How many speakers from small amp?

[Sounds Good]

I picked up a 50w SMSL SA50 amp to power a set of patio speakers.

I was reading the manual and Amazons description and noticed under specs it's kind of confusing on the amount of speakers it will power?

Do you think it would be ok to also hook up a set of inwall speaker in my upstairs hallway through a impedance matched volume control?

 

[TLS Guy]

I picked up a 50w SMSL SA50 amp to power a set of patio speakers.

I was reading the manual and Amazons description and noticed under specs it's kind of confusing on the amount of speakers it will power?

Do you think it would be ok to also hook up a set of inwall speaker in my upstairs hallway through a impedance matched volume control?

You have a Bridged Load amp. We have not had this question before.

You will have to be careful. Normally you can common negatives, but not positives on the load.

I have looked at quite a few circuits of impedance matching stereo controls and they do common the negative, and this would blow up your amp.

I suspect you can only drive one stereo pair with this amp.

My advice is to get a meter, and test the control. If there is continuity between the speaker negatives and or the case you can not use that control with that amp without a disaster.

 

[Sounds Good]

After reading and rereading many times it sounds like it means one pair per posts, meaning pair as one + and one -. So total would be one pair of speakers.

I hooked it to the impedance matched volume control for my hallway and it works great! So I don't think that will be an issue...

Ill prob just play it safe and order a speaker selector.

 

[TLS Guy]

After reading and rereading many times it sounds like it means one pair per posts, meaning pair as one + and one -. So total would be one pair of speakers.

I hooked it to the impedance matched volume control for my hallway and it works great! So I don't think that will be an issue...

Ill prob just play it safe and order a speaker selector.

You lucked out! That control obviously does not sum the grounds, if it did your amp would be toast long ago, instantly on switch on in fact.

 

[highfigh]

You lucked out! That control obviously does not sum the grounds, if it did your amp would be toast long ago, instantly on switch on in fact.

What brands if controls are you referring to? I don't think I have ever seen one that uses common negative, although I didn't check the ones we used in the late-'80s and most solid state amps wouldn't have a problem with that, anyway. Obviously, it doesn't mean it would work with all amplifiers. I just did some repair work at a restaurant and the control uses auto-transformers; when I measured continuity between the Negative terminals, it was open. I don't usually use the resistive type.

 

[highfigh]

I picked up a 50w SMSL SA50 amp to power a set of patio speakers.

I was reading the manual and Amazons description and noticed under specs it's kind of confusing on the amount of speakers it will power?

Do you think it would be ok to also hook up a set of inwall speaker in my upstairs hallway through a impedance matched volume control?

Are you using that amp to save space? If not, I would recommend using something else, that's made for this application.

One example is the AudioSource AMP-100, which has two sets of speaker terminals, an input level control with channel balance, auto turn-on with Input 2 having priority over Input 1 and it's not much more than $120. It's not tremendously powerful, but it works- I have used their amps and haven't had any kind of problems.

Do you think you might add more speakers in the future?

 

[TLS Guy]

What brands if controls are you referring to? I don't think I have ever seen one that uses common negative, although I didn't check the ones we used in the late-'80s and most solid state amps wouldn't have a problem with that, anyway. Obviously, it doesn't mean it would work with all amplifiers. I just did some repair work at a restaurant and the control uses auto-transformers; when I measured continuity between the Negative terminals, it was open. I don't usually use the resistive type.

I did not look at brands. I looked at some impedance matching auto transformer circuits and some have the negs bonded.

We have not had this issue before to my knowledge.

There are not quite a few chip amp devices that can be bridged. The reason is that one chip can be a stereo amp or two can be a more powerful stereo amp. This is recent.

In the normal situation there is no reason not to common the negatives since in the vast majority of amps the negative is at ground plane.

May be these control manufacturers have taken these developments on board, but I would bet not all have.

So if you have an amp using bridged chip amps, you had better be careful what you connect it to and check for connected commons.

Obviously this has been an issue, because of the amp manufacturers warning.

 

[slipperybidness]

I did not look at brands. I looked at some impedance matching auto transformer circuits and some have the negs bonded.

We have not had this issue before to my knowledge.

There are not quite a few chip amp devices that can be bridged. The reason is that one chip can be a stereo amp or two can be a more powerful stereo amp. This is recent.

In the normal situation there is no reason not to common the negatives since in the vast majority of amps the negative is at ground plane.

May be these control manufacturers have taken these developments on board, but I would bet not all have.

So if you have an amp using bridged chip amps, you had better be careful what you connect it to and check for connected commons.

Obviously this has been an issue, because of the amp manufacturers warning.

As you know, I'm currently working on paralleled chip amp. Reading the datasheets on that LM4780 chip, it states that you can "parallel as many as needed to drive the intended load".

Those chips can also be bridged, but suffer same problems of other bridged amps.

 

[TLS Guy]

As you know, I'm currently working on paralleled chip amp. Reading the datasheets on that LM4780 chip, it states that you can "parallel as many as needed to drive the intended load".

Those chips can also be bridged, but suffer same problems of other bridged amps.

Your chip amps can be parallel bridged, which is unusual. In your case joining the negatives would not be an issue.

However the class D amps in the OPs amp must be the usual floating load bridge. So if the negs were joined it would no longer be floating load, with instant disastrous results!

So we now have another area of confusion with a big snake pit, as if we don't have enough already.

 

[lsiberian]

I think it should be pointed out that bridging an amp only gives you at most a 3db gain in output and a lot more risks. I won't bridge amps because in my view the gains are not significant enough to warrant the risks.

 

[TLS Guy]

I think it should be pointed out that bridging an amp only gives you at most a 3db gain in output and a lot more risks. I won't bridge amps because in my view the gains are not significant enough to warrant the risks.

This is not the usual situation, as the owner has no choice in the matter.

It is the designers choice if he wants to use two chips or one in the power amp.

If he decides to use two, then the amp is built that way and can not be unbridged.

If there was no warning about it from the manufacturer the owner would have no idea they were a couple of bridged amps. Worse, I suspect few owners have even a clue what a bridged amp is and its significance.

This issue is something we now need to be aware of, so we don't inadvertently give advice lethal to these type of amps.

 

[highfigh]

I did not look at brands. I looked at some impedance matching auto transformer circuits and some have the negs bonded.

We have not had this issue before to my knowledge.

There are not quite a few chip amp devices that can be bridged. The reason is that one chip can be a stereo amp or two can be a more powerful stereo amp. This is recent.

In the normal situation there is no reason not to common the negatives since in the vast majority of amps the negative is at ground plane.

May be these control manufacturers have taken these developments on board, but I would bet not all have.

So if you have an amp using bridged chip amps, you had better be careful what you connect it to and check for connected commons.

Obviously this has been an issue, because of the amp manufacturers warning.

The bridged vs common issue is like the late-'70s car stereos, when some companies finally were able to use a stereo chip per channel, so the output of a head unit with floating ground jumped to 12W/ch, from the 3.2W/ch of a common ground model.

A lot of head units died when connected to cars with one wire per speaker and the negative terminal connected to the metal tab that held the terminal strip, but was also part of the stamped speaker frame.