Marantz pm7003 + Infinity primus 250


New member
Username: Qw11

Post Number: 2
Registered: Mar-18
Hi Guys,
I'm using Marantz pm7003 amplifier paired with Infinity primus 250 speakers. Going above 85% of the volume knob the lows are becoming weaker the sound is distorted and sometimes the protective circuit is triggered. Why is this happening? Should i look for new amp or new speakers?

Platinum Member
Username: Jan_b_vigne

Dallas, TX

Post Number: 18507
Registered: May-04

The amp is going into clipping; AY_enUS754US756&oq=what+is+amplifier+clippling+distortion&aqs=chrome..69i57.1449 9j0j1&sourceid=chrome&ie=UTF-8

Bass requires more power than the upper frequencies and your volume control is not linear. Output for any setting on the control is relative to the input level from the source. So 85% on the VC is almost always too high. Turn down the control or risk blowing out your speakers.

Doubling wattage - all else equal, which it never is - will only gain you an additional 3dB on peaks, not at average level settings. To play louder without driving the amp into clipping requires at least another +6dB of electrical sensitivity from the speaker system or 10 times the RMS wattage of your current amplifier. Additional speaker sensitivity will raise all frequencies (more or less, given the flatness of the response from each speaker being compared) and the music will sound louder with less rotation of the vc (using the same amplifier). The amp will be producing less wattage, be further away from clipping and the speakers will put more loudness into the room. All things being equal, which they never are.


New member
Username: Qw11

Post Number: 3
Registered: Mar-18
Thank you very much for the great explanation.
I think i should consider replacing my old infinity's with KLIPSCH KF 28 which are rated at 98dB and can handle up to 150W RMS.
« Previous Thread Next Thread »

Add Your Message Here

Bold text Italics Create a hyperlink Insert a clipart image Add a YouTube Video
Need to Register?
Forgot Password?
Enable HTML code in message

Main Forums

Today's Posts

Forum Help

Follow Us