TomWaterman

Re: Marinair LO1166 transformers
« Reply #20 on: June 11, 2009, 05:42:10 PM »
This sort of idea:


-T


TomWaterman

Re: Marinair LO1166 transformers
« Reply #21 on: June 12, 2009, 09:04:51 PM »
Anyone got any expeerience?

Cheers Tom

Re: Marinair LO1166 transformers
« Reply #22 on: June 13, 2009, 06:26:35 AM »
This is a touch pedantic, but a correctly biased 283 board will put around 80mA (+/- ~ 5mA) through the 1066 primary.

If you're not using a 283 to drive the 1066, why use a 1066? Why not try a smaller nickel / iron t/former from the likes of Cinemag? Some of Sowter's silicon / hybrid lam transformers can also handle a fair amount of DC on them (I recently discussed this with the ever-helpful Brian Sowter).

Anyway, I'm playing Devil's Advocate somewhat - I await with interest your results on the 1066 circuit - could be interesting. A bonus being that modern recreations of the 1066 are pretty affordable (Colin @ Audio Maintenance).

Justin

Oh yeah - one thing to note: a correctly set-up 283 + 1066 doesn't actually measure *that* high in THD (well, by olde-worlde standards anyway). Considering it's designed to sustain a high amount of DC, if you 'synthesise' a current source to put 80mA across the primary, do you really reckon the effect will be that dramatic?
« Last Edit: June 13, 2009, 06:32:34 AM by thermionic »
Prepare yourself. You are about to become the voice of Interplanetary Parliament.

TomWaterman

Re: Marinair LO1166 transformers
« Reply #23 on: June 13, 2009, 08:48:17 AM »
Thanks Justin, fair point about the current. Thanks for letting me know!

I have a few here to try and a few ideas, namely starting by looking at smaller cores to get a more noticeable effect, however like you say 1166s can be had very cheaply. I had some from Colin and a few other Carnhill types, can't argue with the sub 20quid pricing for a cketchy test!

You are corrrect, I am not expecting a massive change, but I thought it would be an interesting experiment, I am more than half expecting to discard the attempt and move on to another plan.

Which Sowter models are you referring to?

Cheers Tom

Re: Marinair LO1166 transformers
« Reply #24 on: June 15, 2009, 07:04:57 AM »
http://www.sowter.co.uk/acatalog/SOWTER_TRANSFORMERS_PRO_VINTAGE_TRANSFORMERS_5.html#a40

Sowter make LL1066 replacements. Although they're smaller in physical size (their main selling point I suspect - getting Carhills into a 1u rack is awkward) I don't know how their saturation characteristic differs.

Also have a look at the 8403 - it's got a hybrid silicon core which doesn't magnetise permanently in the same way a mu core does. Having said that, Brian Sowter's easily contactable, so I'd pick his brains before trying anything (I don't know exactly how much DC the Si core units can handle; I know they can handle *some*).

Justin
Prepare yourself. You are about to become the voice of Interplanetary Parliament.

TomWaterman

Re: Marinair LO1166 transformers
« Reply #25 on: June 15, 2009, 08:26:51 AM »
Thanks Justin.

I hadn't considered the 8403 with its core type.

My first idea was to contact Sowter, but thought I'd try and prove the concept with the Carnhill I have here first.

I may actually get a custom Sowter which is smaller and more easy to saturate.

Once I know where I'm going I will call them up.

Cheers Tom


 

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