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Old 27th Jul 2009, 9:57 pm   #4
yestertech's Avatar
Join Date: Dec 2002
Location: Coulsdon, Surrey, UK.
Posts: 1,622
Default Re: Bush VHF61 Quiet on VHF

Has the set any evidence of damp storage ? I have had a number of VHF64/94s which exhibited low gain + extended bandwith at IF
Having ruled out any obvious faults, I came to the conclusion that damp in the IFTs had possibly reduced their Q. I could find no other sane explanation.
As Leon says, you need BOTH EF89s to be 100% Changing both of these for new valves can yield another 12 db of gain compared with aged ones.
You could also disable S24 (on the trader sheet) as this appears to decrease the gain when switched to FM by slightly increasing the negative feedback.

Where I am in Surrey, the average levels of R2/3/4 seem much lower than the IBA stations. I find I need an external aerial to really make these close the magic eye.


PS is it just me or is the sound quality of the '61 pretty dire anyway ( as it has no 'tweeter' ) - despite the applied feedback
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