Does this cable exist?

[steve_1979]

The kind gent from the AVI forum has also made up a second cable with a resistor in each leg so that I can compare the two. It also connects the ground connection before the hot and has a Neutric phono plug.

It'll be interesting to see which one I prefer if there are any differences.

 

[andyjm]

Dave and Andyjm aren't wrong but I think they are overthinking the problem. I've lost count of the number of mono leads and stereo to mono Y-adaptors I've soldered up over the years, nothing has ever been damaged. Just don't try the same trick with loudspeaker outputs.

it is generally bad practice to short the outputs of drivers together. For wimpy line level drivers you would probably get away with it and avoid damage, but you are relying on the output impedance being high enough to allow summing to take place without introducing too much distortion.

i would note the OP is using the headphone output, which will have beefier drivers and lower impedance making the outcome of shorting the drivers more likely to end badly.

 

[steve_1979]

Before trying the cable I also asked Ashley James just to double check that it would be safe to use a stereo to mono cable and he said that it's fine.

Many subwoofers mono the stereo signal too without issue.

 

[steve_1979]

I've just tried the first stereo to mono cable (the one without the resistors) and it works perfectly when plugged into my slave DM10 speaker. I tested it with The Beatles which has very separate left and right channels and it sounds fine as far as I can tell.

The second stereo to mono cable (the one with the resistors) still hasn't arrived yet but I'll let you know my findings on that one when it arrives in the next couple of days.

 

[davedotco]

Before trying the cable I also asked Ashley James just to double check that it would be safe to use a stereo to mono cable and he said that it's fine.

Many subwoofers mono the stereo signal too without issue.

There is no point in getting into an argument over this, but the theory put forward by Andyjm and myself is sound though in practice in this case it might not be an issue. I certainly would not use such a cable myself, I would find another workaround.

Subwoofers do indeed combine left and right channels together, but they use a properly designed, though very simple circuit to do so.

 

[steve_1979]

Before trying the cable I also asked Ashley James just to double check that it would be safe to use a stereo to mono cable and he said that it's fine.

Many subwoofers mono the stereo signal too without issue.

There is no point in getting into an argument over this, but the theory put forward by Andyjm and myself is sound though in practice in this case it might not be an issue. I certainly would not use such a cable myself, I would find another workaround.

Subwoofers do indeed combine left and right channels together, but they use a properly designed, though very simple circuit to do so.

No arguments here Dave.

The theory that you mentioned in an earlier post does does indeed make a sort sense to me (admittedly my knowledge on the subject is pretty limited). I can see what you mean but as to whether or not it's safe to try this in practice is beyond my level of understanding. Everything seems to be working fine though and there were no puffs of smoke or funny metalic smells coming from the speaker so I'm happy with the result.

 

[shadders]

Before trying the cable I also asked Ashley James just to double check that it would be safe to use a stereo to mono cable and he said that it's fine.

Many subwoofers mono the stereo signal too without issue.

There is no point in getting into an argument over this, but the theory put forward by Andyjm and myself is sound though in practice in this case it might not be an issue. I certainly would not use such a cable myself, I would find another workaround.

Subwoofers do indeed combine left and right channels together, but they use a properly designed, though very simple circuit to do so.

No arguments here Dave.

The theory that you mentioned in an earlier post does does indeed make a sort sense to me (admittedly my knowledge on the subject is pretty limited). I can see what you mean but as to whether or not it's safe to try this in practice is beyond my level of understanding. Everything seems to be working fine though and there were no puffs of smoke or funny metalic smells coming from the speaker so I'm happy with the result.

Hi,

Short term damage may be negligible, but long term use may cause the output stage to eventually fail, as a positive on the right and a negative in the left, will create a maximum current in the output stage. Maybe there is some output stage design which allows for such use.

Battery may not last as long, if the mp3 is not plugged in for recharging whilst playing.

Regards,

Shadders.

 

[steve_1979]

Hi,

Short term damage may be negligible, but long term use may cause the output stage to eventually fail, as a positive on the right and a negative in the left, will create a maximum current in the output stage.

Why would the damage be gradual?

If anything was going to go poof I'd have thought it would happen sooner rather than later.

 

[Oldphrt]

Any combining of two channels from output stages will require a resistor in series with each output, or damage may be caused and the sound quality will be poor. 1k would be about right.

 

[steve_1979]

I've tried both cables now and AFAICT they both sound the same. The one with the resistors might be very slightly quieter but it's hard to say for sure because it takes half a minute to power down the speaker and swap the cable over.

 

[avole]

so put them resistors in !

On another topic, who is Dr Teddy Tan and has he, or his company, taken over AVI?

 

[steve_1979]

so put them resistors in !

I've been using the cable with the resistors just in case.

The DM5 still sounds great even in mono and just plonked on top of the fridge in an echoey kichen. We were listening to Sultans of Swing while cooking spagetti bolognese earlier.

On another topic, who is Dr Teddy Tan and has he, or his company, taken over AVI?

Eh?

 

[avole]

He's a new director on the AVI board, apparently, an investment professional from Singapore.

Is this a sign of big changes at AVI?

 

[steve_1979]

He's a new director on the AVI board, apparently, an investment professional from Singapore.

Is this a sign of big changes at AVI?

You obviously know more than me. I've never heard that name before. Out of interest where did you hear/read about it?

 

[avole]

well, from a friend, anyway.

It is true - see here: https://beta.companieshouse.gov.uk/officers/6Ej0NYYtWqMIo2uVUWhTuq5Ra8M/appointments

I was wondering more whether this was a precursor to manufacturing outside the UK, and, if so, whether AVI are going to introduce wifi/bluetooth enabled products, as I suggested during my brief time on their forum !

 

[steve_1979]

well, from a friend, anyway.

It is true - see here: https://beta.companieshouse.gov.uk/officers/6Ej0NYYtWqMIo2uVUWhTuq5Ra8M/appointments

Interesting.

I was wondering more whether this was a precursor to manufacturing outside the UK, and, if so, whether AVI are going to introduce wifi/bluetooth enabled products, as I suggested during my brief time on their forum !

Apparently there is something new in the pipeline coming from AVI soon but it's exact nature is cloaked in a shroud of secrecy at the moment.

There were several rumors on the AVI forum. One was the use of wifi/bluetooth conectivity or DSP integration. Other rumors are that there's a new valve powered four way horn speaker with matching turntable currently being developed but at this time none of the rumors are anything more than speculation and wild guesses.