Alonsou Posted October 18, 2021 Posted October 18, 2021 Hello, I have a question, Couple weeks ago, I was using my Kef 104/2 speaker set powered with an Adcom GFA-5400 Amp, I've been using this set up for many years without a single issue, all of a sudden, I heard a really loud high pitch noise, so I ran and turned everything off, gave it a few minutes and try running everything again, just now to see that something was very odd, sound was not the same, sounded muffled and distorted, so my first guess was the amp has gone bad, but I was quick to rule that out by just bypassing the amp completely and go straight from the receiver to the speakers with no other component in between, and the sound was the same, muffle and distorted, so my question is the following. What could be wrong here? I am guessing I might need a new set of caps, so I am looking at Falcon Acustics, I am very handy at soldering, so that is not an issue, just a few years ago I recapped completely a Fisher 500C tube receiver. So, I am making a good guess here?
Alonsou Posted October 18, 2021 Author Posted October 18, 2021 Ohh I forgot to mention... this happened to both speakers... same distortion on both.... very odd honestely.
Weka Posted October 19, 2021 Posted October 19, 2021 Could be a good idea to hook up some other speakers to the receiver to verify it's not the faulty item. 1
Quark Posted October 19, 2021 Posted October 19, 2021 39 minutes ago, muon* said: Check the drivers also. Yes, I'd be having a good listen for dead tweeters/mids.
Ratbob Posted October 19, 2021 Posted October 19, 2021 I recently rebuilt my 104.2s, well, an SNA member did the crossovers for me but yeah, Falcon Acoustics caps. I did the dust covers and Ferrofluid, which was quite easy. However, both speakers blowing at the same time seems odd to me. I’m thinking it’s the amp. 1
Alonsou Posted October 19, 2021 Author Posted October 19, 2021 Thanks for all the replies. Good points to look at, however.. I already have another set of speakers on the receiver working with no issues. The amp is already powering those speakers as well. If I wire the speakers (Kef's) to any receiver I get the same issue of muffle and distorted noise, it just has me puzzled that it happened to both speakers though at the same time. When it happened I was playing them at about 1/4 the max power, so I know I didn't over drive them, I will double check the amp one more time, but I am pretty sure the amp its fine. I do have a spare set (full asssembly) of mids and tweeters for the Kefs so I will try that next as well.
Monkeyboi Posted October 22, 2021 Posted October 22, 2021 On 20/10/2021 at 4:13 AM, Alonsou said: Thanks for all the replies. Good points to look at, however.. I already have another set of speakers on the receiver working with no issues. The amp is already powering those speakers as well. If I wire the speakers (Kef's) to any receiver I get the same issue of muffle and distorted noise, it just has me puzzled that it happened to both speakers though at the same time. When it happened I was playing them at about 1/4 the max power, so I know I didn't over drive them, I will double check the amp one more time, but I am pretty sure the amp its fine. I do have a spare set (full asssembly) of mids and tweeters for the Kefs so I will try that next as well. Very unusual for both speakers to fail simultaneously but not beyond the realms of possibility. I would suspect the midrange and or tweeter drivers have somehow been damaged. This may be due to the failure of some crossover components associated with these drivers. So before replacing the drive units I would thoroughly check out the crossover network components, specifically the capacitors in the mid and high frequency sections. A shorted capacitor in the tweeter circuit would surely spell death to the tweeter's voice coil. For what it's worth I'd be having the Adcom amp checked out. The strange high pitched sound you heard just prior to failure could be caused by high frequency instability or oscillation in the amplifier. Also check your connections and interconnects are in good condition and securely plugged in. Consider all components in the audio chain to be suspects. This includes the pre-amp and source you were listening to at the time of the failure. Hope you get it sorted. Cheers, Alan R. 1
Ruffter Posted October 26, 2021 Posted October 26, 2021 Yeah my worry would be bad amp has blown the speakers. Would hate for you to fix the speakers, hook them up and blow them again. cheers, Andrew
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