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Impedance Matching - Tube Amp/Speakers

Hi, I am not technical guy, so excuse my questions. This weekend my friend did check bias on my VTL ST-85, which I recently did buy, and he also measured my speakers Dunlavy SM-1. Multimeter showed him that they are 4 ohm spekares (althought, on paper, they should be 6 ohm). He told me that this is not good combination - 4 ohm speakers and tube amp. So, is it safe using VTL ST-85, or tube amps generally, with 4 ohms or 6 ohms speakers? I am really confused because I like sound, but also dont want damage my amp or speakers.
arzach
philjolet's avatar
philjolet
2,306 posts
 
It is worth mentioning that the impedance of the speaker will affect the sound and control the amplifier has.

You may notice a bit of extra bloom in the bass or loss of control.

Not a big concern but you could try the different outputs on the back of the amp (presuming they give you a choice) and use the one you like best.

fwiw...
larryi
3,922 posts
 
You should try the speaker with both the 4 ohm and 8 ohm tap to determine which sounds better. Using either is entirely "safe" in terms of not damaging gear.

The 4 ohm tap will deliver less power, but, it will increase the damping factor, something that may improve the frequency response (typically, tighter, better defined bass).
almarg's avatar
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almarg
9,670 posts
 
Guys, according to the Stereophile review linked to above there is only 1 output tap, "optimized" for 5 ohms, with power output being specified for 4 ohms. Some photos of the rear panel that can be found via Google's image search function appear to confirm that there is only 1 tap.

Unsound, thank you most kindly!

Regards,
-- Al
arzach OP
4 posts
 
Thank you guys, alot of useful infos for me. I can confirm that my version of ST-85 has only 1 output tap, and also there is no triode/tetrode switch as on newer model. When I was comparing sound of Dunlavys with tubes (VTL) and with some solidstates (Teac ABX-10, SAC Mediatore monos), I noticed that SS has better bass control, speed and transients, but I expected that. Maybe better preamp could cover this area.
unsound
7,329 posts
 
FWIW, in my conversations with the late great John Dunlavy, he had a strong preference for ss, and especially Class D amplification.
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