Transformer question

[martthie_08]

Hi, I am looking for some infos on a suitable transformer for the output of the SRPP based Pultec (Jakob's design). The schematic calls for a 2:1 transformer, I am quite new to transformers, so I assume that means turns ratio.

What I have here is an old UTC A20 matching transformer, can it be wired up for 2:1? The specs (from CJ's site) are:
primary impedance: 50, 125/150, 200/250, 333, 500/600
secondary impedance: same values as primary
Can it be hooked up as 600 Ohm primary and 150 Ohm secondary, to get a square_root(600/150) = 2:1 configuration?

Alternatively - would a A22 interstage / output transformer be better suited? This puppy specs out at 500 CT on the primary side and 500 / 125 (split) on secondary. Doing the math for a primary series/ secondary parallel configuration would be sqare_root(500 / 125) = 2:1 , is this correct? On the downside, this one has a LF cutoff at 40Hz , but it is only 2dB...

Thanks for any help on this! cheers, Marten


(edited: typo)

 

[gyraf]

You'll probably ned a 2400:600 Ohms transformer for this. Lower-Z transformers will limit your low-end.

 

[martthie_08]

ok, thanks Jacob, I was assuming that transformers are only defined by their characteristic of reflecting impedance (and their frequency response / and watts).

So 2400:600 is indeed a different beast than a tranny with 600:150 impedance ratio?