PIONEER RT-909 Pinch Roller

Nagravox

$174.00 AUD 

PIONEER RT-909 PINCH ROLLER    

This Pinch roller is for the specific model shown as a pair. They are new fresh manufactured in the EU for Nagravox using a modern synthetic black rubber formulation. 

The moving assembly is our 'deluxe' type with special low noise precision roller bearings instead of plain bushes.

All our kits and parts use specially sourced, new, freshly manufactured components from reliable manufacturers whom we have been dealing with for many years. NO NOS (new old stock) NO 2nd hand items!!  Never buy or use a 2nd hand pinch roller - its just not worth it!

Nagravox continually researches pinch rollers, manufacturers and materials and is pleased to be able to offer a comprehensive assortment for a number of machines. Although we are specialists in Revox, Studer and Nagra we are also responding to many inquiries for other makes. 

SHARING SOME  EXPERIENCE and RESEARCH on PINCH ROLLERS

  • HARDNESS / SOFTNESS. Contrary to popular belief, the PR must be rigid and definitely not soft.  It must NOT deform around the tape so that the capstan also drives the PR. Yes I know this goes against what some people  think. BUT just stop for a minute and think carefully on the following  statement.  The PR does not drive the tape! The PR's function is to apply an even pressure against the tape on the capstan shaft thus causing the capstan to drive the tape not the pinch roller. The operatives are an even spread and that the capstan drives the tape. A soft pinch roller will deform against the capstan too much at the edge contact and result an increase in wow and flutter and increased wear on the tape and capstan shaft.  If you can feel your pinch roller is 'soft' - then certainly it is not hard enough! Hardness should be around 75 - 90 (Shore A).  Soft would be considered 65 - 70. Too soft is less than 60 and too hard >95. All our pinch rollers are in the region 75 - 85.
  • Pinch Roller profile. If you research the history of pinch rollers, Studer tried many different formulations, bush systems and profiles. Originally profiles were  wide, flat and pinch rollers harder. Then they tried reducing the edge conflict by reducing width and profiling with a slight convex shape and softer ADP formulations so pressure was concentrated in the centre. The problem with this is that it is difficult to align the tape exactly at the peak of the convex profile. Then they went back to a flat profile and a harder formulation.  No doubt if Studer had continued we would have seen other trials and tribulations. 
  • AGE. How old is that 'new' pinch roller you bought? There are a mere handful of pinch roller manufacturers in the world . Some cling to old dated designs and profiles. Others believe they will make a fortune by making them as cheap as possible. Cheap Chinese I believe are available. A bigger problem is many vendors acquire over the years NOS stock of pinch rollers at a bargain price.  Here is our answer to a very misguided supposition by most people. Always get a pinch roller that is FRESH manufactured. Ask when it was manufactured? Our pinch rollers are fresh manufactured. We order and get PR's every 3 -6 months.  
  •  The correct PR pressure is very important for obvious reasons. Adjust exactly as per manufacturers instructions which is easy enough to do on Revox and Studer. Most conditioned later shafts are a dull grey and PR pressure should be 0.7 - 0.9 kgf. On older smooth shafts the pressure should be 1.2 - 1.4 kgf. 
  •  The condition of your motor shaft is paramount.  A shiny shaft matching the tape profile is an indication the shaft has done a lot of hours work and will not grip the tape effectively resulting in an increase wow. The shaft should be a dull grey colour.  Shafts can be reconditioned and the dull grey restored using a special micro bead blasting technique. 
  •  The tape tension is also important because the PR / capstan is a regulating system not a driving system. This is controlled rudimentarily in early and most Revox machines with back tension fixed but in later and Studer machines it is measured and controlled dynamically and can be precisely set / calibrated.
  •  PR's as they get old, particularly urethane formulations, get softer increasing wow and flutter.  This is a natural degradation not because they tried to make a very soft PR !  Modern ADP formulations maintain their rigidity longer because they are better formulations but in time they will also get softer or break up as they age. In contrast, the black rubber formulation with age tends to get harder, crack and deform or develop a glaze also increasing wow and flutter.  Both materials are appropriately specified and used. Its up to you which one you prefer.Both formulations used in our pinch rollers are carefully determined and controlled so as to maintain surface contact rigidity and minimise wow and flutter over their lifetime. Sometimes we offer ADP and others only black rubber and some both  - this is based on our findings as best for the model considered.
  •  Using old or NOS tape is the main reason pinch rollers wear. There is absolutely no reason to use so called NOS or old tape bought usually on ebay as a bargain and still shrink wrapped.  New fresh manufactured tape is so superior and minimises dirt and tape particle (shed) build up. SUPPORT our last two tape manufacturers in France and the USA and buy new tape. Its not expensive and you will be amazed at how damn good your machine can work and sound. 

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