Gordon Macfarlane Posted August 14, 2014 Posted August 14, 2014 Hi guy's work on the rebuild of the MingDa is proceeding slowly as I work through the practical issues such as creating enough space for all the new and larger components to fit inside. I fabricated a case to use during the 'beta testing' stage and this will be replaced with something with properly mitred joints if all goes to plan. You can see the new Lundahl 1673 choke in its new position at the back between the 2 mains transformers (will be covered by screening can for safety. I have replaced all the parts in the B+ power supply with new and higher rated equivalents. The power supply electros will be mounted in a solid wooden block underneath where the choke is now sitting. Added inrush current limiting resistors on the 274b b+ supply as per Earles suggestion. At the moment I am busy repopulating the signal tube circuit with Kiwame resitors and stenghtening the ptp wiring scheme with teflon insulated stand offs. Tube sockets have also been replaced by better quality components for greater reliability. 2
Sir Rab of Everest Posted August 14, 2014 Posted August 14, 2014 Sounds like fun. I look forward to reading about the sonic result!
frankn Posted August 14, 2014 Posted August 14, 2014 It will have to be better after all the time, effort and bling bits being inserted. That, plus the length of time between listening to it before mods and after - the ol' audio memory isn't that good. Good fortune with the build - I'm sure it will sound wonderful.
Gordon Macfarlane Posted August 15, 2014 Author Posted August 15, 2014 (edited) It will have to be better after all the time, effort and bling bits being inserted. That, plus the length of time between listening to it before mods and after - the ol' audio memory isn't that good. Good fortune with the build - I'm sure it will sound wonderful. You may not be aware frankn but one of the preamp transformers melted and so I decided to rebuild the B+ circuit as part of the repair. Not really so much a case of bling being inserted as better engineered products. I didn't choose the Lundahl choke , as an example, because of the name so much as a recommendation from 2 well respected valve amp designers and builders who are not know for their use of bling. The Kiwame resistors are around $1 each so hardly bling. Agree audio memory can be dodgy especially after 6 months Thanks for you well wishes. Edited August 15, 2014 by Ozcall
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