motor pickup

DIY, Accesorii , Tips&Tricks
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momolo
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motor pickup

Post by momolo »

Daca stie cineva - caut motor pentru pickup belt-drive la bani cat mai putini. Ori pe alternativ, ori mai bine pe continuu cu posibilitatea de reglaj turatie. Am investigat pe net si am gasit doar in Australia ceva cat de cat http://www.decibelhifi.com.au/category22_1.htm" onclick="window.open(this.href);return false;

Ideal ar fi un motor independent, adica montat in propria carcasa (cilindru) si care se pune pe o masa alaturi de pickup. Problema e si cu pretul, am gasit pe net mai multe variante insa preturile sunt enorme.

Bucsa se poate face la comanda funtie de turatie insa gasirea motorului e problema principala.

Forta necesara nu e mare, trebuie sa invarta un platan relativ usor, acril de aprox 2,5 Kg.


Si mai am o intrebare - nu inteleg cum functioneaza in cazul acestei aplicatii un motor de curent continuu care este alimentat simplu, cu plus si minus, fara feedback ?! (precum in link). Eu stiu ca functie de sarcina poate varia turatia unui motor si mai stiam ca cele pe continuu au nevoie de un control activ bazat pe un feedback care se poate face ori prin "citirea" unor infasurari suplimentare la motor, ori pe celule optice, ori senzori magnetici, etc.
prostia, ignoranta, lipsa educatiei elementare sunt cele mai letale arme de distrugere in masa.

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LEKTOR
Posts: 1774
Joined: 05 Oct 2008, 16:08
Location: Audiofilsburg

Re: motor pickup

Post by LEKTOR »

BELT DRIVE

Hysteresis Synchronous
Belt Drive

All early turntables and still a few today use the Hysteresis Synchronous drive system. This is a good choice for fixed speed designs for the speed is locked to the power line frequency. Thus, the drive system has a good source of regulation. Speed stability is good and drift is very low. The weakness here is the difficulty to produce variable speed.

DC Belt Drive

This is a belt drive system which uses a conventional DC motor as the drive source. The advantages here are cost, variable speed potential and reverse rotation. The weaknesses are great however. These motor systems suffer from temperature drift and load sensitivity. I.E. the platter will speed up over time and it will slow down under stylus load. This is not a serious drive system. It is usually found on budget DJ turntables. DJ's typically que between two turntables and rarely play anything over a 3 minute song. In that short time, the speed variations do not show substantially. But play a full album side and they will. After the DJ makes some money, these tables are always traded in for better direct drive turntables.

DC Servo Belt Drive

These systems use a sensitive regulator to monitor the voltage to the motor. There is marked improvement in long term speed drift and static stylus drag sensitivity. FG servo gives better absolute accuracy

FG Servo Belt Drive

Frequency Generator Servos or Tachometers, offer the most sensitive way to control a DC drive system. The Tachometer provides a direct readout of motor speed and thus is able to control the motor most effectively. This drive system offers the best control of both long term speed drift and static stylus drag friction. It cannot however respond fast enough to dynamic groove friction. But if the platter is heavy enough, the flywheel effect will deal effectively with most dynamic groove friction effects.

Alte chestii

- http://www.isolation-racks.com/power-su ... -motor.htm" onclick="window.open(this.href);return false;

- http://www.turntable-power-supply.com/index.htm" onclick="window.open(this.href);return false;

- http://www.teresaudio.com/verus-motor.html" onclick="window.open(this.href);return false; ( cei care fac pe CERTUS - http://teresaudio.com/certus/" onclick="window.open(this.href);return false; )

- http://www.mclennan.co.uk/dcservo.html" onclick="window.open(this.href);return false;

- http://www.needledoctor.com" onclick="window.open(this.href);return false; - la parts
... living a vi(ntage)king analog lifestyle in a digital world ...

apanoiu
Posts: 23
Joined: 19 Nov 2008, 16:31

Re: motor pickup

Post by apanoiu »

poate te-ar ajuta un servomotor.
acestea merg foarte lin, cuplu imens(nu cred ca te ajuta neaparat asta) si au si encoder de turatie.
Fiind cu perii insa, are un anume zgomot.
Poate unul asincron... dar mai greu de controlat turatia.

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momolo
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Posts: 13944
Joined: 02 Oct 2008, 10:11
Location: Bucuresti

Re: motor pickup

Post by momolo »

Multumesc voua de info! Ma gandeam sa imi confectionez un pickup insa treaba asta e foarte complicata si consumatoare de timp. Mai simplu ar fi de bricolat unul deagata, insa chiar si asa e naspa cu timpul si umblatul pe drumuri.....

Beleaua este ca un pickup (actual, nou) audiofil care sa presteze la cote inalt-onorabile costa cam multicel. Te si minunezi pe ce se cer cateva mii de euro in materie de turntable audiofile din noile generatii ! O solutie ar fi si cu vintagele de varf insa aparatele astea sunt extrem de delicate atat la transport cat si la utilizare. Foarte riscant de cumparat pickup prin posta iar cele (vintage) bune costa si ele sume importante.
prostia, ignoranta, lipsa educatiei elementare sunt cele mai letale arme de distrugere in masa.

Obelix
Posts: 1444
Joined: 19 Jan 2009, 13:01

Re: motor pickup

Post by Obelix »

Singura mare problema ar fi palierul pe care platanul se invarte, in rest nu e vorba decat de timp...
(NU ma refer la brat aici)
Un motor de casetofon cu reglaj incorporat nu ajunge ? Nu cred ca solutia constructiva are vreo importanta deosebita, daca motorasul e n "cutiuta" lui independenta (cu "sforile" de transmisie la vedere)

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