Is this a phase splitter?

[tom-vdl]

Hi there,

I am hoping there is someone on this forum that can tell me if the attached schematic is a phase splitter or not.

I tried the concept in my balanced mosfet amp using a small power transformer with two 12V secundairies and it seems to be working reasonable fine. However when I searched the internet for phase splitters yesterday I couldn´t find anything similar (All transformer based splitters seem to have a center tapped secundary with the CT grounded)

If it is a proper phase splitter, are there any pro´s or con´s that I need to be aware of?

Thanks for your response
Tom

 

[DrG]

Yes it is a phase splitter... but I'm not sure about the pro's and cons...

 

[Steven]

phase splitter

Yes it is a phase splitter, but because the grounding of the secondary is via resistors both phases are not really 'isolated' from each other. If you have a grounded center tap then both phases are less dependent on the loading of each other. Now you have to be careful that the load resistance or impedance on both phases are at least equal and better also quite high.

Steven

 

[tom-vdl]

DrG, Steven,

Thank you for your response.

Steven,
As I am drivng two identical N-cannel medium power mosfets from this splitter the difference in loading between the two sides will not be very large. The major difference I think is the gate capacitance which changes with Vdrain-gate. I think I will explore this configuration a bit further.

Tom

 

[planet10]

http://www.edcorusa.com/magnetics/audio/wsm/wsm10k-10k.htm

the transformer above gets good press for those that have used it, and is quite modest in terms of resources required to get a pr.

dave

 

[john curl]

This type of phase splitter is used in my 40 year old design,Telefunken portable radio with germanium transistors. It still sounds good today, better than most 'modern designs'. Another good trick is if you have a secondary center tap, you can bias both sides of the output stage through it, and not have to add extra resistors.

 

[ChrisA]

DrG, Steven,

gate. I think I will explore this configuration a bit further.

Tom

While a center tapped power transformer will work, the bandwidth and harmonic distortion specs will not be good. You can buy a "real" audio coupling transformer, special built for this purpose for about $10.

And yes, you do want a real center tap not a "virtual center tap" made from resistors.

That said, you can build a phase splitter from any kind of inverting unity gain amp and it's own input. Many times a simple op-amp can outperform a transformer. But then op amps require power, transformers don't.

 

[cbdb]

That cct will produce a dc current across the secondary, how much effect it will have (like early saturation) depends on the details, but its somthing to watch for, and easy to fix with a centre tap

 

[Steven]

That cct will produce a dc current across the secondary, how much effect it will have (like early saturation) depends on the details, but its somthing to watch for, and easy to fix with a centre tap

No, not necessarily. If both halves use the same resistors, there is no DC voltage across the secondary, so no early saturation.

Steven

 

[cbdb]

Sorry Ithought I saw a B-, not 2 B+s