BassmanBruce Posted November 22, 2012 Share Posted November 22, 2012 I have had my pair of laScalas now 4 months and still love them. I started off with my Marantz 8b power amplifier that I tube and capacitor rolled till I got what I liked best. Mullard 60's xf2 and Russian K-40y coupling capacitors turned out to be the winners. I have a pair of Dynaco Mk III's that I have done some mods to and tried them with the laScalas but perfered the Marantz 8b. I put the Dynaco Mk III's on the bench and converted them to triode mode, and tried them again on the LaScalas. All I can say is wow, the Mark III's are now the winners!!! Dynaco Mark III mod description- Poseidon driver boards with Telefunken 12AX7 smooth plate first stage, RCA clear top 12AU7 second stage, GE 6550a outputs. Panasonic EF series coupling capacitors. Amps now in triode mode with output tube screens tied to plates through 100 ohm resistors. These Mark III amps sound fantastic on my LaScala's now, and the poor 8b is now on my "B" system. Very sad!!!! Hope you all have a marvelous Thanksgiving, Bruce Quote Link to comment Share on other sites More sharing options...
moray james Posted November 22, 2012 Share Posted November 22, 2012 Bruce that's great stuff and Kudos to you for your time effort and willingness to share. Have you tried a pair of NOS RCA7025 in place of the 12AX7? Find a pair and try them. If you don't like them I will buy them off you. Bery best thanks Giving regards to you Moray James Quote Link to comment Share on other sites More sharing options...
sunnysal Posted November 22, 2012 Share Posted November 22, 2012 surprising outcome no doubt. the 8b is hard to beat by any stretch of the imagination. I do like my mkIVs a LOT though with my klipschorns. where can I see more info about the poseidon board? all the best, Tony Quote Link to comment Share on other sites More sharing options...
Marvel Posted November 22, 2012 Share Posted November 22, 2012 http://www.diytube.com/phpBB2/index.php There is a link for different boards ... Bruce (Marvel... []) Quote Link to comment Share on other sites More sharing options...
BassmanBruce Posted November 22, 2012 Author Share Posted November 22, 2012 Hi Tony and thanks for your post. The Poseidon boards are from Triode,USA http://store.triodestore.com/diytubemk3.html Also look at www.DIYTube.com When I went to triode mode with my Mark III's is when they really started to shine. I have had a pair of Mark IV's and sold them after I bought the 8b. I still have a Stereo 70 in my collection. Thanks again, Bruce Quote Link to comment Share on other sites More sharing options...
BassmanBruce Posted November 22, 2012 Author Share Posted November 22, 2012 Hi Moray and thanks for your post. I have several dozen RCA 7025 tubes in my collection. Will sort out a high Mu pair and will try them. I was using a pair of GE black plate 3 mica 5751's, but found that I liked the Telefunken smooth plate 12ax7's better into the LaScalas. Into my previous speakers I perfered the 5751's. Thanks for your comments and best to you, Bruce Quote Link to comment Share on other sites More sharing options...
rpampt Posted November 23, 2012 Share Posted November 23, 2012 Hey Bruce. That's good to hear. Ihave a pair of MK III's I've just gone through and recapped and changed out any out of spec resistors. Have been considering the Poseidon boards, but just haven't made a final decision. Sounds like quite a change from the original. Could you give a little more detail on the Poseidon board changed the sound? BTW, what preamp are you using and do you know what the output impedance is? I was told that the Poseidon board necessitates having a preamp with low output impedance. I don't understand the details. Quote Link to comment Share on other sites More sharing options...
sunnysal Posted November 24, 2012 Share Posted November 24, 2012 I forgot to mention that I have my MkIVs modded with a switch that allows me to strap the pins on the EL34s into "triode" mode, I too prefer the sound in "triode". regards, T Quote Link to comment Share on other sites More sharing options...
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