Hi everyone, I was planning to build my first gainclone, first amp actually, and I need some advice on what transformer I should use.
I'm planning on getting one of Brian's NIGC kits, and was going to get a custom wound antrim toroidal from Harbuch. Now I've been reading up quite a bit on these boards over the last week and tried using the search engine. There's ALOT of information to absorb my head is swimming right now..
What voltage should I get ? there seem to be varying opinions, such as matching it with your intended speakers, that higher voltages sound better given with acceptable safety boundaries. I will be running some old acoustic research 6 ohm 87db speakers for a start, but play on building speakers as well at some later date.
Also should I get dual secondaries or a centre tap toroidal or something else? are there pros and cons?
Lastly, shielding should I worry about it or not. I have the choices of EN60742 spec, SAFETY SCREEN, ELECTROSTATIC SCREEN and AS3200.1/IEC601.1 spec.
I'm planning on getting one of Brian's NIGC kits, and was going to get a custom wound antrim toroidal from Harbuch. Now I've been reading up quite a bit on these boards over the last week and tried using the search engine. There's ALOT of information to absorb my head is swimming right now..
What voltage should I get ? there seem to be varying opinions, such as matching it with your intended speakers, that higher voltages sound better given with acceptable safety boundaries. I will be running some old acoustic research 6 ohm 87db speakers for a start, but play on building speakers as well at some later date.
Also should I get dual secondaries or a centre tap toroidal or something else? are there pros and cons?
Lastly, shielding should I worry about it or not. I have the choices of EN60742 spec, SAFETY SCREEN, ELECTROSTATIC SCREEN and AS3200.1/IEC601.1 spec.
I would suggest 300VA with 2 x 24V secondaries. Higher voltage sound better in my experience. I'm currently using 3 x 12V batteries per rail and it is improvement over 2 x 12V . My speakers are 6 ohm.
Go with dual secondaries as the kit is designed for such setup.
I have a pair of monoblocks with transformers having screen between primary and secondary, but I didn't really observed any big gains with that, so it's rather optional but not really a must.
Go with dual secondaries as the kit is designed for such setup.
I have a pair of monoblocks with transformers having screen between primary and secondary, but I didn't really observed any big gains with that, so it's rather optional but not really a must.
trnas
I want a 25v-0-25v transformer for mine but seem to be having problems finding one. J-car sell a 18v-o-18v one but i think this is too low. Remember that with 5% regulation, which is guite good, you will lose more voltage across the secondaries. If you find a good one in N.Z post a note up here so i can see it. I'm off to China for a holliday, so will look there as well. Good luck
I want a 25v-0-25v transformer for mine but seem to be having problems finding one. J-car sell a 18v-o-18v one but i think this is too low. Remember that with 5% regulation, which is guite good, you will lose more voltage across the secondaries. If you find a good one in N.Z post a note up here so i can see it. I'm off to China for a holliday, so will look there as well. Good luck
Thanks for the quick reply Peter, I think that answers all my questions
So your GC would be running at ~36 volts would it? I assume that would be about the same as 24v VAC after it's been thru the rectifier.
I did forget to mention that I'm building the dual mono kit and powering off one transformer, but I think you assumed that, so that's cool
Enzedone
I was getting my from Harbuch which is in Australia, custom wound so better tolerances and quality than the ones u get at Jaycar and the like and shouldn't work out much different in price
Where abouts in the country are u? I'm in Chch. You could order with me and save on postage I guess, if you're around the area.
There are quite a few other places u should be able to find toroidals though. Altronics (global PC), and more professional places for example Radcliffe electronicals. I know a guy that does custom winds in Chch but they are pretty expensive. 2 x 25 V should be easy to find since it's one of the standard values. I hope u speak chinese mate, finding stuff over in China is hard enough as it is sometimes, thought I'm sure if u can find it it will be very cheap
So your GC would be running at ~36 volts would it? I assume that would be about the same as 24v VAC after it's been thru the rectifier.
I did forget to mention that I'm building the dual mono kit and powering off one transformer, but I think you assumed that, so that's cool
Enzedone
I was getting my from Harbuch which is in Australia, custom wound so better tolerances and quality than the ones u get at Jaycar and the like and shouldn't work out much different in price
Where abouts in the country are u? I'm in Chch. You could order with me and save on postage I guess, if you're around the area.
There are quite a few other places u should be able to find toroidals though. Altronics (global PC), and more professional places for example Radcliffe electronicals. I know a guy that does custom winds in Chch but they are pretty expensive. 2 x 25 V should be easy to find since it's one of the standard values. I hope u speak chinese mate, finding stuff over in China is hard enough as it is sometimes, thought I'm sure if u can find it it will be very cheap
Are we looking at the same chart?
http://users.bigpond.com/harbuch/harbuch/toroids2.HTM
At 300 VA the regulation can be 6.5, 6 or 5 %
goto 625 VA and it drops to 4%
800 and 1000 to 3%
I thought I would use them cuz quite a few australian posters here seem to recommend and use them, and custom wound cores should have more attention to detail and tolerances are likely to be tested and be at specifications. Unlike there mass produced counterparts.
Buying from Australia is just the same as buying within NZ nowdays anyway.
http://users.bigpond.com/harbuch/harbuch/toroids2.HTM
At 300 VA the regulation can be 6.5, 6 or 5 %
goto 625 VA and it drops to 4%
800 and 1000 to 3%
I thought I would use them cuz quite a few australian posters here seem to recommend and use them, and custom wound cores should have more attention to detail and tolerances are likely to be tested and be at specifications. Unlike there mass produced counterparts.
Buying from Australia is just the same as buying within NZ nowdays anyway.
zBuff said:
What's the delivery likely to be on a 300va transformer from Oz? I've thought about buying from Harbuch for my next amp, but am a bit shy when it comes to paying half the price again for postage.
I'm in Auckland, and have previously bought my transformers through Farnell. They charge only $10 for delivery.
Cheers!
Farnell they're an international company aren't they? I did a quick search on them and found out they have a branch in New Zealand too.
Assuming Farnell InOne is the same Farnell.
Was the Farnell u brought from in Oz?
Delivery between here and Oz I was always lead to believe was almost the same price as within New Zealand, courier rates are anyway.
It seems we have a few Kiwi's on this board
http://www.diyaudio.com/forums/showthread.php?s=&threadid=46490&highlight=
Ppl on the above thread reported the following prices
225va 22v secondary toroids for $45 AUD
300VA 25-0-25 AU$55.33
160VA 18-0-18 AU$44.99
Once you convert them to NZD that's still pretty cheap even with postage.
Global PC (Altronics) has 300VA 25-0-25 for $96 NZD Jaycar for some reason doesn't stock 300VA in 25v, only 18v,40v and 50v
I've emailed Harbuch a price enquiry, so I'll post back on this thread when I get a reply from them. You never know they might do a discount for bulk (assuming there are that many kiwis and aussies on this board).
Assuming Farnell InOne is the same Farnell.
Was the Farnell u brought from in Oz?
Delivery between here and Oz I was always lead to believe was almost the same price as within New Zealand, courier rates are anyway.
It seems we have a few Kiwi's on this board
http://www.diyaudio.com/forums/showthread.php?s=&threadid=46490&highlight=
Ppl on the above thread reported the following prices
225va 22v secondary toroids for $45 AUD
300VA 25-0-25 AU$55.33
160VA 18-0-18 AU$44.99
Once you convert them to NZD that's still pretty cheap even with postage.
Global PC (Altronics) has 300VA 25-0-25 for $96 NZD Jaycar for some reason doesn't stock 300VA in 25v, only 18v,40v and 50v
I've emailed Harbuch a price enquiry, so I'll post back on this thread when I get a reply from them. You never know they might do a discount for bulk (assuming there are that many kiwis and aussies on this board).
zBuff said:
Farnell Inone is the same international company but they have distrubution through out NZ too. I have bought stuff from them. They are not shops like Jaycar etc, I am pretty sure you can only web/phone orders.
http://www.rsnewzealand.com/ is another one very similar to Farnell but I find it is better.
zBuff said:
Delivery between here and Oz I was always lead to believe was almost the same price as within New Zealand, courier rates are anyway.
It seems we have a few Kiwi's on this board
I have found that its OK for things that are small and light but I think the postage on a toroid might rule it out
zBuff said:
But they do have 25V 160VA ones and you get a small discount for buying 2 of them so they are good for dual mono GCs! I got two for $110 (with trade card) and then $10 off from some coupons that came with a jaycar catalog
Pics of it soon
zBuff said:
Let us know what they quote for postage!!
I've had a look at Jaycar's torroids and -- I don't know, they just feel cheap. In my uneducated opinion, for what they are, Jaycar may charge a little too much for them.
I know that Harbuch don't have a problem freighting to NZ, but they didn't given me an indication of price when I made a casual enquiry recently. I will have to find out more when it's time for a serious order.
I know that Harbuch don't have a problem freighting to NZ, but they didn't given me an indication of price when I made a casual enquiry recently. I will have to find out more when it's time for a serious order.
Shipping seems quite expensive at $28.50 AUD 
for the first 2 kg then $7 per kg there after. This is via air parcel post though. I'm asking again for any other shipping options.
Just trying to reclarifying the price on the toroidals, inital enquires seem quite expensive though but it might be because I asked for stuff which wasn't in stock.
H8421 AUD62.30 nett, 3kg packed
and T8421 AUD73.85 nett, 4kg packed
I'm going to ask at another local place that I can get trade prices at Radcliffe electronics. Don't know whether the quality will be any better than Jaycar though.
The Hunt continues
for the first 2 kg then $7 per kg there after. This is via air parcel post though. I'm asking again for any other shipping options.Just trying to reclarifying the price on the toroidals, inital enquires seem quite expensive though but it might be because I asked for stuff which wasn't in stock.
H8421 AUD62.30 nett, 3kg packed
and T8421 AUD73.85 nett, 4kg packed
I'm going to ask at another local place that I can get trade prices at Radcliffe electronics. Don't know whether the quality will be any better than Jaycar though.
The Hunt continues
A friend told me that amplimo toroidal transformers are very good!
http://www.amplimo.nl/amplimo.html
Each toroidal Amplimo of 160VA 25V 3.2A have Diameter 110mm and a price of +/- 45 dollars
http://www.amplimo.nl/amplimo.html
Each toroidal Amplimo of 160VA 25V 3.2A have Diameter 110mm and a price of +/- 45 dollars
Why to complicate what it is so simple? 
Well, is my opinion but however, my GC have a conventional trafo, a 120VA 24-0-24 (5A is enough) and sounds good. The chip is not high end, is low so, do not invent
Again, is my opinion but I know exists many people with this concept.
Cheers to everyone
Well, is my opinion but however, my GC have a conventional trafo, a 120VA 24-0-24 (5A is enough) and sounds good. The chip is not high end, is low so, do not invent
Again, is my opinion but I know exists many people with this concept.
Cheers to everyone
Just got another email back from Harbuch seeems I can get 240 V 25VAC duals for $50.30 which are in stock, that's a pretty good price.
at 230V that would be around 24VAC
The killer would still be the freight though at 28.50 for the first 2 kgs then 7 per kg thereafter.
I still think I'm going to get a couple though.
at 230V that would be around 24VAC
The killer would still be the freight though at 28.50 for the first 2 kgs then 7 per kg thereafter.
I still think I'm going to get a couple though.
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