Go Back   Home > Forums > >
Home Forums Rules Articles diyAudio Store Blogs Gallery Wiki Register Donations FAQ Calendar Search Today's Posts Mark Forums Read

Analog Line Level Preamplifiers , Passive Pre-amps, Crossovers, etc.

Help appreciated with removal of AC switch in my tube preamplifier PSU.
Help appreciated with removal of AC switch in my tube preamplifier PSU.
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
Reply
 
Thread Tools Search this Thread
Old 5th November 2017, 04:15 PM   #1
simsalabim is offline simsalabim  Netherlands
diyAudio Member
 
simsalabim's Avatar
 
Join Date: Jul 2014
Location: Haarlem
Default Help appreciated with removal of AC switch in my tube preamplifier PSU.

Hi,

i would appreciate if someone could help me with the following;
As i am building a custum casing for my tube preamp of alu, this instead of the now used thin platesteel which feels kinda cheap.
To keep it tidy, i like to remove the AC switch 120/240V as i donít need it as we have 240V over here.

IMG_8662.JPG

From the transformator there are two wires going to this switch, a brown one, which is on the 120V side and a red one, which is on the 240V side, i presume these are the phase.

There is also a white wire from the transformator to the AC inlet, i presume this is the zero.

In order for me to remove the switch do in need to only use the red one?
And isolate the brown?

Sorry that i have little understanding how this transformator works, hope you can help me out!

Thank you on beforehand!

IMG_8661.JPG
  Reply With Quote
Old 5th November 2017, 04:26 PM   #2
scottjoplin is offline scottjoplin  Wales
diyAudio Member
 
scottjoplin's Avatar
 
Join Date: Dec 2015
Location: Penrhyndeudraeth
If there are only three wires going to the transformer then, yes, just use the red one and isolate the brown one safely, for example with some heat shrink tubing over the cut end
__________________
Woofer Assisted Wideband is the New Testament renounce the anachronistic acronym FAST
  Reply With Quote
Old 5th November 2017, 04:44 PM   #3
kaputt is offline kaputt  Germany
diyAudio Member
 
kaputt's Avatar
 
Join Date: Sep 2011
Location: Berlin
The brown could use some heat shrink anyways as the insulation has been damaged by hot soldering iron...

What type of preamp is this? I'm just curious as the construction seems a bit "special".
__________________
Oh boy, I live in the snake oil thread...
  Reply With Quote
Old 5th November 2017, 04:47 PM   #4
simsalabim is offline simsalabim  Netherlands
diyAudio Member
 
simsalabim's Avatar
 
Join Date: Jul 2014
Location: Haarlem
Thanks Gents!
Much appreciated.

Will safely isolate the brown wire and remove the AC switch
  Reply With Quote
Old 6th November 2017, 12:02 AM   #5
maikel76 is offline maikel76  Thailand
diyAudio Member
 
Join Date: Aug 2013
Location: BKK
Yep, I can confirm. Place the red wire on the outlet in stead of the white wire. One less connection.
  Reply With Quote
Old 6th November 2017, 11:13 PM   #6
simsalabim is offline simsalabim  Netherlands
diyAudio Member
 
simsalabim's Avatar
 
Join Date: Jul 2014
Location: Haarlem
Default Help appreciated with removal of AC switch in my tube preamplifier PSU.

Hi Gents,

Something strange happened,

i now only have half the volume as i had before.

Could this be related to the switch?

I also replaced some resistors, but with the same R so i donít understand what happened here?
(replaced some 0.5W PR with 2W AN tantalumís, same R)

Any advice about the volume? could it be that i needed the brown wire instead of the red?
What would be strange as the brown was on the 120V side of the switch.

Whatís going on?

Last edited by simsalabim; 6th November 2017 at 11:34 PM.
  Reply With Quote
Old 7th November 2017, 12:52 AM   #7
maikel76 is offline maikel76  Thailand
diyAudio Member
 
Join Date: Aug 2013
Location: BKK
Quote:
Originally Posted by simsalabim View Post
Hi Gents,

Something strange happened,

i now only have half the volume as i had before.

Could this be related to the switch?

I also replaced some resistors, but with the same R so i donít understand what happened here?
(replaced some 0.5W PR with 2W AN tantalumís, same R)

Any advice about the volume? could it be that i needed the brown wire instead of the red?
What would be strange as the brown was on the 120V side of the switch.

Whatís going on?


Iím afraid you really need to measure some voltages. Seems like your system runs on 120V now? Did you double/triple checked the values on those resistors (sorry to ask)?
  Reply With Quote
Old 7th November 2017, 12:59 AM   #8
simsalabim is offline simsalabim  Netherlands
diyAudio Member
 
simsalabim's Avatar
 
Join Date: Jul 2014
Location: Haarlem
Quote:
Originally Posted by maikel76 View Post
Iím afraid you really need to measure some voltages. Seems like your system runs on 120V now? Did you double/triple checked the values on those resistors (sorry to ask)?


Hi,

yes, i did triple checked them, Wattage shouldnít be a problem, no?

Will try to measure V tommorow, however the transformator is now on the 240V inlet, with red wire, should be correct, i donít know the V the transformator makes, i donít have a schematic, jt is from a small company this preamp, and the schematic is not public.
  Reply With Quote
Old 7th November 2017, 01:05 AM   #9
maikel76 is offline maikel76  Thailand
diyAudio Member
 
Join Date: Aug 2013
Location: BKK
Quote:
Originally Posted by simsalabim View Post
Hi,

yes, i did triple checked them, Wattage shouldnít be a problem, no?
Aah good. Wattage shouldnít be a problem

Quote:
Will try to measure V tommorow, however the transformator is now on the 240V inlet, with red wire, should be correct, i donít know the V the transformator makes, i donít have a schematic, jt is from a small company this preamp, and the schematic is not public.
If youíre in doubt please measure that too, but donít make yourself too difficult. Measure the wires to that switch first after un-soldering.
Also good to make a small schematic on paper.
  Reply With Quote
Old 7th November 2017, 10:53 AM   #10
simsalabim is offline simsalabim  Netherlands
diyAudio Member
 
simsalabim's Avatar
 
Join Date: Jul 2014
Location: Haarlem
Default Help appreciated with removal of AC switch in my tube preamplifier PSU.

But if i un-solder the transformer, no Voltage would be in the system, so how to measure which Voltage the transformer operates at through each of the (red and brown) A/C supply wires?

Or am i missing the point?

I have a normal multi meter.

Thanks!

Last edited by simsalabim; 7th November 2017 at 10:58 AM.
  Reply With Quote

Reply


Help appreciated with removal of AC switch in my tube preamplifier PSU.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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Hp1740a oscilliscope push switch extenders removal paul cheacker Equipment & Tools 0 7th June 2016 07:49 PM
Tube preamplifier lpd Swap Meet 0 3rd November 2012 10:31 PM
CD6000OSE - tube output stage - help appreciated :-) ernesternest Digital Source 37 11th December 2009 06:03 PM
My first tube preamplifier:) whee Tubes / Valves 4 29th September 2006 02:26 PM
Tube preamplifier gchrist Tubes / Valves 9 11th March 2004 04:06 PM


New To Site? Need Help?

All times are GMT. The time now is 10:20 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2018 DragonByte Technologies Ltd.
Copyright ©1999-2018 diyAudio
Wiki