How to test audio transformers ?

Hi,
I recently bought some vintage trafos on ebay, and i would like to check if they work properly before involving them in my builts...Is there a good way to do this ?
Kind regards,
Hugo

Do you have any data on them?

Cheers

Ian

ruffrecords said:

Do you have any data on them?

Cheers

Ian

Click to expand...

Hi Ian,

There are 1 pair of utc A-10, triad HS-29, HS-56v, marinairs T1444, T1452.
I do not have them in front of me, i do not rember the pins layout...but i will add it if needed

thank you

hugo said:

Hi Ian,

There are 1 pair of utc A-10, triad HS-29, HS-56v, marinairs T1444, T1452.
I do not have them in front of me, i do not remember the pins layout...but i will add it if needed

thank you

Click to expand...

OK, so you have pin out data available. As a first test just check continuity of each winding. 600 ohm windings typically have a dc resistance of a few tens of ohms and 10K windings can be as much as 1K or so.

Cheers

Ian

ruffrecords said:

OK, so you have pin out data available. As a first test just check continuity of each winding. 600 ohm windings typically have a dc resistance of a few tens of ohms and 10K windings can be as much as 1K or so.

Cheers

Ian

Click to expand...

thank you, i will start by this

dang, where did you get the HS-29?

CJ said:

dang, where did you get the HS-29?

Click to expand...

I have 6 of them ^^...i think that was the last time they appeared on internet

probably from Andy in San Jose, CA.

CJ said:

probably from Andy in San Jose, CA.

Click to expand...

no, but who is him ? I am still looking for other trafos...A-24, HS-50....

I would do as Ian suggested measure Continuity and DC resistance.

It's good that you are testing them before the building the projects.

In my last 2 builds, a 4 channel API style preamp and 2x Neve 1272 I couldnt get them to work and I even though I did a lot of troubleshoot somehow I never considered a transformer failure.
Wrong , I should have checked the transformers before I put them in the circuits, now  I test all the transformers when they arrive from shipping even new ones.

The 4 channels API had a shorted Input transformer, this was a new transformer I bought from CAPI, the Ed Anderson ones. It came shorted from factory, Jeff from CAPI sent me a replacement.

The 2x Neve 1272 I had bough vintage original transformers and one of the output transformers had an open primary and open secondary.

I would have saved a lot of time and patience in this build if I just had measured them before using.