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  #1  
Old 16th February 2015, 11:39 PM
Paul Stoneman Paul Stoneman is offline
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Join Date: Apr 2014
Location: Tiverton
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Default Pre3 with shunt mod

Good evening fellow DIYer's,

Can anyone help please. I have just prior to Christmas made a PSU and Pre3 with shunt remote volume control, Neotech input and output wiring, some Mundorf Supreme caps and Psvane reference valves. It sounds glorious but some background noise mainly hiss, not much but still audible. I have tried Mills 47K and AMRG 47K resistors with the 50K pot. As a side it is noisier when running in balanced mode.
A friend who also has a Pre 3 asked me to convert his which was purchased pre built as standard but with the better caps, to remote and shunt but has found that the extra noise is too much in his system. In an effort to do a comparison I have changed mine back to normal remote operation and although very nice, it is not in the same league as before.
Does anyone know a way of reducing the gain and hopefully the noise without squashing the amazing dynamics and life, would a change of resistor in the shunt solve the noise.

Many thanks to all for keeping us novices afloat. Paul.
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  #2  
Old 16th February 2015, 11:49 PM
John Caswell John Caswell is offline
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Location: Wokingham, Berkshire
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Default Re: Pre3 with shunt mod

Hi Paul,
All of the gain is after the volume control so a shunt pot mod will reduce the signal but not the noise generated after it.
That having been said I did a small mod to my PreIII by inserting a secondary volume control (ca 250K) between the two stages and adjusted for best results.
Drawing to follow tomorrow.

John
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  #3  
Old 17th February 2015, 08:55 PM
Paul Stoneman Paul Stoneman is offline
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Default Re: Pre3 with shunt mod

Good evening John,
Many thanks for your help, I am open to any ideas.
Kind regards Paul.
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  #4  
Old 4th March 2015, 10:39 PM
Paul Stoneman Paul Stoneman is offline
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Join Date: Apr 2014
Location: Tiverton
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Default Re: Pre3 with shunt mod

Good evening John,
A few days ago you kindly offered to send a drawing of a secondary potentiometer as per your Pre3. I know you are a busy man just by seeing all your helpful replies. When you get a chance could you please forward the details.
Kindest regards and thanks Paul.
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