The single biggest issue is magnetic induction - those tiny little transformers are in the same metal case as a big-honkin' toroid, which even if shielded, has magnetic flux all around. So in a perfect world, the input transformers are both on the same side of the case, and as far from the power transformer as possible - this means, most likely, a mirror set of PCB.
The F6 production pieces put the little transformers to the rear and the big
transformer to the front, as with the M2 layout.
Best noise figures I get are <100 uV output noise (20-20K unweighted), and
worst case <200 uV. This is pretty good, but is typically achieved by rotating
the big transformer a bit until the noise is equal in both ch.
If you add shielding, You can do better. You can make a steel band for the
big transformer, and put some mu metal over the little transformers and get
about 6 dB reduction.
You can make a steel band for the
big transformer
That steel band it got to be connected to the chassis or gnd?
Or it is just a "belly belt" not connected to chassis or gnd, used to trap a part of the magnetic field in it (loop in short circuit)???
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Here...
http://www.tonepublications.com/MAGPDF/TA_034.pdf
...is the link to the Tone Audio issue containing the review of the J2. Starts on p. 172.
http://www.tonepublications.com/MAGPDF/TA_034.pdf
...is the link to the Tone Audio issue containing the review of the J2. Starts on p. 172.
Hmm..can't edit my post?
Here's a direct link to Tone Audio's review.
First Watt J2 Power Amplifier – Reviews | TONEAudio MAGAZINE
Here's a direct link to Tone Audio's review.
First Watt J2 Power Amplifier – Reviews | TONEAudio MAGAZINE
Is it still possible to get all parts for DIY J2? That is, if the schematic get's published... I'd like to build one someday.
Not published, still in production. Us greedy boyz will have to be patient. At least as far as I know. It is on my bucket list too.
Source?You may want to consider acquiring the Semisouth devices while you can.
Dennis
Thanks,
Russellc
You may want to consider acquiring the Semisouth devices while you can.
Dennis
Which Semisouth part for J2 amps should I stock up?
That steel band it got to be connected to the chassis or gnd?
Or it is just a "belly belt" not connected to chassis or gnd, used to trap a part of the magnetic field in it (loop in short circuit)???
There would be a miniscule advantage to grounding it. It is there to
trap the magnetism.
Which Semisouth part for J2 amps should I stock up?
Good question! I also need this info as well.
Russellc
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