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Impedance matching 8ohm speakers to 4ohm sub

Perhaps a simple question: I have 8ohm Meadowlark Swallows driven by a custom-rebuilt vintage, 7591-based tube amp with the standard 4/8/16 ohm taps. I'm considering adding an REL sub with 4ohm impedance. If I use the High Level input to the REL, as apparently preferred by everyone on AudioGon, wont the amp see the 4ohm and 8ohm impedances in parallel from the speaker taps as 2.7ohms? Does this then preclude using the High Level input to the REL given I am using a tube amp. Almarg reply welcome.
elunkenheimer
mechans
3,048 posts
 
I am speaking from complete ignorance on the subject, but I am surprised that if the sub was not powered. Let me repeat that the sub was not powered that a 7591 amp could power the sub at all. Is it possible for such amps and I do own several "golden age EL-84, 7591,7868 based amps" to do it. Thry work their little tubes off just making the mostly mid and treble range music, yes there is bass but not sub woofer bass.
arh
366 posts
 
Since the Rel is self powered it won't draw much current at all because it is really only looking at the voltage that your amp is putting out. Your amp will basically see the 8 ohm load. You should not have a problem
Alan
elunkenheimer OP
31 posts
 
You guys are great. Thanks for the responses. It might have been easier to assess had the REL specs listed the input impedance of the High Level input which Almarg rightly suggests would be around 100k ohms. Just didn't think of that. And Arh I hadn't thought about the fact that the REL design approach is only looking at voltage. And Stanwal, I have noticed that there seems to be a feeding frenzy for the older S-series subs from REL, whereas the front-firing later versions seem to loose their resale value more rapidly, particularly the T-series.
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