Transformer and pot for BrianGT kit

[poeee]

I've just ordered a BrianGT kit and was wondering about some choices regarding a transformer and a pot.

Transformer choices are these.

18V-0-18V 160VA Toroidal Transformer - AU$48
25V-0-25V 160VA Toroidal Transformer - AU$48
18V-0-18V 300VA Toroidal Transformer - AU$69.95

That what Jaycar has that would be suitable (I think).

I was wondering which would be the better of the 3, also counting in the price difference between the 160VA and 300VA? Also, is there a better of cheaper place in Australia to buy/order a transformer?

As for a pot for volume control, i'm not exactally sure what I need for it. Is one of these link the right thing? It's cheap, maybe there is something that will do the job better?

This is my first time with something like this, so all the help I can get would be greatly appreciated!

[mcs]

I would choose one of the 18-0-18V transformers - I think 2*25V is a bit high.

160VA is enough, but the 300VA may be a better choise

Best regards,

Mikkel C. Simonsen

[parrymike]

I thought that the required secondary voltage really depended a lot on your speakers, i.e. 18V for 4ohms and upto 25V for 8ohm.

How would 18V secondaries perfom/affect the sound when driving 8ohm speakers? Is 25V too high?

Mike

[mcs]

Originally posted by parrymike
I thought that the required secondary voltage really depended a lot on your speakers, i.e. 18V for 4ohms and upto 25V for 8ohm.

It does - if you need maximum power. But remember that many "8 ohm" speakers aren't really 8 ohm - but closer to 6 (or even 4).

So I think 22V is a good choise for many "8 ohm" speakers, but 25 is a bit high.

How would 18V secondaries perfom/affect the sound when driving 8ohm speakers? Is 25V too high?

It doesn't affect the sound at all - you just get less output power. I use a 2*15V transformer myself with "8 ohm" speakers.

Best regards,

Mikkel C. Simonsen

[rnoble]

Poeee,

I'm from Melbourne which isn't too far from you. Don't buy the Jaycar transformer's they're not good quality and they want too much for them. I was recommended Harbuch's by a very respectable amplifier manufacturer, which make great antrim toroidal trannies of very high quality.

You can bascially order what you like - I have ultimately ordered 4 225va 22v secondary toroids twice for around $45 each plus about $10 for postage. Great quality trannies at a really good price - they use courier so you normally get them in 1 or 2 days.

I don't work for them! Just passing on my good experiences.

They've got a site - http://ourworld.compuserve.com/homepages/harbuch/

The range is unbelievable, pick whatever secondary voltage you like ( although my 6 channels of BrianGT are working very well with 22v secondaries as recommended - although my speakers are 6 ohm nominal and I'm bi-amping they work fine. I wouldn't go above 24 but would go to 20 or even 18 if I was running 4 ohm speakers. The LM3875 whitepaper is very good for working this out.

Hope this helps.

[rabbitz]

I'll second that on the Harbuch transformers. Excellent quality and normally cheaper than the Jaycar or Altronic toroidals. Just bought bought 2, 300VA 25-0-25 AU$55.33, 160VA 18-0-18 AU$44.99 plus AU$9.35 for shipping.

The respected amplifier manufacturer wouldn't be run by Hugh would it?

[rnoble]

Originally posted by rabbitz
I'll second that on the Harbuch transformers. Excellent quality and normally cheaper than the Jaycar or Altronic toroidals. Just bought bought 2, 300VA 25-0-25 AU$55.33, 160VA 18-0-18 AU$44.99 plus AU$9.35 for shipping.

The respected amplifier manufacturer wouldn't be run by Hugh would it?

Yeah it was Hugh from AKSA who put me onto them, I put my GC's in a couple of his cases too.

[Peter Daniel]

As to the pot, this is the one you should be geting: "Silver-Carbon" Pot ex Tawan - Photo - & ignore my ugly Pinky!

[poeee]

Thanks for the info, and you aren't the only people who have told me to get Harbuch transformers.

Another question... Although I will more than likely be running 8ohm speakers, there may be the chance that one day I will be running 4ohm speakers, as I have some good car audio stuff (running Hertz HSK splits in my car at the moment, which are renowned for their mid bass). So keeping that in mind, what would be the "ideal" transformer for me? Should I go with a 18v 160VA or go a bit higher in VA?

"Silver-Carbon" Pot ex Tawan - Photo - & ignore my ugly Pinky! - those little pots seem like a winner, and I can get them from Jaycar. Thats WIN WIN!

[Peter Daniel]

IMO, higher voltage produces better sound with those chips. So even if you use 4ohm, it is still advantage. I was testing recently amps powering 4 ohm ScanSpeak speakers (2 x 24 VAC on transformer) and didn't observe any problems.