Tube DIY Asylum

RE: Tom, i'm not sure what you mean by that. nt

208.54.37.166

David Smith

In Reply to: RE: Tom, i'm not sure what you mean by that. nt posted by DAK on July 12, 2014 at 19:41:33

I think he means turn each tube into a half-wave rectifier?

Dave

Follow Ups:

RE: Tom, i'm not sure what you mean by that. nt - DAK 21:16:57 07/12/14 (2)
Do you mean connect pins 2 and 8 and connect pins 4 and 6. Then from 1st tube pin 8 to 2nd tube pin2 and from p6 to 2nd tube p4??? cheers, Dak
- RE: Tom, i'm not sure what you mean by that. nt - Tre' 22:33:22 07/12/14 (1)
  Tie the two plate together in one tube, (ie, connect pin 4 to pin 6)
  Do the same to the other 5ar4.
  One end of the high voltage secondary winding of your power transformer goes to one tube and the other end goes to the other tube.
  Pin 2 of each tube tie together and are one side of the heater.
  Pin 8 of each tube tie together and are the other side of the heater and the cathode.
  Tre'
  
  Have Fun and Enjoy the Music
  "Still Working the Problem"
  
  Edits: 07/13/14
  - RE: Tom, thank you very much. nice illustration too! nt. - DAK 11:51:47 07/13/14 (0)
    .
+1 - drlowmu 20:26:47 07/12/14 (9)
Treat each dual sectioned diode as one diode, by paralleling the sections, and hook up AC like its a half wave rectifier.

Works well in medium and high powered tube amps, to be avoided in low powered SE amps with high mu driver tubes that will "sense" the paralleled rectifiers' mis match as adding an audible skewing of the sound. Diction and enunciation suffers on a really good amp and high efficiency speaker system, my direct experience in 2013. Not a problem on lower efficiency speakers, with those, usually two are better, more slam.

Jeff Medwin
- Gusser says: - gusser 12:11:31 07/14/14 (0)
  http://www.americanradiohistory.com/Archive-Poptronics/70s/1971/Poptronics-1971-07.pdf#page=80&zoom=auto,-154,683
  - http://www.americanradiohistory.com/Archive-Poptronics/70s/1 (Open in New Window)
- RE: +1 - Lew 08:32:22 07/13/14 (7)
  What you wrote about the effect of paralleling tube rectifiers in a low power SE amplifier is very interesting. If you look at the wave form that emerges after paralleled rectifiers, does it look any different from that which emerges from a single rectifier, with all else kept constant?
  - RE: +1 - drlowmu 14:05:18 07/13/14 (5)
    Hi Lew,
    
    I don't bother to look at waveforms such as you propose. My building is evaluated by ear, so I built a amp with provisions for both rectifier approaches, and heard what both ways sound like. I "was", at the start, in my theoretical mind, a dual rectifier guy, it had "half ther Z " etc.
    
    But my EARS could not make out clearly the diction and enunciation, on my Gilbert and Sullivan operas, so I am back to one dual rectifier, not two. I have been told by my friend Dennis Fraker that this would be the case with a highly sensitive driver tube ( mu of 70 to 100 ) and he suggested to me to use the current production JJ 5U4GB, which is reasonable in cost at $16.00 and directly heated. Will give it a try next !! Two other people I know in DIY audio with high efficiency speakers, had my same listening - learning experience in 2013.
    
    Jeff Medwin
    - OK - Lew 08:14:12 07/14/14 (4)
      I like your response, because it implies that you don't know the reason why one rectifier sounds better than two in this application, which is fine. I wondered only about the part of your original statement that implied you do know the reason (or that Dennis might know it): "low powered SE amps with high mu driver tubes ...will "sense" the paralleled rectifiers' mis match".
      
      I was skeptical about this stated mechanism, not about the accuracy of your observation.
      - Another power supply example : Skewed sonics - drlowmu 09:30:01 07/16/14 (3)
        
        In Reply to: RE: OK posted by Lew on July 14, 2014 at 08:14:12
        
        Hi Lew,
        If I use UNeven wires to parallel two 120 VAC windings on two high powered Signal-brand power transformers ( 10 A. secondaries ) that run my chintzy CD player, it sounds "skewed and NOT as good" to me. When I use equal wiring from my AC source, a "star" wired implementation, with 11 AWG Fulton Brown speaker wire it sounds very good to me. YMMV. See my photo.
        When you have high sensitivity speakers ( 100 dB or more ) one can really hear whats going on !!!
        Allows you to do a better tube design implementations. The dudes listening to with 95 db speakers will not be able to sense it as easily, often times not at all, due to marginal speaker sensitivity.
        Its never ending, makes audio a FUN hobby to try to get it right.
        Jeff Medwin
        
        Edits: 07/16/14 07/16/14
        
        RE: Another power supply example : Skewed sonics - Swanson 04:23:25 07/18/14 (1)
        
        In Reply to: RE: Another power supply example : Skewed sonics posted by drlowmu on July 16, 2014 at 09:30:01
        
        Dude,
        I'm all for trying new things out,but let's see some circuit protection.
        Unless I'm just not noticing them,I don't see a single fuse anywhere.Being in the electronics tech business by profession,I have seen some pretty nasty electrical fires.Believe it or not,they can start very quickly and spread pretty fast before you have time to find the proper fire extinguisher.We all have our "fetishes" and "obsessions" about how our circuits should be built but overload and fire protection should come before anything else.Remember,the circuit breakers in your load center are only there to protect the wiring in the walls and cielings in your house.They are not there to prevent your DIY projects from arcing and sparking and turning into aurora borealis.
        
        RE: Another power supply example : Skewed sonics - drlowmu 06:48:16 07/18/14 (0)
        
        In Reply to: RE: Another power supply example : Skewed sonics posted by Swanson on July 18, 2014 at 04:23:25
        
        Hi,
        
        Good point. Look under the AC swich I added on the far left top side of the chassis, in the corner, on the rear panel. Under the toggled portion, is an AC fuseholder assembly. See the fluted rear cover? Its in lieu of the stock fuse holder on the board, which is vacant as it would be redundant.
        
        The AC switch ( On-OFF-On ) allows me to start the unit with a fuse in place, and for my own critical listening, and ONLY when I am in the room, I can bypass the fuse with a switch at my discretion.
        
        I don't recommend others do this, it just works out OK for me.
        
        This is not "fun" - op48no1 09:29:12 07/17/14 (0)
        
        In Reply to: RE: Another power supply example : Skewed sonics posted by drlowmu on July 16, 2014 at 09:30:01
        
        This is self-delusion.
  - Really? :-) (nt) - Chip647 08:43:34 07/13/14 (0)

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