Altec 436 / RS124-ish Clone

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syn

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Oct 10, 2005
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649
Maybe it's because you're using different valves than specified. The right ones aren't a fortune to buy.
please disregard pinout and octal/noval types
6n5p=6bc8
6cg7=6sn7=6n8s
so I've been told.
I might be wrong but they look alike from the data sheet. Not identical, but close. Please, bear in mind that all voltages are spot on, as on the schematic with no gain reduction applied, apart from 6al5 generated CV.
 

Rob Flinn

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Jun 3, 2004
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Location
Sussex, UK
please disregard pinout and octal/noval types
6n5p=6bc8
6cg7=6sn7=6n8s
so I've been told.
I might be wrong but they look alike from the data sheet. Not identical, but close. Please, bear in mind that all voltages are spot on, as on the schematic with no gain reduction applied, apart from 6al5 generated CV.
Right. You should be able to get around 18dB of GR before the vari mu valve loses the will to go on. I can't remember how low the sidechain voltage goes though. As WInston has said the ECC189 works a bit nicer in this box than the 6bc8.
 

syn

Well-known member
Joined
Oct 10, 2005
Messages
649
I can't get more than -3.5VDC from the side chain. If I get more, I get nasty distortion to go with it. No signal = 0VDC at the sidechain.
 
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