Are my speakers supposed to do this?

Hi all. Thanks for reading this thread. I just put a new preamp (Eastern Electric Minimax) into my system and am noticing some weirdness in my speakers. When everything is on but no music is playing I noticed that both the left and right drivers of my monitors (Tyler Acoustic taylos) are moving forward and backwards very slowly but at a very steady rhythm. Takes about a second for them to move forward and then another second to move back. They repeat this cycle until I turn the amp off. This doesn't seem normal to me. I never noticed this with my previous pre. When I play music through the system it seems okay, no obvious distortion although I do notice my drivers moving (from my listening position 7 feet away) in a similar way - slow in and out although it doesn't seem as cyclical.

When I first put the Minimax preamp into my system there was a very loud hum and some static pops coming through the speakers. I lifted the ground on the pre with a cheater plug and the hum & static went away.

Did I damage my speakers? I want to try and trouble shoot but am afraid that damage already may have been done and I don't want to make it worse.

When I first put the Minimax preamp into my system there was a very loud hum and some static pops coming through the speakers
Amazing that the pre tested OK.
Re, testing: Rather than the speakers, shouldn't you be sending the amps for a check-up??
Ykm -

My speakers are middle of the road in terms of driving them (88db). They are basic 2 way monitors, nothing exotic. I've used different pres in my system and never had problems. I am convinced that the issue is with the pre, but I will be sending my amp for a check up just in case. What kind of speaker conditions do you think would cause the problems I'm experiencing?

Gregm -

It IS amazing that the pre tested ok. I have my doubts that this is really the case. My Belles amp will go back for a check-up soon. David Belles is out of town for a few weeks so until then ...

For those of you still following this thread my speakers checked out okay. No damage or problems.

Thanks to all for the suggestions.
Tooter, I was trying to find out any possible clue so to ask the speakers too. If the pre was "causing" your power amp motor boating, the amp is marginally stable. There are many thousand pres out there, the pres you used did not cause any problem with your power amp does not mean it was the EE MM if the power amp was marginally stable. This is not wrong because a hifi equipment designer would sometimes want his gear to deliver better sound with some trade off of slight stability or output power or heat generation or.... An engineer finds a power amp motor boating will first of all fix the power amp. Apologise if I have made some agressive assumption before knowing all the designs of your gears.


No offense taken! No need to apologize. I am just not clear on what you mean by power amp "motor boating" and "marginally stable". Can you elaborate? What part of the amp's design is deficient which would lead to it being "unstable." I'm not an engineer but Belles amps have gotten great reviews and I've used them with many speakers and pres without incident.