A Crossover Design on Single Exposed Board

[Full Range]

Have had a crossover project in the works since I became the owner of the La Scalas

That project was to make the ( originally two piece ) gentle slope exposed crossover fit into a single board design that will be exposed to view & showcase the crossover and have easy access to the Autoformer attenuating section for db adjustments as required

I am more versed in Mechanical Engineering so I have employed an associate to build the crossovers for me for a small cost and the offer of a listen on the system when it's all connected up

The Crossover design is loosely based on the ALK gentle slope type AP12-500 & AP12-6000 configurations

As all the drivers in my speakers are not standard - some changes needed to be made

The original design of these crossovers was - as a two piece system as that fits the Klipsch Heritage range

We put our thinking caps on and have come to a design agreement and tweak for a single board based on Troels Gravasens observations as we have plenty of available board space

We have designed this build as a single board - all coil distances are to Troels recommendations

The layout design was made maximise neatness and avoid component interaction.

We did not forget that the attenuators being transformers also need to be treated as inductors for spacing issues.

Soon after we simplified the connectivity of all three driver sections on the crossover alleviating many connection points, and a new schematic was drawn up

(I won't post the schematic as ALK the designer has removed them from the web site due to plagiarism)

This crossover still has the separate mid range and tweeter attenuation features for fine tuning

First we did a basic layout of the components on the floor with the view to tweak as needed for best performance and fit

A close up of the tweeter attenuator - This component will allow me to tweak db volume to suit speaker placement and room size

The coils for the Bass and Mid sections are hand wound and weigh over 3 pounds US -approx 1.5 kg each

We chose and used a good speaker colour match plywood board - and started the component fit

You will see a set of wire cutters and the tape measure @ 500mm to judge scale

The crossovers are finished - my associate has done a fantastic job and has emailed me a couple of photos of the finished crossovers

For all soldered connections Mundorf Silver/Gold solder was used

I chose to use a Duelund resistor to service the Bass & Mid range

Top side layout

Underside

Will apply finishing touches in the form of -

1) A frame that will incorporate in the design grab points for easy lifting

2) When funds allow I will have a perspex cover made for dust protection ( like a TT cover )

3) Labels for connection identification points

4) A Klipsch logo or badge to each board as a finishing touch

Edited July 20, 2016 by Full Range

[minermark]

Looking good.

[CECAA850]

Neat project. Let us know how they sound.

[Full Range]

I'm sure you all like to know the main parts used in the build

Capacitors

Jentzen Audio Cross Caps for the Bass section

Jentzen Superior Z caps for the Mid and Tweeter section

Sonicap in all other areas

Duelund resistor for its sonic signature

All wiring is silver plated stranded copper with teflon coating

Solder is the Mundorf silver / gold mix

The terminals are Audiophile High-quality 5-way binding posts The fully insulated design prevents the accidental shorting of speaker wires

And I really like the free-spinning metal ferrule feature on the tightening knob, this allows for a secure connection.

Will also use gold plated copper ring terminals on hookup wire and speaker wire connections

[pzannucci]

Why did you not rotate one of the inductors 90 degrees? They are close enough to cause mutual inductance and are the design specs including that inductance?

[Full Range]

Why did you not rotate one of the inductors 90 degrees? They are close enough to cause mutual inductance and are the design specs including that inductance?

A good point

The actual size of the boards is 18.5" X 14.5" (470mm x 370mm)

And the distance between the large coils is from memory 8.66" (220mm) at the centres

I haven't collected them yet but can confirm when they are in front of me

This distance is baced on Troels Gravasens recommend distances

If the crossovers display issues during testing we will rotate

[DeanG Crossovers]

Those are plenty far apart from each other, don't worry about it.

[Full Range]

Those are plenty far apart from each other, don't worry about it.

Thanks Dean

The whole design was checked and rechecked and tweaked for simplicity at every stage

These crossovers came together and the design grew as an organic procedure between myself and the expert

He told me that he had the odd midnight brain wave and also made a few changes at the last minute.

[DeanG Crossovers]

I hate picking on the hard work of others, but you really need one of these:

http://www.heattek.com/products/custom-industrial-ovens/varnish-dip-bake-systems.html

[Full Range]

I hate picking on the hard work of others, but you really need one of these:

http://www.heattek.com/products/custom-industrial-ovens/varnish-dip-bake-systems.html

Don't need a baking oven for 2 crossovers Dean

In any case Northern Australia is at times hotter than an oven

[Arash]

thought it might help to know how I wind inductors like this:

I've wrote about the method I use. it's in Persian language you can check here and there is also a video clip you really don't need to know Persian to understand what I do.

good luck,

[Full Range]

The inductance coils I have used were actually made professionally at Mike Lenehan Audio in Australia

http://www.lenehanaudio.com.au

[Arash]

The inductance coils I have used were actually made professionally at Mike Lenehan Audio in Australia

http://www.lenehanaudio.com.au

image.jpg

Uh I'm afraid I saw the thumbnail and thought inductors are in maze! now I zoomed in full size and I can see those are leads made me thought so. so I wondered if you winded them yourself and I wanted to help there good to use them. those are made of high AWG wire. I never can wind an inductor with wires thicker than #14AWG because lactic acid makes my hand insensible

[pzannucci]

Why did you not rotate one of the inductors 90 degrees? They are close enough to cause mutual inductance and are the design specs including that inductance?

A good point

The actual size of the boards is 18.5" X 14.5" (470mm x 370mm)

And the distance between the large coils is from memory 8.66" (220mm) at the centres

I haven't collected them yet but can confirm when they are in front of me

This distance is baced on Troels Gravasens recommend distances

If the crossovers display issues during testing we will rotate

Ah, didn't realize the size from the picture. I took another look and saw the size of the wire cutters - got it

[Full Range]

Update

I have been testing the crossovers - giving them some burn in time, and have found them very agreeable

Sound is beautiful at this crossover point @ 500htz for this setup combination

Myself and the builder of the crossovers, have given a score of 9 out of 10

I will however tweak the crossover minimally by replacing or adding

1) Pathaudio earthed Resistors to the tweeter section

2) Mills Resistors to the tweeter PCB

3) Duelund standard Resistor

4) Jentzen flat wax Inductor Coils to service the mid and tweeter sections

I feel and hope that these tweak additions to the crossovers will take the La Scalas to another level and then I will sit and enjoy the music forever more ( famous last words )

Just taken a short video ( hope it does the system justice )

 

 

[TasDom]

Update

I have been testing the crossovers - giving theme some burn in time, and have found them very agreeable

Sound is beautiful at this crossover point @ 500htz for this setup combination

Myself and the builder of the crossovers, have given a score of 9 out of 10

I will however tweak the crossover minimally by replacing or adding

1) Pathaudio earthed Resistors to the tweeter section

2) Mills Resistors to the tweeter PCB

3) Duelund standard Resistor

4) Jentzen flat wax Inductor Coils to service the mid and tweeter sections

I feel and hope that these tweak additions to the crossovers will take the La Scalas to another level and then I will sit and enjoy the music forever more ( famous last words )

Just taken a short video ( hope it does the system justice )

Nice looking set up and sounds very nice thru my PC>Optical>Oppo>MiniX>Belle's

[Full Range]

An update is in order for the crossover build

While I was waiting for the delivery of the resistors and 1 uf Vishay capacitors in the mail, I made some hook up wire for the drivers to the external connection of the crossovers

I used 8 TC Kimber cable in this application with great results

[Full Range]

A few days after the hookup wire was finished, resistors arrived

A day was chosen to do the changeover

The resistor upgrade was completed

And while having a listen to the system after our handiwork with some coffee to calm the nerves the mail man delivered another parcel.

The Vishay 1837 0.01uF 160v foil capacitors.

So we fitted these in. The Vishay's are used for shunting internal inductance of the parent capacitor

The transformation is amazing the extra detail we could hear in some instruments is nothing short of amazing

A very worthwhile changeover In My Humble Opinion

[Full Range]

Here is a photo of the top view with labels

All that remains now is the Jentzen Inductors - wax flat wire to replace the Solis twisted wire coils and the box frame to finish it off

[Tarheel]

Very nice system....would like to hear it in person. I've got to do the bass extensions one of these days.

Thanks for posting!