Phase splitters

[acorn]

Which would be the better of the two phase splitters for a small Push-Pull EL84 amp , a concertina type or along tailed pair as used in the EL84
Dynaco valve amp taking into consideration the high frequency response, I would not like a falling top response after about 10K Hz.

Acorn

[pre65]

Had you considered converting it to balanced input ?

[acorn]

Philip

I am looking to obtain the best high frequency response without getting to complicated, a lot of phase splitters suffer from high frequency roll off, so open to suggestions.

Acorn

[JamesD]

I prefer the sound of the concertina providing it drives equal impedances over a LTP unless the LTP has a BIG resistor in it or a CCS - then the difference is moot to my ears.

Better than both is the iron concertina http://home.earthlink.net/~jeremyepstei ... rtina.html or an input phase splitting transformer such as the Sowter 3575.

James.

[Neal]

Yes probably moot, although, I'd use the LTP, you'll get good balance if you don't mind loosing gain by using a high'ish value tail resistor and slightly different value load resistors say 2~3% smaller for the first half. you could also tweak the following grid leak resistors as well.

[cressy]

Best ive heard to date (based on my preferences) other than balanced input is the transformers. These were sowter 3575s. Ive just bought some for a customers balanced output passive pre, brand new a pair is 124 quid including vat and postage so they aint cheap. But to me they are worth it, someone might have some second hand you could buy? Cheers ant

[acorn]

Thanks lads

Food for thought, indeed.

Acorn

[Mike H]

+1 for 'iron concertina', if you can't do balanced inputs. This would be a gapped 1:1 transformer.

[JamesD]

umm isn;t it a gapped 1:1:1 or 1:1:1:1???

[JamesD]

As per the input stage of this amplifier for gapped 1:1:1:1...

[Nick]

Isnt that just cathode feedback? The actual phase splitting is in the secondary.

[Mike H]

umm isn;t it a gapped 1:1:1 or 1:1:1:1???

Sorry I was thinking of capacitor coupling, so no, is like a split choke.

[JamesD]

Nick,

That is certainly one view...

or view it as a split load inverter as both anode and cathode deliver equal power into the two loads...

And the two loads are the two sides of the balanced output winding

Looks like a split load invertor, works like a split load invertor and sounds like a very good split load invertor otherwise known as a concertina phase splitter and this one uses iron to pass the power from input to output hence iron concertina....

It has very good balance and I guess that might be due to the double balanced nature of the beastie i.e. split load and transformer inversion...

[Nick]

Nick,

That is certainly one view...

or view it as a split load inverter as both anode and cathode deliver equal power into the two loads...

And the two loads are the two sides of the balanced output winding

Looks like a split load invertor, works like a split load invertor and sounds like a very good split load invertor otherwise known as a concertina phase splitter and this one uses iron to pass the power from input to output hence iron concertina....

It has very good balance and I guess that might be due to the double balanced nature of the beastie i.e. split load and transformer inversion...

I guess it a tail of two splitters

Or two splitters, one in the tail.

[JamesD]

Always useful to have a split in tail....

But it also has enough cathode degeneration to reduce the anode gain to unity - as does a resistor split load inverter...

the nice thing about the iron concertina is that it impedance balances both sides so unequal capacitance in the loads doesn't unbalance the input unlike a resistive concertina