705 crossovers

Options
need some help. I found one of my 705's had some fried caps and resistors. I have replaced them with some suggested parts from PartsExpress I and still getting a little distortion from that speaker. I have replaced the tweeter and the 3.5 midrange and swopped the speaker from left to right channel the crackling is about 80% better then before but at mid to high volume it just starts to break up. what am I missing or is the parts I installed the problem. I can do the DIY work but just dont know enough about what I should be looking for or parts I need to replace. TIA83cg2l4caz66.jpg
54hdmgqwg2kg.jpg
zi6kggpic9yp.jpg
dq8yak6nsamw.jpg
«1

Answers

  • Gardenstater
    Gardenstater Posts: 4,242
    edited January 2023
    Options
    If swapping the speakers L and R made it 80% better, then you probably have a problem upstream. I would clean all connections with DeOxit next.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • jghglofer
    jghglofer Posts: 100
    Options
    sorry that not what I meant. after changing out the resistor and the capacitor made it 80% better and then I switched the two speakers to make sure it wasn't coming from the right channel. the problem is in the speaker.
  • Gardenstater
    Gardenstater Posts: 4,242
    edited January 2023
    Options
    Perhaps some of the other components that were not visibly "fried" were damaged when whatever event happed that fried the other ones. Another thing is to make sure there isn't a polyswitch on the board that may be the culprit.

    One way to check this may be to swap crossovers within the speakers and see if the problem now goes over to the other speaker.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • VR3
    VR3 Posts: 28,232
    Options
    Those resistors in the top right corner look like they were hot at some point, could be a place to look
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • jghglofer
    jghglofer Posts: 100
    Options
    Thanks for the info
  • Emlyn
    Emlyn Posts: 4,415
    Options
    Since you're in there already it may be a good opportunity to replace all the caps and resistors with better stuff and compare with the other speaker to see if that one's worth doing too.
  • VR3
    VR3 Posts: 28,232
    Options
    Agreed at a minimum those small electrolytic caps would go and could even be bad at this point
    - Not Tom ::::::: Any system can play Diana Krall. Only the best can play Limp Bizkit.
  • jghglofer
    jghglofer Posts: 100
    Options
    if you guy could guide me in the right direction. with resistors and caps. TIA
  • pitdogg2
    pitdogg2 Posts: 24,783
    Options
    jghglofer wrote: »
    if you guy could guide me in the right direction. with resistors and caps. TIA

    How deep would you like to go?
  • jghglofer
    jghglofer Posts: 100
    Options
    Well a new crossover from polk is 200. But if I can get some help here on what to buy and witch cap goes where I would rather do that. I just don't have the knowledge when it comes to resistor values and same with the caps. So let's talk and if it makes more sense to buy the oem crossover then that's what I do
  • Emlyn
    Emlyn Posts: 4,415
    Options
    The new crossover from Polk sounds like a good deal moneywise.
  • jghglofer
    jghglofer Posts: 100
    Options
    Emlyn wrote: »
    The new crossover from Polk sounds like a good deal moneywise.

    I agree but if I can improve the sound with a DIY I don't mind. But if no improve then yes. The few parts I bought cost 25 bucks for both crossovers and did it while watching the games Sunday.
  • Gardenstater
    Gardenstater Posts: 4,242
    Options
    Swapping the crossovers between speaker enclosures and seeing if the problem follows the crossover, would differentiate between a driver issue and crossover issue. Then at least you would know for sure precisely where the problem lies.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • jghglofer
    jghglofer Posts: 100
    Options
    Swapping the crossovers between speaker enclosures and seeing if the problem follows the crossover, would differentiate between a driver issue and crossover issue. Then at least you would know for sure precisely where the problem lies.

    I will do that. and hope it is a driver issue. I did replace the tweeter with a new polk one and the 3.5 mid driver I swopped with one from my 702's.
  • Gardenstater
    Gardenstater Posts: 4,242
    Options
    I suppose the alternative could be swapping the drivers if that is easier.
    George / NJ

    Polk 7B main speakers, std. mods+ (1979, orig owner)
    Martin Logan Dynamo sub w/6ft 14awg Power Cord
    Onkyo A-8017 integrated
    Logitech Squeezebox Touch Streamer w/EDO applet
    iFi nano iDSD DAC
    iPurifier3
    iDefender w/ iPower PS
    Custom Steve Wilson 1m UPOCC Interconnect
    iFi Mercury 0.5m OFHC continuous cast copper USB cable
    Custom Ribbon Speaker Cables, 5ft long, 4N Copper, 14awg, ultra low inductance
    Custom Vibration Isolation Speaker Stands and Sub Platform
  • jghglofer
    jghglofer Posts: 100
    Options
    I suppose the alternative could be swapping the drivers if that is easier.

    that was already done and it didn't make a difference. but I will swop the xo and see I just want to make sure it's not a rattle of some sort
  • F1nut
    F1nut Posts: 49,987
    Options
    The question that needs an answer is what caused the damage to your crossover in the first place?
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • jghglofer
    jghglofer Posts: 100
    Options
    I would say I pushed them a little hard
  • F1nut
    F1nut Posts: 49,987
    edited January 2023
    Options
    jghglofer wrote: »
    I would say I pushed them a little hard

    What are you driving them with?
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • jghglofer
    jghglofer Posts: 100
    Options
    F1nut wrote: »
    jghglofer wrote: »
    I would say I pushed them a little hard

    What are you driving them with?

    a pair of adcom gfa-565 I had them rebuilt
  • F1nut
    F1nut Posts: 49,987
    Options
    So, rated at 450 wpc @ 4 ohms. You must have been really cranking it...lol

    Interesting though that only one speaker was damaged. Might give pause about the performance of the amp that was driving that speaker.

    One thing I noted about those amps is their rated 1000 damping factor. To obtain a rating that high requires a ton of negative feedback, which IMO is not a good thing.

    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • Emlyn
    Emlyn Posts: 4,415
    Options
    Must've cranked up the volume to 11. It's one better than 10.
  • jghglofer
    jghglofer Posts: 100
    Options
    F1nut wrote: »
    So, rated at 450 wpc @ 4 ohms. You must have been really cranking it...lol

    Interesting though that only one speaker was damaged. Might give pause about the performance of the amp that was driving that speaker.

    One thing I noted about those amps is their rated 1000 damping factor. To obtain a rating that high requires a ton of negative feedback, which IMO is not a good thing.

    do you know what caps I should replace. and what should I replace them with
  • F1nut
    F1nut Posts: 49,987
    Options
    In your amp? No.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • jghglofer
    jghglofer Posts: 100
    Options
    F1nut wrote: »
    In your amp? No.

    I am talking about the crossover
  • F1nut
    F1nut Posts: 49,987
    Options
    jghglofer wrote: »
    F1nut wrote: »
    In your amp? No.

    I am talking about the crossover

    The standard upgrade is to replace all the caps and resistors in both crossovers. However, I don't know if that will solve your issue because there's too many unknowns.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk

  • Clipdat
    Clipdat Posts: 12,696
    Options
    At this point you "might" just be better off buying the complete replacement crossover from Polk.

    Because if there is an issue with your amps, the same thing will likely happen again, assuming you are planning on listening at the same volume levels again.
  • jghglofer
    jghglofer Posts: 100
    Options
    Clipdat wrote: »
    At this point you "might" just be better off buying the complete replacement crossover from Polk.

    Because if there is an issue with your amps, the same thing will likely happen again, assuming you are planning on listening at the same volume levels again.

    that why I thought it would be easier to replace some caps then to buy a crossover and end up frying it. just my way of thinking
  • Clipdat
    Clipdat Posts: 12,696
    Options
    Oh, yeah. I see what you mean. Maybe try to avoid long excursions above 100db :)
  • F1nut
    F1nut Posts: 49,987
    Options
    jghglofer wrote: »
    Clipdat wrote: »
    At this point you "might" just be better off buying the complete replacement crossover from Polk.

    Because if there is an issue with your amps, the same thing will likely happen again, assuming you are planning on listening at the same volume levels again.

    that why I thought it would be easier to replace some caps then to buy a crossover and end up frying it. just my way of thinking

    Replacing only some caps is not a way to figure out what the issue is and can get costly. The cheapest thing to do at this point is buy the stock crossover from Polk.
    Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a t-u-r-d by the clean end."


    President of Club Polk