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Old 16th Mar 2019, 2:46 am   #10
Synchrodyne
Nonode
 
Join Date: Jan 2009
Location: Papamoa Beach, Bay of Plenty, New Zealand
Posts: 2,943
Default Re: Pre-amp for Linsley-Hood?

Quote:
Originally Posted by ronbryan View Post
The JLH modular pre-amp referred to in post #4 is in the July 69 edition of Wireless World, detailed here:-
http://www.keith-snook.info/wireless...Design-DCD.pdf
That used a shunt feedback RIAA stage, which H.P. Walker later demonstrated (with supporting mathematics) had a rather poor signal-to-noise ratio (14 dB worse) as compared with a series-feedback circuit. On that basis the H.P. Walker modules might represent a better starting point for suitable circuits from approximately the same period.

The H.P. Walker circuits may be found in WW 1971 May, p.221ff, and WW 1971 June, p.295ff. His article on low-noise amplifiers was in WW 1972 May p.233ff, and the resulting debate with JLH occupied WW 1972 August p.389, WW 1972 November p.520, WW 1973 January pp.11,12, and WW 1973 April pp.193,194. All worth reading…


Cheers,
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