Pages 54-55,set to 4 ohm setting under first time setup.Link. [http://filedepot.onkyousa.com/Files/own_manuals/DTR-70.1_80.1_En_web.pdf?CFID=1260084&CFTOKEN=20724004&jsessionid=f0308c64dd069e5119396f792f3e29581373]
9 responses Add your response
A preamp/processor normally doesn't have a impedance (ohm)selector for speakers.It does most likely have a crossover for small,or large,or frequency to cutoff bass to the speakers. Your power amp may.If your power amp does,it would most likely have a switch on the back of it (power amp).The power amp should say how many ohms it handles on the back of it too.
yep.. you can quit looking for that setting now that your new proc is in the mix..
JBL amp, huh? Is the power output of the JBL amp similar to that of the Onkyo? Compare the 4 ohm ratings for each amp & receiver? if so you should be fine.
Most stand alone amps DO NOT have switches for impedance. Some do have taps to optimize impedance matching between the amp and the speakers. Such as 2, 4, or 8 ohms. Some might not.
Amp to speaker matching is important and about the time someone gets into going with separate pieces, as you have done, is when the dealership, or buyer should be in the know as to what amp can accommodate what speakers properly enough in terms of at least the power requirements of and for each.
The Switch or setting as was said above are like training wheels for the plug and play novice. Loads of amp makers offer no such flexibility. Therefore its important to check for yourself what the maker of your speakers says are proper power ranges theyll operate in/with, and as well, what amounts of power and at what impeadance the amp makers amps will output.
Many amps will double their power ratings when applied to a halved impeadance. EX 100 wpc @ 8 ohms could equate to 200wpc @ 4 ohms.
Such is not always the case however so you must ask, read or inquire for yourself and the safety of your equipment.
Most every amp has its output rated at an 8 ohm standard. Id venture a guess here, that IF your JBL amp is identical or betters your former receiver in the 8 ohm range, the JBL will do just fine. The primary issue with amps and speakers is an under powered condition . And not an overpowered one.
Lastly, once all is connected, and the volume is set to its lowest settings off and slowly raised, youll get a very good idea right there as to how well matched you are though not precisely just an idea. Barely cracking open the volume and getting exceptionally loud sounds says youve more than enough power for the speakers. Having to go way on up on the volume knob to perhaps near its limits says the opposite . Usually. If all is connected & setup rightly.
i was always using separates, the onkyo receiver was only used as a pre amp tho. this allowed me to select 4 ohms in tbe onkyo and run my jbl amp @190 wpc in 4 ohm.
now, with the exception of the new processor, all the components/speakers are the same. the only difference is that the amp must now run @ 125 wpc in 8 ohms ( no ohm switch in 80.1.)
my concern is the unmatched ohm rating my 4 ohm rated m&k s125 speakers which are now being fed power from the 8 ohm rating.
i think the 8 ohm 125 wpc will be enough but i just wanted to double check if the mismatched ohm ratings are a problem.
sorry if i seem a bit confused, im not an experienced audiophile.
thanks so much for your help
Since you were using the Onkyo receiver as a preamp, the 4 ohm speaker output impedance setting had no effect because you were not using the speaker outputs.
Since you've been using the power amp with the speakers, you are good to go with the new preamp. The power amp sees your speakers as a 4 ohm load, so it'll be able to provide up to 190 wpc.
The only JBL multi-channel amps I could find are the S5125,and the S7125.Both of those state do not use less than 8 ohm speakers on the back of the unit.8 ohms is the home theater standard like mentioned above.Its odd that M&K who seamed to focus on home theater to stray away to 4 ohms.I had their first(I think)sub woofer from the 80s.Running those speakers on one of these JBL amps can be risky for the amp.If your amp is a different model,double check the back of the amp,and owners manual.On my earlier post,I said the processor normally doesn't have an impedance switch.The reason for that is,I was told in the 90s there was a couple of them that had the switch in the processor.They weren't the normal.They only worked with their own equipment,and had a special 25 pin plus cord that connected to their own brand of gear.I can't remember the brand,but it wasn't Onkyo,or JBL.Like mentioned above,if your using Rca or balanced connection,the impedance can *not* be switched by processor.Some Onkyo amps have the ohm selector on the back of them.The majority of the amps say what they can run on the back of the amp.4 ohms is twice the load of a 8 ohm load.Harman Kardon may have a suggestion for you.Some of their processors are Lexicon,but I don't know who made the amps.If I don't post,its because my internet is having intermittent problems.Link for those amps I mentioned.[http://www.jblsynthesis.com/Uploads/Files/Site/JBL/S7165-S5165-S820%20OM%20hires.pdf]