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Well, I'm trying to build a turntable

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  • #16
    Made a test plinth in the shape of a Tee yesterday and mounted the arm and motor. This evening I mounted a Euro-style terminal block to handle the motor wiring (don't have a pic of that, this pic is yesterday with the ugly wiring for testing).

    This weekend I should be able to mount a cartridge and Monday I should be able to wire it (I'm waiting on terminals to solder to my wire).

    The test plinth clearly has a cross-grain issue, it likely would not survive a humidity swing too happily. But it was quick and easy. Once I get further with my testing, I'll make a new plinth and accommodate other issues I've already found.

    For feet I'll use Vibrapods that will fit over some particle board discs that will hold them in place.

    Still need to have an epiphany over wiring. The wire is run down the top of the arm because I ultimately plan on using a lift mechanism, and wiring on the bottom of the arm would interfere. I don't want to create a channel for the wire because if this works out, I'll be making a carbon fiber version of the top and bottom plates, and the carbon fiber is thin enough that I cannot have a channel. So I'm thinking about keeping the wire up top, and then diving under the arm at the first aluminum spacer, and then back up through the hole. Once the wire exits the hole on top, it will terminate with a plug that plugs into a jack next to the arm, so I can easily remove the arm/cartridge to work on it.

    An interesting project so far, learning quite a bit about turntables.

    The thing is, when I decided I wanted to try vinyl again, I kicked the idea around a while before getting a Technics table (well two, because I got one that didn't work and then one that does). But I stopped by a record shop and discovered that all their jazz albums are listed at giveaway prices. A little checking seems to indicate that classic rock vinyl is stupid expensive, but a two album/three side Keith Jarrett album $5. And it actually sounds superb. Ahmad Jamal albums just a few bucks. Roland Hanna $3.50. Some very difficult to find in digital format.

    Kinda fun.

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    • #17
      If you need some parts hit me up I have some cart parts and other parts as well. You’re only limited by your knowledge and persistence to expand your knowledge and to achieve what you want in getting the satisfaction that you made it

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      • #18
        Originally posted by carlthess40 View Post
        If you need some parts hit me up I have some cart parts and other parts as well. You’re only limited by your knowledge and persistence to expand your knowledge and to achieve what you want in getting the satisfaction that you made it
        Thanks! I think I have most everything I need now or on the way.

        I just hope it works or can be made to work. The first test is coming up soon.

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        • #19
          Phil, you may have already thought about this, but to properly match a cartridge's compliance to a tonearm, you need to know the effective mass of the arm. It is as simple as taking the counterweight off and then dropping the cartridge mounting end on a digital postage scale. Most cartridges today with a compliance of about 20 um/uN are happy in an arm of about 8 to 10 grams. Google tonearm cartridge calculator and you should find a couple.
          -Bob

          The PEDS 2.1 mini system
          My A7 Project - another small desktop speaker
          The B3 Hybrid Dipole - thread incomplete and outdated

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          • #20
            Originally posted by BOBinGA View Post
            Phil, you may have already thought about this, but to properly match a cartridge's compliance to a tonearm, you need to know the effective mass of the arm. It is as simple as taking the counterweight off and then dropping the cartridge mounting end on a digital postage scale. Most cartridges today with a compliance of about 20 um/uN are happy in an arm of about 8 to 10 grams. Google tonearm cartridge calculator and you should find a couple.
            Thanks Bob.

            Yep, someone @ another forum did tell me to check that. I did check it several nights ago right before I put it away for the night, I think I was right in that range. I'll have to check again because a lot has been changing.

            Figured out a way to make an arm rest. There is a socket-head cap screw through those spacers, the arm has a hole that fits over that screw's head.

            I don't need anything more secure than that, because if I need to move the entire table, the arm has to come off (the thing you learn quickly when it comes to unipivot arms is that there is nothing holding them in place but gravity, so if you're going to transport the table, best to remove the arm).

            Still pondering ideas to make a DIY cueing lifter. And anti-skate. And feet.

            At this point I really need to get a cartridge mounted and perform some testing, before going much further.

            Waiting on Amazon to deliver my T4P to 1/2" adapter. I have a sort of "beater" T4P cartridge that might work well with it for testing this thing, and the adapter was only $10.

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            • #21
              The T4P adapter arrived. After getting my cartridge mounted, I found I had to raise the arm about .25".

              That tiny digital scale I got on Amazon sure is nice for setting tracking force, very sensitive. Got that dialed in at 1.25-grams.

              When I set the stylus in a groove, it leaned over a tiny little bit. So I had to adjust the azimuth using my left/right counterweight method. It just took a tiny shift, maybe less than 2 degrees. I went too far the first time. Right now it is set by eye, I don't have a cartridge setup kit, just the scale.

              But it works! My test album is an old Ahmad Jamal Trio album, which is approx. 65-YO (I'm 55). I got it on eBay for $3.50 shipped because I wanted a test album and I like Ahmad Jamal. If you're going to HAVE to listen to something while testing, might as well like it.

              I've listened a while with headphones, it sounds "fine." It is tracking fine. I need to figure out the isolation feet, it needs some isolation.

              Also really need to figure out a cueing device. I don't even have a finger lift yet ($2, ordered from China). My hands aren't as steady as they once were. Yowsa.

              I think I'll drag it upstairs and connect it to the hifi to get a better sense of how it sounds.

              Here is a pic of it playing:



              And here is a movie proving it works:

              http://www.jpthien.com/temp/IMG_5158.MOV

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              • #22
                I like it, the cool factor is off the charts. I certainly approve of your album choice...

                It would look much more finished if the front leg of the base was rounded into a semicircle. Some added mass in the base might be useful also.

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                • #23
                  Originally posted by Billet View Post
                  I like it, the cool factor is off the charts. I certainly approve of your album choice...

                  It would look much more finished if the front leg of the base was rounded into a semicircle. Some added mass in the base might be useful also.
                  Yep, that plinth is just a proof of concept. I'll radius the corners and round the edges of the final version. I also have a rocker switch on the way that I can wire for 33/off/45. I can't really build the final plinth until I receive that rocker switch.

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                  • #24
                    Been working on isolation, trying different materials.

                    Specific problem was, setting coffee cup on table while playing something, resulted in pickup of too much noise. My reference is the Technics SL-J33, which still captures the coffee cup "tap," but not to the same degree. The SL-J33 has four spring feet (one in each corner). The current iteration of my DIY prototype had no isolation whatsoever, just wood.

                    After trying a bunch of different materials, I found that my wife's Ikea cork pot trivets did the best job of providing some isolation without destroying the sound quality. She had three, now she has two.

                    I CNC cut a few feet "caps" from the cork, including shallow pockets to capture the current BB (Baltic birch) feet and voila, about as perfect as I could hope. I can now listen and drink coffee.

                    I'm waiting on the power switch so I can finish wiring my prototype (need to make the ground wires look neat, too). Also need to figure out a wall mounting shelf (do I want vinyl storage? how will I route wires? will the phono preamp go on the shelf with the table?). While I'm thinking about the wall shelf, I'm sure some things will occur to me about how to improve the design of the final table.

                    I ordered an Ortofon 2M Red cartridge for the thing. Amazing how the surface noise dropped (from the old and near dead Technics T4P in a 1/2" adapter). We (wife and I) only have a couple of hours on the Ortofon, waiting for it to break-in some more.

                    Probably going to order a Grado Black or Blue next, just because I'm having a blast and want to try some different cartridges. I've got very little $ into this table, so easy for me to justify ordering some different cartridges to try.

                    Shot of current table with 2M Red cartridge playing red vinyl (more like orange, but) Roland Hanna Perugia.

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                    • #25
                      I am thoroughly impressed. That's a great project.
                      -Bob

                      The PEDS 2.1 mini system
                      My A7 Project - another small desktop speaker
                      The B3 Hybrid Dipole - thread incomplete and outdated

                      Comment


                      • #26
                        That looks utterly brilliant, and really cool playing the red vinyl.

                        As a matter of interest, does the red vinyl wear more than black? If the black product has carbon as a lubricant, wha do the coloured LPs use?

                        I have all the early Beatles LPs as Japanese red mono pressings, also a few coloured bootlegs and am afraid to play them much in case I wear them out.

                        Well done!

                        Geoff

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                        • #27
                          Originally posted by Geoff Millar View Post
                          That looks utterly brilliant, and really cool playing the red vinyl.

                          As a matter of interest, does the red vinyl wear more than black? If the black product has carbon as a lubricant, wha do the coloured LPs use?

                          I have all the early Beatles LPs as Japanese red mono pressings, also a few coloured bootlegs and am afraid to play them much in case I wear them out.

                          Well done!

                          Geoff
                          Huh, I do not know. I don't play it often, it is a Roland Hanna Perugia disc that is newer, I just thought it would be kind of interesting to play a red album with my red cartridge.

                          The surface noise from this Ortofon 2M Red is insanely low, and having only played the Perugia once or twice, I figured it would be a good test to see how quiet vinyl can be. It is pretty darn quiet.

                          But I don't know how durable it is.

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                          • #28
                            The Ortofon 2M Red turned out to struggle with piano in the last 1/3rd or so of albums. Checked my alignment repeatedly, it was as good as I could get it. Increased tracking force to 2G from the recommended 1.8G, and piano was better but still edgy. Also, cymbal crashes were a bit dull/lifeless on the Ortofon.

                            I finally decided to just order an Audio Technica AT-VM95E. About the same specs as the Ortofon (slightly lower output I guess) and half its price, popped it on the table, all problems solved. Funny thing is, if you google "Ortofon 2M Red distortion," you'll find a lot of people describing exactly the same problem as I was having. I went with that cartridge because the reviews @ Amazon were so favorable.

                            With that solved, I'm moving onto anti-skating.

                            Also, I've needed a decent way to clean records. I've been testing all sorts of DIY methods including wood glue (works a treat), and finally switching from relying merely on playing the records to looking at them with a loop. It was amazing how much all my test methods were leaving behind.

                            In my youth, I used a Discwasher. It had directional pile which sort of lifted debris from grooves. It worked okay, I didn't have anything by which to compare it I suppose.

                            So I kept coming back to the Audio Technica AT-6012 on Amazon and @ Best Buy. Reviews were favorable. Similar scheme to the Discwasher, but I was sure it was just a velour type cloth and didn't have the directional pile. I was wrong. I picked one up, and the pile IS directional. It is also much, much (did I say much?) finer a pile than the Discwasher was.

                            They have holes in the thing where you're suppose to add the included fluid, which will be dispenses through the resevoir. Instead, I run a bead of the fluid down the leading edge, wet the album for a few spins, then roll it to dry the album. I swear each time I use it, it gets the album a little bit cleaner. I'm playing some classical albums sourced for ninety-nine cents from the bins at Goodwill, and they sound remarkably quiet.

                            So onto figuring out anti-skate. I guess it should be 1/10th the tracking force, so .2 grams. So I need to figure out how much weight I have to apply at what distance from the pivot, to achieve .2g.

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                            • #29
                              Worked on anti-skating today. To test, I spun the platter by hand while the stylus rested on an blank CDR. Sure enough, the cartridge wanted to move to the center (spindle) rather quickly.

                              So I added a solder lug (bent) between the wand and the rear pillar, and a spacer washer of similar thickness in front.

                              To this I attached a string tied to a 1g weight, and used a bent cable tie as a fulcrum. With this attached to the arm, the stylus stayed in one place on the CDR as I spun the platter.

                              So now I need a weight I can actually use (that 1g weight goes with a set that belonged to my father, and which I sort of cherish). I need to bend-up a piece of wire to make a better fulcrum. AND, I need some fishing line (I think that will work better than the string I robbed from my wife's crafts). I think I can find some old fishing line near a pond not too far from my house.

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                              • #30
                                IF,,,,, your really going to get into playing lp’s, a vacuum record cleaner is the way to go! Unless you got the cash for an ultrasonic machine. They are better still.
                                Another thing that I find invaluable is a product called “Gruv Glide”. Check it out and most Guitar Center stores carry it.

                                I really like reading about what your doing!

                                Have Fun! Mark

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