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   Home » Melquiades Amplifier » A different breed of 6C33C amplifier. (85 posts, 5 pages)
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04-06-2012 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,216
Joined on 10-12-2006

Post #: 81
Post ID: 18041
Reply to: 18040
Power to the People!
fiogf49gjkf0d
Nice job, KOT, and nice trace near clipping!  It's always good to see a full, symetrical wave.  Did you say you did or did not connect the halves of the 6C33C?  Of course I ask because of the power you cite at clipping...  Please remind me, what is the driver, again?  With 3-stage and joined plates you might get close to 40W, but likely not such perfect response.

Best regards,
Paul
04-06-2012 Post does not mapped to Knowledge Tree
KOTriode
Posts 40
Joined on 07-19-2010

Post #: 82
Post ID: 18042
Reply to: 18041
New 6C33C SE mono block.
fiogf49gjkf0d
Paul,I used both halves of 6C33C this time, I planned to use two 6C33C and uses each half for more power, but that would shortened the life of 6C33C if run one triode at max power dissipation. I used the C3G as driver, since I dont use negative feedback, I dont need an extra stage. Yes you can get a little bit more power if you used negative feedback to lower the distortion but I want to keep the circuit as simple and pure, I like the sound that way. I got about 22W before clipping and close to 30W at 10% distortion and that is good enough for now.
04-06-2012 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,216
Joined on 10-12-2006

Post #: 83
Post ID: 18044
Reply to: 18042
Driver Sound, Vodka, and Feedback
fiogf49gjkf0d
KOT, I do not know the sound or character of that driver, at all, but I do think of the 6C33C as "vodka", since it is "tasteless", but it has some "kick".  So, what have you mixed to flavor your vodka, and why did you settle on that driver?

As for goosing power along with typical feedback, this seems to work only as long as one stays in any case inside the original "un-goosed" envelope; or, perhaps, one might gain a useful Watt or 2.  I generally find A2 to be like this, basically only good for a little more A1.

Again, from the traces, your bias settings look "correct", anyway!


Best regards,
Paul S
04-06-2012 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 9,650
Joined on 05-27-2004

Post #: 84
Post ID: 18045
Reply to: 18040
Clipping....
fiogf49gjkf0d

 KOTriode wrote:
Amp at close to clipping level 20.4W, I am surprised that sine wave looked pretty symmetrical. Still has couple chassis left for the Melquiades, the problem is the 400V supplies which required extra power supplies. This interstage amp is so much simpler and easy to build at the expense of the interstage cost.

KOTriode,

the 20.4W is about right. Hoiwever the absolute power is not so important in my view, even though it might be important in case of lower sensitivity that you use. The total power and the amount of distortions is not so indicative in my view to characterize the operation of amplifier. To me it would be more important to see the image of the be trace at let say 22W. I mean I would like to see the first sight of clipping and I would like to see that with your given load the clipping is absolutely symmetrical. If not, and if the loading of the tube that I use is give to me the right sound then I would plays a bit with current/voltage balance to make sure that the right and bottom clips are happen at the very same time and congruous by shape.

Also, you do not specify the frequency of the trace. Did not go over the conversion of your scope time marking into frequency but looking at the sleight asymmetry of the bottom half I think it was relatively low frequency signal. It always useful to know what the frequency and operating current was as it gives a perspective over the inductance of the transformer.

One more thing I learned as I was working on Milq. I tend to put the amp at fill power, get the very first clip by driving the generator lower and lower, make the clip symmetrical and then trace what section of my amplifiers responsible for the clip. An amp might be clipping by driver stage or by output stage. You need to make sure that the clip you get is purely transformer limitation and nothing else.

From the personal perspective, as I said, if you like the 6C33C then I would really love your to try the Milq driver and compare with the result you got with your driver.

The Cat


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
04-06-2012 Post does not mapped to Knowledge Tree
KOTriode
Posts 40
Joined on 07-19-2010

Post #: 85
Post ID: 18046
Reply to: 18045
6C33C mono block @ clipping
fiogf49gjkf0d
Paul, I tried this tube in few other amps and also on a phono amp and I like the sound of this tubes, perhaps it  matched with the speakers/amp combination better than other, still there are lots of other tube out there that I would like to try.
Romy, The trace that I posted on previous page is at 1Khz , I always used this frequency as reference. Attached is the trace tabout 24W @ 1Khz where both top and bottom show clipping, the regulated power suppy and adjustable bias made it easy to tune this amp.The bias adjustment is a trade off:- If you adjust bias so that clipping is symmetrical (lower bias current), then at lower power the distortion is pretty high, you can check that the sine wave is not symmetrical is lower level.- If you adjust the bias current for lowest distortion at power before clipping occurs (bias current is much higher), the distortion is much lower and the sine wave is more symmetrical, however when heavy clipping occur, the the sine wave is not symmetrical.


IMG_7960a.JPG
Page 5 of 5 (85 items) Select Pages:  « 1 2 3 4 5
   Target    Threads for related reading   Most recent post in related threads   Forum  Replies   Views   Started 
  »  New  6C33C myths: audio Moronometr...  Overdrive warning light...  Melquiades Amplifier  Forum     3  42986  06-22-2005
  »  New  More 6E5P-6C33C amps...  Russian 6e5p - 6C33C...  Melquiades Amplifier  Forum     22  158989  04-12-2009
  »  New  Borbely Audio Take on 6C33C..  Borbely Audio Take on 6C33C...  Melquiades Amplifier  Forum     0  14066  12-21-2009
  »  New  To drive the 6C33C.....  Limits...  Melquiades Amplifier  Forum     65  474022  07-10-2005
  »  New  The short "6C33C Survival Guide"...  Ac filament.....  Melquiades Amplifier  Forum     20  274065  12-18-2007
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