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Thought on OTL tube amps

Just curious....how do these sound/perform compared to tube amps with transformers? Why do you prefer one or the other? Any particular brands of OTL amps you would recommend listening to? You can see my system on my tag here...listen mostly to rock and roll with a smattering of jazz and a bit of classical once in a while. The next stop on my amplifier adventure is an OTL model, and I have no intention of trading it for either SET I currently have, as I'm very happy with both. One of the ways I enjoy experimenting with different "sound" is by switching up the amps. Just trying to solicit some opinions, of which I know there are many strong ones here at A-Gon. Thanks in advance!
afc
xonex77
42 posts
 
Paralleling a choke/inductor/coil in the amps 4 ohms output will  be  less than 4 ohms and same thing to a voice coil of 4 ohms will  be  less than 4 ohms due to ohms law,then sound will be louder due to less resistance and more current.The only way to increase the impedance of the speaker is to put a coil/inductor   in series with the voice coil,which of course it kills dynamics.
atmasphere's avatar
atmasphere
7,068 posts
 
It not exactly clear what you are talking about, but if I read this right you are incorrect about increasing the impedance of a speaker. One way to do it is to put drivers in series rather than parallel; of course that is a design issue.

There are a good number of 16 ohm speakers made these days, on account of the fact that 16 ohms works extremely well with tubes. The speakers we use at our shop are 16 ohms. They have two woofers which are in series.
almarg's avatar
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almarg
8,673 posts
 
Ralph (Atmasphere), I think that when Xonex77 refers to "increasing the impedance of a speaker" in the second sentence of his latest post, he is referring to increasing the load impedance seen by the amplifier, for a given speaker. But more significantly, in the first sentence of that post he appears to be envisioning that a Zero, when inserted between an amp and a speaker, would act as an inductor (rather than acting as an autoformer), with much of its inductance placed in parallel with the speaker's impedance. Resulting in a lower overall impedance, as seen by the amp, than if no Zero were present. Which as you'll certainly agree is not correct.

Best regards,
-- Al
 
xonex77
42 posts
 
Most OTL design  require high high impedance speakers,flaws in the design that these amps should work without these impedance matching,but not all OTL have these inherent disadvantage,I have an OTL using KT120 or VV52/300B output tubes  that welcomes 4 or 8 ohms  and a   full-range speakers.But if I insert  the ZERO, it  kills every thing.  
realdeal
62 posts
 
Sorry to say that the atmas are not stand alone OTL tube amp but need output transformer  plain and simple.
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