Unknown Toroid VA Rating

[AlistairH]

I have an old budget amp, an Ariston AX 910, which I'd like to upgrade to an LM3875 based gainclone.

I'm not sure of the power rating of its toroidal tranny. It's label indicates the following specs but no VA figure:

230V single primary
0-20V dual secondary

It has a serial or manufacturer number of ED10069-45116#2 but a Google search reveals nothing.

The power input for the amp is protected with a T2AL fuse. Based on this and its physical dimensions of 40mm height and 100mm diameter and comparing with other manufacturers datasheets, I'm guessing it is a 120VA, possibly 160VA.

Can anyone confirm that?

 

[Mooly]

100 x 40 mm is small. I would say 100 VA max. The weight would be a good indicator as well.

 

[sreten]

Hi,

Its a moot point whether a gainclone would be an upgrade,
but for sure bought cheap it is a great source of hardware
for building a gainclone.

To me it looks like a gainclone already. I'd upgrade it.

rgds, sreten.

 

[AlistairH]

100 x 40 mm is small. I would say 100 VA max. The weight would be a good indicator as well.

It weighs 1.4Kg. Browsing through numerous manufacturers' websites would seem to indicate it is a 120VA. I might purchase something that could provide a little more oomph.

Its a moot point whether a gainclone would be an upgrade

It is indeed a chip amp. It uses Philips TDA1514A chips. Upgraded to LM3875s would certainly be an improvement. This Ariston amp as is sounds pretty lifeless. OK for background music in the workshop but not in the least bit engaging for serious listening.

 

[DPH]

If you go about getting a new transformer, you're going to quickly find that it's more cost effective to go whole-hog in on a new design versus using bits from what you have.

120 VA for a stereo AB amp with ~25-26V rails is certainly fine for a first run. Of course, that will depend on how loud you listen.

 

[AlistairH]

120 VA for a stereo AB amp with ~25-26V rails is certainly fine for a first run. Of course, that will depend on how loud you listen.

You're quite right. The sensible thing to do is upgrade the chips first while using the current tranny. I can always upgrade that at a later date if deemed necessary.

 

[Mooly]

It weighs 1.4Kg. Browsing through numerous manufacturers' websites would seem to indicate it is a 120VA. I might purchase something that could provide a little more oomph.

The weight is in 120 va territory but not perhaps the size. I think all you can safely say is that its somewhere in that area. Unless you are running continuous high power testing its of little relevance in an amp like this. Even an 80va tranny has more than enough ability to annihilate the original chips 😀

 

[AndrewT]

I measured a pair of Clairtronic toroids last night, but forgot to post the results this morning.

100mm diam by 40mm high = 160VA
90mm diam by 40mm high = 100VA

 

[AlistairH]

Thanks for that Andrew. As Mooly says, assuming it's in the range 100-120VA is about all I can do - unless there's an easy way to measure it that I'm unaware of.

I'll use it as is initially and see what the performance is like. Given that I'm likely to give this to my son and his living room isn't the biggest space I don't imagine it will be driven hard enough to make a difference 😀