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PostPosted: 13 Jun 2018, 03:39 
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Joined: 06 Jun 2008, 18:23
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Location: Australia
Suncalc designed a two stage cathode follower preamp. Previously I married a 4SU premp with a Pass BoZ jFet stage to drive SS amps. Now an all tube preamp.

http://retro-thermionic.blogspot.com/2018/06/lagoon-two-stge-tube-preamp-with.html
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Projects:"retro2308" - chip based headphone amp | ”Calibre 834” - tube phono MM preamp | ”najah” - Raw 180W Tripath Class D power amp | "Icon" - Shuguang CV-181Z preamp


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PostPosted: 18 Jun 2018, 19:14 
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This preamp was a commission job do gone now. Back to old faithful. Fortunately another tube preamp.


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PostPosted: 04 Sep 2019, 23:19 
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The preamp had some issues which I have only just come to realise was due to excessive gain. By dropping Rp to 15k and Rk to 390ohms (thanks Bruce) gain and associated hiss can be tamed. In this new build I use a Hammond wood cheek chassis painted (Epoxy paint and etch primer) hammertone blue. Two selectable inputs, external PS, Alps blue velvet pot and 4oz solid brass gold plated knob. Russian PIO caps for interstage and output. Tubes are Mullard re-issue with a heavy tube ring.

Sound is very fast, snappy with tones of bass. Good solid sound. Now called “Lagoon 3”.
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PostPosted: 07 Sep 2019, 23:58 
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Had hiss and gain problems with the cathode follower so now Bruce’s SRPP. Still some hiss and too much gain but I have the 12AX7s in because I don’t have any good U7s which is what Bruce has suggested. Sounds good though.

I’ll order some and try.
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