BIG nano core SUT challenge

the road not taken.
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jarek
Posts: 62
Joined: Wed Feb 02, 2005 10:02 am

BIG nano core SUT challenge

Post by jarek »

hey dave and others!
after few dark ages i'm back to the audio obsession, with
an assault on the pussyfied EAR 834 to begin with. i'm on a search for
a challenging SUT. i have some +/- fuzzy ideas and a source of
cores to explore. i'm looking for somebody willing to wind and experiment :)
here are some thoughts:

0) BIG toroid core! to maintain inductance at low freq. and ultra-low signal;
take SU-1/2 as an inspiration. the problem which i see here is to get
the right LCR parameters: right resonant freq., the right Q etc. i have no experience here.

1) the material: after some update i was left with Co amo or nano;
according to my source, the initial linearity should be very much the same,
and nano cheaper than Co amo and available in big sizes;
there are two variets of nano: square loop with mu=150.000 and flat loop
with mu=30.000 with the lowest losses up to date. it has also fairly
constant mu with freq.(for the Co amo it varies up to 10 times), although i'm not
sure how important that is.

my first choice would be flat loop nano, but can get both cores to experiment with.

2) the core can be wound to my specs, with the tape width = 20mm max
being the limiting factor. i was thinking of 65mm OD, 40mm ID 20mm height
with around 1cm2 effective core area. core encapsulated rather
than epoxy potted, as, according to my source, potting introduces some losses and lowers mu (up to 10%)

the boundary conditions: 1:10 and 1:20 turns ratio; acceptable loads 50-220 Ohms
when referred to the primary (but applied on the secondary)
mumetal enclosed, but no fancy boxes as I will put it into a steel
box and then inside the preamp enclousure; paper or
teflon isulation etc etc

maestro? how does it look?

cheers,
jk
jarek
Posts: 62
Joined: Wed Feb 02, 2005 10:02 am

Post by jarek »

Ok, was very surprised not to get any reply, perhaps I've knocked a wrong door...finally Pieter took the challenge.

Cheers,
jk
dave slagle
Posts: 2085
Joined: Sat Jan 22, 2005 3:54 am
Location: NYC
Contact:

Post by dave slagle »

Hey Jarek,

Sorry forum was down for a bit. Pieter is the perfect person to do this since he works with toroids. Let me know of the results

dave
Get Your Fix
www.hifiheroin.com
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