Se Amp with Push Pull Transformer

DougL · 11:44 PM

I was reading "Designing Valve amplifiers" By Morgan Jones (Highly Recommended) and saw the page for cancellation using one valve, page 392.

I had some questions.
First, would each winding be 2*RP as a rule of thumb?
Would Av = 2 * mu/mu+1 ~ 1.8?

The circuit looks like it might work great with a toroid and maintain "perfect" balance. It would also work with something like the Lundahl LL1663, but not most classic push pull transformers.

I was thinking I could have a bit different amp.
Any thoughts are appreciated.

I was sketching concepts on my pad for this and thought I'd throw it out for comments.

Doug

Elias · 2nd November 2009, 06:37 PM

Hello,

got any picture of the concept?

- Elias

DougL · 2nd November 2009, 06:40 PM

I will Sketch one up today.

45 · 2nd November 2009, 07:31 PM

Quote:

Originally Posted by DougL

I was reading "Designing Valve amplifiers" By Morgan Jones (Highly Recommended) and saw the page for cancellation using one valve, page 392.

I had some questions.
First, would each winding be 2*RP as a rule of thumb?
Would Av = 2 * mu/mu+1 ~ 1.8?

The circuit looks like it might work great with a toroid and maintain "perfect" balance. It would also work with something like the Lundahl LL1663, but not most classic push pull transformers.

I was thinking I could have a bit different amp.
Any thoughts are appreciated.

I was sketching concepts on my pad for this and thought I'd throw it out for comments.

Doug

I think it could work well with triodes like the 6080/6AS7 that have a very low mu anyway....

Cheers,
45

dsavitsk · 2nd November 2009, 07:42 PM

It seems like such a nice concept. However, the problem is that the AC signals will exactly cancel each other out leaving you with almost exactly no output. That is, it is an error in the book.

Sims are from Slagle from a while back. Also, if you search AA for "chokertina" there was a discussion on this in 2003.

45 · 08:36 PM

I was thinking about something like the Klimo Beltaine. Using the 6AS7, one triode is the amplier and the other for the DC balance only. Cathode follower config. if you like. Probably it doesn't work as well because the DC side has to be a current source.
I don't have the book by Morgan Jones .

Cheers,
45

DougL · 2nd November 2009, 09:30 PM

Here is The Concept.

Push pull transformer with split, not center tap primary.
Standing current cancels. And since there is only 1 tube and Icathode and IPlate are equal until A2, the current ballance should be "perfect".

Morgan Jones said it was a problem to drive.

Doug

DougL · 2nd November 2009, 09:32 PM

Quote:

Originally Posted by dsavitsk

It seems like such a nice concept. However, the problem is that the AC signals will exactly cancel each other out leaving you with almost exactly no output. That is, it is an error in the book.

Sims are from Slagle from a while back. Also, if you search AA for "chokertina" there was a discussion on this in 2003.

Really?

Thanks.

Sounded too good to be true.

Doug

Matt.B.H. · 2nd November 2009, 11:07 PM

It should work. The ac signals at the anode and cathode are opposite phase right?

smoking-amp · 2nd November 2009, 11:20 PM

"The ac signals at the anode and cathode are opposite phase right?"

Yes, but they are then connected to the same phase connections on the xfmr where they then cancel out.

Some related ideas here:

DC compensated SE output transformer

29th October 2009, 11:44 PM	#1
DougL diyAudio Member Join Date: Feb 2004 Location: Wheaton IL. Blog Entries: 25	Se Amp with Push Pull Transformer I was reading "Designing Valve amplifiers" By Morgan Jones (Highly Recommended) and saw the page for cancellation using one valve, page 392. I had some questions. First, would each winding be 2RP as a rule of thumb? Would Av = 2 mu/mu+1 ~ 1.8? The circuit looks like it might work great with a toroid and maintain "perfect" balance. It would also work with something like the Lundahl LL1663, but not most classic push pull transformers. I was thinking I could have a bit different amp. Any thoughts are appreciated. I was sketching concepts on my pad for this and thought I'd throw it out for comments. Doug __________________ Scienta sine ars nihil est - Science without Art is nothing. (Implies the converse as well) Mater tua criceta fuit, et pater tuo redoluit bacarum sambucus Last edited by DougL; 29th October 2009 at 11:44 PM. Reason: spelling

2nd November 2009, 06:37 PM	#2
Elias diyAudio Member Join Date: May 2003 Location: Where you live	Hello, got any picture of the concept? - Elias __________________ Reinventing the wheel ! Free wavelet software for audio analysis click here!

2nd November 2009, 06:40 PM	#3
DougL diyAudio Member Join Date: Feb 2004 Location: Wheaton IL. Blog Entries: 25	I will Sketch one up today. __________________ Scienta sine ars nihil est - Science without Art is nothing. (Implies the converse as well) Mater tua criceta fuit, et pater tuo redoluit bacarum sambucus

2nd November 2009, 08:17 PM	#6
45 diyAudio Member Join Date: Dec 2008 Location: United Kingdom	I was thinking about something like the Klimo Beltaine. Using the 6AS7, one triode is the amplier and the other for the DC balance only. Cathode follower config. if you like. Probably it doesn't work as well because the DC side has to be a current source. I don't have the book by Morgan Jones . Cheers, 45 Last edited by 45; 2nd November 2009 at 08:36 PM.

2nd November 2009, 11:20 PM	#10
smoking-amp diyAudio Member Join Date: Dec 2001 Location: Hickory, NC	"The ac signals at the anode and cathode are opposite phase right?" Yes, but they are then connected to the same phase connections on the xfmr where they then cancel out. Some related ideas here: DC compensated SE output transformer __________________ Ohms Law V = I R

2nd November 2009, 11:07 PM	#9
Matt.B.H. diyAudio Member Join Date: Jul 2009 Location: Cheltenham	It should work. The ac signals at the anode and cathode are opposite phase right?

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
6C33B-C push pull with output transformer	vincent_brient	Tubes / Valves	20	5th June 2009 06:49 PM
Output transformer push pull	om kalsoum	Tubes / Valves	7	7th May 2007 09:48 PM
Push-Pull converter with a gapped transformer ??	Joseph Hynes	Power Supplies	30	25th December 2005 03:38 PM
modify parallel push-pull EL84 to single push-pull	chungtat	Tubes / Valves	12	3rd November 2005 11:25 PM
how to determine P1 from P2 of a Push-pull transformer?	up4	Tubes / Valves	10	13th June 2005 10:54 PM

New To Site?	Need Help?
Register to Participate Search Privacy Statement Contact Us	Frequently Asked Questions Did you forget your password? Mark Forums Read