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dynaco mk3 kt-88 or 6550?

R

rk's

New Member
Hi there , just read some info from the Dynaco catalog. It says that the early mk3 used kt-88 ,and the late models used 6550. I'm not sure what model I have, Early or late? Any idea as to where the serial # located ?Right now I'm using it with Tungsol 6550,and I would like to try it with kt-88. Which of the 2 would sound better? Or are they interchangable? Any help would be greatly appreciated. Randy
 
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The Tung-Sols are great tubes but supposedly the Genelex Golden Lions were better. They sure bring a premium and were in the one I found. Sold them for $265, put RCA 6550s in the amp and got $395. Personally I don't feel either were worth the money, but someone did. I guess the Mk IIIs were the poor man's McIntosh back in the day. After I replaced the Selenium rectifier, and filament caps I ran it on a Shahinian Obelisk and the amp seemed to perform best at higher levels.
 
Either tube will work fine in your Mark III's. But unless you can score some Genelax KT88's it's not likely that your going to prefer KT88's any better then the Tungsol 6550's.

Craig
 
FYI, Kara Chaffee wrote a very reasonable and smart article on optimizing the Mk III, in AudioXPress I think it was. Worth looking up! Kara is the engineer-designer of deHavilland products, and a real asset to the audio community.
 
Yup I have a copy of that article. My front end board isn't all that different in basic design in my ultimate Mark III's upgrade package to her design. The difference is I didn't design it to adhere to the limitations of the Mark III layout and voltage restraints so its not a drop in resolder existing wires like most all other Mark III upgrade boards. I also used more readily available triodes 12AX7 and 12AU7.

Craig
 
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NOSValves said:
I also used more readily available triodes 12AX7 and 12AU7.
Click to expand...
Do you remember what she calls for in that article?

I have a pair of Lafayette LA-70s (circuit nearly identical to Dyna MKIII) that I want to rebuild along the lines of that article someday... I believe Dennis Boyle of Chimera Labs found the OPTs on the Lafayettes to be very high quality 6550 units, second only to the Heath W-6 units. At one time he had something like 12 pairs of the LA-70s.
 
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