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JBL s312ii and a big amp = problems???

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  • JBL s312ii and a big amp = problems???

    I recently upgraded my setup to a larger, and true audiophile grade amplifier. However, I quickly found that the this new amp is too much for the JBL s312ii speakers… I found that at higher volumes, there was a slight clicking sound… Now I am not listening to hip hop, this was Spotify on highest quality, going from a PC into the MODI. I was listening to some light acoustic guitar and a simple kick drum.

    I heard a light click/pop… at first I did not know what it was I was hearing… it took me a second… then I realized it was the voice coil tapping the back of the speaker’s magnet… Something to note is I listening to Abbey Road on vinyl and didn’t notice this issue at all…

    Well after looking at the JBL’s specs sheet (I am the original owner) It became pretty clear that there speakers really should not placed with this amplifier… they are rated to 250 watts MAX… most of the time when I see max and RMS ratings on the same speaker, the RMS rating is about ¼ that of the MAX rating, in this case maybe 65 watts RMS?

    That brings me to my question… I am on a budget, a tight budget… what should I do here?

    1.) New woofer that can handle the power?
    2.)Look for something used??? A local has a pair of old school Cerwin Vega 12t speakers... the 12” woofer was replaced with a Parts Express unit
    3.)Build a new setup entirely? I have built several 3 way setups in the past… maybe a 4 way setup with subwoofer, bass/midbass, midrange and tweeter?

    -Carver c-1 preamp
    -Denon POA-1500 amplifier (150 watts RMS per channel)
    -Pioneer PL-10 w/ Pickering XV-15/625E cart
    -Schiit Modi 2 UBER
    -JBL S312ii (250 watts max)


    Also I searched another forum and found some mentions of the amp being poorly designed and going into “oscillation”. But typically oscillations like this don’t cause problems in the base range, but rather huge harmonics up into a higher frequencies typically damaging tweeters and destroying the amplifier in the process ...

    I also got a chance to speak with a local gentleman who has owned a shop here locally doing repairs for close to 35 years. In fact he serviced these amplifiers when they were still under factory warranty. He says these are one of his favorite amplifiers of all time, and that he happens to still use one in his personal set up.
    I also got a chance to speak with a local gentleman who has owned a shop here locally doing repairs for close to 35 years. In fact he serviced these amplifiers when they were still under factory warranty. He says these are one of his favorite amplifiers of all time, and that he happens to still use one in his personal set up.

    All that being said I truly believe the problem is that the JBL speakers just are not up to the task of handling this monster of an amplifier.

  • #2
    What monster amp are you referring to? I wouldn't start a mashup of parts, or buy a mashup of parts. If you're truly on a budget, first off, turn it down.. This amp apparently isn't designed to work with speakers below 8 ohms. These are nominally rated at 8 but could be dipping. If you see it bottoming out while playing vinyl you could be getting subsonic rumble and these are vented speakers which could behave poorly that low. Turn on the subsonic filter and try again. Plug the port and try again. Try a high pass filter (above the subsonic filter).

    Comment


    • #3
      Originally posted by dwigle View Post
      What monster amp are you referring to? I wouldn't start a mashup of parts, or buy a mashup of parts. If you're truly on a budget, first off, turn it down.. This amp apparently isn't designed to work with speakers below 8 ohms. These are nominally rated at 8 but could be dipping. If you see it bottoming out while playing vinyl you could be getting subsonic rumble and these are vented speakers which could behave poorly that low. Turn on the subsonic filter and try again. Plug the port and try again. Try a high pass filter (above the subsonic filter).
      Thank you for your reply

      Answering your questions and/or replying to your comments

      the amplifier is a Denon POA-1500

      i didn’t buy ‘a mashup of parts’ I acquired gear over time and upgraded components as time went on

      yes turning it down is a fine option... however this is something I noticed while checking the amp out for the first time... and honestly I throw parties and like to have the safety net of speakers that can handle the amplifier in question

      I am only on a budget because I just bought an amplifier lol... gotta keep the wifey happy

      People use this amp at 4 ohm all day long... this thing has a transformer nearly the size of your head and 33000uf 71v capacitors nearly the size of a Coke can... furthermore the service manual clearly states the amplifier an handle 4 ohm nominal speakers... so I don’t believe the amplifier is the issue at all

      As I stated in my first post... Vinyl worked fine. The issue was noticed while listening to music through the MODI

      I considered subsonic rumble. That’s not the case hear. A long time ago I isolated the turntable and even located it on the opposite side of the room...

      What is happening here is that when something fast and somewhat low frequency happenens, like a kick drum keeping simple 4/4 time strikes the drum skin at higher volumes, subsonic rumble is a very different behavior than this...

      I have tried using the subharmonic filter, but as expected there was no real difference. On this amplifier it starts a roll off at 16hz... most music doesn’t even get recorded below 20hz

      as for a high pass filter I don’t believe this amp has one, nor do I have a stand alone

      Comment


      • #4
        So if we could please keep are replies narrowed to the below questions and WHY?

        1.) New woofer that can handle the power?
        2.)Look for something used??? A local has a pair of old school Cerwin Vega 12t speakers... the 12” woofer was replaced with a Parts Express unit
        3.)Build a new setup entirely? I have built several 3 way setups in the past… maybe a 4 way setup with subwoofer, bass/midbass, midrange and tweeter?

        Comment


        • #5
          If it’s only happening when using modi....common sense would dictate therein lies the issue?

          To answer your questions directly a new woofer might not be needed if you find the real problem.....maybe the modi output voltage is too hot? Does the amp have gain attenuation....try dialing it back if it does.

          cerwin Vega wasn’t exactly known for quality.....why did your friend change them if they were good?

          if your just not happy with your speakers it would probably be more beneficial to copy someone else’s designs from scratch than it would be to cobble a junk woofer into yours.

          edit.....and I wouldn’t call #3 budget by any means!

          Comment


          • #6
            Amplifier clipping can sound a bit like voice coils slapping.

            Comment


            • #7
              Maybe your new amp has more current than the old one and at the same “volume” can drive the woofer farther where the last one was running out of steam. I have an old 60wpc denon stereo receiver that has all sorts more low end power than a 75wpc denon surround receiver I used to own. I’ve seen it with onkyo and Yamaha stereo units too that had lower ratings but could really move a woofer more than wimpier amps of higher rated power.

              Comment


              • #8
                Originally posted by Mountainman Bob View Post
                If it’s only happening when using modi....common sense would dictate therein lies the issue?

                To answer your questions directly a new woofer might not be needed if you find the real problem.....maybe the modi output voltage is too hot? Does the amp have gain attenuation....try dialing it back if it does.

                cerwin Vega wasn’t exactly known for quality.....why did your friend change them if they were good?

                if your just not happy with your speakers it would probably be more beneficial to copy someone else’s designs from scratch than it would be to cobble a junk woofer into yours.

                edit.....and I wouldn’t call #3 budget by any means!
                thanks for the great reply!


                I have considered that with the MODI... I need another source or two to really be sure

                Cerwin Vega made some great stuff early on D9, D3, 12t, 15t, etc... but the Cerwin Vega most people are familiar with is modern lates 80s-2000s garbage

                It’s possible to find drivers that will work well with the existing cabs but typically requires retuning at least the port... I honestly am just done with them...

                budget is in the eye of the beholder...

                Comment


                • #9
                  Originally posted by dynamo View Post
                  Maybe your new amp has more current than the old one and at the same “volume” can drive the woofer farther where the last one was running out of steam.
                  thank you for your reply... this is kinda my tho as well

                  I absolutely does. Before I had a couple AVRs and then a Integra ADM2.1. This Denon POA-1500 it way more gusty than any gear I have ever had

                  Comment


                  • #10
                    What are those big meters on your Denon doing when you hear the strange noises? This is a somewhat older amp, are you sure it is in good working order?

                    150 watts is hardly a "monster" amp.

                    Everything was fine before the Denon? What were you using then?

                    Comment


                    • #11

                      Originally posted by djg View Post
                      What are those big meters on your Denon doing when you hear the strange noises? This is a somewhat older amp, are you sure it is in good working order?

                      150 watts is hardly a "monster" amp.
                      Peaks of about 65 watts... read up on the amp. This is not your typical amp at all... 150 rms per channel is way more than you are going to see in most home audio amps... I mean how many times have we seen a 100x5 home theater receiver that only pulls 200 watts at the wall... lol. You are getting caught up in a rating... I have seen plenty of 100x2 amps that have nothing on my old Marantz 2238b (40x2)

                      I have seen too many people say “mine is bigger than yours” but nobody ever wants to whip them out and put them on the table...

                      i dont care if it’s a monster to you... most people would consider it a monster. Yes there are amplifiers that make more power out there... if raw power was the goal I would grab a 1000w x 2 Crown... but then someone would get a 2000x2. I don’t care about that... it’s not really the point

                      ‘Its a monster’ and ‘that’s no monster’. Is just an opinion

                      Comment


                      • #12
                        Originally posted by Ericfx1984 View Post

                        thanks for the great reply!


                        I have considered that with the MODI... I need another source or two to really be sure

                        Cerwin Vega made some great stuff early on D9, D3, 12t, 15t, etc... but the Cerwin Vega most people are familiar with is modern lates 80s-2000s garbage

                        It’s possible to find drivers that will work well with the existing cabs but typically requires retuning at least the port... I honestly am just done with them...

                        budget is in the eye of the beholder...
                        The source input on that amp is 1v.
                        More than likely it’s less than your old one......try the attenuation (which I see it does have) at 1 or 2 o’clock instead of pegged.

                        Comment


                        • #13
                          I have several Outlaw Audio monoblocks at 200/ 8 ohms 300/ 4 ohms. I have a Yamaha M80 downstairs. I have two Class D Audio 250/ channel. I think I know what a monster amp is, and I don't consider any of my amps "monsters".

                          Just my opinion.

                          Comment


                          • #14
                            I should also have mentioned that I have experienced damaged electronics do this.

                            that demon looks nice. If you intend to keep it, I would consider a recap, resolder, and bias check.

                            Comment


                            • #15
                              Originally posted by djg View Post
                              150 watts is hardly a "monster" amp.
                              +1. It may be physically large, but that's how 150w amps were thirty years ago. Whatever the problem is it's not due to the amp being too large. If anything it's on the small side for 250w speakers. It may well be clipping.

                              www.billfitzmaurice.com
                              www.billfitzmaurice.info/forum

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