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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
larryi
3,992 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).
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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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swampwalker
5,138 posts
 
SS has better bass control, speed and transients, but I expected that. Maybe better preamp could cover this area.
While I am a big proponent of building a system around a great pre-amp, IMO, you are not going to get significant improvements in the areas you mentioned unless you change amplification. V. good tube amps can provide all of those elements, w/o sacrificing the good things that tubes do. This is all theoretical. I've never heard your amp and the speakers only once. YMMV.
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