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Old 16th March 2021, 04:05 PM
John Caswell John Caswell is offline
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Join Date: Dec 2005
Location: Wokingham, Berkshire
Posts: 1,640
Default Re: Phono 3 noise issues

Bulk Foil resistors are very good for low noise areas in valve stages but you need to be careful to use them within their ratings.
I think, without checking, they are mostly rated at 600mW so should be fine for phono stages, but obviously calculate the rating required, and also take out a new mortgage to fund them.
Just checked on Farnell/RS, they are rated at 600/400mW so care is required, and they are not standard E12/E24 series so you may have to series/parallel them, yet more expense!


Last edited by John Caswell; 16th March 2021 at 04:12 PM. Reason: Addnl info
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Old 17th March 2021, 11:42 AM
bikerhifinut bikerhifinut is offline
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Join Date: Jan 2006
Location: Penrith, Cumbria
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Default Re: Phono 3 noise issues

You weren't kidding John!
I think I will have a look at everything else before even thinking about shelling out for bulk foils.

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Old 17th March 2021, 02:00 PM
bob orbell bob orbell is offline
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Join Date: Nov 2009
Location: kettering northants.
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Default Re: Phono 3 noise issues

A bit of an eye opener Andy . Bob
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Old 17th March 2021, 08:22 PM
Damien Damien is offline
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Join Date: Mar 2021
Location: Howden, East Yorkshire,UK
Posts: 24
Default Re: Phono 3 noise issues

Hi Andy

Thanks for the offer but the difference in design is so small there seems little point building a III.

Glad to hear you’ve been inspired to do another yourself though

The latest is that the 150uF caps arrived & fitted in the PSU & phono power input.

As they were sold in pairs I also fitted the spare in C3 position having shorted R4.

Slight reduction in the mains hum but as I said before it wasn’t audible at anything like sensible listening levels.

I,ll try & stop fiddling & enjoy listening for now but wil no doubt come back to John’s resistor suggestions & the phono III RIAA tweak later.

Thanks for everyone’s suggestions.

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