Good question, I guess it's mainly about supply and demand. Normal toroids probably sell by the truck load, balanced toroids I can only presume sell every now and then. After speaking to Peter at Airlink I know that Airlink only started selling balanced toroids as one of the staff there is a Hifi nut, and he and a load of his mates wanted balanced toroids, so now Airlink sell a small range to suit demand. Should they suddenly sell by the thousands I'm sure the price would drop dramatically.

I recognise the argument relating to economies of scale, but aren't the materials costs of a 1000va transformer the same irrespective of whether it's balanced or not? You can get decent 1000va transformers for £48 retail so,I'm still struggling to see the justification.

m.rapidonline.com/electrical-power/115-230v-toroidal-transformers-dual-primary-82719

I could accept perhaps a 50% premium for making low numbers but that still leaves a heck of a lot between the transformer price and the selling price of any of these items. Everyone has their own scale of value, but to me there's nothing magical or exceptional here. We are still talking about a transformer in a box. Sure, some boxes will cost more than others, but every single example I've seen is better hidden away.

These ones are still almost double what I'd be willing to pay, but they might be of interest to someone here, so I'm posting a link.


www.ebay.co.uk/itm/1kVA-1000VA-230v-Mains-Isolation-Balancing-Toroidal-Transformer-Audio-Studio-/322013104735?hash=item4af97a0a5f:g:S4MAAOSwo0JWINZZ

I bet he's a reseller so if anyone finds a price from the manufacturer, the price could well be where I'd expect it.

www.amethyst-designs.co.uk/Toroidal_transformers/

I take it that's not a balanced transformer then  His description reads like it is, so I guess that means he knows as much as me.....notalot!

mind you, I didn't look too closely. I just went on his description 

The transformer link I posted is for trafos that are found in audio equipment, and a 1kva one is still only £48 retail. Now a box that is nicer than the Airlink cases can be had for say £50 retail. A couple of sockets and some wire, maybe another £10 retail. As these are all retail prices I don't see why a manufacturer has to charge so much more when there is little assembly needed and he'd already be getting the bits at below retail prices, especially if he's making the transformer.

when I see things like this, they just make me feel like it's a rip-off

www.stoneaudio.co.uk/?product=powerblok+pure+balanced+mains+units

Thanks for the extra info Philip. You're right. The prices I cited don't include vat, but anyone buying them to sell on in a Balanced Mains device could claim the input tax back. For a DIYer, they would cost another £12 but this is still light years away from the prices most manufacturers of balanced mains kit charge.

Are those Amethyst transformers suitable to make a DIY balanced mains then?

I don't want to create any thread drift here. What I was driving at was identifying either a cheap DIY alternative, a cheap ready-made alternative, or finding out why a cheap alternative wasn't possible. So far I'm not convinced there's good justification for the prices charged.

I didn't see the right secondary voltages on the rapid link - probably didn't look hard enough, but look at this one -

uk.farnell.com/block/rke-1000-2x115/transformer-toroid-230v-1kva/dp/2428707

That's not cheap at all.

Obviously there are many suppliers of toroidal and other transformers, but 1KVA at 2 x 115V secondary's won't be that cheap. One last NVA comment, Perspex cases of the thickness used aren't cheap to obtain either...

All I can confirm is that the concept can work really well and I believe this type of isolation is used in studios too.

I understand that acrylic cases won't be cheap. However you won't find any expensive casework on the Stone Audio ones and many others. If I was after one, it would have to be a DIY jobbie. I'd hope it would look a lot prettier and cost a fair bit less than theirs. 

Edit: And I see Richard has freely given his costings, which is good of him and informs the discussion. Makes interesting reading because over £200 goes on case and sockets and only £76 on the transformer. How then does the Stone Audio example get so expensive? It's half as much again for the same VA rated transformer and I don't see £20 worth of case and sockets, let alone £200.

The Airlink ones are cheaper but again the case and sockets can't amount to much of the cost. If you're willing to put up with a home brew case and cheaper sockets, a DIY model could be very affordable, which is What I was trying to work out.

I'd love to see a balanced mains device with a smaller, cheaper case and only one or two decent but cheap sockets, released at a price that doesn't take a lend like some models clearly do IMO. 
 

Hate to be a party pooper but I do hope full consideration is given to simple matters like the terms of your home insurance cover when considering DIYing such a significant piece of electrical hardware as proposed...

Saving money by lashing together a headphone amp running off a 9v battery is one thing - constructing a mains supply that will essentially power your entire set of HiFi boxes with their various demands is quite another. Spending thousands to hear a nice piece of music with less distraction does sound like overkill to me but there are decidedly cheaper alternatives (such as the already mentioned Airlink units) and some piece of mind in the knowledge that if (god forbid) your house did burn down due to an electrical fault you just might have some recourse in law in the event of a disputed claim.

Not paranoia - just hard facts.

Electrical faults account for a sizeable portion of domestic house fires so yes, PAT testing and certification would be essential safeguards (and necessary additions to the DIY cost)