Connecting a subwoofer with a SpeakOn input to different types of amplifiers and problems

[Burns]

Hi,
My problem:
Does this phenomenon also occur in your case, that a subwoofer connected to a stereo amplifier in class AB via a Neutrik Speakon connector - high level, so when the subwoofer is turned on, turned off manually or turned on via auto mode, the music is interrupted from the speakers for a fraction of a second? As if the stereo amplifier detects that its impedance is changing at the output terminals. The amplifier detects that an additional system is connected, which is an active subwoofer?

All because my amplifier is M6Si, i.e. fully balanced, I connected it according to the first diagram, all three wires connected, and you have to connect it according to the second one marked in purple

I found a further development of my problem on this forum:

Audiogon Discussion Forum

I will be connecting 2 T/9x's to my system (B&W 805 D4) driven by a NAD M33. I am wondering if there is any audible difference between connecting th...

forum.audiogon.com

"tony1954
1,166 posts
01-12-2023 at 04:46pm
@macg19

"@tony1954 for balanced amps you just need to "float" (not use) the ground for the supplied speakon cables. The "issue" is 60Hz hum. Doesn't apply to either RCA inputs."

I am not sure you are correct with this. Below is the response I received from Rel regarding hookup to my MF integrated.

"Your Musical Fidelity M6si is a balanced differential amplifier, if you're hooking up a pair of T/7i's, don't hook it up to the negative speaker terminal with our SpeakOn cable. Instead hook it up to the phono ground terminal and twist the red & yellow wires together and wire into the positive on each channel.

If you only have one T/7i, then wire it from the preout to the low level input on the back of our sub. The low level uses the same exact audio filters as the high level. "

this still does not end my problem because due to the lack of connecting the black wire to the subwoofer the autoOn function does not work and there is also a break in the sound with the yellow and red wires connected when I turn on the subwoofer.
The situation with the break in the sound only occurs when the amplifier has an active balanced XLR input, when the source is RCA there is no break in the sound when turning on the subwoofer.
I got a hint to connect the black wire to the housing (external pin) of the free RCA socket.
Can the black SpeakOn wire also be connected to the GND of the turntable? M6si has a GND connector.
Maybe someone can draw what this short circuiting of the amplifier is about if it is balanced and has one subwoofer connected with three Speakon wires?
Once we deal with this problem, I will move on to the next question how to connect 2x Topping B200.
I am anticipating further questions, at the moment I have the subwoofer connected via RCA Y, so I am avoiding this problem. Ultimately I want to keep the Spekon connection directly connected to the speaker terminals so I can quickly change amplifiers.
Regards

 

[Burns]

Topping 2xB200
Someone asked if the B200 has a balanced output stage. The answer was that it doesn't. In that case, how do I connect an active subwoofer with a speakOn connector? According to the diagram I'm attaching?

I have and will have one subwoofer, but I want to keep the R and L connections to it, because I know of many songs where the bass can be played or migrate between the L and R speakers

 

[Sokel]

Topping 2xB200
Someone asked if the B200 has a balanced output stage. The answer was that it doesn't. In that case, how do I connect an active subwoofer with a speakOn connector? According to the diagram I'm attaching?

I have and will have one subwoofer, but I want to keep the R and L connections to it, because I know of many songs where the bass can be played or migrate between the L and R speakers

As far as I have seen the teardowns, that's an already bridged amp and that could be tricky if connections include ground, depending the output circuit.
Better ask Topping about it, there's no other way to make sure you won't blow up something.

 

[antcollinet]

Please

OK

Can the black SpeakOn wire also be connected to the GND of the turntable?

Yes - if you mean the ground wire connection at the back of the amp, I would not connect it back at the turntable end of the ground wire.

Maybe someone can draw what this short circuiting of the amplifier is about

I haven't got a picture, but I'll try to describe it.

Consider first an unbalanced amplifier. The red terminals have the high-level amplified music on them, and the black terminal is connected to ground. This connects fine to the high-level inputs of your sub. The music signal goes into the red terminal, and the grounds of the sub and amp are connected together by the black terminal.

With a balanced amplifier, both the red and black terminals carry the music signal. The signal on the black terminal is inverted compared to the red terminal (balanced - one goes high while the other goes low). When you connect to a speaker, this is not a problem (the speaker has no ground connection); it just sees double the voltage across its terminals - this is how balanced amps deliver more power with the same power supply voltage.

But you have a problem with the sub. The black terminal on the sub is connected to ground, but the black terminal on the amp is driven with a high-level voltage. If you connect them together, then you are shorting the amp output to ground. At best, this will trigger protection; at worst, it will break the amp if the protection is not good enough. (This is just as bad as connecting red to black on any amp.)

The solution is the purple wiring. Red amp outputs into the sub signal inputs, but a ground connection to an actual ground point on the amp (which the black speaker terminals are not) such as Rca ring, XLR pin1 (or as you have suggested) ground terminal (easiest and probably best)

 

[Sokel]

OK


The solution is the purple wiring. Red amp outputs into the sub signal inputs, but a ground connection to an actual ground point on the amp (which the black speaker terminals are not) such as Rca ring, XLR pin1 (or as you have suggested) ground terminal (easiest and probably best)

That can create a giant ground loop though under circumstances.
It must be tested with caution.

 

[antcollinet]

Topping 2xB200
Someone asked if the B200 has a balanced output stage. The answer was that it doesn't. In that case, how do I connect an active subwoofer with a speakOn connector? According to the diagram I'm attaching?

I have and will have one subwoofer, but I want to keep the R and L connections to it, because I know of many songs where the bass can be played or migrate between the L and R speakers

What is (are) your source(s), and how are you intending to connect into the B200? As I explained elsewhere, by far the best solution is to use low level connections to your sub. That way you don't have to worry about whether or not the amp is balanced. It is probably better quality also.

You also have Pre-Outs on your MS6I. It would be far better to use those out to the sub, than this messing about with high level connections.

And why are you considering changing from it. Despite the excellent measurements of the B200, the MS6i also has excellent ratings - the difference is not going to be audible. And the Ms6i has more power also: I would not go anywhere near the B200 if I had that amp.

You also said in your Audiogon post that you were using a Nad M33 - is that no longer the plan?

 

[antcollinet]

That can create a giant ground loop though under circumstances.
It must be tested with caution.

How so (or at least how so compared to an unbalanced amp). The grounding arrangement is the same as an unbalanced amp using the black speaker terminal for ground. It is just connected to ground at a different point on the chassis. (assuming the internal ground connections of the amp are AES compliant - a big assumption, I know)

And it has to be better from a ground loop perspective than "leaving it floating" unless there is hum?

 

[Sokel]

How so (or at least how so compared to an unbalanced amp). The grounding arrangement is the same as an unbalanced amp using the black speaker terminal for ground. It is just connected to ground at a different point on the chassis.

You're right in general, my concern is about what this connection will form with the amp's input stage which probably is connected to ground.
The sub will then have two ways to choose,one of them through the amp and back.

Is more of a hunch really.

 

[Burns]

@antcollinet, thank you. You've written it out very nicely - I understand. Thank you very much
- I'm missing information about the yellow wire. Red to R, yellow to L, black to ground?
- Before the B200 is the Toppinf E70 dac and L70 DAC
- I know about the RCA outputs in the M6Si and L70, I have them connected like that, but it forces me to switch cables and forces me to adjust the volume level in the subwoofer every time I change the amplifier or gain from Low to High. SpeakOn from the speakers will probably allow me to avoid this.
- Do you praise the M6si? Others do not necessarily praise its measurements. I am happy with the M6si, with the B200 too. I have already bought the B200, you are advising me against it a bit late. So what, sell the B200?

 

[antcollinet]

I'm missing information about the yellow wire. Red to R, yellow to L, black to ground?

It is a colour in the speakon cable. They are just using yellow for left channel. You need both right and left in the sub so the sub gets both channels bass to sum to mono.

I know about the RCA outputs in the M6Si and L70, I have them connected like that, but it forces me to switch cables and forces me to adjust the volume level in the subwoofer every time I change the amplifier or gain from Low to High.

Well then my advice is : stop changing amplifiers and gain It is not necessary once your system is set up and running. On the other hand - if you enjoy playing in this way, it is a price of the playing. Better than putting your equipment at risk by high level connections (which you still have to change if you swap amps)

Do you praise the M6si? Others do not necessarily praise its measurements. I am happy with the M6si, with the B200 too. I have already bought the B200, you are advising me against it a bit late. So what, sell the B200?

Sorry for being late. But yes, unless you can use one of the amps in a second system somewhere, then you don't need both.

Speaking personally I would not sell the M6si. But since you have both to compare side by side you can make up your mind for yourself.

Unless you compare accurately level matched and blind, don't use sound quality as a criteria - that should not be making a significant difference.

Instead, decide on how you feel about the features (eg the useful pre-outs for your sub ), aesthetics, feel of quality/user interface, and (importantly) after sales support in case something goes wrong.

Or just keep both, and continue to enjoy playing

 

[Burns]

if I connect the subwoofer via speakon from the speakers I could only change the banana plugs from the amplifiers. The question of connecting the speakon with the B200 remains. On the advice of @Sokel I wrote to Topping

 

[antcollinet]

I could only change the banana plugs from the amplifiers.

Not if one or more of the amps you are changing is balanced. Then you must also change the ground connection. And if only one is balanced, then you are risking getting it wrong while making the change, and damaging an amp.

But yes - getting an answer from topping is best.

 

[Burns]

Not if one or more of the amps you are changing is balanced. Then you must also change the ground connection. And if only one is balanced, then you are risking getting it wrong while making the change, and damaging an amp.

But yes - getting an answer from topping is best.

you are absolutely right, if the two amplifiers have different topology, then with the same connection I have the same problem again. Then I have to connect one via RCA and the other via SpeakOn.

One more question if I connect two RCA amplifiers to the only subwoofer via a Y splitter. Both will be on hold. Only one amplifier will play, but I accidentally turn on the second one without playing music, can I double the voltage and damage the amplifier built into the subwoofer, which has a class AB amplifier?

 

[Sokel]

One more question if I connect two RCA amplifiers to the only subwoofer via a Y splitter. Both will be on hold. Only one amplifier will play, but I accidentally turn on the second one without playing music, can I double the voltage and damage the amplifier built into the subwoofer, which has a class AB amplifier?

The Y-splitter will also connect the two amps themselves, not only the sub.
Think about it.

(Y-splitters should be illegal in my book)

 

[antcollinet]

The Y-splitter will also connect the two amps themselves, not only the sub.
Think about it.

(Y-splitters should be illegal in my book)

Nothing wrong with Y splitters if used to connect two destinations to one source.

The other way round - not so much.

Two outputs should not be connected together. It is another form of short circuit.

 

[Burns]

everything is clear, thanks

 

[Burns]

As far as I have seen the teardowns, that's an already bridged amp and that could be tricky if connections include ground, depending the output circuit.
Better ask Topping about it, there's no other way to make sure you won't blow up something.

Subwoofer SpeakOn high level connection
"Hi,
Thank you for your information. Based on your model, we do not recommend such a connection. If you really want to connect, it mainly depends on whether the high level of your speaker can accept the bridged signal. That is, it cannot have one end grounded. If one end is grounded, it is equivalent to short-circuiting the power amplifier.
Regarding whether the speaker is actually grounded, you can contact the speaker manufacturer to make inquiries. ^.^

Best Regards,
Topping"

 

[Sokel]

"Hi,
Thank you for your information. Based on your model, we do not recommend such a connection. If you really want to connect, it mainly depends on whether the high level of your speaker can accept the bridged signal. That is, it cannot have one end grounded. If one end is grounded, it is equivalent to short-circuiting the power amplifier.
Regarding whether the speaker is actually grounded, you can contact the speaker manufacturer to make inquiries. ^.^

Best Regards,
Topping"

Yep, same story with almost all bridged amps, ground is the enemy.

 

[Burns]

Yep, same story with almost all bridged amps, ground is the enemy.

So if so, how can one connect +left, +right and ground (black) in the air in a fully balanced structure and the consequence of this is the loss of the Auto On function?

 

[Sokel]

So if so, how can one connect +left, +right and ground (black) in the air in a fully balanced structure and the consequence of this is the loss of the Auto On function?

Honestly, I would ditch any thought of high level connection as it is.
Line level all the way, even if you have to include something in between, after all it's a sub, you won't miss any "quality" .