Active crossover types

[levimax]

I had looked at it, even considered ordering it too, but I'm not too comfortable about building a PSU and eventually leave it unattended.
Plus there's already one laying around half unused.
Does it really make that of a difference three more volts?

The way the P05 works is that you use a 16 volt AC "Wal-Wart" which drops the mains voltage down to 16 volts AC and then the P05 converts that to +/- 15 volts DC. This makes things very safe as the mains work is all done with a commercial double insulated and thermally protected Wal-Wart.

Don't confuse a single 18 volt supply with a +/- 15 volt supply... they are different animals and not interchangeable.

 

[Killingbeans]

Does it really make that of a difference three more volts?

Three volts more than the op-amps max spec? Yes. That's when the magic smoke gets released.

 

[dennnic]

Don't confuse a single 18 volt supply with a +/- 15 volt supply... they are different animals and not interchangeable.

Is it too much to ask for an explanation?

Three volts more than the op-amps max spec? Yes. That's when the magic smoke gets released.

No, no, three volts more than everyone keeps advising to use. The op amp I'd use would be rated at least at 20v.

 

[Killingbeans]

Don't confuse a single 18 volt supply with a +/- 15 volt supply... they are different animals and not interchangeable.

Yes. Very good point. I assumed that dennnic was talking about a +/-18V supply. If it's single rail, then it's not going to work.

 

[dennnic]

Yes. Very good point. I assumed that dennnic was talking about a +/-18V supply. If it's single rail, then it's not going to work.

I'm afraid you lost me completely. Does a +/- X volts means two separate 15V leads? Do I need both of them or what?

 

[Killingbeans]

Is it too much to ask for an explanation?

The circuit on Rod's page is designed for dual rail supply. It needs both a positive and a negative rail.

It needs to be redesigned to have DC bias if you want to use it with a single positive rail.

 

[dennnic]

The circuit on Rod's page is designed for dual rail supply. It needs both a positive and a negative rail.

It needs to be redesigned to have DC bias if you want to use it with a single positive rail.

Redesigning it threatens with a much more magic smoke. I like the term, tho.
Gonna look into that project again.

 

[dennnic]

The circuit on Rod's page is designed for dual rail supply. It needs both a positive and a negative rail.

It needs to be redesigned to have DC bias if you want to use it with a single positive rail.

May I ask you to glance at Teddy Pardo specs?

https://teddypardo.com/wp-content/uploads/2021/01/DualTeddyCap_UM.pdf

It's rated at 2x24 volts and a 18v. Does 2x24v mean +/-24v?

 

[Killingbeans]

Don't think so. The XPS seems to have some dual rails, but not the other models.

 

[gene_stl]

If you don't want to build, Marchand sells a lot of nice stuff. But there are many many analog crossovers available both kit and built.
There are also DSP solutions that allow you to program in all kinds of other tricks too. Parts express has one that will get you going for under $200
(DSP 408) Some audiophiles might look down their noses at it. I would love to try it but I probably won't.

 

[levimax]

I'm afraid you lost me completely. Does a +/- X volts means two separate 15V leads? Do I need both of them or what?

Shoot that is a nice looking supply you have but I don't think it will work. Just to clarify a split rail supply i.e. +/- 15 volt has a (+) and (-) and a "center" lead. It will measure 30 volts between (+) and (-) and half of that compared to the center. Pretty much any audio circuit uses a supply like this internally. Unfortunately "splitting" a single rail DC supply is going to be harder and more expensive than building a split rail from scratch.

 

[JayGilb]

May I ask you to glance at Teddy Pardo specs?

https://teddypardo.com/wp-content/uploads/2021/01/DualTeddyCap_UM.pdf

It's rated at 2x24 volts and a 18v. Does 2x24v mean +/-24v?

No, that indicates it has two separate regulated +24vdc outputs.
From your link:

Only the TeddyXPS has +- voltages.

 

[dguillor]

I am an Electrical Engineer, who studied audio amplifiers and loudspeakers while at university. I have been an audio hobbyist since university and have designed and built several active crossover speaker systems. I have studied crossover filters, both analog and digital.

I believe that there are many op amps that will be transparent in the crossover application. If you only want to implement one of the standard, fourth order or less,, crossover types, an analog circuit will provide as good a solution as digital. A digital crossover will provide the ability to have very steep cutouts, which can be helpful in eliminating resonances, like aluminum cone woofer breakup.

 

[dennnic]

If you don't want to build, Marchand sells a lot of nice stuff. But there are many many analog crossovers available both kit and built.
There are also DSP solutions that allow you to program in all kinds of other tricks too. Parts express has one that will get you going for under $200
(DSP 408) Some audiophiles might look down their noses at it. I would love to try it but I probably won't.

I do like their stuff, but shipping from USA with taxes and everything else usually costs more than a product itself.

On the other hand, I do like the idea of DIY and that's the main problem!

Shoot that is a nice looking supply you have but I don't think it will work. Just to clarify a split rail supply i.e. +/- 15 volt has a (+) and (-) and a "center" lead. It will measure 30 volts between (+) and (-) and half of that compared to the center. Pretty much any audio circuit uses a supply like this internally. Unfortunately "splitting" a single rail DC supply is going to be harder and more expensive than building a split rail from scratch.

Thanks for the explanation. It seems that the most elegant solution would be to buy a 15-0-15 transformer and a power cable and put it besides Rod's power supply and crossover in the same box.

I believe that there are many op amps that will be transparent in the crossover application. If you only want to implement one of the standard, fourth order or less,, crossover types, an analog circuit will provide as good a solution as digital. A digital crossover will provide the ability to have very steep cutouts, which can be helpful in eliminating resonances, like aluminum cone woofer breakup.

Good to hear. I was about to go with the 4th order, in order to extend the full range as low as possible. Although, it struggles under 250 Hz.
A lot of chip op amps were already mentioned. What would be your pick?

 

[levimax]

Thanks for the explanation. It seems that the most elegant solution would be to buy a 15-0-15 transformer and a power cable and put it besides Rod's power supply and crossover in the same box.

If you are going to put a mains transformer in the box you only need a single mains to 15 volt transformer as the P05 is designed to take ~ 16 volt AC and convert it to DC and filter it and split it into +/- 15 volts. The way you are thinking about the transformer is how it would work with a "Power Amp" linear supply but at the low voltages and currents needed the P05 uses a voltage doubler and IC voltage regulators to increase and regulate the voltage.

While having the mains voltage in the box eliminates having a "Wall Wart" it does create issues for DIY. If you go this way be very careful with the mains wiring and grounding and fusing as mains level voltage and current can be deadly and easily start fires. In addition having mains voltage and a mains to 15 volt transformer inside the same case as everything else is going to increase the chance of picking up hum. Of course you can do it safely and effectively but it is a lot harder for a one off DIY project. Personally I go with the Wall-Wart solution as it is so much easier and I can use a smaller enclosure.

 

[gene_stl]

I agree you would be better off on your first project using a wall wart if you can find a suitable one for Serbia's line voltage. 240 volts is sort of unforgiving.

In a previous life I was researching line voltage safety for a project and discovered that 50 to 60 hz is the most efficient frequency for electrocuting a human being. I thought that was sort of amusing.

What is the diameter of your full range? Which one is it?

 

[dennnic]

I agree you would be better off on your first project using a wall wart if you can find a suitable one for Serbia's line voltage. 240 volts is sort of unforgiving.

In a previous life I was researching line voltage safety for a project and discovered that 50 to 60 hz is the most efficient frequency for electrocuting a human being. I thought that was sort of amusing.

What is the diameter of your full range? Which one is it?

Who'd say, there is a logic behind that 50/60 Hz after all. Not much used for that application tho!

You're right, I'm going to go with a wall wart for a start. There is one that's potentially suitable - topping 15V AC.

Here's the driver and some photos:

https://www.sonido.hu/adat_pdf/sfr-145a.pdf

 

[gene_stl]

Is the diameter 145mm? Looks like it's nicely made.

 

[dennnic]

Is the diameter 145mm? Looks like it's nicely made.

145 mm altogether and around 90-100 mm surrounds excluded (cone only).

 

[gene_stl]

so you should have a tweeter for the top two octaves. And a wooofer for the bottom four.