Denon DRA 435R


New member
Username: Traveler_27

Beulah, N.D. USA

Post Number: 1
Registered: Sep-12
This is my first time and question on line. I have a Denon dra 435r tuner and in the manuel it states under amplifier section: 80w+80w at 4 ohms and 55w+55w at 8 ohms. Then on the back by the speaker connections it states A or B 6~16 /speaker, then A+B 12~16 / speaker. Can some body explain what all this means. I'm new at this so any help is great.

Gold Member
Username: Magfan


Post Number: 2979
Registered: Oct-07
The power output of the receiver is based on the speaker impedance. For transistor amps.....otherwise known as solid state, power typically goes UP as impedance goes down. In a robustly built amp, power will double when impedance is halved.
Your Denon is listing the power output at 4ohms which is the low 'typical' value for speakers and at 8ohms which is more normal for HT speakers.
The speaker outputs.....listed as A or B should NOT drop below 6 ohms and have recommended maximum of 16 ohms. This will be the nominal rating for each speaker. When you see A+B as the control, you need to compute the impedance of the speakers in parallel. For SAME speakers, this is 1/2 of the impedance listed. A pair of 8ohm speakers will be OK, by this listing.
The REAL way is to compute the value of speakers in parallel and forget the A+B nonsense listed. For 2 identical speakers in parallel, you simply divide the impedance by 2. For 8 ohm speakers, that would be 4 ohms. A pair of 4 ohm speakers would end up as 2 ohms and NOT be allowed. The amp would NOT like you to do this.
Special case: Speakers are not a single impedance. The impedance varies over the entire frequency range and will be above or below the 'nominal' value at any given point. THAT is the single real hassle with speaker impedance. Your 8ohm speakers? Can range from below 4 ohms to over 12 or 14 ohms and still be called '8 ohm nominal'. IF the impedance dip is at a frequency which also demands a lot of power....say in the bass region somewhere, than your amp won't like a pair of them as A/B speakers, no matter what.
Very few higher than 8 ohm speakers are made these days. And some 4 ohm speakers will even drop below 3. Extreme examples will be below 2ohms and are deal breakers for less than stellar amplifiers.

What kind of speakers are you thinking about? This is a pretty old receiver, isn't it?

New member
Username: Traveler_27

Beulah, N.D. USA

Post Number: 2
Registered: Sep-12

Thanks for answering my question on speaker ohms and impedance and what I should be using on my system. Yes this is a older system, I think it is an early to mid 90's system, but it th newest of the two system I own, my old system is a Harman/Kardon system manf. in the early 70's and if differantly an 8ohms system. On speakers I was thinking about the Bic America DV64, but then look through the Parts Express cat., I thought it might be educational to build some speakers. Don't know what I'll do. On the HK system I'm running HK-20 speakers.

Again thank for you information.

Silver Member
Username: Ornello

Post Number: 122
Registered: Dec-12
When you use two pairs of speakers the net impedance declines (halves), so use speakers of higher impedance when using two pairs. The amp can handle one set of 6 Ohm speakers, but not two, because that would yield 3 Ohms. Two pairs of 12 Ohm speakers yields 6 Ohms of impedance.

When using two pairs of speakers the impedance is cut in half.

The impedance rating of speakers, as mentioned above, is only a nominal value, but the values given are useful enough.
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