Hum - Low Volume - amp?

ajanzalone
ajanzalone Posts: 128
edited September 2008 in Troubleshooting
Well I was just starting to enjoy my vintage stereo system again ....
Audio Research SP5 - Quad 405 - Polk Monitor 10's

Then, of course, I turned it on today......
with the volume set at "0", ...........

Immediately a grumbling was heard through both speakers .....
I turned the volume up a notch and the grumbling went away, return to "0" quiet ... ok

I then noticed a very low hum in both speakers. I had to get within 6 inches to hear it.

I set the pre-amp to TV, turned the volume up 1- 2- 3- 4- 5 then 6,
(about 40% volume), and it just started to sound like normal level .....?
Normally it gets loud enough to rattle the windows on 4 .....

I checked the amp fuse and it was OK

I suspect the sound I was hearing through the speakers was from the pre amp's output of 10/15 or 20 watts?

So, did I blow an amp or capacitor?
Any thoughts as to what this could be?
amplifier caps ? ..... or power section ......?

Of course, I have been anxiously awaiting the arrival of my new DV-48AV, (DVD/SACD player),
which will be here tomorrow, according to UPS:(

Tony
Audio Research SP5 Preamp
Quad 405 Amp
Pioneer Elite DV-48AV -
Outlaw 950 preamp/processor
Polk Monitor 10's
Velodyne VRP 1200 Sub Woofer

Success is having what you want ... but Happiness is wanting what you have!
Post edited by ajanzalone on
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  • ajanzalone
    ajanzalone Posts: 128
    edited September 2008
    Is there a way to test the voltage at the "Amp & Pre-amp" so I can narrow down as to which unit is at fault?

    Tony
    Audio Research SP5 Preamp
    Quad 405 Amp
    Pioneer Elite DV-48AV -
    Outlaw 950 preamp/processor
    Polk Monitor 10's
    Velodyne VRP 1200 Sub Woofer

    Success is having what you want ... but Happiness is wanting what you have!
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  • ajanzalone
    ajanzalone Posts: 128
    edited September 2008
    Keiko wrote: »
    I'm not an expert on this but a couple things I can suggest is checking your interconnects and use good quality, well shielded IC's. A good surge/power conditioner certainly wouldn't hurt either.

    Yeppers..clean the interconnects ..........
    I opened the Amp..
    Checked all the fuses.. all OK
    I cleaned the Quad proprietary - DIN contacts and the RCA contacts with a soft pencil eraser ....

    Hooked everything up.... and Viola .... loud and clean again....! Got me stumped ..... ?

    Hooked up the New Pioneer Elite DV-48AV, (DVD/SACD player) with some standard CD's .. WOW! .... more musical then I have ever heard them..

    I can't wait for the SDCD music to arrive, that I ordered....

    Thanks Tony
    Audio Research SP5 Preamp
    Quad 405 Amp
    Pioneer Elite DV-48AV -
    Outlaw 950 preamp/processor
    Polk Monitor 10's
    Velodyne VRP 1200 Sub Woofer

    Success is having what you want ... but Happiness is wanting what you have!
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  • ajanzalone
    ajanzalone Posts: 128
    edited September 2008
    Keiko wrote: »
    Cool! Wait till you hear what SACD delivers. :D

    Might want to consider investing in some good interconnects and speaker cables Tony. It only gets better. Welcome to The Dark Side bro. ;)

    I have already replaced all my RCA to RCA connectors to Gold tipped cables from "Monoprice.com" ......
    but the Quad amp has a proprietary DIN to RCA cable and I have not found one in Gold yet .... I even called Quad ....:(

    Yep I am getting excited:D

    Tony
    Audio Research SP5 Preamp
    Quad 405 Amp
    Pioneer Elite DV-48AV -
    Outlaw 950 preamp/processor
    Polk Monitor 10's
    Velodyne VRP 1200 Sub Woofer

    Success is having what you want ... but Happiness is wanting what you have!
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  • ben62670
    ben62670 Posts: 15,969
    edited September 2008
    You can send me your din cable, and I can build you one in silver?
    Ben
    Please. Please contact me a ben62670 @ yahoo.com. Make sure to include who you are, and you are from Polk so I don't delete your email. Also I am now physically unable to work on any projects. If you need help let these guys know. There are many people who will help if you let them know where you are.
    Thanks
    Ben
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  • ajanzalone
    ajanzalone Posts: 128
    edited September 2008
    ben62670 wrote: »
    You can send me your din cable, and I can build you one in silver?
    Ben

    Ben:
    Thanks for your offer ....
    I have not yet decided if I will upgrade to a newer amp ...

    or get the Quad 405 updated by data techs ........ who make this product and more.
    They have a local tech that will install and test the Quad 405 rebuild ....
    http://cgi.ebay.com/Quad-405-High-End-replacement-board-with-OPA627_W0QQitemZ130243103993QQcmdZViewItem?_trksid=p3286.m20.l1116

    I just found this cable on ebay
    http://cgi.ebay.com/4-Pin-DIN-to-RCA-Quad-33-44-303-405-to-RCA-Amp-Cable_W0QQitemZ110286699851QQcmdZViewItem?hash=item110286699851&_trksid=p3286.m63.l1177#ebayphotohosting

    Thanks
    Tony
    Audio Research SP5 Preamp
    Quad 405 Amp
    Pioneer Elite DV-48AV -
    Outlaw 950 preamp/processor
    Polk Monitor 10's
    Velodyne VRP 1200 Sub Woofer

    Success is having what you want ... but Happiness is wanting what you have!
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