input transformer - mumetal casing etc. - Page 2 - diyAudio
Go Back   Home > Forums > Amplifiers > Tubes / Valves
Home Forums Rules Articles diyAudio Store Gallery Wiki Blogs Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Tubes / Valves All about our sweet vacuum tubes :) Threads about Musical Instrument Amps of all kinds should be in the Instruments & Amps forum

Please consider donating to help us continue to serve you.

Ads on/off / Custom Title / More PMs / More album space / Advanced printing & mass image saving
Thread Tools Search this Thread
Old 19th December 2011, 02:45 PM   #11
Account disabled at member's request
Join Date: Jul 2009
now it works....must have been my wireless connection.

is there any model which could be considered a direct equivalent of the sowter part?
  Reply With Quote
Old 19th December 2011, 02:46 PM   #12
male42 is offline male42  Russian Federation
diyAudio Member
male42's Avatar
Join Date: Jun 2010
Location: Kemerovo Russia
I have made myself such transformers. and recommend a dual screen .. need to check in practice
  Reply With Quote
Old 20th December 2011, 02:54 PM   #13
Account disabled at member's request
Join Date: Jul 2009
Cinemag replide and stated that the CMLI-15/15B would be a good choice to replace the sowter part.

is the dual shielding necessary from a practical point of view?
  Reply With Quote
Old 20th December 2011, 02:57 PM   #14
SY is offline SY  United States
On Hiatus
SY's Avatar
Join Date: Oct 2002
Location: Chicagoland
Blog Entries: 2
It can't hurt! I've gotten such excellent noise rejection performance from the Cinemags (and Jensens) that I just go with it and try not to question their wisdom.
"You tell me whar a man gits his corn pone, en I'll tell you what his 'pinions is."
  Reply With Quote
Old 20th December 2011, 05:09 PM   #15
kevinkr is offline kevinkr  United States
diyAudio Moderator
kevinkr's Avatar
Join Date: Sep 2004
Location: Boston, Massachusetts
Blog Entries: 6
Dual shielding is quite important if the transformer is a conventional EI core type which has poor rejection of external magnetic fields. Toroids and C-cores tend to need less shielding as they seem to contain their own magnetic fields more effectively and in so doing are also generally less susceptible to external fields.

I use transformer coupling extensively in my system, and use shielded transformers everywhere except in the driver stage and OPT. The IT is an unshielded Lundahl C-core which given the high signal levels is not a problem. I do go to some trouble to keep power transformers far away from these transformers if possible.
"To argue with a person who has renounced the use of reason is like administering medicine to the dead." - Thomas Paine
  Reply With Quote
Old 20th December 2011, 08:16 PM   #16
diyAudio Member
trobbins's Avatar
Join Date: Feb 2009
Location: Melbourne, Oz
This paper from 1938 includes a good level of practical measurements to guide those wanting to diy. I may be wrong, but I think the casing metal sheet used for some old floppy disk drives was made from a better magnetic shielding type of steel - it was certainly quite maleable for bending in to shapes.
  Reply With Quote
Old 20th December 2011, 08:21 PM   #17
diyAudio Member
Wavebourn's Avatar
Join Date: Sep 2006
Location: Pleasant Hill, CA
Send a message via Skype™ to Wavebourn
I once bought on eBay SMD - mount transformers made for DSL modems. They are tiny, but have 12 Henry windings, both input and output. Stacking such transformers I am getting different ratios. Then found good cases for them: bought a lot of motors made for cassette recorders.
The Devil is not so terrible as his math model is!
  Reply With Quote
Old 20th December 2011, 08:28 PM   #18
diyAudio Member
ruffrecords's Avatar
Join Date: Jun 2007
Location: Holt, Norfolk
Originally Posted by Alexontherocks View Post
one of the solutions might be this:

EDCOR Electronics Corporation. PCW10K/10K


EDCOR Electronics Corporation. WSM10K/10K


Thanks again
The trouble with Edcor is they are relatively low inductance transformers - that's why they are cheap. The two mentioned have primary inductances of 8H and 11H respectively. At 20Hz these look like about 1K ohms rather than 10K so unless you can be sure your driving source impedance is a lot less than 1K at 20Hz you will certainly have poor low frequency amplitude and phase response as well as distortion.


  Reply With Quote
Old 20th December 2011, 08:30 PM   #19
DF96 is offline DF96  England
diyAudio Member
Join Date: May 2007
Originally Posted by Alexontherocks
I have plenty of tools and machines (a friend has a CNC/metalwork shop) so forming, bending and such would not be a problem..
I understand that mu-metal loses much of its permeability when machined or bent, so it needs to be processed again after forming.
  Reply With Quote
Old 20th December 2011, 08:32 PM   #20
Gluca is offline Gluca  Italy
diyAudio Member
Gluca's Avatar
Join Date: Nov 2004
Location: Back to Italy
I have been running 15/15B since ages ... I own 2 pairs. Good stuff.
  Reply With Quote


Hide this!Advertise here!
Thread Tools Search this Thread
Search this Thread:

Advanced Search

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
Input transformer: floating input = distortion ErikdeBest Tubes / Valves 13 20th January 2009 09:36 AM
Designer casing Gabster Group Buys 4 8th January 2009 11:13 AM
My new Pass ONO and the use of MuMetal harryeng Pass Labs 15 19th December 2005 08:27 PM
Casing dimensions Mlaen Solid State 1 20th February 2005 06:32 PM
Mumetal For Sale planet10 Swap Meet 11 6th November 2002 07:16 AM

New To Site? Need Help?

All times are GMT. The time now is 12:31 PM.

vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2017 DragonByte Technologies Ltd.
Copyright 1999-2017 diyAudio

Content Relevant URLs by vBSEO 3.3.2