To fuse or not ???

victor. askew
victor. askew Posts: 50
edited June 2011 in 2 Channel Audio
Hello to all. What is the school of thought out there on the installation of correctly sized fused protection for your spkrs. Most of us own spkrs that we want to hold on to and we all know that replacment drivers are hard or in some cases for me impossible (Yamaha) to come by ( thank god for E bay). Any thoughts? Thanks.
Amps- Nakamichi PA 7 & PA 5.
P Amp- Classie Audio. Nakamichi CA 5
Tape- Tandberg 3014A.
Tape- Nakamichi 600.
CD Calif Audio Tercet 3.
CD-Rotel 1078.
Spkrs- Polk Audio RTI 150 Towers.
Spkrs- ADS L1290 Towers.
Spkrs- Yamaha- NS 670,NS 500m,NS 200m, NS 200ma
NS 200ma hybrids.
Post edited by victor. askew on
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Comments

  • treitz3
    treitz3 Posts: 19,033
    edited May 2011
    Hello and welcome to Club Polk. What exactly are you trying to protect.....and from what?
    ~ In search of accurate reproduction of music. Real sound is my reference and while perfection may not be attainable? If I chase it, I might just catch excellence. ~
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  • FTGV
    FTGV Posts: 3,649
    edited May 2011
    Using a little common sense and an appropriately sized amp used within it's limits (ie.not continously driven in to clipping)should negate the need for fusing.
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  • dorokusai
    dorokusai Posts: 25,577
    edited May 2011
    Agreed, no gfuse is good gfuse.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • DON73
    DON73 Posts: 516
    edited May 2011
    Can an amplifier clip because of a defect? A fuse would be good to have in this case. My ADS L 710s and L 810s are both fused and some of my Polks are fused. In the late 70s I talked to the head of ADS and he told me fuses were not necessary and that sensible control of the volume was all the protection the speaker needed.:smile: What would be the maximum size fuse for a speaker? Some of mine have 1amp and two had 10amp that I changed to 1amp. The 1amp fuses in my Monitor 7s sometimes blow at moderate volume.
    TO ERR IS HUMAN. TO FORGIVE IS CANINE.
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  • zingo
    zingo Posts: 11,258
    edited May 2011
    Amps would not clip because of a defect, but they may pass DC current or surge because of a defect or issue. Circuit protection is not ideal for sound quality, but if your speakers/drivers and not replaceable, you could fuse it for protection.

    If going that route, I would suggest something resettable like a polyswitch instead of an actual fuse.

    071-254_s.jpg

    http://www.parts-express.com/pe/showdetl.cfm?Partnumber=071-254
    Jake
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  • heiney9
    heiney9 Posts: 25,165
    edited May 2011
    DON73 wrote: »
    Can an amplifier clip because of a defect?

    They can clip because of a defect, but a speaker fuse will most likely not protect the speakers if the amp fails because of a defect. IE; the amp passes a high level of dc to the speakers. The fuse won't protect the speakers. If the amp shorts out, the fuse most likely won't protect the speakers, etc.

    Fuses are not necessary if you have proper amplification and don't overdrive that amplification.

    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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  • heiney9
    heiney9 Posts: 25,165
    edited May 2011
    zingo wrote: »
    Amps would not clip because of a defect, but they may pass DC current or surge because of a defect or issue. Circuit protection is not ideal for sound quality, but if your speakers/drivers and not replaceable, you could fuse it for protection.

    If going that route, I would suggest something resettable like a polyswitch instead of an actual fuse.

    071-254_s.jpg

    http://www.parts-express.com/pe/showdetl.cfm?Partnumber=071-254

    To be clear the above doesn't protect against a defect or issue or DC surge.

    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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  • FTGV
    FTGV Posts: 3,649
    edited May 2011
    Keep in mind that polyswitch/fuse protection is usually only applied in series with the tweeter.They are dumb devices in that they cannot differentiate between a clipped or unclipped waveform,they only protect against excess current which ofcourse is determined by their rating.As Zingo pointed out they won't protect against a DC fault condition but since there will be a series capacitor ahead of the tweeter DC will effectively be blocked.Unfortunately the woofer has not such protection.
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  • kappclark
    kappclark Posts: 136
    edited May 2011
    heiney9 wrote: »
    To be clear the above doesn't protect against a defect or issue or DC surge.

    H9
    What does protect against the dreaded dc surge ?

    I had my 20 yr old amp in for service a few years ago, and after tuning up and replacing the relay, he installed fuses for the speaker outputs ... I thought it was a good idea, but recently, 2 4A fuses have blown in the left ch...I do not abuse the amp by any stretch (Parasound hca500 with Polk Mon 60's)) .. so what do the fuses protect, exactly ?
    *************************
    ** Bill Clark Windham, VT **
    *************************
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  • FTGV
    FTGV Posts: 3,649
    edited May 2011
    kappclark wrote: »
    What does protect against the dreaded dc surge ?

    I had my 20 yr old amp in for service a few years ago, and after tuning up and replacing the relay, he installed fuses for the speaker outputs ... I thought it was a good idea, but recently, 2 4A fuses have blown in the left ch...I do not abuse the amp by any stretch (Parasound hca500 with Polk Mon 60's)) .. so what do the fuses protect, exactly ?
    As I mentioned the tweeter will be protected because it has a capacitor in series with it.As for the woofer you are at the mercy of the amplifiers DC fault protection circuit should it so have one.Thats not always the case.
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  • kappclark
    kappclark Posts: 136
    edited May 2011
    FTGV wrote: »
    As I mentioned the tweeter will be protected because it has a capacitor in series with it.As for the woofer you are at the mercy of the amplifiers DC fault protection circuit should it so have one.Thats not always the case.

    good to know .. thanks - maybe I will send an email to the good folks at Parasound.
    *************************
    ** Bill Clark Windham, VT **
    *************************
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  • FTGV
    FTGV Posts: 3,649
    edited May 2011
    kappclark wrote: »
    .. so what do the fuses protect, exactly ?
    I touched on that in post #9.It protects against over current( over powering).Exceeding the current rating of the fuse will make it fail ,which if sized correctly will protect the driver from excessive power levels that might exceed it's thermal limits.
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  • rkscwh
    rkscwh Posts: 3
    edited June 2011
    My son (7yrs) cranked the volume Blew the fuse for the tweeter. It's a 1amp - 250V fuse. I purchased the speakers used and want to know if this is the proper size fuse.
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  • dorokusai
    dorokusai Posts: 25,577
    edited June 2011
    rkscwh wrote: »
    My son (7yrs) cranked the volume Blew the fuse for the tweeter. It's a 1amp - 250V fuse. I purchased the speakers used and want to know if this is the proper size fuse.

    Yes, its fine.
    CTC BBQ Amplifier, Sonic Frontiers Line3 Pre-Amplifier and Wadia 581 SACD player. Speakers? Always changing but for now, Mission Argonauts I picked up for $50 bucks, mint.
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  • victor. askew
    victor. askew Posts: 50
    edited June 2011
    The dreaded DC surge can be held at bay by having output relays internal to your amp, which will open at the first sign of DC discharge at the amps output devices/stages. The inline fuse which I did install into my system will protect the spkrs from being overdriven by excessive volume beyond the rating to which it was designed. I am using 1.5 amps fuses and yes I have blown a few but am very happy to replace a fuse vice replacment of a spkr or its driver. I went dowm that road with the 3 Phase Linier amps that I have owned.:smile:
    Amps- Nakamichi PA 7 & PA 5.
    P Amp- Classie Audio. Nakamichi CA 5
    Tape- Tandberg 3014A.
    Tape- Nakamichi 600.
    CD Calif Audio Tercet 3.
    CD-Rotel 1078.
    Spkrs- Polk Audio RTI 150 Towers.
    Spkrs- ADS L1290 Towers.
    Spkrs- Yamaha- NS 670,NS 500m,NS 200m, NS 200ma
    NS 200ma hybrids.
    · Share on FacebookShare on Twitter