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   Home » Melquiades Amplifier » Building Melquiades: Chronicle of full-range (45 posts, 3 pages)
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  »  New  To Milq builders: corrections, simplification, modifica..  Talking about amp…....  Melquiades Amplifier  Forum     16  121540  05-17-2007
  »  New  6 Channel Version of Super Melquiades..  The first Milq screw up....  Melquiades Amplifier  Forum     131  1202699  08-08-2007
  »  New  Has anyone built the DIY Melquiades amp??..  You did not reply what music you are listening….....  Melquiades Amplifier  Forum     2  35641  08-24-2007
  »  New  Melquiades For Dummies™ - step by step...  Amp still open...  Melquiades Amplifier  Forum     28  202351  08-29-2007
  »  New  The short "6C33C Survival Guide"...  Ac filament.....  Melquiades Amplifier  Forum     20  363207  12-18-2007
  »  New  Full range Melquiades implementation..  Solved...  Melquiades Amplifier  Forum     81  522884  02-23-2011
  »  New  Building Melquiades: questions and answers...  PeaceMAT XS™...  Melquiades Amplifier  Forum     96  530113  10-09-2007
11-19-2017 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,570
Joined on 10-12-2006

Post #: 41
Post ID: 24568
Reply to: 24567
This ought to liven things up!
Thanks, BR.  This time of year is usually pretty dead.



Best regards,
Paul S
11-20-2017 Post does not mapped to Knowledge Tree
S.yorke
Posts 3
Joined on 11-15-2017

Post #: 42
Post ID: 24569
Reply to: 24568
Not so active nowadays
Thanks for the heads up. Just that there are so many versions being built with different operating points over the decade. Not  sure if 200V/240mA , 650:8 ohm sounded right for my case?
11-20-2017 Post does not mapped to Knowledge Tree
Romy the Cat


Boston, MA
Posts 10,049
Joined on 05-28-2004

Post #: 43
Post ID: 24570
Reply to: 24569
50% help...
 S.yorke wrote:
Dear Romy,What would be your suggestion on the operating point and OPT impendance if I were to drive a single driver Back loaded horn speaker with over 102db/W? Knowing that you have mentioned a range of operating points in the forum, I still not too sure what would best for my setup. Thanks in advanced.  

S.yorke,
 
The operation point is simple to recommend, the OPT impedance is more complicated subject. The 6C33C is kind of current-loving type of tube. I run it at a little below 200V and as much current as I need.  With bass channel when I need as much power as I can get I use 275mA-190mA that made it sub 60W plate dissipation. Usually 55W on plate is max that I tend to drive the tube, not that you cannot go high if you need. Be advised that higher plate dissipation lower the plate output impedance, so you might factor it in. With all other things equal and regardless the specific demands of a given speaker I feel that the best is to drive 6C33C (if you use both filaments) with 47-53W. Note that specific configuration of current vs voltage is not too critical and might be easily offset by OPT ratio. You can use anything between 160V and 220V, and the current accordingly, that all will be fine.
   
The OPT impedance is a very complex question, not so “complex” but rather the answer is very much deepens from the acoustic system you use, your loading objectives, type of the sound you need, your operation point, the way how you integrate you speaker into the room, your personal, preferences, type and design of OPT you use and many other factors. I personally use a fully heated 6C33C logins it from 400R to 1400R and this is a huge margin. So I will stay away from any specific loading reconditions, not he last fact is that I do not know those “yellow drivers” and what they need to sound appropriate.


"I wish I could score everything for horns." - Richard Wagner. "Our writing equipment takes part in the forming of our thoughts." - Friedrich Nietzsche
11-21-2017 Post does not mapped to Knowledge Tree
Paul S
San Diego, California, USA
Posts 2,570
Joined on 10-12-2006

Post #: 44
Post ID: 24571
Reply to: 24570
Variable Resistors
BR, I have never used Romy's amp design, but I have used 6C33C SETs with Lowthers.  I do not use my Lowthers FR, for reasons that are fully explicated throughout this site, so I don't worry about LF from those drivers.  IMO, their best is MF up to treble.  In fact, IMO, their overall performance is decidedly compromised by feeding them LF signal.  In any case, use variable resistors and test terminals to set operating points, and this will give you a chance to tune to taste.  In general terms, the Lowther does not need to be "clamped down" by the amp, and I got the best results with higher output impedance/lower plate dissipation than I might have used.  Likewise, much discussion here on OPT options via multi-tapped OPT.


Best regards,
Paul S
10-06-2018 Post does not mapped to Knowledge Tree
S.yorke
Posts 3
Joined on 11-15-2017

Post #: 45
Post ID: 25126
Reply to: 24570
VR2 issue leading to jump in current on 6C33 tube
Dear Romy,it had been a while before I hv return to your goodself and here.The Meliq had been built according to your circuit. However, after a few days' breaking in period. The VR2 have issue and causing sudden increase of current... I think it might be the quality of the Bourn. Here is my question. Even if I had the VR2 replaced, it is like a time boom while I was enjoying music in the near future. Also, if the 6c33c itself is not perfectly match pair, how should I adjust and match both channels? If I were to adjust VR2 , do I aim to have both channel balanced in output or voltage at grids?
Is there a failsafe method to alter this part of the circuit in case this VR2 Failed again?
Thanks in advance.
Best Regards,S.Yorke
Page 3 of 3 (45 items) Select Pages:  « 1 2 3
   Target    Threads for related reading   Most recent post in related threads   Forum  Replies   Views   Started 
  »  New  To Milq builders: corrections, simplification, modifica..  Talking about amp…....  Melquiades Amplifier  Forum     16  121540  05-17-2007
  »  New  6 Channel Version of Super Melquiades..  The first Milq screw up....  Melquiades Amplifier  Forum     131  1202699  08-08-2007
  »  New  Has anyone built the DIY Melquiades amp??..  You did not reply what music you are listening….....  Melquiades Amplifier  Forum     2  35641  08-24-2007
  »  New  Melquiades For Dummies™ - step by step...  Amp still open...  Melquiades Amplifier  Forum     28  202351  08-29-2007
  »  New  The short "6C33C Survival Guide"...  Ac filament.....  Melquiades Amplifier  Forum     20  363207  12-18-2007
  »  New  Full range Melquiades implementation..  Solved...  Melquiades Amplifier  Forum     81  522884  02-23-2011
  »  New  Building Melquiades: questions and answers...  PeaceMAT XS™...  Melquiades Amplifier  Forum     96  530113  10-09-2007
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