Paul Hynes SR7 and SR4 Build Calendar Thread

[AngeloVRA]

3 hours ago, sakso136 said:

Guys , i need some help for my newly bought sr5t second hand.

i bought the unit with 110 v fuse, and i forgot to switch it to 230 v when i connected it to my system.

the fuse appearently blew up, and i hope the ps is ok.

i need to buy a new fuse now and i m asking some clarifications.

at the back of the lps it is written :

fuse 1,6 A time delay

110v/240 v.

is it normal to have same specs for 110v/230v?

should i order 1,6 A slow bow?

any idea wich brand should i go with, thinking qsa blue….

thks a lot!

Hi @sakso136

 

If 1.6A fuse was enough for 110v operation, then the same should be more than enough for 220v operation which would draw approximately half the current. That would serve as your "margin" when getting audiophile fuses.

 

Good luck!

[AngeloVRA]

20 hours ago, Lebouwsky said:

The specified voltage (V) rating of a fuse is where it is garantied to function properly. When a higher voltage goes through the same fuse it might blow without causing an actual danger for the divice. 
 

Hi @sakso136

 

Adding to the above, the voltage rating of a fuse mainly refers to the fuse’s ability to prevent internal arcing across the melted fuse link after it blows. For example if a 220v volt fuse is used in a circuit with 600v, after the fuse blows due to an overcurrent condition, the current may still arc across the melted fuse link and conduct electricity. For the SR5, just use 230v fuse whether it’s used for 110v or 230v 
 

[AngeloVRA]

Hi @sakso136

 

Here are some calculations for you:

if your SR5 has 1 rail, it probably has an 80va transformer which will draw 80va//220v = 0.4A. You can unscrew the front panel, take it off and you will see the transformer label..

 

 

However when you switch it on, for the first few seconds there will be an inrush current. The SR5 does not have a soft start module unlike the SR7T/DR7T. Hence it is recommended that you fuse 300% of steady current. That will be 0.4A x 3 = 1.2A…. Then you round up to the nearest fuse, which is 1.6A (2.0A is still okay)

 

if your SR5 has 2 rails, then it will most probably have 150va transformer (the maximum size of transformer that would fit the SR5 chassis) which will draw 150va/220v = 0.70 amp…. Fuse it at 0.70A x 3 = 2.1A to take care of inrush current and avoid nuisance fuse breakage. 
 

Hope that helps.