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

Post Subject: 6c33c ampPosted by KOTriode on: 9/8/2011

Yes, it would be very interesting to hear the difference between a 6C33C amp with and without tube regulation, but also they are too many thing to try too, ... the possibility is endless here.
My recent experience with two different 845 amplifiers that I have built led me to believe the regulator is the way to go (for my taste), although the comparison is not fair since the two amps are a little bit different in parts used but most importantly the transformers are the same, both used the NC20 interstage with the same vintage (I was lucky to score these brand new rare beauties), the output transformer, the X10S are also pre ISO, one is brand new, the other , the black one, I bought it used. Both used same input tube (I have an octal and 9 pins socket, but actually used only one) direct coupled to the 845 driver tube, connected to NC20, Let me explain the amp difference:- The one with Wenge wood chassis: power supply used tube rectifier, Tango choke, polypropylene filter cap and two oil caps. - The one with 212E tube:the amp started out with 845 driving 845, later was changed to 212E by a friend request to try his 212E tube but was never changed back to the 845. The power supply is rectified with same 5R4GB and is regulated for output and driver tube, the pass tube used was 6AS7. When I first heard the 212E amp with 845/845, I was amazed by the difference in dynamic, the low frequency response (felt as the amp went an octave lower) and this is enough to blow me away, it must be the regulators (right or wrong).
The 6C33C was not intended for horns nor ESL, I have to listen to it and find the best fit for it in the future.
Regarding the 211 tube, I have tried many time, but never fond of it, the 212E amplifier have an option to try the 211 as driver with a flip of the switch, but I always listened to the 845 driver. As output, I think the 211 may need higher load than 10K, my thought was to build a parallel 211 using the same X10S, would represent a 20K load. Well, this PSE 211 is in the work along with couple other, I was hoping to finish them within a year.
In the coming month, after the 6C33C settle, I will have a chance to do a shootout with my other amp and will report the findings, but the battle wont be fair, because other amp used top notch part while this 6C33C does not.

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