Quick Output Transformer Question

dsavitsk · 19th April 2006, 11:08 PM

I am going to use a pair of the Edcor transformers for a headphone amp. My headphones are 32 ohm, and I'll probably put a 32 ohm resistor in parallel. Do I need to do anything different to use the amp as a preamp? That is, will seeing a 10K, or a 50K input impedence cause reflection problems? Will I need to use a different resistor on the secondaries, or would transformers with a 600 ohm tap be a better idea? Thoughts?

leadbelly · 19th April 2006, 11:21 PM

These would work with a tube that could handle a 2K load:

http://www.edcorusa.com/classx/match...XSM10k-150.htm

I'm no guru, but the fact that they are interleaved whereas the $17 ones are not would work to your benefit.

dsavitsk · 20th April 2006, 01:05 AM

They are certainly cheap enough to try them both, so I may do that. If the tube wants a higher impedence, could I simply add a resistor in series with the headphones?

And, to the original question ... is the 16 ohm output okay as a line stage or will there be frequency problems?

Geek · 20th April 2006, 02:31 AM

You want the tubes to see a constant load for best fidelity.

Using an Edcor with an 8 ohm secondary, then paralleling a pair of 18 ohm resistors (9 ohms) will provide an excellent load match with 32 ohm phones.

I did some experiments with this on my 6FD7 amp, which has a switched headphone output and XSE15-8-5K's and it seems optimum.

ttan98 · 20th April 2006, 04:36 AM

Hello fellows,

Do you know which company(ies) makes VERY high QUALITY transformers, single ended and Push pull, in the states and international?

Edcor?, Hammond? Sowter? etc

Geek · 20th April 2006, 07:08 AM

If you mean DC to daylight with zero phase shift (

), I hear Lundahl is a good place to start

19th April 2006, 11:08 PM	#1
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	Quick Output Transformer Question I am going to use a pair of the Edcor transformers for a headphone amp. My headphones are 32 ohm, and I'll probably put a 32 ohm resistor in parallel. Do I need to do anything different to use the amp as a preamp? That is, will seeing a 10K, or a 50K input impedence cause reflection problems? Will I need to use a different resistor on the secondaries, or would transformers with a 600 ohm tap be a better idea? Thoughts?

19th April 2006, 11:21 PM	#2
leadbelly diyAudio Member Join Date: Dec 2002 Location: Calgary, Alberta	These would work with a tube that could handle a 2K load: http://www.edcorusa.com/classx/match...XSM10k-150.htm I'm no guru, but the fact that they are interleaved whereas the $17 ones are not would work to your benefit. __________________ Aerodynamics are for people who can't build engines. Enzo Ferrari

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
Quick transformer question	Brit01	Tubes / Valves	5	23rd July 2009 07:26 PM
Quick output transformer wiring question	wicked1	Tubes / Valves	4	30th April 2008 03:56 PM
Another quick transformer question	Hiwatt25	Chip Amps	6	8th February 2008 10:56 AM
Quick Transformer Question	krzanik	Tubes / Valves	2	17th May 2007 09:15 PM
quick transformer question	VictorG	Tubes / Valves	2	9th January 2004 09:00 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

20th April 2006, 01:05 AM	#3
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	They are certainly cheap enough to try them both, so I may do that. If the tube wants a higher impedence, could I simply add a resistor in series with the headphones? And, to the original question ... is the 16 ohm output okay as a line stage or will there be frequency problems?

20th April 2006, 02:31 AM	#4
Geek diyAudio Member Join Date: Sep 2004	You want the tubes to see a constant load for best fidelity. Using an Edcor with an 8 ohm secondary, then paralleling a pair of 18 ohm resistors (9 ohms) will provide an excellent load match with 32 ohm phones. I did some experiments with this on my 6FD7 amp, which has a switched headphone output and XSE15-8-5K's and it seems optimum.

20th April 2006, 04:36 AM	#5
ttan98 diyAudio Member Join Date: Apr 2006 Location: Melb	Hello fellows, Do you know which company(ies) makes VERY high QUALITY transformers, single ended and Push pull, in the states and international? Edcor?, Hammond? Sowter? etc

20th April 2006, 07:08 AM	#6
Geek diyAudio Member Join Date: Sep 2004	If you mean DC to daylight with zero phase shift ( ), I hear Lundahl is a good place to start

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