Stereo amplifier question about AB switch and some bonus questions

[Audioordeal]

Hello, new member, bear with me and thank you in advance for your time and comments.

I bought my first stereo amplifier Yamaha A-S501 and ELAC Debut 2.0 B5.2 Bookshelf Speakers and so far I'm not impressed by these highly praised budget speakers, but that might be a separate thread since I'm still testing them.

I have a few questions about the amplifier usage that might be silly but can't seem to find answers easily.

1. Amplifier has a switch to use an additional set of speakers and I would like to compare my previous speakers with it. Switch has three options A, B or A+B. My question is can I use the switch while the amplifier is turned on and music is playing and can I freely switch between A and B speakers to compare them every few seconds or can this damage the amplifier?

2. Can turning treble, bass and balance knobs quickly somehow damage amplifier?

3. Amplifier goes to standby after 8 hours (that function can be switched off). Is it best to use the remote on/off button so that amplifier goes to standby mode without pressing the physical on/off button on the device and powering it off completely (power cycling daily)? Or would it be better to just leave it on all the time and waste some electricity.

4. Is it true that one should never turn on the amplifier if there are no speakers connected? I assume same goes for using the AB switch if there isn't a second pair of speakers connected.

Thank you for any recommendations and have a great day.

 

[8th-note]

1. You can use any options on on the speaker selector switch when the amp is running. The main thing is to always have the volume at a low level when you are switching. There could be a thump or some sort of short term signal when a new selection is engaged and you don't want to take any risk that it could damage your speakers. It's likely that your Yamaha will produce no transients when you switch speakers.

2. Turning the tone or balance knobs quickly won't damage your amplifier.

3. I would always put your amp in standby when you are not listening to it. There's no reason to leave it on. When you turn it on you might try a test to see if the amp sounds the same immediately after turn-on vs. 15 minutes later. I would bet that it will sound the same.

4. There is no problem turning an amp on if there are no speakers connected but DO NOT connect speaker terminals to the amp when it is running. Always do any connections to any piece of gear with it turned off - this goes for RCA cables too. They can make a buzz when partially connected. When you turn the amp back on make sure the volume control is set to zero and slowly turn it up in case something is amiss. In fact, it is a good idea to set the volume to zero every time you turn your amp off and check to make sure that the volume is low or zero before you engage any source component. Sticky little fingers or other gremlins could have messed with the volume control while you were away and you don't want to blast your speakers when you start playing music.

A modern amp like your Yamaha is pretty much bulletproof. Unless you do something really dumb like short the speaker terminals it's going to be very forgiving of how you work the controls. You can switch sources, switch speakers, mess with the tone controls, and utilized every other function with the amp running without a problem. Just have the volume turned down to a low level and you will be fine.

 

[somebodyelse]

On 4. some valve amps will blow a fuse if you try turning them on without speakers or a dummy load connected. That may be where this idea comes from.

 

[Audioordeal]

1. You can use any options on on the speaker selector switch when the amp is running. The main thing is to always have the volume at a low level when you are switching. There could be a thump or some sort of short term signal when a new selection is engaged and you don't want to take any risk that it could damage your speakers. It's likely that your Yamaha will produce no transients when you switch speakers.

2. Turning the tone or balance knobs quickly won't damage your amplifier.

3. I would always put your amp in standby when you are not listening to it. There's no reason to leave it on. When you turn it on you might try a test to see if the amp sounds the same immediately after turn-on vs. 15 minutes later. I would bet that it will sound the same.

4. There is no problem turning an amp on if there are no speakers connected but DO NOT connect speaker terminals to the amp when it is running. Always do any connections to any piece of gear with it turned off - this goes for RCA cables too. They can make a buzz when partially connected. When you turn the amp back on make sure the volume control is set to zero and slowly turn it up in case something is amiss. In fact, it is a good idea to set the volume to zero every time you turn your amp off and check to make sure that the volume is low or zero before you engage any source component. Sticky little fingers or other gremlins could have messed with the volume control while you were away and you don't want to blast your speakers when you start playing music.

A modern amp like your Yamaha is pretty much bulletproof. Unless you do something really dumb like short the speaker terminals it's going to be very forgiving of how you work the controls. You can switch sources, switch speakers, mess with the tone controls, and utilized every other function with the amp running without a problem. Just have the volume turned down to a low level and you will be fine.

1. You can use any options on on the speaker selector switch when the amp is running. The main thing is to always have the volume at a low level when you are switching. There could be a thump or some sort of short term signal when a new selection is engaged and you don't want to take any risk that it could damage your speakers. It's likely that your Yamaha will produce no transients when you switch speakers.

2. Turning the tone or balance knobs quickly won't damage your amplifier.

3. I would always put your amp in standby when you are not listening to it. There's no reason to leave it on. When you turn it on you might try a test to see if the amp sounds the same immediately after turn-on vs. 15 minutes later. I would bet that it will sound the same.

4. There is no problem turning an amp on if there are no speakers connected but DO NOT connect speaker terminals to the amp when it is running. Always do any connections to any piece of gear with it turned off - this goes for RCA cables too. They can make a buzz when partially connected. When you turn the amp back on make sure the volume control is set to zero and slowly turn it up in case something is amiss. In fact, it is a good idea to set the volume to zero every time you turn your amp off and check to make sure that the volume is low or zero before you engage any source component. Sticky little fingers or other gremlins could have messed with the volume control while you were away and you don't want to blast your speakers when you start playing music.

A modern amp like your Yamaha is pretty much bulletproof. Unless you do something really dumb like short the speaker terminals it's going to be very forgiving of how you work the controls. You can switch sources, switch speakers, mess with the tone controls, and utilized every other function with the amp running without a problem. Just have the volume turned down to a low level and you will be fine.

@8th-note thank you for taking the time to answer all my questions, much appreciated.

I'm aware that volume from different sources can differ I was testing the system yesterday and there was even difference in volume on same computer when switching from digital to analog but thank you for pointing it out. I don't have children but I wouldn't be surprised if cats decided to turn the knob one day, one has even auquired taste for cables on my 3D printer and they have to be supervised constantly.

I did the test that you mentioned and didn't hear any difference 15 minutes later, sometimes it is quite hard to hear the difference even immediately after changing settings so I'm not surprised it seemed to sound the same.

Thank you for the heads up about RCA cables... can I connect them when the amp is in standby mode or does it have to be completely off... I understand it's better to be safe than sorry and I plan to figure out what works best and leave it, just wanted to ask, my guess is that it could be ok to connect if it is in standby?

Thank you for reassuring words about amps being bulletproof just trying to educate myself and prevent any damage and many things aren't mentioned in manuals and common sense is not so common.

I'm still figuring this out and speakers are decent but they sounded too boomy. Slowly getting there, looks like it had to do with connections and computer settings... I wish it was more plug and play but I'll figure it out. My 10-15 years old 5.1 system that was around 150€ sounded better at first and connecting mobile phone also produced better sound than my PC but I'm slowly figuring it out.

I have a feeling I'll buy and test other speakers and sub soon and most likely invest in USB DAC to bypass computer or just use analog RCA. Went from 5.1 to stereo so that it would be easier than buying AVR and there are still some hurdles to overcome.

Thanks again, hopefully this thread also helps others with same questions. Have a great day

 

[Audioordeal]

On 4. some valve amps will blow a fuse if you try turning them on without speakers or a dummy load connected. That may be where this idea comes from.

 

[Audioordeal]

You are correct I kept getting answers about valve amps and couldn't find the answer about the type of amp I use... better safe than sorry.

Thank you for your comment and pointing that out for any unaware valve amp users.

 

[somebodyelse]

Boominess may be as much about the room and the placement of the speakers as the speakers themselves, or an unfortunate combination of a room mode with the response peak a little over 100Hz.

Erin's review noted a step in frequency response that made the speakers sound 'wrong', but the good directivity meant it could be easily corrected with EQ. If you're lucky the Yamaha's treble control will work at about the same frequency. If not there are software solutions for PC and phone that could do it, and should be able to help with boom too. Won't be much help if you're using other sources though.

 

[8th-note]

You should be fine to hook up cables when the amp is on standby. I have a Krell preamp that has no on/off control (if it's plugged in it's on) and I just make sure I depress the mute button if I change connections.

You mention getting a DAC and I wanted to say that it's really important to use good electrical hygene when messing around with digital sources. I blew out one of the woofers in my Thiel CS6 speakers when I tried hooking up my Denon blu-ray player to my DAC. I didn't have the mute button pressed and the volume was at a moderate level. I got a blast of digital hash which cost me several hundred dollars to have the woofer rebuilt.

 

[Audioordeal]

Boominess may be as much about the room and the placement of the speakers as the speakers themselves, or an unfortunate combination of a room mode with the response peak a little over 100Hz.

Erin's review noted a step in frequency response that made the speakers sound 'wrong', but the good directivity meant it could be easily corrected with EQ. If you're lucky the Yamaha's treble control will work at about the same frequency. If not there are software solutions for PC and phone that could do it, and should be able to help with boom too. Won't be much help if you're using other sources though.

The boominess is most likely due to pc settings, bad motherboard audio, bad tosslink, the digital optical connection seems the worst of the things I tested so far. Looks like I'll have to buy a decent USB DAC to bypas integrated audio and even then success is not guaranteed. Shame that when I connect phone to amp it gives better results than my upper midrange mobo/pc. All very dissapointing but at least I had something to compare it to and I figured out something isn't right because my worst nightmare would be to use something for a decade and than figure out it could be better all that time. My audio ordeal is not over yet.

 

[Audioordeal]

You should be fine to hook up cables when the amp is on standby. I have a Krell preamp that has no on/off control (if it's plugged in it's on) and I just make sure I depress the mute button if I change connections.

You mention getting a DAC and I wanted to say that it's really important to use good electrical hygene when messing around with digital sources. I blew out one of the woofers in my Thiel CS6 speakers when I tried hooking up my Denon blu-ray player to my DAC. I didn't have the mute button pressed and the volume was at a moderate level. I got a blast of digital hash which cost me several hundred dollars to have the woofer rebuilt.

Thank you for answer about the standby and for pointing the danger of digital sources and sorry for your loss. Looks like my computers audio is far from decent and I'm looking into USB DAC to bypass all this Windows shenanigans, but there are new hurdles on the horizon such as Windows volume control, USB interference etc. Went stereo to have less hurdles but it's not as simple as I hoped. Thanks again for solving pieces of this puzzle.

 

[antcollinet]

The boominess is most likely due to pc settings,

Pretty unlikely. Much more likely to be a room mode causing a high bass peak. This might be mitigable by speaker positioning, or might need room treatment or EQ to resolve.

bad motherboard audio, bad tosslink,

No, nothing to do with boominess.

the digital optical connection seems the worst of the things I tested so far. Looks like I'll have to buy a decent USB DAC

There will be no audible difference between USB and TOSLINK unless one is failing to work properly - and then you'll get gross effects such as pops / clicks / crackling hiss. If you are not hearing those, or similar then the connections will be audibly identical.

Doesn't mean you are not hearing a difference, but any difference won't be coming out of the audio system.