Amplifier Hummmmmmm

inspiredsports

aboroth00 wrote: »

I'm not so sure about the CATV filter, not to be confused with actual power conditioners. But typically power conditioners do not help with ground loop hums which is what I meant

Got it. Agreed, the AC side alone will not help with ground loop hum. Most of the higher cost conditioners have a feature to filter the cable.

aboroth00

inspiredsports wrote: »

Got it. Agreed, the AC side alone will not help with ground loop hum. Most of the higher cost conditioners have a feature to filter the cable.

Yeap, I have the panamax 4300ex and the apc h10 which both have CATV filters. However, i agree with the poster above that it does rob signal strength and in some cases can add voltage to the line.

heiney9

jinjuku wrote: »

You don't need a power conditioner for the amp because it already has it's own conditioner designed into it.

Some do, the inexpensive amps, some don't, the expensive ones. Pretty general quote that is mostly incorrect.

And I believe you are referring to "regulated" which can be different than "conditioned"

H9

aboroth00

heiney9 wrote: »

Some do, the inexpensive amps, some don't, the expensive ones. Pretty general quote that is mostly incorrect.

And I believe you are referring to "regulated" which can be different than "conditioned"

H9

Typically power amps are neither regulated or conditioned. Usually these would limit current and would be counter-productive to the design of the amplifier. However some power amps have an internal ground and surge protection.

As for the benefits of regulating voltage or conditioning the amp, there are arguments on either side. As for conditioning, i'm not even sure what that word means, reduced RF interference, making sure the current is something something. It just seems like a general term to make your equipment better!

Janne

Have you tried using optical connections between your gear. I have a PC connected and it was humming and making noise until I got it connected with an optical cable. Using cheater plugs is maybe not the best way of improving your home safety.......

inspiredsports

Janne wrote: »

Have you tried using optical connections between your gear. I have a PC connected and it was humming and making noise until I got it connected with an optical cable. Using cheater plugs is maybe not the best way of improving your home safety.......

Did you have it connected using USB or the sound card? (I've found this to be more prevalent with USB)

The way the internals of a PC are grounded, you will generally get hum when plugged in to 110 VAC or even using a power brick.

If the power cord is 3-prong, using a cheater plug (gray 3 to 2 grounding adapter) will generally solve your problem. If you have an external 3 prong monitor, etc. attached that has a 3-prong power cord, they will probably need a cheater plug too.

You are correct that fixing the ground loop problem is better than using cheater plugs.

Janne

inspiredsports wrote: »

Did you have it connected using USB or the sound card? (I've found this to be more prevalent with USB)

The way the internals of a PC are grounded, you will generally get hum when plugged in to 110 VAC or even using a power brick.

If the power cord is 3-prong, using a cheater plug (gray 3 to 2 grounding adapter) will generally solve your problem. If you have an external 3 prong monitor, etc. attached that has a 3-prong power cord, they will probably need a cheater plug too.

You are correct that fixing the ground loop problem is better than using cheater plugs.

It was connected through the sound card and the analog out. When I put in the optical it went dead quiet. You are right about PC grounding. I always seems to get a hit when my hands are a little moist.

inspiredsports

Janne wrote: »

It was connected through the sound card and the analog out. When I put in the optical it went dead quiet. You are right about PC grounding. I always seems to get a hit when my hands are a little moist.

Thanks,

I'm not big into digital yet and I use my laptop (docked to a keyboard, mouse and monitor) as my main computer. When my laptop was hooked to my DAC and then on the my preamp, especially with USB, the hum was horrible. A cheater plug on the both the laptop's power brick and extra monitor is the only way I've found to cure this as I don't have optical on this rig. I've been told USB is wired internally in such a way as this is unavoidable.

I guess my shock risk is less as the power brick notches down the potential and I am rarely touching the extra monitor, but I appreciate where you are coming from about grounding adapters.

All of my components and Cables and antennas are good, but my computer is the odd man out that needs this cheat.

OP's problems will probably be solved when he restores all proper grounds to his breaker box.

heiney9

aboroth00 wrote: »

Typically power amps are neither regulated or conditioned. Usually these would limit current and would be counter-productive to the design of the amplifier. However some power amps have an internal ground and surge protection.

Well, I'm not going to get into a big arguement, but this is exactly the reason inexpensive power amps and receivers are regulated. Typically power amps and receivers on the lower end of the scale ARE regulated. But it's up to the designer to decide where to cut corners in order to meet a price point.

H9

aboroth00

heiney9 wrote: »

Well, I'm not going to get into a big arguement, but this is exactly the reason inexpensive power amps and receivers are regulated. Typically power amps and receivers on the lower end of the scale ARE regulated. But it's up to the designer to decide where to cut corners in order to meet a price point.

H9

Sorry H9, there must've been some confusion. By regulation, I meant voltage regulation to stabilize the voltage. However, regulation and conditioning, are such general terms, that so many concepts fall under them.

How are inexpensive power amps and receivers regulated? The only things "regulating" my power amps are the fuses which are in the way of blowing it up.

I'm not quite sure what features on higher end amps you're talking about. But there seems to be quite a few exotic technology or concepts out there which CLAIM to improve sound.

jinjuku

heiney9 wrote: »

Some do, the inexpensive amps, some don't, the expensive ones. Pretty general quote that is mostly incorrect.

And I believe you are referring to "regulated" which can be different than "conditioned"

H9

We are talking about the 7605, correct? I believe that amp as a rather large transformer in it with a fairly stiff amount of capacitance.

heiney9

jinjuku wrote: »

We are talking about the 7605, correct? I believe that amp as a rather large transformer in it with a fairly stiff amount of capacitance.

It maybe "stiff", but in the owners manual it talks about the "custom torrid" for better power regulation...........that to me indicates the PS is regulated.

My Pass amp is unregulated meaning it must be "ultra stiff". I'm not poking fun at the Adcom or even saying it's a bad piece. It's very nice, and I'm a fan of Adcom. I'm just pointing out that most power supplies ARE regulated and in many instances, especially in receivers, one of the by products of a regulated power supply is also to allow for current limiting because the product isn't built to perform outside whatever that pre-determined threshold is.

My Adcom 545 had fuses for the rails but the PS was still regulated. I know for a fact Adcom's are over built and even though they have regulated power supplies they DO NOT have any current limiting except for the fuses.

I also agree there are a lot of variables in design and just because a PS is regulated doesn't mean it's bad or worse than an unregulated piece of gear. I was just simply pointing out many of the higer end amps (not all) seem to favor an unregulated power supply scheme.

Please don't read too much into it.

H9

aboroth00

heiney9 wrote: »

It maybe "stiff", but in the owners manual it talks about the "custom torrid" for better power regulation...........that to me indicates the PS is regulated.

My Pass amp is unregulated meaning it must be "ultra stiff". I'm not poking fun at the Adcom or even saying it's a bad piece. It's very nice, and I'm a fan of Adcom. I'm just pointing out that most power supplies ARE regulated and in many instances, especially in receivers, one of the by products of a regulated power supply is also to allow for current limiting because the product isn't built to perform outside whatever that pre-determined threshold is.

My Adcom 545 had fuses for the rails but the PS was still regulated. I know for a fact Adcom's are over built and even though they have regulated power supplies they DO NOT have any current limiting except for the fuses.

I also agree there are a lot of variables in design and just because a PS is regulated doesn't mean it's bad or worse than an unregulated piece of gear. I was just simply pointing out many of the higer end amps (not all) seem to favor an unregulated power supply scheme.

Please don't read too much into it.

H9

The difference between regulated Power supplies and unregulated power supplies have nothing to do with current limiting. The regulation is used here to deal with voltages. Fuses are pieces that regulate CURRENT, preventing too much current and blowing an amplifier.

A regulated power supply will "stiffly" regulate the the rail voltage with varying mains voltage. A unregulated PS is not "stiff" or "ultra-stiff" it is the opposite. There is no regulation.

In a linear regulated PS, it is important to regulate the voltage, and that's why the Adcom manual indicates it can do it so well. There is nothing wrong with regulated PS'. They are not inherently worse at doing their job. MOST amplifiers have regulated power supplies.

It is not necessarily true, that most "high end" solid-state amplifiers have unregulated power supplies. Levinson is an example of this.

heiney9

Ok, I'm not going to argue...........I didn't say all regulated supplies have current limiting. What I said some regulated supplies are used because they can be designed to limit current.

Anyway, I didn't mean to split so many hairs because there are all varieties of amps, some are regulated, some are unregulated. I've seen some high end amps that are both but I've never seen a lower end amp unregulated. There is a reason for that.

Anyway I'm done here as we're just talking in circles.

H9

aboroth00

heiney9 wrote: »

Ok, I'm not going to argue...........I didn't say all regulated supplies have current limiting. What I said some regulated supplies are used because they can be designed to limit current.

Anyway, I didn't mean to split so many hairs because there are all varieties of amps, some are regulated, some are unregulated. I've seen some high end amps that are both but I've never seen a lower end amp unregulated. There is a reason for that.

Anyway I'm done here as we're just talking in circles.

H9

I will say again, regulated supplies have NOTHING to do with current limiting. A protection circuit is used to protect too much current from going through the amp. Otherwise a regulated power supply will keep on chugging until the whole amp goes in smoke. The only other thing that limits current are again fuses.

I'm not too well versed on the topic, not being a physicist or an engineer. From my understanding an unregulated power supply will have a constant power draw, at any volume, being very inefficient. This constant power is deemed to be desirable as there is no voltage sag. The only problem with this design is that as current increases the voltage dips, the amp will not double its power in the half the impedance. A regulated PS can vary its rail voltage and regulate it despite varying main voltages, and is more efficient doing this.

Just because you only see a feature on a "high end" amp, doesn't mean it's necessarily better if that's what you're implying. Why are most lower end amps Class A/B? Because it's more efficient than class A amps, so we see it in the lower end spectrum almost exclusively. Nothing wrong with them.

heiney9

Ok I guess you want to continue to discuss. I stated not to read too much into my comments so NO.........I wasn't implying unregulated is better for every application. You do have it right that a "stiff" supply can (theoretically) double power into half impedance loads, but that doesn't tell the entire story and there is a downside.

fully regulated power supplies are "stiff" - this means that they will work up to a level and no more, period. They could make it easier to double the power into half the load, but they will not allow for dynamic power bursts much above the nominal rating.

To this day, I have heard only one product with fully regulated power supplies which sounded right (and then some!), and that is Levinson. All others of the same breed sounded very well defined but somehow shut in, too controlled for my liking. And their prices and sizes were, well, generous. opinion of the author, not my opinion.

What happens is briefly this - with regulators, we want to decrease the voltage as much as we can to keep our regulator transistors well within their Safe Operating Area (SOAR), but above the absolute necessity.
If we have a say 50W/8 Ohm output, that requires 28.3V peak voltage, so we'll very likely regulate at say 32V. However, in case of unregulated power supplies, our lines will be say 34V at peak output, rising to say 36-38V off load. Working backwards, our regulated amp will start to clip at 32V, minus voltage drops on amplifier transistors (say 1.3 V for driver and output stage), which is 30.7V, or 59.2W/8 Ohms. In case of unregulated supplies, assuming good dimensioning, our voltage will drop only 1-2V below off load voltage because the capacitors will supply short term power, which will allow us an output of (38-2-1.3) 34.7V, or 75.7W/8 Ohms.

When the load is halved, i.e. when it is 4 Ohms, a regulated power supply will allow double the power (assuming it's designed to do so), but with the same limitations as above. Typically, it will start to limit available current at loads below 4 Ohms, while a capacitor smoothed one will also do so, but to a much lesser extent, at least in peaks.

full voltage regulation should be applied to all stages of a power amplifier except the driver and final output stages, which for the sake of dynamics, especially into difficult loads, and economy, should be kept on capacitor smoothed supplies.

This explains better than I ever could.

H9

P.s. Again I'm not arguing superiority. There is a lot more to the design of the power supply. Unregulated has it's advantages as does regulated.

heiney9

In case of unregulated supplies, assuming good dimensioning

This is the reason why receivers and inexpensive amps are regulated. They don't have the proper "hardware" to allow for the capabilities an unregulated supply could demand. It takes larger chassis, more heat sinking and a larger transformer(s). In the case of a receiver not only is cost an issue but space is at a premium. In an amp cost is the main consideration.

The Levinson is a special case.

H9

ben62670

The Adcom's are not regulated power supllies. They are straight up transformer to rectifier to caps. No regulaters in them.

heiney9

ben62670 wrote: »

The Adcom's are not regulated power supllies. They are straight up transformer to rectifier to caps. No regulaters in them.

The older 2 channel aren't regulated but the newer multi-channel appear to be, but they could only be partially regulated.

In hindsight I'm really sorry I brought this up, because I do agree with aboroth00, the terms are used very generally and it's not right to assume things based on general terms. There are several stages to a power supply and it's impossible to really assess anything with out a schematic and a specific model in mind.

H9

aboroth00

Yeap... didn't mean to argue anything just clarifying the details. These terms as I said earlier, are very general and it can be easily confused.

As for regulated vs unregulated, it's one of those audio things again where one isn't necessarily better than the other. Implementation, Caps, rectifiers, and many other factors contribute to the amp that H9 had accurately put.

As for amp vs amp, let your ears steer you! Watts, current, voltages aside.

FTGV

Typically and regardless of price point DC voltage regulation is usually reservered for the input and voltage gain stages of an amplifier.Extending the regulation to the output stage adds considerably to the cost and complexity( not mention the questionable benifits)therefore it is rarely seen except in some very hi end products .Outside of DIY I'm sure there are others but I'm only aware of Krell and according to the quote above Levinson apparently has used this approach.

FTGV

heiney9 wrote: »

My Adcom 545 had fuses for the rails but the PS was still regulated

heiney9 wrote: »

The older 2 channel aren't regulated

heiney9 wrote: »

This is the reason why receivers and inexpensive amps are regulated. They don't have the proper "hardware" to allow for the capabilities an unregulated supply could demand.

Actually for cost reasons the opposite is true and regulation will be limited to the input/voltage gain and preamp stages in the case of the reciever or int amp.

heiney9

Yeah, Fred I did a pretty good job of confusing the issue, even in my own mind. :redface:

As far as the Adcom's...............just quoting literature and I am assuming they mean the input and voltage gain stages not the output.

H9

jinjuku

Extron has a nice white paper on regulated supplies in amplifiers. Check it out.

heiney9

jinjuku wrote: »

Extron has a nice white paper on regulated supplies in amplifiers. Check it out.

read it already

leftwinger57

I too just experienced a hum that I never had. I moved my rack and it went away, then returning to it's right position the hum came back. I found out that the culpret was a plug strip that looks like a conditioner but it 's just a better ac distribution platform. This was somehow touching the heat sinks on my Adcom and after raising it off the unit the hum was gone.....lw