Testing Turns Ratio On Output Transformer

[RickyLee]

Was just thinking that I could do my voltage test again but take a reading on each side of the Primary to the center tap.

But 30 ohms of winding resistance should not show anything that way? I am thinking I should se a drastic voltage difference as the center tap is quite a ways off from being centered.

 

[RickyLee]

First off, I just did the turns ratio test all over again. I also noticed that my first test parameters were off due to me labeling the 4 ohm tap as the 8 ohm tap (6800) and 3400 on the primary.

I not only did the entire primary test Brown to Blue, I also did this test each side to the center tap. And of course, the imbalance shows up huge on the output/secondary.

First is the entire primary ratio to secondary:

VAC in on primary to give 1VAC on output tap

16 ohm 13.24 to 1 2805

8 ohm 18.59 to 1 2765

4 ohm 26.43 to 1 2794

2 ohm 37.17 to 1 2763

These figures are a bit closer to 3.4K spec now that I used the right output tap.



But each side of the primary is way off on this. Which leads me to ask if a huge 30 ohm power resistor could be placed in series with the low 30 ohm side winding? This would balance the load a bit closer but then slightly alter the frequency response and winding capacitance ect?

Here's the numbers:

Brown to Red CT

16 ohm 9.55 to 1

8 ohm 13.45 to 1

4 ohm 19.08 to 1


Blue to Red CT

16 ohm 6.24 to 1

8 ohm 8.77 to 1

4 ohm 12.50 to 1

Just more stats to chew on . . . .

 

[RickyLee]

100VAC in to entire primary Brown Blue = 7.8VAC 16 ohm tap

100VAC to Brown Red CT = 10.9VAC 16 ohm tap

100VAC to Blue Red CT = 16.4VAC 16 ohm tap

So basically, this OT will have one side of the push pull/one EL34 doing most of the work while the other side EL34 is barely breaking a sweat. This sounds like the way to generate more distortion, not less headroom.



Basically, the same principle from the guys that like the mismatched phase inverter or output section?

I can't help but think that they put the center tap in the wrong place. Even more so after I had that bad secondary HT tap on a power transformer I bought new from Weber.

 

[VanR]

That OT sounds suspect. One word: ClassicTone by Magnetic Components. Great transformers at a great price.

http://www.triodeelectronics.com/outrformajcm.html