| monomonster |
| i want to build a power supply for the sonic impact t-amp i have and because i want a sweet looking slim case (:D) a good torodial transformer would be cool. the thing is i heard that there are many "levels" of torodial transformers and most are not audio quality + i live in israel so it better be made in europe so shipping will be cheaper. i searched the forums i could not locate a good source. please help |
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| wintermute |
Not sure if Ireland counts as close enough but you could try these guys out http://www.antrimtransformers.com/catalogue.php?sec=446 either their custom ones or one of their standard range. I just bought a standard range 300VA 2X 20V secondary, but havent used it yet. (I'm lucky there is an Antrim authorised manufacturer here in Sydney). I've heard good things about Antrim before and their pricing is good (at least here in Aus).
Tony. |
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| teddy_pardo |
Hi,
I tried with Antrim last week, the trnsfo was 80 GBP, but the problem is that they charge additional 103 GBP for shipping (to Israel)!
Teddy |
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| wintermute |
yikes!!!! you might be better trying harbuch here in Australia... on an exchange rate basis would be better off for starters... I bought a 300VA dual 20V secondary for a bit under $70 a week or so ago, and that was a potted one, the non-potted is 7% cheaper...... don't know about the shipping but I would imagine a lot less than that!!!
Harbuch is licenced to make Antrim transformers.
Tony.
edit: I think the base price without GST or potting was about $53 AUS, which is about 25 UK pounds!!! |
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| monomonster |
| you have a link maybe? i searched google and found nothing. |
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| joensd |
You can get pretty high quality transformers at Schuro:
http://www.schuro.de/preisl-v-rkt-ms-sw.htm
I think prices are outstanding for what they are but ordering there can be a pain (like no reply or similar).
These transformers feature magnetic shielding, shielding between primary and secondary, special iron core, etc...
You want to build a separate power supply case?
In that case IŽd use a standard toroid and nothing fancy/shielded/potted or so.
DonŽt know what the T-amp can take voltagewise but IŽd reckon a 9VAC/50VA would fit and be plenty IMO. |
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| wintermute |
sorry here is the link :) http://www.users.bigpond.com/harbuc...uch/default.htm
I bought one of the standard range ones, but while I was there they said that they will do custom ones for audio, low flux density etc... I didn't enquire as to the price difference for a custom one though...
Tony.
edit: the ex stock ones are cheaper too.... i was going to get a 225VA but it wasn't a stock item, the 300VA was and was $10 cheaper :). |
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| BenY |
monomonster,
You can get your transformer here in Israel if you know how to order for your needs,ie audio...
That`s not really a problem,
Contact me direct and i will tell you how to.
Yuval. |
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| BrianL |
| I believe Avel-Lindberg is a British-based company |
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| Vidalgo |
monomonster ,
check RS Israel
not so expensive because local shipping |
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| monomonster |
| looks like a cool site, they really ship from israel? i noticed they don't have any prices. |
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| Vidalgo |
Yes, it's israel branch of RS Components UK. Office in Rishon. Local stock, probably not for all items.
Prices. Long time ago, next link was running for price info:
http://price.rsisrael.co.il/ , but not today.
Check prices by phone or go to RS Global for an reference points. |
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| teddy_pardo |
Hi,
I ordered today C-core transformers from Rozen et Miller (thank you Yuval for the lead). They are located at Salame 33 Tel Aviv. I'm supposed to get them in a week so I will let you know about the results. Anyhow the guy is very nice and seems to know what he is doing.
Teddy |
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| yehuda |
I have ordered toroidial transformers from Farnell Israel, which shippes from England.
Cha'g Sma'ach!!
Yehuda |
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| I_Forgot |
| quote: | Originally posted by monomonster
the thing is i heard that there are many "levels" of torodial transformers and most are not audio quality |
Did you also hear what it is that makes some toroids suitable for audio and some unsuitable?
I_F |
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| wes-ninja250 |
Audiophile-grade toroidal transformers are wound with oxygen-free copper wire, silver-plated with teflon coating, have gold-plated cores, and magnetically defluxed mounting hardware. Also, the winding machine uses tube-based logic with an even number of factory employees. Factories with odd numbers of employees produce transformers which are distorted and unpleasing to the human ear.
Seriously, any decent transformer with good regulation should work fine. And good regulation generally comes "free" with a large VA rating.
Wes |
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| pmkap |
Other than the last statement regarding regulation and size, the preamble is sadly all too typical of the mockery of those who evidently never made measurements or comparisons.
Toroids do have smaller extraneous magnetic fields than other geometries, and above a certain size, they are smaller and less expensive. But the typical low cost toriod, with no shielding between its overwound primary and secondary, has very high bandwidth via its high capacitive coupling, making a resonable tube output transformer, passing whatever noise is on the mains line. Toriods with interwinding shields are quite expensive.
Other geometries such as shielded or split bobbin EI cored, flatpacks and C/R-Cores with physically separated windings, measure, and SOUND better.
Certainly, powerline filtering can address some of these issues, but little beats using a properly specified transformer.
FWIW |
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| wes-ninja250 |
pmkap:
I do not for one moment believe that an unshielded, inexpensive toroidal transformer is unsuitable for use in audio-equipment power supplies.
Wes |
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| wintermute |
When I went to Harbuch they said that that do 160VA transformers wound on a 300VA core specially for audio. the bigger core reduces the flux density... (which I assume leads to less electromagnetic emissions).
Tony. |
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| wintermute |
| quote: | Originally posted by wes-ninja250
pmkap:
I do not for one moment believe that an unshielded, inexpensive toroidal transformer is unsuitable for use in audio-equipment power supplies.
Wes |
Hi Wes, If you had used some of the ones I have had, you may change your mind ;) I've had major problems with radiated noise from (not so cheap) Toroidals!
Tony. |
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| pmkap |
| quote: | Originally posted by wes-ninja250
pmkap:
I do not for one moment believe that an unshielded, inexpensive toroidal transformer is unsuitable for use in audio-equipment power supplies.
Wes |
Of course you don't.... nor did I say they were not suitable. I'm simply saying there are better alternatives. My solid state poweramps use bog standard Avel toroids. I didn't wan't to muck other geometries with their external magnetic fields and its predeliction to cause hum, and at the time, I was unwilling to spend double the cost for interwinding shielded ones. We all make our decisions based upon both technical and economic constraints.
But when it comes to solid state source components or a popgun supply for a T-amp, and I see a toroid lacking an interwinding shield, I'm saddened. Saddened because, at least for a simple split or single rail ps, one could use a flat pack transformer which minimizes external magnetic fields, has far less capacitive coupling and bandwidth, and is roughly equivalent in cost. I don't care how good your regulators may be, these transformers will simply produce a better component.
http://www.mcitransformer.com/i_4-05_2.html
Then again, I live in NYC, and where you live your mains may well be perfect, noise free sine waves. I'm very happy for you.
Nor do I particularly care that you 'do not believe for one minute....', because if you'd actually tried, or evaluated alternatives, you would have said so. You simply stated your 'belief', not anything based upon empirical experience or technical knowledge. Faith based engineering..... thats a new one. |
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| planet10 |
I was going to recommend checking out the fellow member from Turkey who is selling c-Core trafos made in his locale... but with someone in Telaviv making them, that might well be a better place to go (i'd take a c-core over a toroid -- all else equal)
dave |
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| AndrewT |
Hi wintermute,
I have not tried it but I read that removing the single core secondary output tails and replacing them with flexible cords allows you to move the transformers around without work hardening the copper tails (and risk breaking them).
Now you can rotate the toroid around its mounting bolt to minimise the hum field effect on the adjacent circuit. |
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| wintermute |
Thanks AndrewT,
I hadn't even thought about rotating the transformer, but given what magnetic fields look like (with poles) it makes sense!! When I next feel brave enough to open up the amp (when I put in a new rectifier/cap board) I'll have to give it a try.
Tony. |
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