Post pictures of anything, with comment...couple words.

[mhardy6647]

lookin' at some vacuum tube amplifier output noise on a real, honest-to-goodness sillyscope (oscilloscope).

 

[Doodski]

lookin' at some vacuum tube amplifier output noise on a real, honest-to-goodness sillyscope (oscilloscope).

I realize this may be dangerous and you might not have a high voltage probe but what does a power supply waveform in a tube amp look like? I owned one very pretty tube amp in my life and have never serviced a tube amp so I know next to nothing about tube amp circuitry. Cute lil 40 MHz O-scope too. It's nice having the readout in the CRT. I just noticed this O-scope has dual time base divisions. Is that also a multiplier like some Tektronix O-scopes have? Or is it a individual time base for each channel of the voltage amplifiers?

 

[mhardy6647]

I realize this may be dangerous and you might not have a high voltage probe but what does a power supply waveform in a tube amp look like? I owned one very pretty tube amp in my life and have never serviced a tube amp so I know next to nothing about tube amp circuitry. Cute lil 40 MHz O-scope too. It's nice having the readout in the CRT. I just noticed this O-scope has dual time base divisions. Is that also a multiplier like some Tektronix O-scopes have? Or is it a individual time base for each channel of the voltage amplifiers?

You're asking a lot of a biochemist.
The power supply's HV will have some 120 Hz ripple on it, but this amp (sort of a Dynaco ST-70 clone; more of a 'restomod' although 100% new production) has, like the original, a choke in the P/S, so the B+ is probably pretty quiet.
It ain't my amp (it's just visiting) so I am not planning to dig too deep. I was asked to assess its noise level. It ain't bad, qualitatively or quantitatively.
The hum's softly audible a few inches from an Altec 515B woofer -- ahem, a rather sensitive driver.

It's been a hum and noise* 24 hours around here!

Oh, as a crazy aside -- I am listening to NPR's All Things Considered while I am sitting here with my laptop, adding noise to the internet for the AI bots to scrape -- and I've heard three soundbites (one featuring the POTUS) with glaringly high levels of ground loop hum on them! As you can guess, today I am hypersensitive to such.
_____________
* NOT to be confused with Sturm und Drang.

 

[Doodski]

The power supply's HV will have some 120 Hz ripple on it

IC. Good to know what kind of bridge it uses or is this some kind of tube power supply setup?

It's been a hum and noise* 24 hours around here!

That is a thing that I have enjoyed when working gear. It creates a warm enveloping energy that I miss when it is gone. Like a low frequency fan's noise that I like too.

NPR's All Things Considered and I've heard three soundbytes (one featuring the POTUS) with glaringly high levels of ground loop hum on them! As you can guess, today I am hypersensitive to such.

LoL... Yes, All Things Considered (ATC) would be something I would want to hear in clear hum less sound so as not to be distracted from the topic of discussion. Is All Things Considered format neutral?

 

[Mikig]

You're asking a lot of a biochemist.
The power supply's HV will have some 120 Hz ripple on it, but this amp (sort of a Dynaco ST-70 clone; more of a 'restomod' although 100% new production) has, like the original, a choke in the P/S, so the B+ is probably pretty quiet.
It ain't my amp (it's just visiting) so I am not planning to dig too deep. I was asked to assess its noise level. It ain't bad, qualitatively or quantitatively.
The hum's softly audible a few inches from an Altec 515B woofer -- ahem, a rather sensitive driver.

It's been a hum and noise* 24 hours around here!

Oh, as a crazy aside -- I am listening to NPR's All Things Considered while I am sitting here with my laptop, adding noise to the internet for the AI bots to scrape -- and I've heard three soundbites (one featuring the POTUS) with glaringly high levels of ground loop hum on them! As you can guess, today I am hypersensitive to such.
_____________
* NOT to be confused with Sturm und Drang.

sturm und drang and biochemistry….unusual combination!!

 

[mhardy6647]

sturm und drang and biochemistry….unusual combination!!

Oh... I don't know...

 

[mhardy6647]

ahem. back to some biology.

In case you've never seen a turkey fly -- and your understanding of turkey aerodynamics was informed solely by the "Turkey Drop" episode of WKRP in Cincinnati*.

Yes, Les, real turkeys can fly.







_______________
*Perhaps the best half-hour of classic American TV sitcom extant -- yes, even, perhaps, bettering Mary Tyler Moore's Chuckles Bites the Dust.

 

[mhardy6647]

... and, just a bit later, hormones and tom turkeys produce the traditional result.

 

[Mikig]

Nel caso in cui non hai mai visto volare un tacchino

no, I've never seen it fly in my area!!

 

[Fahzz]

ahem. back to some biology.

In case you've never seen a turkey fly -- and your understanding of turkey aerodynamics was informed solely by the "Turkey Drop" episode of WKRP in Cincinnati*.

Yes, Les, real turkeys can fly.







_______________
*Perhaps the best half-hour of classic American TV sitcom extant -- yes, even, perhaps, bettering Mary Tyler Moore's Chuckles Bites the Dust.

Sacks of wet cement...

 

[mhardy6647]

Sacks of wet cement...

Oh, the humanity!

 

[nobodynoz]

South of France, by the Riviera...

 

[guy48065]

Old dog learns new tricks.

 

[caught gesture]

Wild white garlic & bee. Iphone

 

[caught gesture]

Cabbage white on white garlic flowers.

 

[mhardy6647]

After an extremely mild winter here in New Hampshire -- spring brought us 22 inches (ca. 56 cm) of snow yesterday.
yesterday:


today:

 

[Doodski]

@mhardy A skiers delight. I wish we could get some precipitation because the reservoirs are <~70%. Not good and the aquifers rely on decades of rain to replenish or more... They are depleted from farming intensity.

 

[mhardy6647]

It was powder (mostly) and today was gorgeous!

 

[Keith_W]

Byron Bay lighthouse lookout. It was a pretty crappy day with awful weather when I visited. I could not get very decent photos, so I tried a technique called ICM (intentional camera movement). ISO 100, f/4, shutter speed 1.5s, and camera shaken during the exposure. It produces a nice painterly effect. I have seen much better examples of ICM, but this was the first time I tried it.

Here is another shot of the lighthouse but without ICM. This one was at f/1.4. The lens vignettes a lot wide open, but to me it adds to the atmosphere and focuses the eye on the lighthouse.

 

[nobodynoz]

Do you drink wine ? I do every day since I was 10 year old.

€17.2 billion in exports of French wines and spirits in 2023...
Wines and spirits stand out among the flagships of French foreign trade in 2023. According to figures published by the FEVS (Federation of Wine and Spirits Exporters), on February 14, 2023, the record amount of €17.2 billion in exports of French wines and spirits marks an increase of +10.8% compared to 2022.