Introducing Seductor, our latest amp!

[Paul Joppa]

We have not made careful measurements of output impedance for any of our amps, but I can give calculated estimates based on transformer wire resistances and published tube curves:

Paramount should be about 2.75 ohms on the 8-ohm tap (damping factor 2.75).

Seductor should be about 1.75 ohms on the 8-ohm tap (damping factor 4.6).

[aragorn723]

91dB is pretty high, but the manufacturer hasn't included an impedance curve, so it's hard to know if the 8 Ohm impedance has any low dips that might be of concern.

-PB

Is there an easy way to measure an impedance curve on the speaker?  The only thing I could find out online from def tech is that they have a "friendly" impedance curve, lol.

Dave

[Grainger49]

Dave,

No, impedance is a complex number.  It contains a resistive and reactive component at every frequency.  You need the X and Y axis and periodic frequency marks on the curve.

Look here, the second graph tells the whole story:

http://bottlehead.com/smf/index.php?topic=3873.msg35184#msg35184

[aragorn723]

Grainger,

Sounds like the easy answer is to keep the large solid state amp and call it a day    That was pretty interesting though, never seen the 2nd type of impedance graph before.  How could someone realistically approach a problem like that?  (Short of picking speakers that are known to be tube-friendly).  I have heard some incredible instrument tone come out of tube amps that just doesn't seem to be produced by solid state, hence the curiosity..  Not to ramble on too much, but a lot of speakers
designed for tubes (i.e. orcas) don't have a tweeter on them?  Do they reproduce treble with that crystal clear sound speakers with tweeters have, or is this catering to another type of audience?

Dave

[Paul Joppa]

There is software available, probably even shareware, that can be used with a computer sound card and an ordinary audio amplifier to measure the impedance curve. More difficult though is to interpret that curve well enough to predict what your ears will say!

[Grainger49]

There are whole speaker lines known for their ease to drive with an SET amp. 

I would ask here.  If you are interested in Seductor, ask in the Seductor folder.  Even though there are few out there the power range is well known.

[4krow]

Choices are a good thing!