Tube Radio
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True, although has anyone done any real tests proving ling term reliability driving 4 ohm loads?
That is the same thing that McIntosh does with their Autoformers. I think the Mac amps sound tubby 9which is sad because I really like the way they look) because they don't increase with decrease ohm load - a 500 WPC amp is just that 500 WPC.
Ok, I'll drink the Kool Aid. I just had my Realistic receiver repaired and my tech suggested that I check the speakers and make sure that they are ok. I tested them at 5 ohm each, so I'm calling them 4 ohm speakers. My receiver says to use 8 or 16 ohm speakers. It suggests reading the manual if I want to use 4 ohm speakers.
1) Does anyone have access to a Realistic STA-64B manual ?
2) Where do I start to get some 8 ohm speakers? I'd prefer to get a pair of vintage speakers as I can't stand all the cheap Chinese crap sold these days. Any suggestions?
so if i bridge the amp(s) i essentially have a 2 channel amp capable of running 2 speakes. so if i have 4ohm speakers attached to the pro power 10 in bridged mode, am I running the amp at a 2ohm load?
Thanks for the clarification !, the soundcraftsmen pro power 10 is positively rated at 2ohm stable, however if the 4 ohm speakers are rated at 2ohm, but spec at 3.7, is that 3.7/2=1.35 ohms (bridged) ? which is under 2ohms, do you see my concern ? thanks agian steveYes, a bridged amp feels 4 ohm speakers as 2 ohm load. If the amp doesn't list 2 ohms unbridged operation in the specs it may be wise to reconsider bridged + 4 ohms.
That sounds hopeful !!, thank you very much for the answer. this place is great, helped me rebuild a soundcraftsmen ma5502 years ago. i'm tempted to get a pair of the eminence lab 15 sub woofers which are rated at 6ohms so, 3 ohms bridged. but at that rate my ears will fail before the amp does.!I found this in another forum. It lists the Pro Power Ten as 900 watts into 4 ohms. That implies it is stable when bridged into 4 ohms. That and since it is listed as stable into 2 ohms unbridged you should be OK.
PRO POWER 10 - (FULL CHASSIS 4 CH, 2 PM860S IN ONE PACKAGE, 6 HITACHI TO3-METAL MOSFETS/CH, DUAL LED DISPLAY, DUAL PCR PS, DUAL FANS, A BEAST, 205W/CH@8R, 315W/CH@4R, 450W/CH@2R or 600WX2@8R and 900WX2@4R, HIGH CURRENT, INTEGRATED BRIDGING).
(from)
http://www.audioheritage.org/vbulle...elp/page11&s=b07de8602b2af60fd59586bd8319d5f4
thank you, from all the information i'm getting it looks pretty good to run it bridged into 4ohms, risky, but it should hold...guess igotta make the decision !I would just go by the nominal rating of the speakers. If you measured them with an multimeter you measured DC resistance, which is different than the impedance.
Thank You, Yes it's extremely clean at loud volumes !, it's been a life long passion to build the perfect system. kinda like the vintage amps rather than the new dj stuff. speakes are home built eminence 15" woofers, 8" mids and horn tweeter, with a seperate 15' sub woofer (passive) built into each cabinet. built a "antique" style cabinet to house everything in. once i got all the amps in, i couldn't lift it !!The impedance of the speakers doesn't change so they would still be called 4 ohm speakers. But the 4 ohms is only nominal, that changes across the frequency spectrum so there could be dips to lower impedance at some frequencies. There is probably an impedance curve for your speakers somewhere. The real question is whether the bridged amp is stable into a nominal 4 ohm load. I have only seen the output rated when bridged into 8 ohm loads which doesn't really say either way.
That sounds like a very nice set up you have going.
Thanks for the clarification !, the soundcraftsmen pro power 10 is positively rated at 2ohm stable, however if the 4 ohm speakers are rated at 2ohm, but spec at 3.7, is that 3.7/2=1.35 ohms (bridged) ? which is under 2ohms, do you see my concern ? thanks agian steve