Crikey!!! amp problemo

danger boy
danger boy Posts: 15,722
edited December 2006 in Electronics
ok.. fired up the home theater today.. and i got distortion city out of the left channel of my Adcom GFA 5400 it's pushing a pair of RT800i's. easy enough speaker to push.

I thought ok maybe it's the interconnect from the pre amp.. swapped it out.. actually got worse F^#@%&*in' hum. With no source coming into it.. no hum. so maybe I blew a line rail fuse or the left input is toast.

how does this happen overnight? the cat was sleeping with me.. so it wasn't her fault. ;)

anyway.. i'm pissing nails for now. Totally screwed with my day... which was suppose to be easy. I was going to DeOxit a vintage Pioneer receivier today.. unitl this happen. Now i gotta do some explorin'. :mad:
PolkFest 2012, who's going>?
Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • amulford
    amulford Posts: 5,020
    edited November 2006
    Check the solder connections at the input connector
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    opened her up.. checked under the hood. and sure enough.. blown fuse. it has 4 internal fuses. and one external power fuse.

    Anthony, i did check the input connectors.. they check out fine. I DeOxited it.. it's back up and running again. Still weird why it blew a fuse...
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    even bigger problem now just developed. i fried one of the RT800i's. the drivers are not working except the tweeter. &#%&^@#+(!!!!!!!! this is bad.

    So when i had the amp hooked up in a different room with a different system... after replacing the fuse.. it was working fine.

    Now i put it back in the home theater and it's toasting speakers. but not the channel that i replaced the fuse in.. the other channel. I'm going to take it out of the system till i can have it checked out.. OMG. I can't believe it completed toasted an RT800i to death.

    If it didn't fry the drivers in the 800i, then it toasted some component in the crossover... either way.. the blue drivers are not working.

    I'll have to call Ken on Monday.
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • Polkersince85
    Polkersince85 Posts: 2,883
    edited November 2006
    Sounds like they are jealous of the Pioneer.
    >
    >
    >This message has been scanned by the NSA and found to be free of harmful intent.<
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  • heiney9
    heiney9 Posts: 25,217
    edited November 2006
    Check the DC Offset at the speaker terminals. DC will kill drivers. The GFA-5400 shouldn't have DC issues, but electronic gremlins are everywhere. Sorry to hear about your misfotune. Crap like this is annoying. You take care of stuff, run it properly and it can still give you trouble sometimes. Very odd that the opposite channel than the one you replaced the fuse is giving you trouble.

    Sorry DB

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    what is the DC offset?
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • heiney9
    heiney9 Posts: 25,217
    edited November 2006
    Here's a link be sure to click on the audio karma link for further details

    http://www.polkaudio.com/forums/showpost.php?p=530759&postcount=38

    Here's another link, this was just discussed so it's easier to post the link than to type another explanation.

    http://www.polkaudio.com/forums/showpost.php?p=533218&postcount=39

    Really though if you have time visit the Audio Karma link in the first link I gave you. It's simple and effective, but you have a volt/ohm meter that reads millivolts.

    Hope this helps

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • BottomFeeder
    BottomFeeder Posts: 1,684
    edited November 2006
    Rats!

    About all I can offer is a heartfelt "bummer, dude!"

    Sorry, Al!
    "Wish I didn't know now what I didn't know then." Bob Seger
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    after swapping out interconnects, speaker cables, etc.. i've reached the conclusion that it's the right channel speaker connectors, binding post that are cutting in and out. I'll have to replace them all.

    I guess it cut out then in again and that burst of juice fried the 800i. Dang it!

    Well, the good news is... heck there is no good news on this one. :(
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • heiney9
    heiney9 Posts: 25,217
    edited November 2006
    danger boy wrote:
    after swapping out interconnects, speaker cables, etc.. i've reached the conclusion that it's the right channel speaker connectors, binding post that are cutting in and out. I'll have to replace them all.

    I guess it cut out then in again and that burst of juice fried the 800i. Dang it!

    Well, the good news is... heck there is no good news on this one. :(

    Doesn't really make sense that a bad connection would fry a speaker. Something still sounds fishy to me. But hey, if that's what it turns out to be it seems like a pretty simple fix.
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    heiney9 wrote:
    Doesn't really make sense that a bad connection would fry a speaker. Something still sounds fishy to me. But hey, if that's what it turns out to be it seems like a pretty simple fix.

    Agreed. but that's the only thing i've found wrong with the amp so far. True, there may well be other problems.
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • Refefer
    Refefer Posts: 1,280
    edited November 2006
    Hmm, maybe time to send it in to the good folks at adcom before it takes out the rest of your speakers.
    Lovin that music year after year.

    Main 2 Channel System

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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    true, true. OneCall says they work on Adcom products.. and they are local to me.. so that's where i'm going to start. I don't want to ship it out if I don't have to. Weight, damage, etc from shipping scares me. I don't have the original box.
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • Dennis Gardner
    Dennis Gardner Posts: 4,861
    edited November 2006
    If you found speaker connections loose, check to make sure your brass jumpers between mids and highs are making contact.
    HT Optoma HD25 LV on 80" DIY Screen, Anthem MRX 300 Receiver, Pioneer Elite BDP 51FD Polk CS350LS, Polk SDA1C, Polk FX300, Polk RT55, Dual EBS Adire Shiva 320watt tuned to 17hz, ICs-DIY Twisted Prs, Speaker-Raymond Cable

    2 Channel Thorens TD 318 Grado ZF1, SACD/CD Marantz 8260, Soundstream/Krell DAC1, Audio Mirror PP1, Odyssey Stratos, ADS L-1290, ICs-DIY Twisted , Speaker-Raymond Cable
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    Dennis Gardner wrote:
    If you found speaker connections loose, check to make sure your brass jumpers between mids and highs are making contact.

    Funny you should mention this.. after i replaced the blow fuse in the Adcom.. i made new jumpers out of 14 guage wire... to replace the brass ones. then all hell broke loose and it blew the crossover in the 800i.

    I'm sure it was just coincidence... the jumpers could not cause this kind of reaction i'm sure.
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • heiney9
    heiney9 Posts: 25,217
    edited November 2006
    WTH DB, are you in the twilight zone? Sounds like an awful lot of coincidence or just plain bad luck. Sounds like you've been messing with some things. So have you narrowed it down? Drivers, tweeters, crossover, fuses, left channel, right channel, poor connections?

    I'm getting frustrated just reading about your misfortune, so I can imagine you are probably quite PO'd as well. Good call to send it in for a check-up, too many wierd things happening all in a row.

    good luck

    H9
    "Appreciation of audio is a completely subjective human experience. Measurements can provide a measure of insight, but are no substitute for human judgment. Why are we looking to reduce a subjective experience to objective criteria anyway? The subtleties of music and audio reproduction are for those who appreciate it. Differentiation by numbers is for those who do not".--Nelson Pass Pass Labs XA25 | EE Avant Pre | EE Mini Max Supreme DAC | MIT Shotgun S1 | Pangea AC14SE MKII | Legend L600 | BlueSound Node 3 - Tubes add soul!
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    it has to be the Adcom GFA 5400 amp... i opened it up again.. as far as i can tell.. everything seems ok. but i'm no electrical engineer or assume to know much about this stuff.

    but the binding posts are cutting in and out.. as well as the right channel RCA input. I think Anthony called that one early on. ;)

    It's not going to be used till it gets back from being serviced.

    I know the more i delve into it.. the more obvious problems i seem to find with it.
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • dkg999
    dkg999 Posts: 5,647
    edited November 2006
    Do the RT800's have the poly fuses on the x-over like the SDA's? You might have blown one of the poly fuses and that's why the drivers aren't working.
    DKG999
    HT System: LSi9, LSiCx2, LSiFX, LSi7, SVS 20-39 PC+, B&K 507.s2 AVR, B&K Ref 125.2, Tripplite LCR-2400, Cambridge 650BD, Signal Cable PC/SC, BJC IC, Samsung 55" LED

    Music System: Magnepan 1.6QR, SVS SB12+, ARC pre, Parasound HCA1500 vertically bi-amped, Jolida CDP, Pro-Ject RM5.1SE TT, Pro-Ject TubeBox SE phono pre, SBT, PS Audio DLIII DAC
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    dkg999 wrote:
    Do the RT800's have the poly fuses on the x-over like the SDA's? You might have blown one of the poly fuses and that's why the drivers aren't working.


    Ummm. i don't know if they do or not. I'm sure i'll find out tomorrow when i call CS. I wonder how much a crossover will run me?
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • reeltrouble1
    reeltrouble1 Posts: 9,312
    edited November 2006
    Db,

    Nad
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    I ordered the crossover for my RT800i today. should be here in a few days.

    Ted, what's up with Nad? I am using a NAD amp while i get the Adcom in for repairs. ;)
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • reeltrouble1
    reeltrouble1 Posts: 9,312
    edited November 2006
    I would keep using it. But then I am very partial to them.

    RT1
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    i do like the NAD 2600A, but it doesn't have the proper connectors for banana plugs.. i guess since it's an older model.

    but, then it is the amp that is suppose to be running the SRS"s.. and i know the Adcom doesn't have the balls to run the SRS's.. i've been there, done that with bad results.

    Update: I heard from the local repair shop today. they indeed found two problems.. the right channel RCA input had a broken solder. and the right channel binding posts had some kind of short as well.

    Still doens't make sense how either one of them could toast the crossover in a speaker. But like someone said.. somehow DC current got inside somewhere and screwed things up.
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    picked up the Adcom amp today. been running now for about an hour or so. no problems yet.. got my fingers crossed. Local repair shop did the work. cost all of $20 :D
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • Blownrx7
    Blownrx7 Posts: 137
    edited November 2006
    What did they do to the unit???
    Not a bad deal if it solved your problems. You can't even get someone to look at a piece of equipment,nevermind fix it, for 20 bucks!
    I fried an amp once because I inadvertently shorted the positive and negative leads so make sure those new jumpers aren't shorting anything out;)
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  • AndyGwis
    AndyGwis Posts: 3,655
    edited November 2006
    Yeah, great question. Who did the work for $20???

    I'd love to find a local place to check out my gear and make sure it's in good working order, just for preventative maintenance. I doubted I could find a place to open one of my amps for $20, much less change out a fuse, much much much less fix some solder and binding post short.
    Stereo Rig: Hales Revelation 3, Musical Fidelity CD-Pre 24, Forte Model 3 amp, Lexicon RT-10 SACD, MMF-5 w/speedbox, Forte Model 2 Phono Pre, Cardas Crosslink, APC H15, URC MX-950, Lovan Stand
    Bedroom: Samsung HPR-4252, Toshiba HD-A2, HK 3480, Signal Cable, AQ speaker cable, Totem Dreamcatchers, SVS PB10-NSD, URC MX-850
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  • amulford
    amulford Posts: 5,020
    edited November 2006
    Did you fry the crossover and not the drivers? Did you check 'em?
    Well, the good news is... heck there is no good news on this one.

    Actually there is a little. You didn't fry that trilam tweeter. They don't make 'em any more.

    You're doing the right thing, send that beyotch in for service. Sounds like a little something or another is loose and giving you the juice.

    What a pain in the ****.

    BTW, you coming out for PF '07?
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    Blownrx7 wrote:
    What did they do to the unit???
    Not a bad deal if it solved your problems. You can't even get someone to look at a piece of equipment,nevermind fix it, for 20 bucks!
    I fried an amp once because I inadvertently shorted the positive and negative leads so make sure those new jumpers aren't shorting anything out;)

    They soldered the input connections.. and there was a screw missing that held something important in place.. that's all they found wrong with the amp.

    It was a local mom and pop electronics repair shop that did the work. I'm glad I didn't have to ship it. :eek: This mom and pop shop, repairs mostly equipment from the 70's. Pioneer, Kenwoods, Fisher... and the like.

    It's been running all day without any problems. Although the design of the amp. it does get pretty warm.
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • danger boy
    danger boy Posts: 15,722
    edited November 2006
    Blownrx7 wrote:
    ;)

    Hey what does your nickname mean? Blownrx7 ? did you toast a Mazda RX-7 :confused:
    PolkFest 2012, who's going>?
    Vancouver, Canada Sept 30th, 2012 - Madonna concert :cheesygrin:
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  • amulford
    amulford Posts: 5,020
    edited November 2006
    Probably has a worked RX7. Those little **** are pretty zippy w/o any work. I had an '86 GXL, it had twin turbos, and it would SCOOT. 90 MPH in third gear...I once drove from here to Miami in that little bugger in 15 hrs., and I stopped to eat twice;)
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