whoaru99
Epic Member
Looks like the rule is that the amp impedance should be 10 times the preamp impedance and this situation puts me just shy of that.
It'll be fine...
Looks like the rule is that the amp impedance should be 10 times the preamp impedance and this situation puts me just shy of that.
That's not a carved in marble requirement, just a general rule of thumb. You should be fine.Looks like the rule is that the amp impedance should be 10 times the preamp impedance and this situation puts me just shy of that.
Yes.Another question, if I have an eq hooked up to the Onkyo via the tape loop, the second amp will get an eq'd signal too, right?
Here is the scoop...
Input impedance of second amp......47000 ohms
Input impedance of Onkyo TX8500 amp.......???
Output impedance of Onkyo TX8500 preamp......???
Should I go for it?
What is the worst that can happen? Could I compromise reliability of the preamp / receiver?
Unfortunately, receiver manufacturers rarely publish specs for preamplifier outputs. Nor are input load specs published for all power amplifiers either which can vary widely from one amplifier to the next. The effects of improper loading between components is no different than it is for phono cartridges - namely irregular frequency response.
Without knowing what the values are for the specific units, it is impossible to answer in the absolute whether there will be any negative sonic effects or not.
there is a check to be made to all of this
speakers powered by different amps can be out of phase with each other unless all amps are the same model
My meaning wasn't to ascribe an exact number on unknown amplifiers that could be driven by a TX-8500, but just as an example. To know the exact number, one would have to know the output impedance of the preamp section (if you're lucky, it will be in the SM. If you're really lucky, it will be in the OM), and the input impedances of amplifiers and then do the math.
It really totally depends on the specific equipment involved. His suggestion could be quite accurate depending on the specific equipment involved.
I'm sure different manufacturers hold to different standards for different reasons. While i recognize the 10:1 rule as a general guideline, there are specific manufacturers whose recommendations go well beyond that in both directions while others specify the 10:1 ratio as a minimum. For example i had a CJ PV-5 with a rated output impedance of less than 200 ohms, yet they recommend driving amplifiers with input impedance of 100k or greater.
I often refer to the Peavey white paper on impedance, it's a good primer and easy to digest. I would offer this segment quoted from there:
Here's the link to the entire white paper, note that the "next page" links are very small : https://peavey.com/support/technotes/concepts/impedance.cfm