Output Impedance?

I made the purchase of a new(used) amp and was wondering how well my 970 output impedance will match up to the input of the new amp. unfortunately i couldnt audition the amp first but did get it for such a good price i couldnt resist, not to mention it still has 4 yrs left on the transferable warranty.

the 970 manual says:
Output Impedance(main-RCA) <600ohms

the new amp is listed at:
• Input Impedance:
Unbalanced - 23.5kohms


what does that mean? greater than 600, does that match a 23.5k? gonk can you explain this please?

i had read allot about impedance mismatches in gear that can cause a total lack of synergy in a system in the past, and am now trying to predict some results by specs.

also does anyone know what the output gain is structured like on the 970? the amp manual shows an input gain of 32db which seems high to me....

thanks in advance

I'm afraid that I can't help on this one. I'm not sure how those specs are going to relate.

thanks anyway, gonk.

Whenever you cascade amplifiers in a system you want the output of one stage to be a low impedance and the input of the next stage to be a high impedance. That way the stage you are driving won't load your source down.

Per the specs above you have a factor of ~40 between the impedance of the pre-amp and the power amp so you should be fine.

Not certain about the reference to impedance mismatches? Are they talking transmission line mismatches, which is a different topic? Or not mixing power amps with wildly different input impedances? For example if you are using a power amp with a FET input it can have an input impedance in the MOhm range which will load your pre-amp differntly than your 23.5 KOhm input amp. Mixing amps like that would have an effect but I'm not sure how significant it would be.

32dB gain isn't bad if that means the whole amp. Based on that number I'm guessing you have a 250 Watt into 8 Ohm power amp?

close, its a 300w @ 8ohms, 500@ 4ohm. class A/B

that makes sense. and i know not to make to much of specs before you hear the gear, im just anxious for a better amp. i think part of my question is result of not hearing it first, i hate not hearing gear before buying it but this was too good of a deal to pass up.

500W at 4 ohms puts the ML Preface putting out 27 db above the 92 db efficiency rating. Approaching jet engine sound levels even on peaks is pretty impressive.

The 970 is saying its output is less than 600 ohms. That usually means the series output resistor is between 47 and 560 ohms. In any case, it will easily drive your power amp's 23.5 k load.

The gain of 32 dB is only 3 dB higher than usual--most are 29 dB, so easily calibrated with the channel trims.

your right, but its not about top volume, its about dynamics and ease to drive the speakers. the new amp made changes i really didnt expect. the sound is so much more open and airy, the clarity and detail is dramatically better. FWIW, its also louder at lower volume according to the 970, which isnt any real benefit just an observation. but this change was so obvious my wife, who was jacked i was getting another toy even noted that it sounded very different(she wouldnt give me the satisfaction of admitting it sounded better ). its class A/B with a 1,200VA transformer, 45,000uF of capacitance, and 12 output devices per channel.... this thing really has the balls to get the job done. im very amazed how drastic the change has been. it does play incredibly loud and clear as a whistle too, but the better impression is the performance at low volumes, its so clear and detailed. its just amazing how much it opened my speakers up, like a cover that was slightly muffling the sound was lifted off them and i can really hear them sing now. im happy.

i bet my electric bill goes up a to prove all that too!

all i need now is a true stereo preamp and im set!