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.

The diyAudio First Watt M2x
The diyAudio First Watt M2x
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 9th July 2019, 07:56 PM   #2311
MEPER is offline MEPER  Denmark
diyAudio Member
 
MEPER's Avatar
 
Join Date: Nov 2017
Location: Copenhagen
Quote:
Originally Posted by Blk Dynamite View Post
Just curious; for the individuals that have built dual monos; when using two trafos on a single IEC, does the fuse rating change? Does the thermistor rating need to change also?

If the thermistor is a "CL-60 like" you can use it for both small and large transformers.


The other question may have some answers…..but two trafoes (one for each channel) on same IEC then the fuse has to be larger than if you only have one trafo (half VA size) for one channel on the IEC. Primary fuse is often dictated by in-rush current which can be very large if you don't have any in-rush limiter but with CL-60 you should be able to rate the fuse after how much power (current) you pull from trafos during operation......and then add some to have a safety margin…..and remember to use slow fuses in primary.
  Reply With Quote
Old 9th July 2019, 08:06 PM   #2312
Blk Dynamite is offline Blk Dynamite  United States
diyAudio Member
 
Join Date: Dec 2016
Quote:
Originally Posted by MEPER View Post
If the thermistor is a "CL-60 like" you can use it for both small and large transformers.


The other question may have some answers…..but two trafoes (one for each channel) on same IEC then the fuse has to be larger than if you only have one trafo (half VA size) for one channel on the IEC. Primary fuse is often dictated by in-rush current which can be very large if you don't have any in-rush limiter but with CL-60 you should be able to rate the fuse after how much power (current) you pull from trafos during operation......and then add some to have a safety margin…..and remember to use slow fuses in primary.

Ok just for an example, say you have a trafo that is 225va and using on a US grid would need ~2A slow blow fuse (which is the bar min. if you double up on that trafo on one IEC it would need at least a 4A but given the safety margin a 6A slow blow would be cool? This is also assuming using a CL 60 type.
  Reply With Quote
Old 9th July 2019, 08:27 PM   #2313
MEPER is offline MEPER  Denmark
diyAudio Member
 
MEPER's Avatar
 
Join Date: Nov 2017
Location: Copenhagen
Try first with 4A and if it can take the in-rush then just keep that. Worst thing that can happen is that the fuse blows. The right fuse is probably the smallest rating slow fuse that can take the in-rush current. The 2A may be just fine.....or even smaller.
  Reply With Quote
Old 9th July 2019, 08:33 PM   #2314
joshua43214 is offline joshua43214
diyAudio Member
 
Join Date: May 2011
Quote:
Originally Posted by Blk Dynamite View Post
Ok just for an example, say you have a trafo that is 225va and using on a US grid would need ~2A slow blow fuse (which is the bar min. if you double up on that trafo on one IEC it would need at least a 4A but given the safety margin a 6A slow blow would be cool? This is also assuming using a CL 60 type.
Depends on what your local voltage really is, and the rating should be max, not min,
225VA/120V = 1.875A
225VA/110V = 2.045A
2A is a bit too high if you have 120V mains. The issue with this scenario is the transformer is under-rated for stereo though fine for mono.

in my case
400VA/120V = 3.333A, I use a 3.1A slow blow, and a C-60 current limiter.
  Reply With Quote
Old 9th July 2019, 08:37 PM   #2315
Blk Dynamite is offline Blk Dynamite  United States
diyAudio Member
 
Join Date: Dec 2016
Quote:
Originally Posted by MEPER View Post
Try first with 4A and if it can take the in-rush then just keep that. Worst thing that can happen is that the fuse blows. The right fuse is probably the smallest rating slow fuse that can take the in-rush current. The 2A may be just fine.....or even smaller.

Cool thanks. Thinking about building something for my pops and was just going over some ideas.
  Reply With Quote
Old 9th July 2019, 08:38 PM   #2316
joshua43214 is offline joshua43214
diyAudio Member
 
Join Date: May 2011
Quote:
Originally Posted by MEPER View Post
Try first with 4A and if it can take the in-rush then just keep that. Worst thing that can happen is that the fuse blows. The right fuse is probably the smallest rating slow fuse that can take the in-rush current. The 2A may be just fine.....or even smaller.
Maybe someone who knows code can address this, but I am pretty sure this is not OK.

I believe each transformer would need to be individually fused at the correct rating. A single 4A fuse could allow one transformer to overheat badly before blowing the fuse.
  Reply With Quote
Old 9th July 2019, 08:39 PM   #2317
Blk Dynamite is offline Blk Dynamite  United States
diyAudio Member
 
Join Date: Dec 2016
Quote:
Originally Posted by joshua43214 View Post
Depends on what your local voltage really is, and the rating should be max, not min,
225VA/120V = 1.875A
225VA/110V = 2.045A
2A is a bit too high if you have 120V mains. The issue with this scenario is the transformer is under-rated for stereo though fine for mono.

in my case
400VA/120V = 3.333A, I use a 3.1A slow blow, and a C-60 current limiter.

My area runs hot so I get 120 w an occasional drop to 117 during summer or winter. Weather here in TX is all over the place so the grid can be all over the place. Thanks for the insight
  Reply With Quote
Old 9th July 2019, 08:46 PM   #2318
Blk Dynamite is offline Blk Dynamite  United States
diyAudio Member
 
Join Date: Dec 2016
Quote:
Originally Posted by joshua43214 View Post
Maybe someone who knows code can address this, but I am pretty sure this is not OK.

I believe each transformer would need to be individually fused at the correct rating. A single 4A fuse could allow one transformer to overheat badly before blowing the fuse.


Geez ok. I guess i'll read what other say to get a handle on the proper approach to this.
  Reply With Quote
Old 9th July 2019, 08:54 PM   #2319
MEPER is offline MEPER  Denmark
diyAudio Member
 
MEPER's Avatar
 
Join Date: Nov 2017
Location: Copenhagen
You are right that best thing is to have individual fuse pr. transformer. But I see many builds that have two transformers to a single IEC where fuse is in the IEC connector. So it happens in real life also in commercial equipment.
  Reply With Quote
Old 10th July 2019, 05:33 PM   #2320
Nelson Pass is offline Nelson Pass  United States
The one and only
 
Nelson Pass's Avatar
 
Join Date: Mar 2001
The diyAudio First Watt M2x
If the fuse value is adequately small to protect a single transformer of the two, then
you should be fine. Generally audio power transformers are run at a fraction of their
rating.
  Reply With Quote

Reply


The diyAudio First Watt M2xHide 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
What make and model are the original drivers in Wilson Watt&Puppy 7 (WATT) aguiarrj Multi-Way 17 24th June 2017 10:39 PM
2.3 watt x 4 or 5 watt x2 SET amplifier using DECWARE Zkit1 and Zkit4 schematics Redwolf92 Tubes / Valves 12 29th October 2014 10:19 PM
diyaudio moderator vs diyaudio member Leolabs Everything Else 6 18th June 2006 08:19 AM


New To Site? Need Help?

All times are GMT. The time now is 02:55 AM.


Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Resources saved on this page: MySQL 15.00%
vBulletin Optimisation provided by vB Optimise (Pro) - vBulletin Mods & Addons Copyright © 2019 DragonByte Technologies Ltd.
Copyright ©1999-2019 diyAudio
Wiki