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Experience with AnTek OPTs?

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Hi,

Does anyone have any experience with the toroidal output transformers
offered by AnTek? This company seems to be more oriented towards
power transformers. I am looking for something to handle up to 20W
in PP and I can't possibly afford Plitron. For the price of the AnTek toroids
offered on Ebay, I could buy a pair of 25W CXPP from Edcor. Would this
be a better option?

Thanks
 
I've got a pair o' AT-1008's on the way and I'll report back with my findings. May be a few months though before I can cobble together something though

I would be open to letting someone borrow them if they have the equipment to test them (analyzers, scopes, etc).

Hi whitelabrat,

long time passed, how did it go with the AnTek OPT's??
Maybe you meant AT-100L as I couldnt find what you typed in your post..

Cheers Michael
 
btw found AnTek's eBay shop:
eBay Store - Antek inc: Transformers, Enclosures, Power Supply

Whitelabrat typed correct, they have OPTs models AT-1008 and so on (not listed on their homepage) but they are without the UL 40% tap.

The ones with UL 40% tap have very low input impedance of around 2 k for their 2 largest trannies, isn't that crazy low, who would buy these??
Or maybe there are suitable projects for PP UL 40% trannies with so low input impedance...
 
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I've got a big backup of projects that just aren't going anywhere. The AT-1008's just sit in a box. Very sad.

My current intent is to do something Screen Drive Parallel Push-Pull with 22JF6's. At about 2k ohm these are intended for PPP with 6L6's, 6550's or similar. I just got novar sockets and big aluminum plates. The amps stuff is trumped by house projects at the moment. :(

I did see thisrecently. It's the only build I've ever seen with these transformers.
 
They have some other models on their website. All of which have %40 taps. I'm going to try the AT-040L (4.8k 40W) ones. Your right, the higher powered ones use low impedance. They must be intended for parallel output tubes. Or low impedance tubes. The 70W version would probably work well for a 6c33c push pull.
Antek - Products - List View[]=2
 
btw found AnTek's eBay shop:
eBay Store - Antek inc: Transformers, Enclosures, Power Supply

Whitelabrat typed correct, they have OPTs models AT-1008 and so on (not listed on their homepage) but they are without the UL 40% tap.

The ones with UL 40% tap have very low input impedance of around 2 k for their 2 largest trannies, isn't that crazy low, who would buy these??
Or maybe there are suitable projects for PP UL 40% trannies with so low input impedance...


PPP EL34s would do fine with those O/P trafos.

The trafos without UL taps go with full pentode mode "finals". Regulate g2 B+ and combine NFB techniques. Short loop plate to grid around the O/P tubes will dispose of damping factor and linearity issues, for the most part. A few dB. of GNFB takes care of linearizing the "iron" and anything left after the short loop NFB has done its job.
 
Thanks Eli! But where can I use the ones with UL 40% and around 2k input, also PPP, then what's the use of the UL 40% tap??
Sorry I'm not too well aquinted with tube stuff but checked one PPP EL34 scheamtic and there's no UL 40% tap OPT, check out the schematic here: http://www.audiofanatic.it/Schemi/Tipo/Valvole/finali/pic_finali_PP/EL34PPP_MagneticFrance.jpg

Good to hear from you labrat, sorry to hear the project is moving so slowly for you, hopefully you can tell us soon how those trannies worked, I'm gearing up for a KT88 PP, check out TubeMack's thread where I am in too as we are probably going to build the same thing. Here's the direct link btw: http://www.diyaudio.com/forums/tubes-valves/156699-mullard-5-20-kt88-pp-blocks.html

Jeb, yeah I noticed the smaller core which could have been a good one regarding the input, but that frequency response looks a little bit freightening doesn't it?
 
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I bought a couple power transformers, transformer pots and output transformers off of them. They keep stock on hand, so shipping is quick. Products seem well made, but unfortunately I haven't built anything with them yet.

great, let us know when you are done! :)

I am thinking whether the UL OPT provides so much?
Or maybe I could get the non UL Antek with a more suitable p-p input impedance for the KT88 PP.

Cheers Michael
 
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I can't talk to Antek OPTs, but I have been using their power transformers for a long time. (At least 6 - 7 yrs) I am a very pleased customer, inexpensive, quiet, cool running, and no trouble so far. (They're in my dac, and several of my amps, as well as client projects from years past.)

I've widely recommended them and no one I know has had any problems with them.

Quick and reasonable shipping, most everything is always in stock.
 
Be sure when you order to talk to John directly. I had to return the AT-040L's I ordered since they were so much physically bigger than the spec sheet indicates. In my case, I had tight physical tolerance so had to return them.

If you do a little looking on the site, many of the power transformers have two different physical dimensions depending on where you look. I have read of reports of some getting power supply transformers with wrong, i.e. 5vac instead of 6.3vac secondaries, etc.

Verify before ordering with John, that is all.
 
Be sure when you order to talk to John directly. I had to return the AT-040L's I ordered since they were so much physically bigger than the spec sheet indicates. In my case, I had tight physical tolerance so had to return them.

If you do a little looking on the site, many of the power transformers have two different physical dimensions depending on where you look. I have read of reports of some getting power supply transformers with wrong, i.e. 5vac instead of 6.3vac secondaries, etc.

Verify before ordering with John, that is all.

I noticed some discrepancies between website dimensions and actual dimensions as well. But, I haven't started the chassis design yet, so it hasn't caused any problems. The 040L's do seem like a nice chunk of iron when you hold them in your hand. Which is why I'm going to try and squeeze 60W out of them :D
 
I've been curious about these as well. The HF roll-off is a little steep on the smaller ones. The AT-070L looks the best on paper (what little paper they have). I'd mainly be curious about what the phase shift looks like over the frequency band in practice. Still, they look good at the bottom end and might be just the thing for a big, honkin' sweep tube amp. Could almost buy a pair of each size for the price of one Plitron set.
 
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