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In the Forum: Melquiades Amplifier
In the Thread: A different breed of 6C33C amplifier.

Post Subject: Killing two birds with one stone with the 6C33C preampPosted by KOTriode on: 9/22/2011

The transformer in this preamp was given from a friend who want to learn how to wind transformer. If I remember correctly it started out as UBT, they were bought (when UBT was operating in the Silicon Valley) at the company swap meet. They were rejected (for frequency response) and was sold for $10, we were told that it can be used as a plate load . So my friend bought them and rewind them as an interstage, the last time he used it for a 211 tube and was not to happy. After more than 10 yrs sitting in my garage, I took it to the bench and load it with the 6C33C at 100V/25ma, it turned out the frequency response was not that bad after all, I presumed that the real low impedance of the 6C33C tube result in a wider bandwidth than using it with the 211 which impedance is 50 times higher.
If you looked at the preamp chassis, you will see that there are 2 set output RCA per channel. My original intent was use it as choke load capacitor coupled preamp, the second output was added after checking the bandwidth as the transformer coupled (I think it was down only -1db or so at both end of the spectrum) on the bench. Killing two bird with one stone... I thought.
I am in California, but if the 6C33C preamp 's sound is up to my expectation, I wouldn't mind shipping it out to Boston for a week of vacation.
PS: Basically you can use any 1:1 transformer with current you want to run the transformer at.

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