Audio Asylum Thread Printer

Get a view of an entire thread on one page

FAQ / News / Events

OTL Asylum

RE: Circlotron with MOSFET output

61.18.170.165

In Reply to: RE: Circlotron with MOSFET output posted by Banat on December 10, 2011 at 00:58:19

You wrote: "Mr Paul Hynes SS Fet Circlotron circuit is basically correct , but need bias circuit for output Fets which is not present on schematic from your link ! , it could be driven with small SET for sure , but I think that tubes 45 / 2a3 / 300 b is not appropriate for this application since the power MosFet devices usually need only few Miliwat for full gate charge/disharge control."

The bias circuit is not an issue since my friend can take care of it. However, for few milliwatt, I guess a step up transformer is more appropriate than any tubes, right? However, we still need gain from the driver, is it?

Anyonbe can think of any small DHT tube that will work in Paul Hyness circlotron output circuit assume we have a step down phase splitting interstage transformer between the circlotron output section and the DHT driver?

Thanks for the info!

Follow Ups:

RE: Circlotron with MOSFET output - Banat 04:30:04 12/10/11 (6)
You need Step Down interstage trans. for sure , not any Step Up trans. ! ,since the lateral power Fet`s works with max.AC voltage gate sving around 12-14 V , so the step down trans. have to be in range from 1:4+4 to 1:10+10 , that step down conversion ratio directly depends from chosen input/driver SET tube & SET Amp/driver configuration .
So any enough linear DHT triode which can produce around 1 W of output can easy drive up to 5 pair of lateral MosFet`s conected in Circlotron power bridge .
BTW , the quality of this small interstage trans. have Crucial impact to final Amp sound .

Best Regards !
__
Enlightened Evolution-Astral Projection
- RE: Circlotron with MOSFET output - Keith Lee 10:15:35 12/10/11 (2)
  Oh! When you say step down, it should be 10+10:1 and 4+4:1 not the opposte, right?
  - RE: Circlotron with MOSFET output - Banat 11:34:27 12/10/11 (1)
    Sorry Keith !
    I made unintentional mistake when I declare driver step down trans. ratio with signed range from 1:4+4 to 1:10+10 , that`s Wrong !
    Right transf. ratio value should be from 4:1+1 to 10:1+1 !
    Again : this driver trans. step down ratio depends from used tube type in SET driver unit and type of the power Fet`s for output Circlotron power bridge .
    What`s important is to keep transf. secondary (1+1) DC resistance value at lowest level as possible , this value have direct influence on the final stability of the SS Fet Circlotron power stage ,`` speed`` of the whole Amp depends directly from this secondary coil DC resistance to .
    Sorry again !
    
    __
    Enlightened Evolution-Astral Projection
    
    Edits: 12/10/11
    - RE: Circlotron with MOSFET output - Keith Lee 11:48:01 12/10/11 (0)
      Hey! come on! No need to apologize! You are helping me now!! So take it easy! I should say thank you to you.
      
      The reason I want to clarify about the ratio issue since I don't want to present a improper info while placing an order for the transformer, and that's it.
      
      Thanks again!
- RE: Circlotron with MOSFET output - Keith Lee 04:59:09 12/10/11 (2)
  My friend will send me a DHT tube (not sure the type number) with plate voltage 130V, plate current 8ma with 5.5K plate resistance and mu of 8, will it work?
  
  Also, can I put one of this specific DHT tube in the driver stage to drive "only one pair" of lateral MosFet connected in Circlotron power bridge?
  
  Thanks!
  - RE: Circlotron with MOSFET output - Banat 05:23:41 12/10/11 (1)
    It is hard to give you any precise reply since this small DHT tube type is unknown !
    But for now Russian 6c45p military grade small triode with pure titanium plate work fine , D3a tube from Siemens triode strapped is OK to , but EL84 ( 6bq5 )triode strapped is very good performer to drive the 2 or even more pairs of power Fet`s connected in Circlotron power bridge .
    
    __
    Enlightened Evolution-Astral Projection
    - RE: Circlotron with MOSFET output - Keith Lee 10:06:45 12/10/11 (0)
      The output device is a pair of IXTH20N50D, and it is a 500V 20A device. How much "max" power it can kicks out from CIRC1 when biasing high bias Class A/B or pure class A?
But the CIRC1 still need gain from the driver stage, right? (no text) - Keith Lee 03:57:29 12/10/11 (1)
no text
- RE: But the CIRC1 still need gain from the driver stage, right? (no text) - Banat 05:02:29 12/10/11 (0)
  Right !
  If we assume that SS power Circlotron stage associated small SET driver Amp need unbalanced input signal voltage around of 2V which coming from PreAmp / or CD , or any other digital source , or similar .
  __
  Enlightened Evolution-Astral Projection

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.

This post is made possible by the generous support of people like you and our sponsors: