Forum Top Banner Ad

Collapse

Ebay Classic organs

Collapse

Announcement

Collapse
No announcement yet.

HC12 questions

Collapse
This topic is closed.
X
X
 
  • Filter
  • Time
  • Show
Clear All
new posts

  • HC12 questions

    Hi everyone. I recently acquired a pair of Allen HC12 cabinets that I hope to use on a Hauptwerk setup. But I have a couple of questions about them.

    First, what range of output power should I look for, in order to drive them properly? As a first-run test setup, I had them on 40W each from an old SS amp I had lying around. This worked OK but seemed like less volume than I would expect. (Setup was as follows: HW > laptop onboard sound > stereo out > mixer > old amp > HC12s.)

    Second, what's going on with the phasing in these cabs?!? I had to replace the surrounds on the Peerless midrange drivers, and when I hooked them back up I realized they were wired out-of-phase from the factory: i.e., signal going into negative terminal, positive terminal to ground. Then, on the back there's a sticker with a note: "On ADC organs, HC-12s are to be in reverse phase." Does anyone know why this is so? Also, given this unusual phasing situation, in my application should I wire them up "straight," or reverse-phased as if I were driving them with an ADC Allen?

    As a matter of interest, these are dated from 1986, and have the original Eminence 15" woofers in them... but with tensile/accordion surrounds, not foam. They look original too, not like re-foam (er, "re-surround") jobs. I had always thought all HC12s had foam surrounds; but then Googling around I found a few comments to the effect that Allen may have switched to a cloth surround at some point, once they realized the foam surrounds were subject to problems. Would be interesting to hear if others have encountered apparently original accordion surrounds on these. I can snap a pic or two of the woofers if anyone is curious.
    Last edited by Scott Dennison; 08-05-2015, 04:12 PM.

  • #2
    Wire them in phase for your project.
    Out of phase for a ADC organ was because they used this speaker specifically for the pedal bass....along with other cabinets HC 15's used for manuals. Don't really know the reasoning except to eliminate any phase cancellation when paired with the HC 15's. Sealed vs Ported maybe? ( 12's are sealed, 15's are ported)
    They are normally wired to Allens 100 watt amp so that should be a start.

    Comment


    • #3
      Most crossover designs for 12 dB per octave slope have driver phase inverted--for a 2 way, the woofer and tweeter are opposite phase; for a 3-way, the midrange is opposite phase of the woofer and tweeter. 2nd order crossover (12 dB/octave) introduce a phase shift at the crossover frequency of 180 degrees, so if the driver phase isn't inverted, then you get null output at the crossover frequency.

      There are other ways to handle this, but this is the most common.

      On the Allen HC 12, the woofer is available separately outside the cabinet to allow for changing the phase of the woofer only--this is to compensate if used along with HC15s or with phase shift caused by speaker location.

      HC12s, I think, are a little less efficient than the HC15, but increasing the power of the amp won't necessarily increase the gain. Just try driving the amp harder. 40 to 60 W is about what Allen amps of the ADC era put out. Maybe up to 100.

      Comment


      • #4
        Scott,

        Welcome to the Forum. I hope this is only the beginning of your participation on the Forum.
        Originally posted by Scott Dennison View Post
        Second, what's going on with the phasing in these cabs?!? I had to replace the surrounds on the Peerless midrange drivers, and when I hooked them back up I realized they were wired out-of-phase from the factory: i.e., signal going into negative terminal, positive terminal to ground. Then, on the back there's a sticker with a note: "On ADC organs, HC-12s are to be in reverse phase." Does anyone know why this is so? Also, given this unusual phasing situation, in my application should I wire them up "straight," or reverse-phased as if I were driving them with an ADC Allen?
        I'm not sure if you had the mid-range speakers wired correctly to begin with, but the 2 mid-range speakers are jumped together with a white wire. On the outside ends, one is an orange wire, and the other end has a black wire. If you can read the schematic, I can post the schematic for the mid-ranges to be sure you have them wired correctly.

        Originally posted by Scott Dennison View Post
        They look original too, not like re-foam (er, "re-surround") jobs. I had always thought all HC12s had foam surrounds; but then Googling around I found a few comments to the effect that Allen may have switched to a cloth surround at some point, once they realized the foam surrounds were subject to problems. Would be interesting to hear if others have encountered apparently original accordion surrounds on these. I can snap a pic or two of the woofers if anyone is curious.
        When I obtained my first organ (MOS-2), I had to order 2 woofers in an emergency for a concert (they never made it), and they both had foam surrounds. I'm not sure when Allen changed the surrounds, but it was definitely between the HC-12 and HC-14/15 era. I've never seen an HC-14 or HC-15 with anything but an accordion surround. That doesn't mean they wouldn't work with foam surrounds, but I don't think that would be original.

        Hope this helps.

        Michael
        Way too many organs to list, but I do have 5 Allens:
        • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
        • Lowrey Heritage (DSO-1)
        • 11 Pump Organs, 1 Pipe Organ & 7 Pianos

        Comment


        • #5
          Aaaah, the light bulb turns on! :emotion-55: Thank you for the informative replies.

          Thanks also for the offer on the schematic, but I've managed to come up with a copy already. I had to do the 9V battery "pop test" to be sure, but I definitely have the midranges wired correctly (in series) now. The only trouble is that one of them has a warped voice coil, which is rubbing and producing some distortion on certain frequencies. The re-foaming was a success otherwise.

          So I contacted Allen and was directed to my local dealer for a replacement driver. Haven't heard back yet but I suspect it won't be cheap. Also have a query in to a speaker service to see about a full recone job. In the meantime I'm tempted to try this:

          http://www.parts-express.com/goldwoo...4-ohm--280-110

          The specs don't line up perfectly with the original Peerless KO40-MRF, but it might be close enough to use as a temporary substitute, at least. Any thoughts?

          Comment


          • #6
            Originally posted by Scott Dennison View Post
            The specs don't line up perfectly with the original Peerless KO40-MRF, but it might be close enough to use as a temporary substitute, at least. Any thoughts?
            At one time, there was a person in Alabama who was re-building Allen's HC-12 mid-range cans and selling them commercially (Birmingham--http://dixiespeaker.com/products/4-vintage-allen-organ-midrange-speakers-8). To be clear, I've never done business with them, but they certainly have the resources. Just be sure you get the mid-range for the HC-12 and not the one for the HC-14/15. Recently, I discovered they are actually different Ohms. You can see where I posted the question on another thread.

            Michael
            Way too many organs to list, but I do have 5 Allens:
            • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
            • Lowrey Heritage (DSO-1)
            • 11 Pump Organs, 1 Pipe Organ & 7 Pianos

            Comment


            • #7
              Interesting questions. I have tested HC-12's side by side with other speakers and find them to have an excellent tone and smooth output, about as sweet as any speaker can be. However, they are notably much less efficient than most other organ speakers, so you must turn up the volume a bit. I wouldn't try to power them with low-end amps, but 50 watts and up ought to work OK.

              I have a pair of HC-12s in the shop that have 15" woofers with textile surrounds. I don't know the history of these, as they came in with an organ built in the early 90's. They sound very good, even with 32' pedal stops, so the bass output isn't that different from the units with foam woofers. I suspect that someone replaced the foam woofers at some point. Or perhaps Allen did start building them with a textile-surround woofer at some point.

              Those midranges are an ongoing issue for sure. The foam rots and they sound terrible. Then the repairs sometimes fail, as yours did, and you wind up with a rubbing voice coil that yields more distortion than the rotten foam did.

              And the midranges in HC-12's are 4 ohms, making replacements harder to find. Allen has in fact stopped selling a 4-ohm replacement unit. They will sell you an 8 ohm midrange and tell you to use just one of them in your HC-12 instead of two, and cover the other hole (or just leave the dead and disconnected speaker in it).

              There used to be a decent Pioneer can-style midrange unit that you could buy for about $15 or so that fit the hole and was an OK replacement. But that item seems to be NLA. I'm a bad boy when it comes to this subject, and I have gone so far as to replace these high-end units with $10 closed-back mids from MCM Electronics. Honestly, I can't hear any deleterious effects from using the fairly cheap replacement units. The screw holes don't line up, but the unit fits the hole almost perfectly. They are easy to use in HC-15's with their single midrange, but a little more problematic on HC-12's with two units side by side, the rims slightly bumping and requiring some trimming with a hack saw. (Yes, I put two 8 ohm drivers in place of two 4 ohm drivers. Perhaps I altered the crossover points by doing that, but I couldn't hear anything wrong with it.)

              After reading several comments about this subject on the forum, I feel less confident about my el-cheapo replacement units. Perhaps I need to do some more serious testing before doing this again. I may post more info in a week or two, as I have some HC-12's coming in next week that will surely need drivers replaced.
              John
              ----------
              *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

              https://www.facebook.com/pages/Birds...97551893588434

              Comment


              • #8
                Originally posted by myorgan View Post
                At one time, there was a person in Alabama who was re-building Allen's HC-12 mid-range cans and selling them commercially (Birmingham--http://dixiespeaker.com/products/4-vintage-allen-organ-midrange-speakers-8).
                Thank you for this lead, Michael. I have a message in to him to see if he offers a recone job on the Peerless driver. Even the re-edged ones are looking better and better: the Allen rep quoted me basically $100 for a replacement.

                Also, to John: was the Pioneer driver you used to prefer by any chance this one? http://www.parts-express.com/pioneer...range--280-020

                My hunch on this is that anything close ought to be OK, since Allen doubled up on the midrange drivers in these cabs. I have read a couple posts suggesting they ended up realizing the second one was more or less redundant, and that's why they went to a single-midrange design with the following-generation HC15. (And partly why they recommend the fix of going to a single new 8-ohm driver, while leaving one 4-ohm as a "dummy" to plug the hole - as you noted.) But anyway, with one stock driver plus one reasonably close substitute of the correct impedance and power-handling, I would think your experience ought to be typical in that the audible difference would surely be negligible - ? Especially in a tandem situation where the lone replacement is essentially just one out of four such drivers.

                Comment


                • #9
                  Originally posted by Scott Dennison View Post
                  My hunch on this is that anything close ought to be OK, since Allen doubled up on the midrange drivers in these cabs. I have read a couple posts suggesting they ended up realizing the second one was more or less redundant, and that's why they went to a single-midrange design with the following-generation HC15.
                  Scott,

                  Not sure if you read that post on my 5400 thread, but you are correct, Toodles is the person who has posted that an HC-12 will work perfectly fine with just one mid-range. I'd think the wiring would have to be different, though, to account for the missing midrange.

                  Michael
                  Way too many organs to list, but I do have 5 Allens:
                  • MOS-2 Model 505-B / ADC-4300-DK / ADC-5400 / ADC-6000 (Symphony) / ADC-8000DKC
                  • Lowrey Heritage (DSO-1)
                  • 11 Pump Organs, 1 Pipe Organ & 7 Pianos

                  Comment


                  • #10
                    Scott,

                    That discontinued item at Parts Express is indeed the one that I used to order for Allen HC cabinets. It was a perfectly good drop-in replacement, and I can't imagine why it is no longer available from any source. Looks like speaker builders and fixers everywhere would love to have such an all-round quality midrange that goes down to nearly 300 Hz with 94 dB sensitivity and with its own attached back-chamber. And I have looked around quite a bit for a similar unit, but have found nothing to match it.

                    My feeling is that Allen wasn't using "textbook" speaker design parameters back when the HC-12 was introduced. I think they relied on someone's good ears more than on the capacitor and inductor charts. I can't imagine why they decided to reverse the phase of the woofer in the HC-12. I suppose they never imagined that organ owners would be faced with mixing speaker types on the same organ.

                    Since the crossovers don't match up with the textbook values anyway, I haven't felt too badly about substituting different types of drivers for the woofers and midrange units when repairing HC-12s. My ears were telling me that the speakers sounded just fine with my substitute drivers. As I said above, I'm having second thoughts about using a cheaper midrange, and plan to do some more experimenting in the shop before doing this again out in a church.

                    I have four HC-12s coming in next week with an ADC Allen, and I suspect they will need full rebuilds. This will give me a chance to compare them side by side with some HC-12s with all-original parts, and with HC-15's and other organ speakers we have in the shop. I will report any significant findings.
                    John
                    ----------
                    *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

                    https://www.facebook.com/pages/Birds...97551893588434

                    Comment


                    • #11
                      The two 4-ohm midranges on the HC12 were wired in series, to give 8 ohms total. So to replace them with one 8 ohm unit, you wire the single 8 ohm unit in place of the dual 4 ohm units.

                      The 4" Pioneer midrange is no longer available anywhere because Pioneer quit making it. I don't know of any modern cone midranges with a deep, sealed back chamber. There are plenty of smaller midranges (3 in to 5 inch) available, they just don't have a chambered back.

                      Comment


                      • #12
                        I've seen quite a few of these same midranges, some in excellent condition, some needing new surrounds, sell for very fair prices on ebay.
                        I'm so poor, my cats get free health care!

                        Comment


                        • #13
                          Just to follow up and close the loop on this thread:

                          I went the middle route on this, between the $100 new Peerless driver from Allen and the $10 Chinese driver from Parts Express. Per Michael's suggestion I contacted Dixie Speaker in Birmingham. Unfortunately they said they were unable to re-cone this driver. But, they were able to sell me a used 4-ohm Peerless driver, with the original cone but with new foam surrounds. This was $40 plus shipping, which seemed reasonable enough, so I went with this option.

                          Got the driver today and installed it - it works fine, sounds great and is clearly the correct/original driver. (It fits the holes perfectly, and has "4 ohm" and Allen part number 292-0041 right on it.) So I would recommend this option to anyone who wants to keep an HC12 stock, but without spending quite so much. (I believe they still have a few of the drivers left.)

                          I'm sure Jim is correct that it'd be possible to find these used on Ebay too, and probably for even less money - especially if you're willing to re-do the foam surrounds yourself. But I wanted to get this done quickly without waiting for a bargain to pop up. So I'm happy with how things worked out.
                          Last edited by Scott Dennison; 08-12-2015, 05:28 PM.

                          Comment


                          • #14
                            Originally posted by jbird604 View Post
                            Those midranges are an ongoing issue for sure. The foam rots and they sound terrible. Then the repairs sometimes fail, as yours did, and you wind up with a rubbing voice coil that yields more distortion than the rotten foam did.
                            One last thought here. I'm not sure if my rubbing VC was due to my own screw-up, or whether it was like that already - stupidly I didn't bother to test the drivers before I dived right in to re-do the surrounds. But it may well have been me who did the damage - the speaker tech I contacted said it's very easy to "pull your voice coil out of round" in the re-edging process. --Just a word of caution to anyone reading this who decides to try the foam job themselves.

                            Comment


                            • #15
                              As I mentioned above, we just received four HC-12s as part of a traded-in organ system. These four, which I haven't yet had time to test in the shop, had all been repaired according to factory recommendation. Which is to say, each cabinet has a single 8 ohm midrange driver that perfectly fits the hole, Peerless, I assume, of the same general type, though it looks a little "different" with some kind of non-foam surround. The second hole in each HC-12 retains the old driver, which was disconnected and bypassed, serving now only to maintain the air-tightness of the box. The woofers appear to have been replaced with some very good rubber-surround high-compliance woofers. So I'm guessing this was done by a committed factory-compliant tech. I'll be interested in comparing these head-to-head with the original-condition HC-12s we already have in the shop.

                              I think I've already mentioned that my preliminary testing in the shop revealed that the HC-12, while having a smooth, well-rounded tone with plenty of bass, is noticeably less efficient than nearly all the other organ speakers I tried it against. The one cabinet which was not any more efficient was a big Walker "credenza" style full-range speaker with a 15" rubber-surround woofer, three 6x9 midranges, and four tweeters. I was surprised at the relative inefficiency of that cabinet. But of course both the Walker and the HC-12 are quite suitable for most organ installations, and can produce plenty of sound when driven by a suitable amplifier.

                              Surprisingly, so far, the most efficient organ speaker I've tested, in terms of sheer raw loudness, is the Rodgers M-6. I didn't have an M-10 to test, but I assume it would be equally loud and would have more high treble output with its multiple tweeters. I can't say that these rather old Rodgers designs from a bygone era are "better" than HC-12s or HC-15s or any other newer speakers. They are not meant for handling much if any bass, so their forte (no pun intended) is the broad middle, and the highs too, in the case of the M-10.

                              Perhaps I'll have time to post some more info when I get some shop time to further evaluate the various speakers we have on hand.
                              John
                              ----------
                              *** Please post your questions about technical service or repair matters ON THE FORUM. Do not send your questions to me or another member by private message. Information shared is for the benefit of the entire organ community, but other folks will not be helped by information we exchange in private messages!

                              https://www.facebook.com/pages/Birds...97551893588434

                              Comment

                              Hello!

                              Collapse

                              Looks like you’re enjoying the discussion, but you haven’t signed up for an account yet.

                              Tired of scrolling through the same posts? When you create an account you’ll always come back to where you left off. With an account you can also post messages, be notified of new replies, join groups, send private messages to other members, and use likes to thank others. We can all work together to make this community great. ♥️

                              Sign Up

                              Working...
                              X