James Transformer BS

dsavitsk · 14th September 2006, 04:15 AM

On one side, my James transformers have a 0, a 4 ohm, and an 8 ohm pin which is straight forward enough. On the other side there are 3.5K and 5K pins, which makes sense, and a B pin and an S pin. Anyone know what these are?

dmcgown · 14th September 2006, 09:17 AM

If I were to guess, B would refer to the B+ connection and S the screen connection for ultralinear connected pentode. You can use an ohmmeter across the windings (either 3.5K or 5.5K taps) and confirm the B connection is higher in resistance than S.

Geek · 14th September 2006, 09:24 AM

Quote:

James Transformer BS

I thought this was going to be a rant thread

pmillett · 14th September 2006, 10:53 AM

The guess above is correct.

There's a datasheet here:

http://euphoniaaudio.netfirms.com/ea...f/6113-25K.pdf

Assuming this is the one...

Pete

ray_moth · 14th September 2006, 11:12 AM

Quote:

I thought this was going to be a rant thread

Quote:

The guess above is correct.

Ha!

lt cdr data · 14th September 2006, 01:29 PM

yes I think that's correct, the b connects to your psu, and the s is indeed screen, try both the 3k5 and 5k and see which you prefer, also try reversing the b going to the tube and the 3k5 to your psu and see which you prefer, its optimised the correct way for capacitance, but you may or may not prefer t'other way around, won't do any harm

JojoD818 · 14th September 2006, 03:11 PM

Quote:

Originally posted by Geek

I thought this was going to be a rant thread

that was my first thought too regarding the title.

I hope it's ok to ask but if I have an output tranny which I know is for an EL34 in PP and I know the B+, UL taps, and plate taps. but I don't know which is 0, 4, 8, 16... how could I check that? my DMM cannot measure any resistance in the speaker side.

dsavitsk · 14th September 2006, 05:14 PM

Quote:

Originally posted by pmillett
The guess above is correct.

There's a datasheet here:

http://euphoniaaudio.netfirms.com/ea...f/6113-25K.pdf

Assuming this is the one...

Pete

Thanks Pete, I looked all over for that.

Quote:

Originally posted by JojoD818

that was my first thought too regarding the title.

I hope it's ok to ask but if I have an output tranny which I know is for an EL34 in PP and I know the B+, UL taps, and plate taps. but I don't know which is 0, 4, 8, 16... how could I check that? my DMM cannot measure any resistance in the speaker side.

I think you could hook up a resistor across the primaries and then measure different resistances on the secondaries.

SY · 14th September 2006, 05:24 PM

Quote:

Originally posted by JojoD818

I hope it's ok to ask but if I have an output tranny which I know is for an EL34 in PP and I know the B+, UL taps, and plate taps. but I don't know which is 0, 4, 8, 16... how could I check that? my DMM cannot measure any resistance in the speaker side.

CAREFULLY apply a high AC voltage (100V through a Variac would be ideal, but 220V mains will work) to the primary, then measure voltages at the secondary. No loading needed.

ErikdeBest · 14th September 2006, 05:25 PM

Hi JojoD

I think you could also apply a (small) voltage to the primary and measure the secondary. The highest reading would be for the 16 ohms, the lowest for the 4 ohm...

Or juist build an amp and try to find out which is which listening to the amp...would make a nice blind test, I think

Erik

14th September 2006, 04:15 AM	#1
dsavitsk diyAudio Member Join Date: Jan 2005 Location: Chicago	James Transformer BS On one side, my James transformers have a 0, a 4 ohm, and an 8 ohm pin which is straight forward enough. On the other side there are 3.5K and 5K pins, which makes sense, and a B pin and an S pin. Anyone know what these are?

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
Simple SE output transformer: James or Edcor?	dogfish	Tubes / Valves	8	12th June 2009 10:23 PM
james 6123hs	totaltech	Tubes / Valves	4	29th August 2008 11:21 PM
Fun with James	Nixie	The Lounge	2	1st March 2007 06:13 PM
Hammond vs. James?	Sherman	Tubes / Valves	56	26th July 2006 01:30 AM
James Singapore	okkyn	Tubes / Valves	4	3rd February 2006 12:39 AM

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

14th September 2006, 09:17 AM	#2
dmcgown diyAudio Member Join Date: Jul 2002 Location: Silver Spring, Maryland, USA	If I were to guess, B would refer to the B+ connection and S the screen connection for ultralinear connected pentode. You can use an ohmmeter across the windings (either 3.5K or 5.5K taps) and confirm the B connection is higher in resistance than S.

14th September 2006, 10:53 AM	#4
pmillett diyAudio Member Join Date: May 2005 Location: Dallas (but I am not a Texan!)	The guess above is correct. There's a datasheet here: http://euphoniaaudio.netfirms.com/ea...f/6113-25K.pdf Assuming this is the one... Pete

14th September 2006, 01:29 PM	#6
lt cdr data diyAudio Member Join Date: Dec 2003 Location: earth	yes I think that's correct, the b connects to your psu, and the s is indeed screen, try both the 3k5 and 5k and see which you prefer, also try reversing the b going to the tube and the 3k5 to your psu and see which you prefer, its optimised the correct way for capacitance, but you may or may not prefer t'other way around, won't do any harm

14th September 2006, 05:25 PM	#10
ErikdeBest diyAudio Member Join Date: Mar 2003 Location: Itoculo	Hi JojoD I think you could also apply a (small) voltage to the primary and measure the secondary. The highest reading would be for the 16 ohms, the lowest for the 4 ohm... Or juist build an amp and try to find out which is which listening to the amp...would make a nice blind test, I think Erik

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