Rola output transformer type K

**osci** · 02-08-13, 09:08 PM

Hi all,

I have an old Rola output transformer.....I think its a type K...as on the top of the OPT it has what I presume to be an identification number which is "KOL 5322" I can't quite make out the 3rd digit, but anyway, in the link is data of the old Rola speakers and output transformer,

Am I reading the data correctly that the OPT I have is indeed an old Rola Type K (KOL 53?2) with a 7,000 ohm primary impedance and a 10 watt power rating?

I'm hoping nomeat or B4L may be able to set me straight on this or anyone that has experience with these tranny's.

Teh tranny is out of an old radiogram which had a pair of 6M5's PP.

**eecs** · 06-08-13, 01:38 PM

Hi,

This site has a heap of information on Single ended, and Push Pull output transformers: . If you have the model number of the radiogram you pulled the transformer out of (or even the brand) I can try to look up the schematic in my AORSM's and confirm the part number of the transformer...if that is any help.

Regards,

Bruce

**Uncle Fester** · 07-08-13, 05:55 PM

The way I see it, K stands for 10 watts and you can compare the measurement in inches on page 12.

OL most likely means open laminate.
The 6m5 works on a load of 7000 ohm so if the transformer came from that set up, it should be right.
Leaves us with the output impedance. If you still had the speaker it might be printed on that, otherwise we will have to assume the 5 stands for the 3.5ohm version.

**beer4life** · 07-08-13, 07:38 PM

Originally Posted by nomeat

The way I see it, K stands for 10 watts and you can compare the measurement in inches on page 12.

OL most likely means open laminate.
The 6m5 works on a load of 7000 ohm so if the transformer came from that set up, it should be right.
Leaves us with the output impedance. If you still had the speaker it might be printed on that, otherwise we will have to assume the 5 stands for the 3.5ohm version.

A real can o' worms here tracing the evolution of the output transformers and speakers.
To cut a long story short, not mentioned, is that essentially there are two types of speaker transformers, Permagnetic and Electro magnetic where the speaker coil is used as a high voltage smoothing/filter element to magnetise the speaker. Methinks you need to match both?

**osci** · 11-08-13, 11:30 PM

Originally Posted by eecs

Hi,

This site has a heap of information on Single ended, and Push Pull output transformers: . If you have the model number of the radiogram you pulled the transformer out of (or even the brand) I can try to look up the schematic in my AORSM's and confirm the part number of the transformer...if that is any help.

Regards,

Bruce

thanks eecs, but I only found out last week that I have access to all the AOSR manuals

, but the chassis it came from is a Fleetwood radiogram, but I can look hat up now, buts thanks all the same.

**osci** · 11-08-13, 11:39 PM

Originally Posted by nomeat

The way I see it, K stands for 10 watts and you can compare the measurement in inches on page 12.

OL most likely means open laminate.
The 6m5 works on a load of 7000 ohm so if the transformer came from that set up, it should be right.
Leaves us with the output impedance. If you still had the speaker it might be printed on that, otherwise we will have to assume the 5 stands for the 3.5ohm version.

thanks nomeat, I didn't think about it that like that but it does make sense, I going to run say 5 volts through it and work out the ratio and impedance thay way,

cheers

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