Idler Wheel Turntables |
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回覆 (2321): Refoaming Lowther / AER Drivers
cleaned up and ready for new surround  
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test fitting - nice  
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I use Elmers glue, its like paper white glue - works very nice. First apply to the inner edge of the foam which makes contact with the paper cone. Finger and thumb allows a smooth gentle pressure along the edge with give it a nice contact. A thin brush also allows spreading of the glue giving a more regular interface.  
Once that has set which is done in a few minutes, you can start applying glue to the metal frame where the foam makes contact. again a thin brush will allow even spread.  
Gentle pressure from finger to the foam to the metal frame allows good pressure contact  
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as good as new !!!  
回覆 (2320): Refoaming Lowther / AER Drivers
unsolder the wires from the speaker posts, this allows freedom of movement while restoring the driver.  
Note the coils are inside the cone and not outside.  
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lowthers are outside. The coils are nicely made.  
disintegration is pretty bad once you start touching the foam  
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to get rid of the existing glue residue, apply some acetone or use nail varnish remover  
anything left over I used some coarse sandpaper to gently scrap away the remaining glue from driver and metal frame  
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回覆 (2319): Refoaming Lowther / AER Drivers
Recently, my drivers were starting to distort and even bits of foam were flying out with excessive volume being played. I had no choice but make the jump in replacing the surrounds. Recent practise on a pair of cheap Lowther allowed me to gain some knowledge first, but those coils were already damaged and rotting away. I got some solder paste which I hope can bring those drivers back to life.  
Anyway, as you can see the surrounds were pretty bad after I guess over 10 years of abuse !  
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WARNING !!! magnets are powerful on this 106 db driver. The spanners can literally fly out of your hands and can move magnetic stuff like poltergeist - keep those expensive watches away ! unless you have Jedi hands, you are warned. The bolts use a no.8 spanner  
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amazingly the spider on the inside is actually perfectly fine !! no need to change unless you have a real itchy asshole !  
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回覆 (2318): Run for your life
No question, no argument, no hesitation please. This has got to be the most ugly looking turntable on planet. Why and who on earth would make something like that for the human race. Its not fair and is total utterly unnecessary.  
If you do see one. Just shut your eyes and run for your life before it gets to you. It really is robbing the human race!  
Its so ugly that it even make any CD player look sexy!  
回覆 (2317): Miyajima Cartridge - they are arrived
回覆 (2316): Tube Turntable AC motor power supply
Thanks for sharing!  
I was looking into different valve oscillation circuits just now. Keep searching and learning! So far, a lot more interesting than building a push pull amp for speakers.  
A few things I am working on for my all valve turntable supply:  
A clean low distortion sine wave to start off with  
A regulate DC power supply  
A stablise AC output voltage  
What else,,,,,,,,what else
回覆 (2315): Tube Turntable AC motor power supply
FYI only:
回覆 (2314): Tube Turntable AC motor power supply
Teach me when you have time.
回覆 (2315): Tube Turntable AC motor power supply
unfortunately i was vacated from my den. the controller is on hold until i can set up my workshop in dongguan..
回覆 (2314): Tube Turntable AC motor power supply
Dr King, so how is your version of the controller going?  
回覆 (2313): Tube Turntable AC motor power supply
it is more complicated than you think. but by all means have fun.
回覆 (2312): Tube Turntable AC motor power supply
Just experimental! Not meant to be a giant killer. As long as I can acheive a variable Hz, adjustable voltage and ok stablitiy, it would be good fun to me lor! Not really that difficult with modern electronic but a touch more care is needed with tubes.  
Doesnt it give you one more good reason to come to HK to visit the 1pk gangs?
回覆 (2311): Tube Turntable AC motor power supply
回覆 (2310): Tube Turntable AC motor power supply
Initial circuit for an experimental all tube Turntable AC motor power supply  
Oscillation - consists of a 6AU6 and one 6CL6. The dividing network which carries all the caps and resistors that control the frequency range from 48 to 52Hz will be made from a few 24 steps series rotory switch.  
Amplication - a typical PP with 12AU7 and a pair of KT88s.  
Output - A 100W telefunken line transformer  
Power supply - tube regulation with a 6336, one EF86 and a 0B2 for B+ and 338 for faliment.  
Output voltage range - 70 to 150V Single phase. For true two phases output, I could add a balanced output transformer in place of a phase cap.  
Feel free to comment and suggest.
回覆 (2309): Tube Turntable AC motor power supply
I would appreciate if you could come over to help me take it out for a look!  
Of course la! Just a few cans would do. I think this is going to be an interesting projects for me. Not the usual SE and PP amps, you know what I mean! I have long been feeling tired on traditional circuits valve amps!  
回覆 (2308): Tube Turntable AC motor power supply
I have no idea about the Rockport motor, as I have never opened up the motor pod.  
I am also very interested to know what model of motor it is, so if you are available sometime next week, I would appreciate if you could come over to help me take it out for a look!  
回覆 (2307): Tube Turntable AC motor power supply
Here is a picture showing the readings using a pair of KT88s in push pull to supply 85Vac to a Linn motor.  
On the far left grey colour small Fluke is the input voltage 0.541Vac  
The middle yellow/grey Fluke 87 is the output voltage to the motor 83.7Vac  
The right hand yellow/grey Fluke 83 is the output Hz reading 47.89Hz  
The scope shows part of the output wave form.  
I think i have a basic building block and resources for two tube turntable AC motor power supplies. What I need to sort out is how good a clean, stable and adjustable Hz wave I can get if not from the wall socket.  
Kong, let me know all you have on the VPI motor, I will do my best to understand and see what can be done on my second supply.  
Cant wait to start this new project! Perhaps next week!
回覆 (2306): Tube Turntable AC motor power dupply
The little hand held signal gen only offer stepped frequency selection. This little creature is only for testing purpose. When in actual construction, I would look into getting a good signal gen. module for the power supply.  
Some say old style analog signal gen is better, others insist on digital. The reolution is not a concern. Is the stability and wave form that I need to look out.  
Looks to me I would use the 2 telefunken transformers to build two power supplies.  
Variable output from 70 to 150V for torque control  
Variable Hz adjustment from 48 to 52Hz for 33 1/3 and 58 to 62Hz for 45rpm. 0.01Hz resolution should be do-able. Much depending on if I can get a good variable cap if i decide to go for analog. For digital scope, I suppose that is no big deal.  
回覆 (2305): Tube Turntable AC motor power dupply
What is the resolution of that signal generator? I believe you need it down to 0.01Hz per step!  
回覆 (2304): Tube Turntable AC motor power dupply
Kongggggggggg..... it works!  
I took out the output transformer in my push pull KT88 amp. Swap the GEC to Svetlana! Connect the Telefunken transformer to the amp. The 50 Hz is coming from a portable signal generator. You can see that the ouput voltage is currently at around 97V show from the Fluke. The input voltage is at roughly 0.7V. I can adjust the output voltage to the motor by turning signal gen volume.  
See I placed a cream colour tape on the motor so you can see its turning. The motor start turning at around 80V.  
I will put the amp on a test bench to see how the sine wave look on a scope.
回覆 (2303): Tube Turntable AC motor power dupply
I believe some users of vintage idler wheel TTs like the Garrard, prefers lowering the voltage a bit to, say, 180-190V. If I am not mistaken, this is supposed to minimize the vibration.  
The VPI SDS’ standard setting also starts and 110V (for their 110V output model), and lowered to around 85-90V once the platter get up to speed!  
回覆 (2302): Tube Turntable AC motor power dupply
I am day off today and Friday. Experimenting at home now and see if the output voltage can turn the Linn motor to normal speed. If it works, it would be a good start.  
Share with your more with photos and results in about an hour.
回覆 (2301): Tube Turntable AC motor power dupply
Just a short recap of what I have posted before regarding the Rockport motor:  
1. The VPI SDS and PS Audio Powerplant 300 (300 watt) could start the platter turning at 33.3, but not 45  
2. The Powerplant 1200 (1200 watt) could start both 33.3 and 45 from stop, but slowed to a stop when I tried to switch from 33.3 to 45 by switching the controller’s output frequency!  
Since these controllers have power range from about 150-1200W, power or current are not likely the issue. Mark believed one of the possibilities was the motor’s back EMF was close to the controllers’ output voltage (220V), so there is not enough power reaching the motor. He suggested that I try turn up the voltage to 240-250V, but since I have no idea what would that do to the motor, I never tried it!  
回覆 (2300): Tube Turntable AC motor power dupply
the controllers couldn’t drive my Rockport motor could be the high back EMF of the motor.  
I think it was you who forwarded Kelly's article and got me into realising the issue in EMF but my little head doesnt offer me sufficient brain cell to fully understand how EMF affect the power supply design. I got to the the point only knowing EMF is there whenever there is a magnetic field . In a motor, the time- varying magnetic field inside the motor creates electric field which in turn creates energy difference between the motor terminals.  
I dont know how big this can affect the power supply design. When I looked into Linn and Naim design principals, I couldnt find anything about their solutions to EMF build up. May be I am too far behind in knowledge. I am just not there yet.  
I dont know if a high current power supply can minimise the effect from EMF. The max output power the Telefunken transformer can handled is 100W. When output voltage is tune at 100V, it can send out 1A current to the motor. Can you help to find out if the Rockport motor consume as much as 1A please?
回覆 (2299): Tube Turntable AC motor power dupply
Not sure how you could solve this in your design, but according to Mark Kelly’s “gesstimation”, the reason why some of the controllers couldn’t drive my Rockport motor could be the high back EMF of the motor.  
I believe Rockport chose the motor due to its high torque, but I am not sure whether there is any relationship between high torque and high back EMF!  
However, Mark he has never seen the motor, and I have no way of checking, that is simply a guess!  
回覆 (2298): Tube Turntable AC motor power dupply
Here is my inital thoughts on a simple experimental Tube Turntable power supply for AC motor.  
The AC sine wave 45Hz to 65 Hz would come from an adjustable signal generator module which can be purchased from the web of a few hundreds HK dollar.  
For the amplication of a 1V sine wave from the Signal gen., I am thinking of a power amp deploying a pair of KT88s in push pull. Basic circuit similar to a normal working audio amp.  
Since most AC motor requrie a driving AC voltage of 80 to 120V. I have the below pair of Telefunken line output that has a 100V line level secondary. These transformers are rated 100W and doesnt have 8 or 16 ohms taps for home speakers.  
Any suggestions or corrections, feel free to shout. Of course, I would make this power supply looking excatly like my home made family amps such as the SV811-3 or PX25 in hammered Metal finish!  
回覆 (2297): Ultrasonic Stylus Cleaner
the test shows a resounding orgasmic result ! especially with female vocals !!! 8^)
回覆 (2296): Ultrasonic Stylus Cleaner
Thx daiwok for bringing the vibrator over last nite, 震得好high ^^
回覆 (2295): Ultrasonic Stylus Cleaner
Years back when I was still playing vinyl, the match box that Ivor from Linn recommented seems to be pretty handy & effective. But this obviously looks more elegant & professional.
回覆 (2295): Ultrasonic Stylus Cleaner
I don't have enough myself as I need one for each cartridge !!! That means just over 50 of these !! @@  
For you Master Limage I will find a way to get you a new vibrator ! 8^)
回覆 (2294): Ultrasonic Stylus Cleaner
Any spare available? My Audio Technica is not working sometimes.  
回覆 (2293): Ultrasonic Stylus Cleaner
A recent bulk purchase of NOS Ultrasonic Stylus Cleaners. These are no longer made and they are much bigger than the Audio Tehnica counterparts !  
As always - SIZE MATTERS !!  
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回覆 (2292): Elite Rock
borrowed this from dkyyu as I always wanted to try the Rock TT with the damping trough.  
currently setup with an Akito (also from dkyyu) tonearm and an acutex LPM420.  
no splashing with the oil yet as I want to hear the setup without the oil first. rightnow, i'm very impressed but the jury is still out...too early to draw any conclusions.  
stay tuned for the next update...  
回覆 (2291): Where did you find it ?
Any member with experience with one of this?  
回覆 (2290): Where did you find it ?
Swiss technology since 1954!  
回覆 (2289): Where did you find it ?
ok folks, we are getting a GROUPON for a 16 inch Terminator !!!  
Why 16 inch ? well for 16 inch platter !  
What if I do not have 16 inch platter ? you can mount the arm on an arm pod and have it sitting independently outside any turntable ! why worry about drilling holes into that beloved armboard !  
Interested ? contact me 8^)
回覆 (2288): Where did you find it ?
Mount your arm on an Edison and listen to WAX !!! and get to the MAX !!!
回覆 (2287): Where did you find it ?
I hate to admit it simply because I only have one. Linear tracking just offer so much more details. Other than the bloody noisy pump which is best located a wall apart from the king's seat, I have zero negative comment on my Terminator at all.  
The only arm that come close in detail retrieve and overall tracking ability is my 12" Morch!  
回覆 (2286): Where did you find it ?
回覆 (2285): Where did you find it ?
Dear Doctor,  
I must pay you a local visit to hear your new Phono ! 8^)