Anyone consider Hammond 108 and 109 series TF's?

[imaradiostar]

They're more cheaply made than some hammond stuff but I wonder if they'd spec out OK for some basic circuits.

take a look:
http://www.hammondmfg.com/107.htm

jamie

[ssltech]

...I'd be a little cautious about the fact that they appear to quote the LF extension down to 300Hz...

They look a little physically small to be doing any meaty lF /high level duty...

Anyone else?

Keith

[imaradiostar]

...I'd be a little cautious about the fact that they appear to quote the LF extension down to 300Hz...

They look a little physically small to be doing any meaty lF /high level duty...

I totally agree! The specs aren't very good judging by what they list. My hope is that these little suckers are as conservatively rated as their tube power and output transformers.

I'm entertaining the idea of trying some of the 109N series and various input and output configurations. They're less than 20 bucks per transformer so it'd be worthwhile to get a few and see how they spec out and sound.

jamie

[cjenrick]

Sometimes you can get away with transformers that don't have that great of frequency response, depending on what you use them for. I bought a bunch of Schure Teleconfrencing equipment that was in 1U rack mount boxes for ten bucks a piece at the surplus store, just for the box for DIY projects. Each one had four of these signal transformers inside. I looked up the specs and found out they didn't have the greatest specs. I tried one for a guitar direct in box and it sounded great. A guitar has a limited bandwidth so it didn't really matter.
Each box also had four Neutrix XLR jacks prewired with ferrite beads and rf caps, which was also a nice score!

[ssltech]

yes that's true, although I'd bet a small amount that the headroom at LF would be very 'starved' indeed if you tried to use them as output transformers in a 600Ω line... just not enough 'metal' perhaps...

[cjenrick]

SSL, very true on core size vs bottom end headroom.

Just a sidenote, you need 5 lbs of M6 to equal 1 lb of permalloy, so core material type has to be considered when predicting transformer performance.

[byacey]

I have used these transformers before, and I wouldn't put them into the signal path of anything that requires better frequency response than the average McDonalds drive thru intercom. These are utility grade transformers that pass some audio...
Bill Y.