Sorry if this seems like a dumb question but...

On a UTC a-25 line output transformer, the frequency response is 40hz-
20Khz. The tranny is designed for DC in the primary of 8ma. Is this
frequency response rating derived with DC on the primary? If this is
the case, would using this transformer in an AC-coupled situation,
increase the low-end frequency response?

Thanks!

In article writes:

20Khz. The tranny is designed for DC in the primary of 8ma. Is this
frequency response rating derived with DC on the primary? If this is
the case, would using this transformer in an AC-coupled situation,
increase the low-end frequency response?

This isn't usualy a "designed for" but rather a "designed to tolerate"
kind of thing. While there may be small differences in frequency
response due to the core getting closer to saturation as it has more
DC flowing through it, it's more likely to affect the headroom
(maximum output level) of the transformer.



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Crumb wrote:

Sorry if this seems like a dumb question but...

On a UTC a-25 line output transformer, the frequency response is 40hz-
20Khz. The tranny is designed for DC in the primary of 8ma. Is this
frequency response rating derived with DC on the primary?

Most probably yes.

If this is
the case, would using this transformer in an AC-coupled situation,
increase the low-end frequency response?

Most probably no.

The 8mA probably isn't having much effect on the inductance
of the tranny, since it probably has an air gapped core, ie, the
Es and Is are bundled together in twp piles and kept together with a
clamp.
If you removed the core, and reassembled it with all the Es and Is
interleaved as much as possible, the LF response may
go lower depending on the voltage applied, and whether this voltage is
enough
to saturate the tranny.
At low signal levels, the LF response will definitely go lower.

Patrick Turner.





Thanks!

(Crumb) wrote in message . com...
Sorry if this seems like a dumb question but...

On a UTC a-25 line output transformer, the frequency response is 40hz-
20Khz. The tranny is designed for DC in the primary of 8ma. Is this
frequency response rating derived with DC on the primary? If this is
the case, would using this transformer in an AC-coupled situation,
increase the low-end frequency response?

Thanks!

I don't klnow specifically how UTC specifies it xformers but I do know
that ion general you can extend the bass response by lowering the
source and or load impedance. The xformer magnatizing inductance acts
as an inducance in parallel with the audio creating a high pass
filter. The lower the source and load Z, the lower the break point.
Also as the core become non-linear you will get odd order distortion
if or drive it too hard at low frequencies.

Hook up the transormer to a scope and generator and play. Vary the
source and load Z. Its a learning experince.

Removing the DC component is a very good thing, certaninly can't hrt.

Mark

Crumb wrote:

On a UTC a-25 line output transformer, the frequency response is 40hz-
20Khz. The tranny is designed for DC in the primary of 8ma. Is this
frequency response rating derived with DC on the primary?

Yes.

If this is
the case, would using this transformer in an AC-coupled situation,
increase the low-end frequency response?

Maybe a little, but not much. It has a split core.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Crumb wrote:

On a UTC a-25 line output transformer, the frequency response is 40hz-
20Khz. The tranny is designed for DC in the primary of 8ma. Is this
frequency response rating derived with DC on the primary?

Yes.

If this is
the case, would using this transformer in an AC-coupled situation,
increase the low-end frequency response?

Maybe a little, but not much. It has a split core.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."