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  • Zaph ZDT build

    Hi Folks,

    I have had most of the parts both towers and centre channel speakers for far too long and am finally getting around to making sawdust.
    The Towers are 3.5way and centre 3 way.
    My problem is I left buying some of the inductors until last, the towers use an 3.6mH Erse Super Q inductor for the lower woofer and thes now seem to be unobtainium.
    Parts Express have them listed on the website not in stock with no ETA, I contacted them and they have said Erse are no longer in business.
    This is weird as their website is still active, I actually managed to order a couple online but then got an email to say the order had been cancelled, an email as to query why has gone unanswered.

    So I have a couple of questions,

    Does anyone know where these might be availble?
    Can I just leave them out and run the towers as 3 ways?
    Last one is a little left field but I do have a pair of 3.0mH inductors from another build no longer in use (both Erse 16ga Super Q). Is it possible I could get someone with the correct knowledge and equipment to wind some more wire onto the these coils to bring them up to the correct spec?

    Thanks in advance for your help. I am currently running a set of Modula MTM's and CJD RS150 as front three in my home theatre system. The plan is to use the ZDT's up front and move everything else to the rear.
    Attached Files

  • #2
    The Erse inductor that isn't available has a resistance of 0.206 ohms. Meniscus Audio has a 15 AWG, 3.5 mH/0.19-ohm steel laminate inductor at $19 which would probably be a very reasonable substitute. It's specified inductance is only 2.8% lower than the Erse and is in stock. Here's a link: https://meniscusaudio.com/product/3-50mh-15sl/

    Madisound has a Solen 14 AWG air-core inductor of 3.7 mH/0.48 ohms at $57 in stock. Its inductance is 2.8% higher than the Erse but its resistance is higher by 0.27 ohms which may or may not be an issue. Here's a link: https://www.madisoundspeakerstore.co...uctors-14-awg/

    Paul

    Comment


    • #3
      Thanks Paul,

      The laminate inductors are showing out of stock as well, I have emailed to see if they have an idea of lead time. I'm not in any particular rush but will sleep better knowing I have a viable option.
      The DCR on the Solen is going to be too high I expect plus I live in NZ so you can double the price of everything once you include exchange rayes and shipping so that would be too spendy.

      I'd still be interest in knowing if modifying the 3.0 mH inductors or running the speakers as 3 ways is an option?

      Comment


      • #4
        Sorry about that. When I was looking at Meniscus' inductors, before finding that specific one, many, if not all of the 18AWG laminates showed Out of Stock on the general page, but for the 15AWG inductors none were shown as Out of Stock. When I clicked on the 15AWG 3.5-mH inductor specifically, I did not notice the small print saying it was backordered. Also, a few minutes after I posted my reply to you, I realized your were in NZ and you'd probably have to deal with exchange rates and shipping costs.
        Paul

        Comment


        • #5
          I found a 16 AWG 3.5 mH/0.28-ohm steel laminate inductor that is in stock and, I think, from India. The company is The Audio Crafts DIY Unlimited. The link I'm providing shows a cost of 690.00INR, whatever that means.

          https://theaudiocrafts.com/x-over-pa...-16-AWG-3.50mH

          Hope this helps.
          Paul

          Comment


          • #6
            INR is the Indian Rupee.

            1 INR = 0.013 USD so the inductor would cost approximately $8.68 plus whatever VAT and shipping charges are involved

            Comment


            • #7
              Thanks aagain for the help Paul, Meniscus have advised these will be in stock next week.

              I would like to know if winding more wire onto the 3.0 mH Erse inductors I have is feasable or a dumb idea?

              Comment


              • #8
                If you can and measure you should be okay and a great idea.

                Comment


                • #9
                  Oh great thank you, I don't have the correct equipment to measure but fairly sure I can find someone to do this for me locally so will investigate.

                  Comment


                  • #10
                    From memory the rs52 went through an update and may not measure the same. Check before diving in too far.

                    Comment


                    • #11
                      Oh dear, I've had the parts for the centre channel for a year or two now and most of the bits for the towers except for the RS52's (which are on backorder), capacitors and the aforementioned inductors. So I'm in pretty deep, not a cheap exercise either, you can double the price and that's what it costing me to land them in New Zealand.

                      I found out why Erse have gone out of business, not sure if it's been posted here but apparently the owner passed away and the suggestion is his wife is just selling of the existing stock.

                      Can anyone confirm that the RS52 has changed and is the new one a drop in replacement?

                      Sent from my SM-G973F using Tapatalk

                      Comment


                      • #12
                        The RS52 has had issues, which appear to be a significant resonance in the surround that didn't exist when I first designed with them, and I ended up dropping them from a new design. As discovered during the Ardent D development, (see thread) recent RS52 have had this resonance which causes an impedance bump and a bump in the response around 2.1kHz. Not desirable. Email exchanges with Dayton did not prove satisfactory. The design was switched to a Morel 1308 dome mid, which is physically compatible for mounting, and electrically similar.

                        http://www.htguide.com/forum/showthr...ghlight=Ardent
                        the AudioWorx
                        Arvo Pärt
                        Isiris MLBL
                        Modula MT
                        Natalie P
                        M8ta
                        Modula Neo D CC
                        Ardent
                        Modula MT XE
                        Modula Xtreme
                        Isiris
                        Wavecor Ardent

                        SMJ
                        Minerva Monitor
                        Calliope
                        Ardent D

                        In Development...
                        Isiris Mk II updates
                        Calliope CC
                        Obi-Wan
                        Saint-Saëns Symphonique
                        Modula PWB
                        Calliope CC Supreme


                        Resistance is not futile, it is Volts divided by Amperes...
                        Just ask Mr. Ohm....

                        Comment


                        • #13
                          Ok then, that is not good news...

                          I'm nowhere near as pedantic about the HT setup as I am with my stereo system. Just to give you an idea I can quote you the output impedance of my preamp but had to go and check the other week as I wasn't sure about the model number of my HT amp. So I'm not going to sit there doing any critical listening for every nuance the speaker produces.

                          Most of the money I have invested so far is in the 6 x RS180's I have so while not ideal I'll change tack if I have to.

                          With this in mind, where to go to from here?

                          Build them anyway, will they sound ok but just not perfect (no glaringly obvious issues)?
                          Is the Morel a drop in replacement (without crossover changes)?
                          Build the centre channel with the RS52 (I have all the parts for this speaker) or the Morel depending on the above and something else for the fronts, maybe the Natalie P?
                          Is there another centre channel using the RS180 that will suit the Natalie P's if I built them? One of the reasons I liked the ZDT was moving to a 3 way speaker and I have a 230mm max height to fit the cabinet. Also aware there may be BSC issues putting a centre speaker in the cabinet but again I'm happy to compromise here and I built the cabinet as well (I've built legs for them since the photo was taken to raise the tweeter closer to ear level)so could modify if needed to fit a bigger speaker plus I hope to move at some stage next year. With any luck I'll be able to wall mount the TV and place the CC on its own stand (dedicated media room is top of the list).

                          Comment


                          • #14
                            Well, I'd hazard that maybe for your CC the bump at 2.1kHz may not bother you much... I suppose the pragmatic thing to do would be to just go ahead for now and build with RS52.

                            The Morel 1308 would mainly require a change in the Fs zobel network, but you may not want to hassle with that. Keep in mind these issues were identified with a speaker that is a somewhat high end design- the dual woofers in the Ardent D cost about $500 each at the time, and now are up to almost $750 each. So, that's a system worthy of a bit of perfectionism.

                            The raw measured performance of the EM1308...




                            Measured in room, with some LF absorbers in place...




                            I expect some folks have more modest goals in mind!
                            the AudioWorx
                            Arvo Pärt
                            Isiris MLBL
                            Modula MT
                            Natalie P
                            M8ta
                            Modula Neo D CC
                            Ardent
                            Modula MT XE
                            Modula Xtreme
                            Isiris
                            Wavecor Ardent

                            SMJ
                            Minerva Monitor
                            Calliope
                            Ardent D

                            In Development...
                            Isiris Mk II updates
                            Calliope CC
                            Obi-Wan
                            Saint-Saëns Symphonique
                            Modula PWB
                            Calliope CC Supreme


                            Resistance is not futile, it is Volts divided by Amperes...
                            Just ask Mr. Ohm....

                            Comment


                            • #15
                              Thanks Jon - I'll build the CC with the RS52 and see how we go from there.

                              Comment

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