Hi Alec,

Your advice NOT to attempt to change taps to preclude a mushroom cloud materializing is the right advice. I would definitely want to have a schematic diagram handy and perhaps talk to a keyboard repair technician before attempting to do anything myself, despite my long experience in electronics. I know a technician here locally in Manchester who repairs musical instruments and I think I will give him a call and see what he has to say.

On the surface of it and as a layman, I would think it would be cost effective for Panasonic to use a universal power supply, but then I'm not in the business. Maybe we need to start a write-in campaign on this issue? Consumer presssure works wonders sometimes.

Thanks for your response, Alec. Take care.

Chuck

Hi Bill,
I didn't know that was your line of work

I think the problem is that if you are talking about an analogue audio signal of a few hundred millivolts, then for 16 bit dynamic range you are literally talking about microvolts of noise being important.

the supply will be used as reference voltages on differential input amplifiers, so the noise will be amplified with the analogue signal. and as you know the switching supply noise is more difficult to filter because the harmonics are at all radio frequency, rather than harmonics of 50 and 60 hertz of a transformer power supply, where the transformer is itself a big inductor that helps the problem.

as you realise that's why the expensive soundcards have 'battleship' filtering, multiple layer ground planes, the shortest possible tracks not to act as radio frequency aerials, and grounded boxes over critical components etc.

I think the difference is that the human ear has an incredible dynamic range (logarithmic scale) and can detect subjective noise most efficiently down to levels that tax even sophisticated noise meters. So the cost of a 'silent' switching supply starts to rise analogous maybe to the cost of 'audio grade' soundcards compared to even good soundblasters.

my respects, my friend

Alec, Johnnie,

I'm just going to plead temporary insanity! Much smoke seen rising from both shoes.

Regards, Peter

Hi Peter,
ok as long as the smoke is not coming from Chuck's transformer (boom boom)

Hi Peter
Just so long as it is only smoke that is rising

Hi All,

My keyboard is sitting next to me neatly covered and my smoke alarm is not beeping. Hope those are sufficient indications that my KN is still healthy and intact! Uh oh - think I better remove the cover and double check.

Chuck

I'm glad I quit smoking 9 years ago
GJ

It might seem a silly question, but who owns the site? Is it Technics, Panasonic, Taiyo ?? - I'm curious to know

presumably we'll know from the email address when an update info arrives?
it must be official technics because of the logo?

If this is any indication, I received an email from Technote directing me to the kn7000 site.
Peter