World-Designs-Forum  

Go Back   World-Designs-Forum > World Designs > Problems
Register FAQ Members List Calendar Gallery Today's Posts Mark Forums Read

Problems For questions and answers re World Designs Projects

Reply
 
Thread Tools Display Modes
  #51  
Old 16th March 2021, 04:05 PM
John Caswell John Caswell is offline
Super Moderator
 
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!

John

Last edited by John Caswell; 16th March 2021 at 04:12 PM. Reason: Addnl info
Reply With Quote
  #52  
Old 17th March 2021, 11:42 AM
bikerhifinut bikerhifinut is offline
Senior Member
 
Join Date: Jan 2006
Location: Penrith, Cumbria
Posts: 1,060
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.

Andy.
Reply With Quote
  #53  
Old 17th March 2021, 02:00 PM
bob orbell bob orbell is offline
Senior Member
 
Join Date: Nov 2009
Location: kettering northants.
Posts: 2,186
Default Re: Phono 3 noise issues

A bit of an eye opener Andy . Bob
Reply With Quote
  #54  
Old 17th March 2021, 08:22 PM
Damien Damien is offline
Junior Member
 
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.

Damien
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT +1. The time now is 08:08 PM.


Powered by vBulletin® Version 3.7.3
Copyright ©2000 - 2021, Jelsoft Enterprises Ltd.
Copyright World Designs