help with connections on RS Hygrade OT

[HTH]

I've scored a NOS RS Hygrade OT rated for 60mA. I'm not enterely sure whether it's a SE or PP tx (or can do both like the hammond 125A).

The attachment below shows the datasheet and the various connections, however, some of the primary options (3k, 5k, 8k) show only two connections which would indicate SE use, whereas there are other options (8k) showing three connections with a CT indicating PP use - right?

There is also a 2k2 tap with four connections - I'm assuming that I would connect tags 1-4 together for one side and tags 4-5 together for the other side and use in SE mode - ???

Any/all help appreciated.

[Tom Phillips]

Yes & No

The attachment below shows the datasheet and the various connections, however, some of the primary options (3k, 5k, 8k) show only two connections which would indicate SE use, whereas there are other options (8k) showing three connections with a CT indicating PP use - right?

I agree That is my interpretation.

There is also a 2k2 tap with four connections - I'm assuming that I would connect tags 1-4 together for one side and tags 4-5 together for the other side and use in SE mode - ??? .

No. If you did that you have a dead short across the primary because #4 would be common to both sides. I think they are just giving you the option to use either 1 and 4 OR 4 and 5 for a 2.2k Ohm primary.

Regards,
Tom

[HTH]

RE: 2k2 tap - that was my 'other' interpretation of it, but I then convinced myself it was a daft idea. of course it makes total sense now you've pointed out the common pin4 (doh!).

I've got a busy few days of OT comparing ahead - got two NOS RS OTs that are suitable for my SE EL84 project. One is an 'Economy' model, the other is a 'Hygrade'.

Should be interesting to hear the differences. The Economy is much smaller and rated for 40mA while the Hygrade is nearly twice the size and rated for 60mA.