Nice crossover setup you created. The buffer boards measure well and they they can handle power amp rail voltages. For the price, they are a bargain. The only downside is the 470 ohm output impedance compared to a high gm toshiba jfet.
For many line level applications, they are adequate.
This turns out to be an excellent point early in the thread.
I was able to set up this measurement and take it.
At 100 Hz, the amplitude difference between halves of the secondary is about 1%. At 20 kHz, the difference is 12% to 13% depending on which flavor of transformer you look at. I tested two different flavors, 600-15K and 150-10k.
The freq roll off is different between halves of the secondary.
These transformers are probably not a good phase splitter just as you predicted.
it may be possible to satisfactorily balance the secondaries with a network but that time would probably be better spent on an active solution.
Thanks for the tip.
That helps improve balance by 1% percent. It is interesting that moving the signal generator ground makes a large difference. One way the halves are 2X different. The other orientation there is an 11% difference between halves.
Then a buffered transformer voltage gain like the M2 with an active splitter output should be reasonably good. Ready for round 2? See if you like it.
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Then a buffered transformer voltage gain like the M2 with an active splitter output should be reasonably good. Ready for round 2? See if you like it.
That is very nice and very M2-ish.
Here is a question. Would it work omitting the transformer, placing a resistor in the drain of M3 and connecting R1 to the drain of M3?
Try the sim and see for yourself.
You can even discard both M3 and the transformer by connecting input directly to R1. Try different ratio of R10&R11 to R9 to adjust gain of the splitter. However, I believe you would find that a transformer voltage gain has a certain virtue not available elsewhere.
You can even discard both M3 and the transformer by connecting input directly to R1. Try different ratio of R10&R11 to R9 to adjust gain of the splitter. However, I believe you would find that a transformer voltage gain has a certain virtue not available elsewhere.
Noted. I will make some changes and see how it works.
I agree that part of the M2 signature must be the transformer. My thought initially was that the transformer could be a good phase splitter for a preamp. Your prediction that the windings would not be symmetric turned out to be exactly on point.
Thanks for the suggestions and for the work you did.
xformers can be Divine phase splitters ..... even if goal is perfect symmetry , but you must use those made for purpose
though , in this world where sound is of utmost importance , some asymmetry can be good
myriad examples around , where spoiling perfect symmetry is one of the tasks ...... PL amps of recent times may be bridged , but Papa did plenty of work to alter perfect symmetry in proper and controlled way
XS amps being most extreme example , in more than one way
though , in this world where sound is of utmost importance , some asymmetry can be good
myriad examples around , where spoiling perfect symmetry is one of the tasks ...... PL amps of recent times may be bridged , but Papa did plenty of work to alter perfect symmetry in proper and controlled way
XS amps being most extreme example , in more than one way
If I get your message, you would recommend building it as a phase splitter and listen to how it sounds rather than be overly concerned about how it measures.
Remember? Check and listen to it just to be sure, a 12% imbalace may still sound good. But I'd test the active splitter first.
In case you have not noticed, you have the option to feed the splitter by connecting R1 to the transformer output of a running M2 or M2X (pin 7 of the Edcor).
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