MagneQuest/Peerless Forum

Welcome! Need support, you got it. Or share you ideas and experiences.

MagneQuest/Peerless Forum

RE: Need help for RIT5 PF

58.8.108.192

In Reply to: RE: Need help for RIT5 PF posted by mqracing on May 16, 2009 at 13:04:21

HI Mike,

Thanks for your suggestion. I tried but still got the same result at 100-120Vpp (42Vrms). So I guess I may have to keep this irons for my 45SE project instead of 300B.

Follow Ups:

RE: Need help for RIT5 PF - mqracing 00:48:29 05/17/09 (9)
Hi.

You changed the primary wire leads to make sure that the blue goes to the plate of the tube? And that red is ground? And you left the sec black wire at ground? On this transformer type having both specified grounds at ground is critical.

If you can tell me a little bit more about your RIT 5 PF---- is it in channel frames or bell ends? Can you measure the primary dc winding resistance from end to end and tell me what that is? Do you have the Junior or the "regular" RIT-5? Do you know what core material the unit has in it?

About your testing--- can you tell me how your doing the testing? And at what frequencies and drive levels are you getting "too much" distortion?
And what is this distortion percentage wise? Do you have a copy of the schematic for your amplifier that we could see?

I'm curious about what your getting--- our RIT-5 (as just one example) was used in a circuit by Gordon Rankin driving (doing this by memory) the big Vaic\Kron VV30--- with pretty good success as I recall.

And could you tell me your name--- at least your first name?

Mike

Builder of MagneQuest™ & Peerless™ transformers since 1989
- RE: Need help for RIT5 PF - KPreeda 04:26:12 05/17/09 (8)
  Hi Mike,
  
  I measured 340 ohm DCR for both primary and secondary. When I ordered, I specified parafeed version with channel frame. The unit was written "RIT-5 PF M6", so I thought it's Senior version.
  
  I connected the transformer as follows:
  
  Primary,
  Tube's plate -> 1uF coupling cap -> Red lug ... Blue lug -> GND
  I also switched the Red and Blue and got the same result.
  
  Secondary
  White -> power tube's grid ... Black -> GND
  I did test with and without 27K resistor terminated. It didn't make different result.
  
  I used sine wave 1KHz for testing. The output looked good to about 100-110Vpp. Then it began to look like sawtooth after 120Vpp.
  
  Please let me know if there might be something else I could try. Thanks.
  
  Karin
  - RE: Need help for RIT5 PF - KevinC 07:09:33 05/18/09 (7)
    With a bifilar wound transformer, switching the polarity of the leads should have a marked effect on the response at 1KHz, due to the marked change in capacitance. Either you didn't actually change the lead polarity (believe me, I've unsoldered wires and then resoldered them just as they were thinking that I'd made a change) or your problem originates elsewhere. Do you have a postable schematic?
    
    Kevin Carter
    K&K Audio
    www.kandkaudio.com
    - RE: Need help for RIT5 PF - KPreeda 07:37:58 05/18/09 (6)
      Hi Kevin,
      
      Here's the schematic. It performs pretty good with resistor loaded but didn't work well when I put transformer in, unfortunately.
      - RE: Need help for RIT5 PF - KevinC 09:10:18 05/18/09 (5)
        
        In Reply to: RE: Need help for RIT5 PF posted by KPreeda on May 18, 2009 at 07:37:58
        
        Given that you don't have an IT in the schematic, we need more info to comment. So,
        
        Where is the IT and how is it hooked up?
        What is the tube to be driven and what are its operating point parameters?
        
        Kevin Carter
        K&K Audio
        www.kandkaudio.com
        
        RE: Need help for RIT5 PF - KPreeda 09:25:35 05/18/09 (4)
        
        In Reply to: RE: Need help for RIT5 PF posted by KevinC on May 18, 2009 at 09:10:18
        
        Hi Kevin,
        
        This is how I connect the transformer. 6W6 was biased at 224V 22mA, -22V cathode bias with 10M45 as plate load. When I connected 27K resistor after the coupling cap as a load, the driver could make more than 300Vpp at the resistor. Replacing the resistor with transformer, I terminated the secondary with the same resistor, the output started to distort, which looked like saw wave, around 120Vpp. I also tried without terminated resistor and got the same result.
        
        I don't have the picture of the distort signal for now. I'll post it later this weekend.
        
        RE: Need help for RIT5 PF - mqracing 15:37:18 05/18/09 (3)
        
        In Reply to: RE: Need help for RIT5 PF posted by KPreeda on May 18, 2009 at 09:25:35
        
        Hi Karin:
        First and foremost--- it is NECESSARY that you hook-up the transformer the proper way. It is not an option, not something that would be nice to do... this transformer will NOT work properly the way you have it hooked up.
        The ill-gotten behaviour that you're getting--- which we too have gotten on the test bench when you hook up either side of this transformer improperly---
        A great customer from Italy of ours bought a pair of transformers which were also bifilar wound--- inadvertently he had hooked up the primary on one unit the wrong way--- he wrote to me and was alarmed that the distortion was unmistakbly much larger on the one transformer than the other one--- and it was in the midband and higher frequencies where the behaviour was so bad.... the fix was simple... once he unsoldered the pri leads on the offending trans and hooked them up the right way... his troubles were gone.
        But the fix is simple--- hook this transformer up the proper way.
        RED on the primary MUST go to ground.
        Black on the secondary MUST go to ground.
        
        If your not seeing or getting some real noticeable changes in the behaviour of this transformer when you switch the primary wires...
        from being hooked up improperly to being hooked up properly... then I would be absolutely stumped.
        MSL
        
        Addendum: Please also note that operating this transformer is at a much greater risk of having a voltage breakdown from pri to sec windings when hooked up improperly. DO NOT OPERATE this transformer other than as prescribed.
        
        Builder of MagneQuest™ & Peerless™ transformers since 1989
        
        Edits: 05/18/09 05/18/09 05/18/09 05/18/09
        
        It's working! - KPreeda 09:23:52 05/22/09 (1)
        
        In Reply to: RE: Need help for RIT5 PF posted by mqracing on May 18, 2009 at 15:37:18
        
        Hi Mike,
        
        It's working now. The RIT5 can now make 300Vpp with great frequency response. I measure 20Hz-28KHz -1dB at 300Vpp. Thank you for your advise and patience explaining your design to me!
        
        Great! - mqracing 20:37:56 05/22/09 (0)
        
        In Reply to: RE: It's working! posted by KPreeda on May 22, 2009 at 09:23:52
        
        Now give them some time to break in and I think you'll find your path to musical bliss :=)
        
        Mike
        
        Builder of MagneQuest™ & Peerless™ transformers since 1989
        
        RE: Need help for RIT5 PF - KPreeda 16:31:37 05/18/09 (0)
        
        In Reply to: RE: Need help for RIT5 PF posted by mqracing on May 18, 2009 at 15:37:18
        
        Hi Mike, thanks for the instruction. I'll try again this weekend and let you know the result.

Post a Followup:

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.