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Audio and Video Talk
Valves / Vacuum Tubes
Mono block project
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<blockquote data-quote="Mars" data-source="post: 952924" data-attributes="member: 817"><p>I've built the one circuit to test the concept of a balanced/unbalanced fixed bias mono block. First I test the amp with a transformer i had on the shelf. After a lot of sweating and puzzlement, the bias is tuned in, and the EL34's are idling at 70%</p><p></p><p><img src="https://i.imgur.com/RqAlyG3.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p><p></p><p>The sound was a bit edgy, and I started looking for ways to apply negative feedback. My options on the OPT was limited to unbalanced global NFB. </p><p></p><p>Next I wired up another OPT (Japanese made CALRAD 6K6:4/8/16) which gave me options to use local cathode feedback on the EL34's. That really improved the sound. </p><p></p><p><img src="https://i.imgur.com/3QXsbYP.jpg" alt="" class="fr-fic fr-dii fr-draggable " style="" /></p></blockquote><p></p>
[QUOTE="Mars, post: 952924, member: 817"] I've built the one circuit to test the concept of a balanced/unbalanced fixed bias mono block. First I test the amp with a transformer i had on the shelf. After a lot of sweating and puzzlement, the bias is tuned in, and the EL34's are idling at 70% [IMG]https://i.imgur.com/RqAlyG3.jpg[/IMG] The sound was a bit edgy, and I started looking for ways to apply negative feedback. My options on the OPT was limited to unbalanced global NFB. Next I wired up another OPT (Japanese made CALRAD 6K6:4/8/16) which gave me options to use local cathode feedback on the EL34's. That really improved the sound. [IMG]https://i.imgur.com/3QXsbYP.jpg[/IMG] [/QUOTE]
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Audio and Video Talk
Valves / Vacuum Tubes
Mono block project
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