Amp causes speaker "pop"

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Maybe someone can help me with this. The amplifier I am currently using is an Adcom GFA 555, 200w/ch amplifier.

When I turn the amp off after listening, a 'pop' occurs through the loudspeakers after the capacitors discharge Im assuming. Adcom amps are known for this, but I have never investigated it.

Will this transient hurt the crossover or drivers in my speakers?

Thanks to all that respond in kind.

Mark Evans

RMAF 2010 Surpasses Expectations

RMAF 2010 Surpasses Expectations

Photo: John Atkinson

t's one thing to know that you're attending what has quickly grown into the largest annual high-end show in the United States. It's something else entirely to try to take in even a third of the 180 exhibits that were spread over the width, breadth and height of the Denver Marriott Tech Center.

RMAF 2010 drew such a huge rush of attendees on the first day (October 15) as to cause at least one overly packed elevator to spend what seemed like a minute in limbo, considering whether it should dare try to ascend. When it finally determined to go up rather than crash down, it moved in fits and starts, and shuddered each time it reached a floor. I think more than one of its occupants took a vow then and there to finally lose some weight. Stereophile ran out of their new-at-the-Show November issue by the end of the second day, and when a member of the Colorado Audio Society donated his collection of back issues to us on Sunday (see the photo), they were all gone within minutes.

Show exhibits extended to eight packed floors, and down into the. . .

Synergistic's Black ART

Synergistic's Black ART

When I reported in our report from the 2009 RMAF that I perceived a degradation when Ted Denney of cable manufacturer Synergistic Research removed his tiny ART devices from the room, it triggered a debate that raged not just in the comments following that report but also in our website forum right up to today. The fact is that these small metal bowls are too small to have a significant effect on the acoustics of a room at frequencies below 10kHz or so, yet they seem to improve the accuracy and stability of stereo imaging and even tighten up the sounds of bass instruments. It is a mystery, therefore, how these devices can work. I have conjectured that perhaps they have an effect on the listener’s state of mind rather than the acoustics, but if so, then I don’t comprehend how that effect can be both repeatable and demonstrable. Whatever they do—if they do anything, that is—therefore, I wasn’t sure what to expect when I went into my final room at the 2010 RMAF, the Synergistic room.

Tidal's "We Build Emotions" Touch My Own

Tidal's "We Build Emotions" Touch My Own

Some of my happiest sonic experiences at RMAF arrived in the last two rooms I visited: the Tidal Audio/Argento Audio Cables/dCS showcase put together by Doug White of The Voice That Is (Newton Square, PA), and the Simon Yorke/CAT/Synergistic/Lansche exhibit assembled by Tim Nguyen of <A HREF="http://blog.stereophile.com/rmaf2010/tone_of_music_sings/">Tone of Music</A> (San Francisco, CA).

Dynaudio - Wadia - Octave

Dynaudio - Wadia - Octave

Perhaps the best sound I heard at RMAF was in the large room on the mezzanine shared by Dynaudio, XLO, and Wadia. The Dynaudio Confidence C4s ($20,900/pair), which I first <A HREF="http://www.stereophile.com/floorloudspeakers/794/">reviewed in March 2003</A>, were sounding as good as I remember them sounding in my own room, perhaps even better. The rest of the system was obviously high-class: a Wadia 971 CD transport ($17,950) fed Wadia's Series 9 Decoding computer ($33,450, comprising the 931 controller and dual-mono 922 DACs), which in turn fed Octave MRE130 tubed monoblocks from Germany ($16,000/pair) sitting on Grand Prix amp stands. Cabling was all by XLO. The 130W Octave amplifiers use two pairs of KT88s in push-pull and the wideband output transformer has a single tap. The amp can also use 6550s or EL34s, and an accessory "black box" increases the B+ storage capacity.

Revel & Mark Levinson

Revel & Mark Levinson

One of my two best sounds at RMAF was from Revel's Ultima Salon2 speakers ($22,000/pair), which have been favorites of mine since <A HREF="http://www.stereophile.com/floorloudspeakers/608revel">Larry Greenhill's review</A> appeared in the June 2008 issue of <I>Stereophile</I>. At RMAF, the Revels were being driven by Mark Levinson No.53 monoblocks ($25,000/pair), which in turn were being fed straight from the variable output of a Mark Levinson No.512 SACD player ($15,000). Cabling was all-Transparent. The superbly stable soundstaging extended beyond the physical positions of the speakers, the tonal balance was one of the most neutral I heard at the Show, and the bass was both extended and defined. I would have stayed listening for longer, but the Show only had 30 minutes more to run and I had two more rooms to visit.

Audio Design from Jan Didden & Bob Cordell

Audio Design from Jan Didden & Bob Cordell

DIY hi-fi used to be an important aspect of audio magazine content 30 and more years ago, but these days it has migrated almost completely to the Internet, with just Ed Dell's <I>AudioXpress</I> magazine still waving the roll-your-own flag in print. Sharing a stand at RMAF were two of the Internet's most notable DIY engineers, Jan Didden from Holland (left) and Bob Cordell from New Jersey (right), and both were venturing into the print medium. Bob had advance copies of his new tome <I>Designing Audio Power Amplifiers</I> for sale, which I will be reviewing in <I>Stereophile</I> early in the New Year. Jan had the first volume of his new bookzine <I><A HREF="http://www.linearaudio.net">Linear Audio</A></I>, which has articles on audio design from Bob, as well as Doug Self, Joachim Gerhardt, Nelson Pass, Siegfried Linkwitz, and many others. But if you have any interest at all in the nuts and bolts of audio design, don't wait for my reviews of these books; check them out for yourself. There's audiophile gold within their pages!

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