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Dirty Power

#61
WayneP said:
Mike,

White noise / hiss will not be related to any electrical service issue. More commonly, it’s simply because the equipment in question has poor background noise characteristics.

The relevant specification for electronic gear is signal-to-noise (aka S/N) ratio. I looked up the specs for your KRK speakers, as well as Ampeg’s bass amps, and they don’t even publish S/N figures. That can often be a red flag.

It’s not uncommon for bass amps or combos not to have the greatest noise properties, but fortunately it’s typically not an issue on stage in a live performance setting.

But for studio or recording work, noise gets to be an issue. Thus it’s always a red flag when I see that any gear I’m considering doesn’t show a noise spec.

Typically, the only solution for a noisy component is to replace it with something better. Often this will require an upgrade in budget.

Manufacturers use different reference guidelines for S/N specs, but I like to see dBA figures in the 100 dB range, and dBU figures in the 90 dB range. Typically gear with those figures should be adequately quiet.

Regards,
Wayne A. Pflughaupt

Pedulla Club #45 Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Administrator, Official Tobias Club #133
Administrator, Fretless Club #943
Big Cabs Club #23
My Basses
My Rig: Stage and FOH Friendly
Pedulla Club #45
Click to expand...
I don't think you will find any bass amp with a broad band S/N ratio of 90-100dB. In fact, that would be typical of an average mixing console. It also depends on how the ratio is defined, if you change the definition, you can change the ratio without changing the actual noise floor.

dBu has nothing to do with noise, it's just a measurement of voltage in dB relative to 0.775V

This is exactly why many manufacturers don't provide any noise measurement data, it's too often mis-interpreted by folks who don't know what they are talking about.
 
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#62
WayneP said:
Mike,

White noise / hiss will not be related to any electrical service issue. More commonly, it’s simply because the equipment in question has poor background noise characteristics.

The relevant specification for electronic gear is signal-to-noise (aka S/N) ratio. I looked up the specs for your KRK speakers, as well as Ampeg’s bass amps, and they don’t even publish S/N figures.

It’s not uncommon for bass amps or combos not to have the greatest noise properties, but fortunately it’s typically not an issue on stage in a live performance setting.

But for studio or recording work, noise gets to be an issue. Thus it’s always a red flag when I see that any gear I’m considering doesn’t show a noise spec.

Typically, the only solution for a noisy component is to replace it with something better. Often this will require an upgrade in budget.

Manufacturers use different reference guidelines for S/N specs, but I like to see dBA figures in the 100 dB range, and dBU figures in the 90 dB range. Typically gear with those figures should be adequately quiet.

Regards,
Wayne A. Pflughaupt

Pedulla Club #45 Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Administrator, Official Tobias Club #133
Administrator, Fretless Club #943
Big Cabs Club #23
My Basses
My Rig: Stage and FOH Friendly
Pedulla Club #45
Click to expand...
The old and new SVT have -80 dB signal to noise ratio.

[Invalid or Expired Link Removed]

[Invalid or Expired Link Removed]

Old V4 (80 dB): [Invalid or Expired Link Removed]

V4BH (80): https://ampeg.com/pdf/V4BH.pdf

V4B reissue (80): https://ampeg.com/data/6/0a020a41e58d5e0b91edd46ce/application/pdf/Owner’s Manual - English .pdf

For other tube amps, I don’t know but going with my ears, my Traynor YBA-3 and Ampeg B18N are probably in the 70-80 dB range, probably more near 80 than 70 but I don’t have the test gear to prove it.

In the DAW realm, modern audio interfaces are usually in the 100 dB range. Example:

https://d1aeri3ty3izns.cloudfront.net/media/6/60816/download_60816.pdf
 
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#63
The other thing to remember about most signal to noise ratio measurements is that they are assumed to be based on voltage and not power. There is a factor of two difference between voltage and power on the dB scale due to the squared term in the power equation.
 
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#64
agedhorse said:
A "surge protector" like that won't do a thing related to the situation you describe. It also won't do anything regarding your high line voltage. It might catch on fire however if is does not have a safety certification to UL 1449. Unfortunately, this is not an uncommon scenario.
Click to expand...

In addition I am lead to believe that you are supposed to replace these devices after a certain number of hits ?
In the UK you can get devices that fit in the consumer unit. They are expensive and some have indicators to tell you replacement is due. I have no personal experience with these.
 
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#67
agedhorse said:
A "surge protector" like that won't do a thing related to the situation you describe. It also won't do anything regarding your high line voltage. It might catch on fire however if is does not have a safety certification to UL 1449. Unfortunately, this is not an uncommon scenario.
Click to expand...
I’m guessing that you do not approve of running anything between supplied power and any devices- a board, an amp, whatever may be. You’re an engineer. I defer to your considerable experience in this realm, as you’ve likely forgotten more than I think I know here. I can barely wait until the day we move from this house. It mocks me. Weird stuff keeps happening here, power aside. Getting back to the AC215A, are you aware of any issues with this unit? Does it comply with UL 1449? If not, I have no problem with sending it back unopened, and am grateful you pointed this shortcoming out- TIA…
 
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#68
Forgive me if this has already been asked... have you checked your mains (power from the wall) with an outlet tester?

If there's a problem there it could cause noise and also be dangerous.

You can get them at a hardware store or home depot/lowes/amazon.

If that goes okay, yeah, get rid of the dimmers. I can't have them in the same area as my gear.
 
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#69
You have a tube amp. Tubes emit noise as well as amplify or otherwise process the signal chain, even the so-called "hi-fi" or "low-noise" tubes. You may have an older tube amp where the filter capacitors are dying, or at least are not at their peak performance, which can cause hum. Your speakers have a tweeter, which functions in the sonic range of the hiss, which was never perceived as a problem until bass cabinets started including tweeters, because the hiss was at the top end where the roll-off happens, if not beyond, the frequency range of the main driver, rendering any hiss inaudible. Welcome to the wonderful world of bass guitar amplification. These are facts of life.
 
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#70
Drredplate said:
In addition I am lead to believe that you are supposed to replace these devices after a certain number of hits ?
In the UK you can get devices that fit in the consumer unit. They are expensive and some have indicators to tell you replacement is due. I have no personal experience with these.
Click to expand...
It depends on the unit's construction and robustness. There are industrial versions, but they are build differently. Hit hard enough with a voltage spike long enough, all it takes is a single hit to fail. This is the danger of lightning storms.

WayneP said:
Correct - sorry about that, I was up way too early this morning! With the "u" I meant "unweighted," but it's usually just stated as " dB unweighted," not dBu.
Click to expand...

Still, you aren't going to find a bass amp with 100dB S/N ratio, I would expect about 80dB unweighted is about as good as it gets and that's 10 times the noise floor you are hoping for.

Gorilla Monsoon said:
I’m guessing that you do not approve of running anything between supplied power and any devices- a board, an amp, whatever may be. You’re an engineer. I defer to your considerable experience in this realm, as you’ve likely forgotten more than I think I know here. I can barely wait until the day we move from this house. It mocks me. Weird stuff keeps happening here, power aside. Getting back to the AC215A, are you aware of any issues with this unit? Does it comply with UL 1449? If not, I have no problem with sending it back unopened, and am grateful you pointed this shortcoming out- TIA…
Click to expand...
Generally I do not because I find that often the devices cause problems rather than solve them. There are rare cases where they can help, but those are where there is specific high frequency noise on the line and the ground is clean/solid.

According to the docs it's listed (a good thing) but they do not state what standard it's listed to (nor is it screen printed on the unit itself in the photos I have seen) . There is a separate listing for "power strips" and "surge protectors".

upload_2023-4-19_20-2-54.png
 
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#71
agedhorse said:
It depends on the unit's construction and robustness. There are industrial versions, but they are build differently. Hit hard enough with a voltage spike long enough, all it takes is a single hit to fail. This is the danger of lightning storms.



Still, you aren't going to find a bass amp with 100dB S/N ratio, I would expect about 80dB unweighted is about as good as it gets and that's 10 times the noise floor you are hoping for.


Generally I do not because I find that often the devices cause problems rather than solve them. There are rare cases where they can help, but those are where there is specific high frequency noise on the line and the ground is clean/solid.

According to the docs it's listed (a good thing) but they do not state what standard it's listed to (nor is it screen printed on the unit itself in the photos I have seen) . There is a separate listing for "power strips" and "surge protectors".

View attachment 5036876
Click to expand...
Thank you. I looked at UL 1499, and as it applies in the case of this device, as long as it has one non-linear component and the device is capable of repeating the ability to divert or limit surge current(2.48) and as a Type 3 Point of Utilization device it must be used with a minimum conductor length of 10 meters- (30 feet). I’m not sure what constitutes a non-linear component, but there is a ferrite ring and a big capacitor in the picture I saw of the guts of the thing. I’m guessing this thing is good up to 30 feet from the box?
 
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#72
A non-linear component is a device like an MOV, TVS or gas discharge tube.

Minimum conductor length indicates that a minimum source impedance to the surge protector is necessary to limit peak current during a voltage spike event.

These are specific to surge protectors, different classes of protector have different requirements.
 
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#73
agedhorse said:
A non-linear component is a device like an MOV, TVS or gas discharge tube.

Minimum conductor length indicates that a minimum source impedance to the surge protector is necessary to limit peak current during a voltage spike event.

These are specific to surge protectors, different classes of protector have different requirements.
Click to expand...
There is a shot of the innards of the 215A on Furman’s site and I can’t copy it, but there is a module they call Extreme Voltage Protection that shuts down in extremes. God knows what’s in it, but adjacent to it looks like what may be a diode, perhaps a Transient Voltage Suppression diode, and on the other side of the module there appears to be a Metal Oxide Varistor, at least it resembles some of the ones on the Littelfuse site.
 
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#74
My house is old, made just a few years after New Mexico entered statehood. My quite wiring unfortunately is on the outside buildings.

But you may just be sensitive to hiss. Even in pro studios, you can hear hiss if you get close to the monitors, but becomes a non issue once the session starts. You hear if usually when you come in first thing and ear fatigue in the evening, you don't hear any. That is why the power supplies for the consoles and tube mics are in another room

What helped is my music room which also doubles as my home office on the part of the house with old wiring is that I also have a UPS + power conditioner , a good one from APC. My buddy also gave a server grade UPS for our living room and that helped a lot. I also have a tube stereo power amp (a rare Mesa ). My wife loves that system and she spins vinyl on that, nowadays a mid grade DAC for streaming and digital sources is 90% of the music we listen to
 
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#76
WayneP said:
Mike,

White noise / hiss will not be related to any electrical service issue. More commonly, it’s simply because the equipment in question has poor background noise characteristics.

The relevant specification for electronic gear is signal-to-noise (aka S/N) ratio. I looked up the specs for your KRK speakers, as well as Ampeg’s bass amps, and they don’t even publish S/N figures.

It’s not uncommon for bass amps or combos not to have the greatest noise properties, but fortunately it’s typically not an issue on stage in a live performance setting.

But for studio or recording work, noise gets to be an issue. Thus it’s always a red flag when I see that any gear I’m considering doesn’t show a noise spec.

Typically, the only solution for a noisy component is to replace it with something better. Often this will require an upgrade in budget.

Manufacturers use different reference guidelines for S/N specs, but I like to see dBA figures in the 100 dB range, and dBU figures in the 90 dB range. Typically gear with those figures should be adequately quiet.

Regards,
Wayne A. Pflughaupt

Pedulla Club #45 Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Administrator, Official Tobias Club #133
Administrator, Fretless Club #943
Big Cabs Club #23
My Basses
My Rig: Stage and FOH Friendly
Pedulla Club #45
Click to expand...
Understood mate, thanks. It’s ok, as long as my equipment isn’t broken, then it’s something I can learn to deal with. My Ampeg in particular offers me too much towards the sound that I like to part with it. It’s at a tech having a once over and potential re-bias to make sure it’s in top condition at the moment. Appreciate the response though.
 
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#78
agedhorse said:
Still, you aren't going to find a bass amp with 100dB S/N ratio, I would expect about 80dB unweighted is about as good as it gets and that's 10 times the noise floor you are hoping for.
Click to expand...
Paragraph 3 from my post:

It’s not uncommon for bass amps or combos not to have the greatest noise properties…
Click to expand...

The section stating figures was referring to recording equipment.

Regards,
Wayne A. Pflughaupt

Pedulla Club #45 Unique Arrangements of Hymns, P&W Standards, and Original Tunes
Administrator, Official Tobias Club #133
Administrator, Fretless Club #943
Big Cabs Club #23
My Basses
My Rig: Stage and FOH Friendly
Pedulla Club #45
 
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#79
Power strips ect. using MOV's can start to cause noise if the MOV has taken a few hits but has not been blown up.

Hiss is a gain structure issue and or the S/N of the equipment itself.
Buzz and hum can be a many other issues or combinations of.

There are few exceptions but most of you "power conditioners" are not doing much more than giving you a convenient place to plug things in.
Some have low and high voltage shut down and are some true voltage regulators. Then there are UPS back up units.
 
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#80
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