On Friday, March 29, 2019 at 2:30:53 PM UTC-4, Peter Wieck wrote:

As an aside, I toured the Veolia Steam Plant in Philadelphia, yesterday. This plant has been in continuous operation since it opened in 1909, and is quite a remarkable place. I got to be up-close-and-personal with the equipment, including the steam and

gas turbines, the boilers, pumps, controls, switchgear, powerhouse and uplink.

Standing under the main step-up transformer (2,300 VAC to 23,000 VAC) is a truly visceral experience. Once one feels that level of "HUM", one will never mistake 60 for 120 ever again.

Relevance:

60 HZ hum suggests a bad or failing rectifier.
120 HZ hum suggests bad or failing filter caps.
50 & 100 for our Euro and Asian friends.

Amazing amount of mechanical-feedback devices in use in these plants - it seems that VFDs and great many "modern" grid-tie devices are simply not sufficiently rugged or reliable at this scale.

Peter Wieck
Melrose Park, PA

My Radiola 33 has gotten a 60 hz hum. I understand replacing a cap therein requires inversion of the apparatus to get the guts out... Anyway, sadly, I'm beyond all that these days. too many obligations.

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On Sunday, May 12, 2019 at 1:41:01 AM UTC-4, mccarty...@gmail.com wrote:

My Radiola 33 has gotten a 60 hz hum. I understand replacing a cap therein requires inversion of the apparatus to get the guts out... Anyway, sadly, I'm beyond all that these days. too many obligations.

A 60 hz hum = a bad rectifier. Which, if I am not mistaken is an 80. Try replacing that tube first.

Peter Wieck
Melrose Park, PA

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On Wed, 3 Apr 2019 18:33:14 -0500, philo <philo@privacy.net> wrote:

60 HZ hum suggests a bad or failing rectifier.
120 HZ hum suggests bad or failing filter caps.
50 & 100 for our Euro and Asian friends.

Try running 36 to 40 HZ thru a powerful amplifier. The effect you feel
is awesome. But watch out for objects falling off shelves, tables, etc.

A local rock band ended a show back in the late 1970s saying they were
going to cause an earthquake. This was in a nightclub. They sure did it.
10,000 watts at around 40HZ. They pre-agreed to pay the bar owners for
all broken glasses that fell. There were several.... I'll never forget
the feeling. AMAZING.

Using my audio generator I found that frequency range.....

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On Friday, March 29, 2019 at 2:30:53 PM UTC-4, Peter Wieck wrote:

As an aside, I toured the Veolia Steam Plant in Philadelphia, yesterday. This plant has been in continuous operation since it opened in 1909, and is quite a remarkable place. I got to be up-close-and-personal with the equipment, including the steam and

gas turbines, the boilers, pumps, controls, switchgear, powerhouse and uplink.

Standing under the main step-up transformer (2,300 VAC to 23,000 VAC) is a truly visceral experience. Once one feels that level of "HUM", one will never mistake 60 for 120 ever again.

Relevance:

60 HZ hum suggests a bad or failing rectifier.
120 HZ hum suggests bad or failing filter caps.
50 & 100 for our Euro and Asian friends.

Amazing amount of mechanical-feedback devices in use in these plants - it seems that VFDs and great many "modern" grid-tie devices are simply not sufficiently rugged or reliable at this scale.

Peter Wieck
Melrose Park, PA

I like to stand under the flourescent light in the kitchen and match my hum to the 60 hz of the flouros. They don't always hum audibly. That way, one gets to "hear" engines out of sync. Heterodyneing of60 and (+-60). I do have a "curly bulb" that rings..
.

Thanx for the 80 rectifier note! A lot easier to try. I've saved all my 80's. Would never've thought of that.Never.

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