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

Pass Labs This forum is dedicated to Pass Labs discussion.

Silent Transformers in Europe
Silent Transformers in Europe
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 2nd June 2015, 11:15 AM   #21
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
> 600VA for a 50W amplifier is 12times factor, we would expect it to be cool and quiet with that rating.

I don't use the output power to calculate a transformer.
I use the actual power consumption.

The F5X has 4A bias per channel.
It has +/-16V rails after rectifiers and regulators.
That means 15Vrms, 5.7Arms at the transformer output per rail.
Which in turn means 171W power consumption.

Using that figure x3 will give you 500VA.
But I want to make sure that the core does not get saturated by the pulse current through the rectifiers.
Hence a 600VA core is specified, even though the winding is still 500VA.

It is not too difficult to simulate the peak value of the current pulse once you know the inductance and resistance of the winding.


Patrick
__________________
xen-audio.com
  Reply With Quote
Old 2nd June 2015, 11:24 AM   #22
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
I use the actual current consumption rather than the 6times to 10times guidance.

4A bias requires a transformer with at least 8Aac secondary winding rating.
8Aac times 2*16Vac results in a 256VA transformer running at 100% of rated capability. It will run hot.
I and others recommend that for cool running the continuous current draw should be around 50% of the winding rating, or a bit less.
That would give a transformer size of around 500VA (well above the 6times guidance).
600VA results in 42.7% of rating instead of 51% for the 500VA.

Our different methods arrive at substantially the same answer.
__________________
regards Andrew T.
  Reply With Quote
Old 2nd June 2015, 11:26 AM   #23
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
Quote:
It is not too difficult to simulate the peak value of the current pulse once you know the inductance and resistance of the winding.
Could you expand on this?
__________________
regards Andrew T.
  Reply With Quote
Old 2nd June 2015, 11:55 AM   #24
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
You can simulate one secondary as a 50Hz voltage source with an inductance and a series resistance.
These you either have to measure or ask your Tx supplier.
Then you connect the rest (rectifiers, caps, regulators, load, .....) and can run Spice to check the pulse current through the series R.
The load in a balanced Class A is easiest, as a constant current sink.

That will give you a good idea as to what the peak current of the secondary would look like.
For our purpose, it is accurate enough.

You can pretty much use this also to check your snubbers and whatever else ......


Patrick
__________________
xen-audio.com
  Reply With Quote
Old 2nd June 2015, 01:13 PM   #25
wuffwaff is offline wuffwaff  Netherlands
diyAudio Member
 
wuffwaff's Avatar
 
Join Date: Aug 2001
Location: Ingolstadt Germany
Quote:
Originally Posted by EUVL View Post
Yes, I also tried many (Schuro, Tauscher, Multi-PCB, ......) and now I only order from Tomaz of Toroidy.
My Aleph-X 100W has no audible hum unless you open the case and put your ears next to it.

A few things on top :

1) Use a core at least 3x your actual load. The F5X consumes 180W and use 600VA core.
2) Draw a schematics including rectifiers, size of caps, current draw after the caps , and voltage you expect.
3) DON'T use potted ones, even though they look pretty (I leant this from a UK manufacturer for the audio industry).
4) Use one bridge rectifier for each secondary.

If there is still a problem, then you need to clean up the mains.
Maybe a big EI isolation transformer in a separate room ?
Or use a 2000W Ncore with SMPS and a Cordell Func Gen as input to generate a 50Hz low distortion sine wave (as mains).




Patrick
Hi Patrick,

at the moment my Tauscher 800VA are potted, they are a bit small for the given VA rating (150x100).
The amp idles at 235watts
Im using 4 double schottky diodes per transformer and them a CLC configuration
In front of the whole music system are two big (1200VA) transformers giving 2x115V for balanced AC.(They are in the cellar below)
At the moment there is also a PS Audio Power Plant which at least sees to it that the absolute DC Offset stays around 0V but does not really reduce the hum.

I also tried resistors between the first capacitor bank and the rectifiers and many other things but nothing really worked.

The first pic shows the schotkys, the second the ripple at the first bank and at the second bank (after the L), the third shows the complete power supply with the main board on top.

So if I order in Poland I should go for the non potted Audio version and specify a core for a higher VA rating?
The only problem Ive got is that the Tauschers are 150mm in diameter and just fit the case, putting in a bigger one would mean a new case.....

William
Attached Images
File Type: jpg 01493.jpg (365.0 KB, 686 views)
File Type: jpg 01506.jpg (331.3 KB, 651 views)
File Type: jpg 01510.jpg (395.6 KB, 645 views)
__________________
een ooievaar is geen konijn want zijn oren zijn te klein!
  Reply With Quote
Old 2nd June 2015, 01:24 PM   #26
6L6 is offline 6L6  United States
diyAudio Moderator
 
6L6's Avatar
 
Join Date: Oct 2010
Location: Denver, Colorado
Silent Transformers in Europe
vitalstates - can you show any photos or provide more info with your experiments / uses of SMPS?
  Reply With Quote
Old 2nd June 2015, 01:25 PM   #27
AndrewT is offline AndrewT  Scotland
R.I.P.
 
Join Date: Jul 2004
Location: Scottish Borders
Toroidy will be able to build on a different shape core.
Ask for max 150mm diameter and he should select a taller core to give your VA requirement.

Can your case take the bulge where the wires come out?
If so tell Toroidy that, otherwise he may aim for a smaller diameter to make sure the bulge fits to the max radius allowed by the 150mm diam.
__________________
regards Andrew T.
  Reply With Quote
Old 2nd June 2015, 01:53 PM   #28
JBL4435 is offline JBL4435  Germany
diyAudio Member
 
Join Date: Oct 2006
l also use these

http://sklep.toroidy.pl/en_US/c/Toro...IO-GRADE-V2/99

and they are simply amazing!

Dead silent in my XA30.5 clone.
Attached Images
File Type: jpg torody2.jpg (60.6 KB, 635 views)
File Type: jpg torody3.jpg (50.6 KB, 621 views)
File Type: png torody1.png (173.9 KB, 216 views)

Last edited by JBL4435; 2nd June 2015 at 01:59 PM.
  Reply With Quote
Old 2nd June 2015, 02:20 PM   #29
EUVL is offline EUVL  Europe
diyAudio Member
 
Join Date: Oct 2003
The Toroidy 800VA without case is dimensioned at 153x65mm. So it should fit.
http://sklep.toroidy.pl/en_US/p/TTSA...age-to-50V/321

The case with potting will add at least 8~10mm in diameter.

Their potted version 800VA is even 170mm.
http://sklep.toroidy.pl/en_US/p/TTSA...age-to-50V/418

The unpotted 1000VA is too large for you at 168mm :
http://sklep.toroidy.pl/en_US/p/TTSA...age-to-50V/322

But then you already use an isolation transformer and a "large enough" Tauscher.
So maybe the hum (50Hz/100Hz ?) is caused by something else ?
Have you tried replacing the L's by R's ?


Patrick
__________________
xen-audio.com
  Reply With Quote
Old 2nd June 2015, 02:46 PM   #30
wuffwaff is offline wuffwaff  Netherlands
diyAudio Member
 
wuffwaff's Avatar
 
Join Date: Aug 2001
Location: Ingolstadt Germany
Hi Patrick,

Ive got some other transformers from Tauscher for my X-BOSOZ and they also hum (100Hz)

Ive tried resistors before the diodes, after the diodes but didt remove the Ls.

What helps is to reduce the load, at 7A bias as they where when driving my Thiels they hummed a lot more than they do now at 4A

There was also a period of time (some months ago) where the humming was almost gone for a few weeks without changing anything......

I also had a look at the Toroidy website, 153mm will not fit as the distance between my heatsinks is 151-152mm.....but the 600VA looks good and maybe can be beefed up a bit as the height is only 58mm (space allows 100).
Ive sent them an email.

William
__________________
een ooievaar is geen konijn want zijn oren zijn te klein!
  Reply With Quote

Reply


Silent Transformers in EuropeHide 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
R-core transformers in Europe tvicol Parts 36 30th June 2019 07:16 AM
Source for transformers in Europe regiregi22 Tubes / Valves 66 27th April 2014 11:40 AM
Cheap toroidal transformers in Europe? Joku Parts 6 8th March 2011 12:40 PM
Heater transformers in Europe? Rundmaus Parts 5 17th February 2011 11:38 AM
Custom transformers in Europe Nisbeth Parts 2 30th November 2004 10:50 PM


New To Site? Need Help?

All times are GMT. The time now is 05:20 PM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright ©1999-2020 diyAudio
Wiki