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Date: Thu, 09 May 2019 15:34:58 +0200
From: DK7FC <selberdenken@posteo.de>
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References: <477297345.20190414143742@gmail.com> <5CB35457.9060303@posteo.de> <592014641.20190414170848@gmail.com> <5CB37097.90104@posteo.de> <853391954.20190509134230@gmail.com>
In-Reply-To: <853391954.20190509134230@gmail.com>
Subject: Re: LF: Another impedance matching question. Paul's audio amps.
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Hi Chris,

I would not recommend the one you selected because it has an unnecessary 
large inner diameter and a  lower height, thus a lower AL value.

I think this is the same one that i recommended from Bürklin: 
https://www.mouser.co.uk/ProductDetail/EPCOS-TDK/B64290A0699X830?qs=sGAEpiMZZMs2JV%252BnT%2FvX8Df1W1GtRs010YpcsJh6dvk%3D
It is also cheaper.
There are other materials available, such as T65, T38, T37, offering a 
higher AL value. Maybe these are even more suitable at that sort of 
frequency but i didn't spend too much time to select the best core for 
each frequency. I use the N30 material from 1 kHz to MF at high power ( 
 > 1 kW for one core) without problems. So this is what i recommend. It 
will work.

73, Stefan

PS: If you want to bridge one of Paul's 2x 7.2 kW amps, you may need two 
of them ;-)
PPS: You may want to build two orthogonal ground loops then, one per 
channel. With SpecLab you can then drive each channel separately and so 
you can build a software rotatable loop by aligning the phase between 
the channels, while staying into the shack when its cold and/or rainy :-)


Am 09.05.2019 14:42, schrieb Chris Wilson:
>
> Hello Stefan,
>
> I  am  now on to building a matching transformer but it seems Buerklin
> have  a  minimum  order  of  60 units! I have found this bigger core at
> Mouser, could I use that instead please?
>
> https://www.mouser.co.uk/ProductDetail/EPCOS-TDK/B64290L0730X830?qs=4l9S5vBWkUJtsO6ZFRCS4g%3D%3D
>