DD vs Belt drive and Single vs Dual capstan?

Keith H

Active Member
When it comes to cassette decks is Direct drive always better than belt drive and are dual capstan decks always better than single capstan decks?
 
hi fellow Akers; Dual capstans, and therefore dual flywheels give more mass to be in motion...and more mass in motion is much less subject to variations in tape speed....more mass, more weight being propelled gives an increased tape speed stability....case in point, on some belt drive reel decks, the flywheels are VERY heavy..more mass to increase tape speed accuracy....dual flywheels also provide two points at which tape is driven along and across the recorder heads....more control of tape movement....
 
Properly executed, the direct drive designs out-perform the belt-drive designs, and dual-capstan designs out-perform single-capstan designs.

Most belt drive cassette decks use a simple DC motor, from makers such as Mabuchi, Sankyo and Matsushita. In time, these will fail, due to brush, commutator and bearing deterioration. Direct-drive motors use no brushes or commutators and use the long-lived capstan bearings as the motor bearings.

An interesting feature of dual-capstan designs is that the leading capstan is designed to have an ever-so-slightly greater angular velocity than the trailing capstan. This results in a constant, steady tape-to-tape-head pressure -- which leads to LOW dropouts. Dual-capstan systems nearly always use a belt to link the two flywheels together, and the condition and nature of the belt is extremely critical.

Fred Longworth
 
When it comes to cassette decks is Direct drive always better than belt drive and are dual capstan decks always better than single capstan decks?
Nope! That's like saying a direct drive turntable is better than a belt drive. Nope again.
 
When it comes to cassette decks is Direct drive always better than belt drive and are dual capstan decks always better than single capstan decks?

Direct Drive, beats belt drive (unless old school simple top loader and easy to change belts on). Dual capstans superior always. Simple beats excessive gadgetry. Practical beats less practical. Technics and ReVox love their DD and simpler mechanisms.
 
Nope! That's like saying a direct drive turntable is better than a belt drive. Nope again.

Sorry, not on a cassette deck. Unless you're a neurosurgeon. Belt changes on 98% of cassette decks are major pains in the rear. They can take many hours.

Sorry, name me a belt drive disc lathe (save for some early Scully models). The last Scully lathe and all the Neumann lathes are direct drive (many a SX 68, and SX 80 lathe uses a Technics SP-02 motor). Accuracy beats sloppy playing back too. The only belt drive I can live with for a turntable happens to be an Empire 598 with a Jelco tonearm as a daily driver. Cerebral Palsy demands mass loaded big time, I demand broadcast accuracy in terms of pitch, 45 minutes must play back 45 minutes every time. And no upgrades necessary, install the cartridge of my choice, set up carefully, and play records.
 
DD is more prone to flutter (fast speed deviation) and belt drive to wow (slow speed deviation). As I learned from the experts on tapehead.

Either system can be executed well and poorly, so there is no absolute order here. Unlike the double capstan system, that is just superior to the single capstan design.

If you want to get it right, using DD reel motors is quite a challenge. The belt system is a bit more forgiving. So a belt drive could be a decently working step-in decky, or an absolute top model, or anything in between. DD systems are usually high-end models, because they were expansive to build, and their construction required considerable expertise from the R&D department.
 
Generalisations generally tend to be wrong.

DD normally is a ticket to lower wow&flutter. But then there are these few Aiwas that, belt-driven, are as good or better.
DD, needing no or less belts, is easier to maintain these days.

Dual capstan is superior, when in perfect shape. With wear and imperfect belts factored in, single capstan is safer and sometimes outright superior. If you have rare, irreplaceable cassettes, play them on a good single capstan deck.

A drawback of single capstan is that it can't employ a pad lifter.
 
Back
Top Bottom