

 
Posted : 29/03/2014 2:39 pm
sideband
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Too early for tape. As Cathovisor says probably for the three standards of 78 around at the time...I just couldn't remember what they were....!

Rich

 
Posted : 29/03/2014 5:19 pm
Brian Cuff
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I have found a grotty copy of the radio tuner and the switching on that is not EQ but a mechanical band-width control. The switch has 5 positions including Off. The others are 3 positions for radio with differing IF bandwidths and a TV position.
On the TV chassis there is another 5 position switch. The positions are TV, Radio and the three gram positions, the 2nd and 3rd of which have simple HF roll-off caps switched in parallel with the volume control track. Nothing clever at all!

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Posted : 31/03/2014 11:14 am
Refugee
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Simple treble cut sounds like the best answer. More like an early scratch filter.

 
Posted : 31/03/2014 11:20 am
Brian Cuff
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Simple treble cut sounds like the best answer. More like an early scratch filter.

Isn't that what "simple HF roll-off" means, Ref? :qq1

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Posted : 31/03/2014 1:52 pm
Refugee
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I tried to keep it simple. It may well be a little more complicated in the set.

 
Posted : 31/03/2014 6:32 pm
IJK2008
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Brian

Amazing piece of work (again!).

I also ordered some of the cloth covered wire from Mullard Magic for a pre war set (a radio of course - a pre-war TV's out my league). I agree it is excellent.

Cheers

Ian

 
Posted : 02/04/2014 8:00 pm
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