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  • #16
    Originally posted by Gordy View Post
    A Board with terminal connections...that's all I want
    If Tom gets one and posts pictures of the PCB inside, that may be possible via other sources ...

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    • #17
      Hi guys, I grabbed one and did some quick and dirty desktop measurements. There is a highpass on the upper channels. Appears to be -3 db down at 120 hz and a 12 db per octave slope. I dont really have a quiet enough room to tell for sure on the low pass for the woofer but nearfield is looking like -3 db down at 150 Hz also with a 12 db per octave slope. I will see if I can get some more accurate measurements for this on Monday.
      Analog is better than digital because it has a better sample rate.

      Comment


      • #18
        It would be neat if there was a hack that, via an added pot, would make the crossover frequency variable.

        Comment


        • #19
          120Hz XO would be fine for many small driver computer speakers. Something on the order of an RS-75A sealed could be "massaged" into a single mid-range/tweeter combo speaker, it appears to me. The DA-160-4/8 in about .5 cu. ft. ported could work as a "sub-woofer" to about 40Hz. Just thinking out-loud...

          Comment


          • #20
            Originally posted by philthien View Post
            It would be neat if there was a hack that, via an added pot, would make the crossover frequency variable.
            High probability this can be easily done.

            Some likely assumptions: (a) The LP Fc is as high or higher than needed; and (b) The LP filter is an active 2nd order Sallen-Key topology.

            Then there will be two resistors in the filter circuit that, combined with two capacitors, determine the LP Fc. Increasing the value of these two resistors will lower the Fc. The Q (or steepness) of the filter will not change as that is determined solely by the 2 caps in the filter circuit.

            Then you could "lift" one side of each of the two (presumably SMT) resistors and insert one gang of a dual gang pot in series with one resistor, the other gang in series with the 2nd resistor. With the pot rotation set at 0 ohms the filter would exhibit the original filter Fc. As the pot's resistance increased, the LP Fc would be reduced.

            Having the module in hand to determine the filter's resistor and cap values would allow a prudent selection for the new pot's resistance (e.g., 5K, 10K etc.). One issue, if the filter caps are SMT and the board is not silk screened with component values, you may have an issue determining the filter's cap values. That may reduce the likelihood of an optimum pot selection - not a show stopper.

            For example, if the two resistors are 10K ohms, inserting a 20K pot will allow the filter's Fc to be varied from its original value to 1/3 its original value. So if the original Fc was 120 Hz, you could now vary it from 40 Hz to 120 Hz.
            Last edited by Millstonemike; 10-14-2017, 02:56 PM.

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            • #21
              Sigh, I really miss the thru hole components. So much easier to hack for us old guys.
              "Everything is nothing without a high sound quality." (Sure Electronics)

              Comment


              • #22
                Originally posted by Millstonemike View Post

                High probability this can be easily done.

                Some likely assumptions: (a) The LP Fc is as high or higher than needed; and (b) The LP filter is an active 2nd order Sallen-Key topology.

                Then there will be two resistors in the filter circuit that, combined with two capacitors, determine the LP Fc. Increasing the value of these two resistors will lower the Fc. The Q (or steepness) of the filter will not change as that is determined solely by the 2 caps in the filter circuit.

                Then you could "lift" one side of each of the two (presumably SMT) resistors and insert a one gang of a dual gang pot in series with one resistor, the other gang in series with the 2nd resistor. With the pot rotation set at 0 ohms the filter would exhibit the original filter Fc. As the pot's resistance increased, the LP Fc would be reduced.

                Having the module in hand to determine the filter's resistor and cap values would allow a prudent selection for the new pot's resistance (e.g., 5K, 10K etc.). One issue, if the filter caps are SMT and the board is not silk screened with component values, you may have an issue determining the filter's cap values. That may reduce the likelihood of an optimum pot selection - not a show stopper.

                For example, if the two resistors are 10K ohms, inserting a 20K pot will allow the filter's Fc to be varied from its original value to 1/3 its original value. So if the original Fc was 120 Hz, you could now vary it from 40 Hz to 120 Hz.
                That would make this amp a real contender. I wonder what it would take to have that pot be in the place of the 'tone' knob.
                Yeah, I'm dreaming, but still, it would be a LOT better that way.

                TomZ
                *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

                *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

                Comment


                • #23
                  It would really be interesting if PE and Dayton would survey the members of this forum to see exactly what we want/need. I don't mind some hacking to get components aligned and working as they should. Maybe the whole sub-filter board left a bad taste. But why not get the feedback of experts like Mike and colab on product that works well out of the box. I know we don't have the amp in hand but offering a 2.1 Amp without the requisite specs is a real downer.
                  "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

                  The Madeleine
                  The Roxster
                  Swopes 5.0
                  Acoustic Panels
                  Living Room Make Over

                  Comment


                  • #24
                    Originally posted by Gordy View Post
                    It would really be interesting if PE and Dayton would survey the members of this forum to see exactly what we want/need. I don't mind some hacking to get components aligned and working as they should. Maybe the whole sub-filter board left a bad taste. But why not get the feedback of experts like Mike and colab on product that works well out of the box. I know we don't have the amp in hand but offering a 2.1 Amp without the requisite specs is a real downer.
                    I'm largely ignorant of what it takes to mod these boards, let alone design one. But... I think that's a great idea Gordy.
                    I want to love this product, but with a 150 Hz crossover point on the subwoofer section it just seems too much like many of the other 2.1 amps on ebay/amazon that just don't quite cut it.... just in a nicer package, and of course Dayton's excellent warranty which is no small thing....

                    Take the 2.1 plate amp Jwjarch used in Paul Carmody's 2.1 amp thread... http://techtalk.parts-express.com/fo...88#post1343388
                    That thing does what it's supposed to, what we expect it to... lots of power to boot. I purchased one out of curiosity and I can vouch for at least my unit's excellent performance, if not it's longevity. Put that thing in a table-top small-amp package and you'd have something there... add bluetooth and PE wouldn't be able to keep them in stock.

                    Not bashing at all, and I don't mean any disrespect to PE/Dayton or anyone... but It does seem like there is so much potential for this and other amps/crossovers... but so many of these things miss the mark we're all kind of hoping for.

                    Of course... I haven't heard it yet.

                    TomZ
                    *Veneering curves, seams, using heat-lock iron on method *Trimming veneer & tips *Curved Sides glue-up video
                    *Part 2 *Gluing multiple curved laminations of HDF *Cello's Speaker Project Page

                    *Building the "Micro-B 2.1 Plate Amplifier -- Part 1 * Part 2 * Part 3 * Part 4 * * Part 5 'Review' * -- Assembly Instructions PDF

                    Comment


                    • #25
                      I would buy a 2.1 amp that had independent volume controls for all 3 channels, along with a variable crossover point with real slopes. Preferably a 3 or 4 position crossover control with labelled detents, so we have some idea where the crossover point actually is. 20 years ago, I had a Sony car stereo system with these features.

                      Comment


                      • #26
                        Originally posted by tomzarbo View Post

                        That would make this amp a real contender. I wonder what it would take to have that pot be in the place of the 'tone' knob.
                        Yeah, I'm dreaming, but still, it would be a LOT better that way.

                        TomZ
                        My bet is the "Tone" control is really the L-R volume control (perhaps not as there are more op-amps on this module than my other reference modules).

                        If the sub channel volume control / gain circuit is sufficient, by itself, to balance the output between the sub and the L-R output, then the "tone" pot (or its replacement pot) could be used for the LP variable frequency control. The tone pot's original PCB connections just jumpered (e.g., fixed at 0 ohms) or some trim pots fitted in..

                        Based on my research, my guess of the module inside. A nice 6800 uf PS bypass cap to handle peaks.
                        Click image for larger version

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                        Last edited by Millstonemike; 10-14-2017, 05:21 PM. Reason: Added "trim pots in Bold

                        Comment


                        • #27
                          Originally posted by Millstonemike View Post
                          My bet is the "Tone" control is really the L-R volume control (perhaps not as there are more op-amps on this module than my other reference modules).

                          If the sub channel volume control / gain circuit is sufficient, by itself, to balance the output between the sub and the L-R output, then the "tone" pot (or its replacement pot) could be used for the LP variable frequency control. The tone pot's original PCB connections just jumpered (e.g., fixed at 0 ohms) or some trim pots fitted in..

                          Based on my research, my guess of the module inside. A nice 6800 uf PS bypass cap to handle peaks
                          How do you find these things. It just blows my mind.
                          "A dirty shop is an unsafe shop, if you injure yourself in a clean shop you are just stupid" - Coach Kupchinsky

                          The Madeleine
                          The Roxster
                          Swopes 5.0
                          Acoustic Panels
                          Living Room Make Over

                          Comment


                          • #28
                            Originally posted by Gordy View Post
                            It would really be interesting if PE and Dayton would survey the members of this forum to see exactly what we want/need. I don't mind some hacking to get components aligned and working as they should. Maybe the whole sub-filter board left a bad taste. But why not get the feedback of experts like Mike and colab on product that works well out of the box. I know we don't have the amp in hand but offering a 2.1 Amp without the requisite specs is a real downer.
                            If only...

                            My suggestions:

                            ​The "must haves"..
                            1. ​Independent filter frequency adjustment for both subwoofer and satellites, 20 Hz to 200 Hz
                            ​2. 12dB/oct HP on the main speakers, 24dB/oct LP on the subwoofer channel
                            ​3. Take a hint from the car audio guys - inset pots for the filter frequency adjustments! Avoid the impact of some doofus screwing up your speakers by turning a knob
                            ​4. Subwoofer level control should adjust level relative to the main speaker output. It should not be independent!

                            The "like to haves"
                            ​1. Variable LF boost (frequency and level)
                            ​2. Peak/ciip indicator and switchable soft-limiting
                            ​3. Speakon connectors (binding posts are so 80s, LOL)
                            ​4. 12/24V DC/DC converter in similar package (for those of us who want to use this in a mobile environment)
                            ​5. Soft-start circuitry with relays to eliminate "pops"
                            Brian Steele
                            www.diysubwoofers.org

                            Comment


                            • #29
                              Originally posted by Brian Steele View Post

                              If only...

                              My suggestions:

                              ​The "must haves"..
                              1. ​Independent filter frequency adjustment for both subwoofer and satellites, 20 Hz to 200 Hz
                              ​2. 12dB/oct HP on the main speakers, 24dB/oct LP on the subwoofer channel
                              ​3. Take a hint from the car audio guys - inset pots for the filter frequency adjustments! Avoid the impact of some doofus screwing up your speakers by turning a knob
                              ​4. Subwoofer level control should adjust level relative to the main speaker output. It should not be independent!

                              The "like to haves"
                              ​1. Variable LF boost (frequency and level)
                              ​2. Peak/ciip indicator and switchable soft-limiting
                              ​3. Speakon connectors (binding posts are so 80s, LOL)
                              ​4. 12/24V DC/DC converter in similar package (for those of us who want to use this in a mobile environment)
                              ​5. Soft-start circuitry with relays to eliminate "pops"
                              Can we make this a sticky? Maybe we could all print it out and mail it to PE. I've been wondering where such amps were for years now. There have been several attempts, but for some reason no one has been able to get it right. Seems absurdly obvious to me, but then what do I know?

                              Comment


                              • #30
                                It is surprising how much we can differ on must-haves.

                                All I'd like to see is a single variable 12db/octave xover that can do 40 or 60 to maybe 400-Hz.

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