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Sugden Connoisseur - lost classic? (part II)

eguth said:
The standard motor mount suspension for the motor pulley to attach to the the belt has flexibility.
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Yes, this speaks to my point above.

Here are my thoughts on the subject of how 'stiff' belts need be employed. None of the following should be taken as criticism of your, or anyone else's, solutions/customizations.

As designed, the BD1/BD2 motor suspension, when combined with the butyl rubber drive belt and tension band working against one another, essentially decouples the motor from those parts that it is connected to. There exists no 'hard' path for resonance to pass from motor to chassis or from motor to platter, with motor noise being attenuated as a result.

With an inelastic Nylon cord substituted for the butyl rubber belt a 'hard' path is created between motor and platter that will effectively conduct noise. This path essentially makes the platter/bearing/chassis/plinth an energy sink for motor resonance. Trouble is, this path also includes the platter/tonearm/cartridge loop.

Should the motor be mounted off chassis, resonance transmission can be better dispersed along many paths via rigid motor mounting, possibly reducing that which travels along an inelastic cord.

Without throwing out the stiffness of drive afforded by Nylon, string, threads, etc, I suspect that a rigidly fixed remote motor with EDPM* O-ring of same cross-section as the original Butyl would offer best of both worlds performance i.e. stiffer than Butyl drive combined with superior motor noise isolation than inelastic cord.

* I suspect that Rega's new EBLT is an anagram for EDPM BELT.
 
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The home- made belt replacement idea is from the great Dr. van den Hul. (Details given with acknowledgement earlier in this thread). He suggested this be tried with any turntable. I did. And never looked back. He did not recommend trying nylon cord. I do. There may be excess play in even a standard BD1/2 setup. The state of your drive chain compliance depends upon many factors; e.g. age of belt, temperature of listening room (average) etc. etc.

Arnold Sugden will have taken into account unknowns before deciding on belt and suspension compliance.

I say "try nylon cord- rather than talking about it". This replacement might be a good, low cost upgrade. If not, you have a useful spool of 2.5mm nylon braided cord for use about the house: on your concubine or wife's hairdo, or in the garage, kitchen or for 1000 other purposes.

For those of you who work on your own version of a BD1/2 for primarily aeshetic improvements- I should mention that aliexpress.com offer a variety of colours in braided NYLON cord . You can design your own custom- colour belt and add zest to your platter.

The drab, conventional, black version- if you go for the 'far out' - cries out for your imaginative innovation.
 
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Standard ~ BD1/2 ~ HUM: A CLARIFICATION

As ever, with everything I say, there is always room for improvement. WABI SABI.

The standard BD1/2 - (on the usual plinths, or those changed or modified primarily to improve their appearance)- transmits hum and noise to the cartridge. This, despite the elasticity provided by the standard suspension and belt. I believe there is more elasticity there than needed. I tested a standard setup with my meniscus (vibration) test and a stethoscope (audibility) test. It was poor. .. far worse than the (modified) BD1. ..as was a highly regarded commercial TT I tested.

Can you hear it? Well...it adds to the noise mountain...and people hear different things differently. I , myself (and I) am extremely sensitive to and annoyed by hum. I was usually aggravated in the old days at dealer's demos- where the hum level was intolerable (not to them- to me). I greatly treasure those good engineers (like pfm's toprepairman) who are expert at hum removal.

I think this unnecessary extra elasticity may allow a NYLON 2.5 mm belt to be used-with little or no audible increase in hum; at least for some- if not all- listeners.

Another benefit is that there will be no increase in noise due to belt 'slap'- i.e. the belt hitting the platter rim. Belt 'slap' is audible with a stethoscope. It adds to the noise mountain- no matter by how little.

The end result will, of course, be affected by the particlular cartridge/arm, and its mount- and by the listener's hearing and sensitivity to what they hear

WABI SABI.
 
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eguth said:
Standard ~ BD1/2 ~ HUM: A CLARIFICATION

As ever, with everything I say, there is always room for improvement. WABI SABI.

The standard BD1/2 - (on the usual plinths, or those changed or modified primarily to improve their appearance)- transmits hum and noise to the cartridge. This, despite the elasticity provided by the standard suspension and belt. I believe there is more elasticity there than needed. I tested a standard setup with my meniscus (vibration) test and a stethoscope (audibility) test. It was poor. .. far worse than the (modified) BD1. ..as was a highly regarded commercial TT I tested.

Can you hear it? Well...it adds to the noise mountain...and people hear different things differently. I , myself (and I) am extremely sensitive to and annoyed by hum. I was usually aggravated in the old days at dealer's demos- where the hum level was intolerable (not to them- to me). I greatly treasure those good engineers (like pfm's toprepairman) who are expert at hum removal.

I think this unnecessary extra elasticity may allow a NYLON 2.5 mm belt to be used-with little or no audible increase in hum; at least for some- if not all- listeners.

Another benefit is that there will be no increase in noise due to belt 'slap'- i.e. the belt hitting the platter rim. Belt 'slap' is audible with a stethoscope. It adds to the noise mountain- no matter by how little.

The end result will, of course, be affected by the particlular cartridge/arm, and its mount- and by the listener's hearing and sensitivity to what they hear

WABI SABI.
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Perhaps 'noise' would be the better generic term here, as 'hum' is derivative of 'induction', as opposed to 'conduction'.
 
I want to retrieve the maximum amount of detail on recordings possible.

That is why I have sought and bought cartridges that are outstanding in presenting fine detail. Live music abounds in fine detail.

Hum swamps detail: even when (and especially when) that detail is filigreed and you cannot hear any hum.

A good test of a system is by how much it differentiates between recordings in respect of detailed information.
 
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