1. Join Now

    AVForums.com uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

Blown me speakers up!

Discussion in 'AV Pre-Amp/Processors & Power Amps' started by Bonzodogdick, Jan 18, 2005.

  1. Bonzodogdick

    Bonzodogdick
    Standard Member

    Joined:
    Dec 1, 2004
    Messages:
    171
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    16
    Location:
    Cloud 9
    Ratings:
    +0
    Dont really know how it happened.

    Been using my Arcam 8R bi-wired to my KEF Q35.2's for a while now. I simply added a 8P power amp (connecting the LF cables to the P amp) and switched it all on. The speakers sort of high pitched squeeked, then I noticed Id lost my top end. It onlt seems to have affected the HF and not the LF, so I dont know what I did wrong :confused:

    Ive ordered a pair of new driver units from KEF at a very resonable £66.81 delivered inc vat, but before I fit 'em and goose them again, I want to know whats happening.

    Any ideas? :thumbsup:

    PS: I treble checked I had the polarities correct, and the H & L F's the right way around.
     
  2. eviljohn2

    eviljohn2
    Well-known Member

    Joined:
    Jul 8, 2002
    Messages:
    7,529
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    86
    Location:
    Near London.
    Ratings:
    +208
    Were there any short circuits? For example, did you remember to remove the jumper bars from the speaker terminals?
     
  3. Bonzodogdick

    Bonzodogdick
    Standard Member

    Joined:
    Dec 1, 2004
    Messages:
    171
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    16
    Location:
    Cloud 9
    Ratings:
    +0
    I know what you mean. No definately no jumper bars between the terminals. Ive been bi-wiring them for a couple of years.
     
  4. alexs2

    alexs2
    Well-known Member

    Joined:
    Nov 13, 2002
    Messages:
    13,896
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    136
    Ratings:
    +1,674
    The high pitched squeak prior to the tweeters packing in sounds a little like feedback of some kind....how were the preamp into the 8P connections made?

    It may also be better to post this in the Arcam forum,as John Dawson and other Arcam folk frequently visit there,and may be able to give much more specific help.
     
  5. Bonzodogdick

    Bonzodogdick
    Standard Member

    Joined:
    Dec 1, 2004
    Messages:
    171
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    16
    Location:
    Cloud 9
    Ratings:
    +0
    Thanks matey. Ill copy my original thread over into the Arcam forum.

    It was connected with stereo interconnects Pre Amp Out - To Power Amp In as per manual.

    The power light on Arcams start Amber in colour, then click on and turn green. The 8P, never turned green, just remained Amber and let out a couple of squeels. When I tried it back to my normal method (ie: 8R Integrated only) was when I noticed the HF had gone awol. Without speakers attached, the power amp light turned green.

    The more I think about it, the more confusing it becomes, but I appreciate your advice. :thumbsup:
     
  6. Cliff

    Cliff
    Well-known Member

    Joined:
    Mar 17, 2001
    Messages:
    4,681
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    137
    Location:
    Kent & overseas
    Ratings:
    +1,833
    Sounds like instability in the power amp when conected to a light load. Driving just a tweeter (through a crossover which might just be a capacitive load) might prove troublesome to some amps. Are your speaker leads long? Are they a fair distance away from your input wiring?
     
  7. Bonzodogdick

    Bonzodogdick
    Standard Member

    Joined:
    Dec 1, 2004
    Messages:
    171
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    16
    Location:
    Cloud 9
    Ratings:
    +0
    Hi Cliff,

    At the moment the speakers are approx 4 - 4.5m away from the units. This is all gonna change at the weekend though cos Im moving my system in between the speakers, so the distance between speakers will be about 1.6 metres with the system in between. (If that makes sense?)
     
  8. Cliff

    Cliff
    Well-known Member

    Joined:
    Mar 17, 2001
    Messages:
    4,681
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    137
    Location:
    Kent & overseas
    Ratings:
    +1,833
    I am assumming you have looked at all the obvious things. Check that the earthing is good between all the amplifier units. Check that the interconnect earths are good between preamps and main amps. Make sure there is no connection between the outputs of the power amps- as was already mentioned (speaker jumpers). The speaker wires should not go near any of the input wiring
    Shortening the speaker leads can only be good, for two reasons. You will reduce the inductance and the chance of stray radiation feeding back into the input stages.
    Can you try the setup with some other speakers instead of the tweeters just as a test in case the same thing happens again!
     
  9. jradley

    jradley
    Active Member

    Joined:
    Jan 16, 2004
    Messages:
    892
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    43
    Ratings:
    +212
    Just a quick note - when bi-wiring leaving the jumper bars on won't do any harm. When bi-amping, it certainly can do.

    It's also a little odd that you say the LF was connected to the 8P, which itself let out a squeel but it was the HF driver that died. As Cliff says squeeling amps is usually a sign of instability. In most cases it's due to incorrect cabling (eg. short circuits or maybe another amps output trying to drive its output)

    Was the 8P known to be good before you added it to the system ?

    Good luck sorting it out,

    John

    Before the incident did you know the 8P to be in working condition ?
     
  10. Bonzodogdick

    Bonzodogdick
    Standard Member

    Joined:
    Dec 1, 2004
    Messages:
    171
    Products Owned:
    0
    Products Wanted:
    0
    Trophy Points:
    16
    Location:
    Cloud 9
    Ratings:
    +0
    Hi John,

    It was actually the first time Id tried the P amp as Id just bought it, but I am convinced it was in correct working order, likewise the integrity of the seller. (See also thread on Arcam forum).

    As per cliffs reccomendation, once Ive got my new drive units Ill hook them up to some cheap & nasty speakers. My only concern is that theyre not bi-wirable, so Im unsure as to the correct connections.

    Thanks for taking the time to help guys. Really appreciate your input :smashin:

    Bonzo
     

Share This Page

Loading...