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Deep End DIY - My first speaker project


acg

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Yesterday, my final delivery from Lucas arrived...finally.  He has had some real trouble winding the big 9H inductors and keeping them stable.  What you see below are his third attempt at getting them right.  The smaller chokes were fine but the big fellows would measure 9H after winding, then he would leave them settle for a week or so and they would have drifted a little (inductance is such a ***** to measure accurately) and then he would pot them and shield them and they would drift by up to 25%.  Anyway, third time was a charm and you will notice that he has given me a number of taps between say 8H and 10H so that I have room to shift the crossover knee (these are for the PLLXO at the amplifier inputs).

 

So many thanks to Lucas.  These have been an ordeal for him but he has persisted until he got a good result which is the most that I could have asked from him.  On his wall apparently he now has a notice warning him never to do these big line level chokes again...just say no!

 

Below is the party that he sent up to me...

591b885ebb4db_ChokingUp1.jpg.c71ca9f112cb318006075f4db6c0a68b.jpg

 

The two littlest ones are for my 4th order high pass CLC T filter for the RAAL ribbon.  They will go in their own shielded box along with some air capacitors to make up that filter.  The middle sized ones are for the MF horn (the smallest horn) and the behemoths are for the mid sized horn channel up on top of the horn stack.  Note the multiple taps on both the larger chokes.

 

591b885dc3302_ChokingUp2.jpg.32cc7e31772bcb3ac1e272f6472e7f43.jpg

 

Anyway, I am glad that all of the amplifier parts are now here and that I can check that everything fits before I send the steel to be powdercoated.

 

 

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7 hours ago, acg said:

Yesterday, my final delivery from Lucas arrived...finally.  He has had some real trouble winding the big 9H inductors

 

The two littlest ones are for my 4th order high pass CLC T filter

 

I thought it was you who convinced me that passive line-level active filters used small, cheap components! Is there somewhere in this thread where you've discussed the design of these?

 

You keep finding ways to prove this project is epic...

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3 minutes ago, BioBrian said:

 

I thought it was you who convinced me that passive line-level active filters used small, cheap components! Is there somewhere in this thread where you've discussed the design of these?

 

You keep finding ways to prove this project is epic...

 

Haha...yes...that is true.  Even that big inductor on its own is reasonably small, but then you jam it in a thick steel case which you top up with beeswax (I think that is what Lucas ended up using to pot it) and suddenly it is a 100mm cube. 

 

The line level caps are certainly smaller in value than for speaker level:  I have a whole batch of nice film caps from 0.001uF to 1uF to use.  If they were at speaker level they would be multiples larger and more expensive. 

 

PS:  I read about your second back surgery...I hope you come good in time!

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48 minutes ago, Newman said:

Are we supposed to cut out the shapes and fit the jigsaw back together again?

 

No.  Here are a couple of images of just the CLD panels in one amplifier.

 

591bfe0b392cb_CLDSNA.thumb.jpg.a2724b96f6f088471d1e8c07429201d6.jpg

 

591bfe3cb6a4c_CLDSNA2.thumb.jpg.25c5e9bd76d5fec260ea9d85c839703d.jpg

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On 5/15/2017 at 10:09 AM, acg said:

 

...another 17 hours on the tools over the weekend...I seemed to do a lot to achieve not very much although I did tap a LOT of holes...now up to 52 hours total steel fabrication time.  Welder is lined up for next week so I had better pull out my finger to get something ready for him!!

 

Only one day at it over the weekend so up to 62 hours tool time.  Nothing to show for it but a lot more swarf.

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  • 2 weeks later...
54 minutes ago, Upfront said:

Hows it all looking Anthony?

 

Good mate...bit hectic at the moment.  Another 27 hours on the tools (89 hours total so far) and a couple of days ago the welder zipped up the first bits of steel but I have not had time to even look at the almost finished articles yet.  I'm taking tomorrow off so hopefully I can get some more stuff done and the last little bit of welding for the horn chassis ready before the welder scoots off for a few weeks.  Will post some photos in the next day or two...but five Bass Cannons are welded up ready for their experiments and the horn stacks are all but done.

 

Also had some more steel cut for the audio rack and the four anti-vibration platforms...in for a penny in for a pound...so I'll be metal working for a few more weeks I reckon before I get through it all.

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Good mate...bit hectic at the moment.  Another 27 hours on the tools (89 hours total so far) and a couple of days ago the welder zipped up the first bits of steel but I have not had time to even look at the almost finished articles yet.  I'm taking tomorrow off so hopefully I can get some more stuff done and the last little bit of welding for the horn chassis ready before the welder scoots off for a few weeks.  Will post some photos in the next day or two...but five Bass Cannons are welded up ready for their experiments and the horn stacks are all but done.
 
Also had some more steel cut for the audio rack and the four anti-vibration platforms...in for a penny in for a pound...so I'll be metal working for a few more weeks I reckon before I get through it all.

Will be interesting to see what you think of the bass cannons mate. Looking forward to the photos.
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The Horn Stack is all but ready for powdercoating...

 

593b9f647ce20_NearlyReady.thumb.jpg.012e28e522420177d3f97976b95cbf7e.jpg

 

Everything is bolted together and the rod pairs are all aligned...there is just 10 minutes to tidy up a few edges and it is good to go.  I was apprehensive how I would go aligning the rod pairs but in the end it worked out.  I am so happy with the design.  The stack just stands there and looks calm and relaxed although the bit of fisheye in these images does not do the general aesthetic justice.

 

593b9f63a8360_NearlyReadyBehind.thumb.jpg.b775664e4aec70856de307406afe7a0c.jpg

 

Below is a close-up of the horn adjustment mechanism:  they slide in and out so they can be physically time aligned to suit the listening position.  It is a fairly simple setup but quite a time gobbler to build and then to align the rod pairs especially when my drill press is not really suited to putting down a 20mm countersink!

593b9f62b967a_AdjustmentMechanism.thumb.jpg.ba2c141a4e74ce310d99e8c93fcace9b.jpg

 

You can see the bushings/bearings pressed into the horn stack through which the rods slide (attached to the back of the RAAL Lazy Ribbon).  Tomorrow I have to press all those fellows out before it can be sent for powdercoating...that is going to take a while because I don't want to undo any of those bolts now that everything is aligned so I am going to have to make up a tool.

 

 

 

 

RAAL Installed.jpg

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Anthony...they look sensational...

 

Me thinks the makers of Dr Who might be contacting you...

Put wheels on them...lasers firing from the rods...

The Raal is the all seeing - computerised eye...

Eliminate...ELiminate...ELIMINATE....

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Great looking frame! Such a good way to align horizontally too. I am eagerly waiting for you to finish this project and make sound!

 

I hope you will keep everything the same, so you would not need vertical adjustments. I experimented a lot with heights and plan on trying different horns so I could not have a fixed frame like this.

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So, I roughly threw together a half height Bass Cannon just to make sure that my concept works and to see if it will be stable and strong enough for the job.

 

As you can see below, I have not bothered to align anything plus I have only half tightened the double ended studs because I have not used the 2mm cork gasket between the braces and the cannons (don't want to bend anything in the mockup phase!).  Also I have not bothered to install a third line of braces whose job is to damp the steel ringing.  It works!  Rock solid...no issues...good to go.  To be honest I was a less shocked by the "look" than I thought I would be, in fact I quite like how they present themselves.  Sure, 8 cannons tall will be imposing but the is no reason that I could not make it 6 or 7 high if helped the overall aesthetic.

 

593f2972f41a7_CannonMockup2.jpg.f42987fb893878eb4af7d265ca45b7eb.jpg

 

593f2974d63d5_CannonMockup1.thumb.jpg.7f8cb49ec86730d69a80b644b21d4907.jpg

 

Except...

 

593f297404336_CannonMockup3.thumb.jpg.ae49b485d9694b90508dff1560d458f6.jpg

 

...I was going to use binding posts at the back end and have already drilled the holes through the 10mm rear plate, but I have realised that I won't be able to solder wire to the back of the binding post and do up the nut to hold the binding post in place (it is one or the other).  Binding posts are not really required in that position, they were just a convenience.  I could reverse them and the system would work:  solder wire between the driver and clamp-down-side of the binding post then push the BP through the hole in the cannon from the inside (reverse the normal direction, so clamp-down-side is inside the cannon), tighten the nut on the outside of the cannon and then solder wire behind the nut.  That plan is a bit arse-about-face so I would like to come up with another idea.

 

One thing that I have thought of is to use a simple cable gland instead of the binding post which will allow the wire through without solder connection...might be a win-win assuming the gland is able to seal properly and not create a pseudo port.  

Image result for cable gland

Does anybody have other ideas? 

 

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Still following this build, with more and more incredulity. Will you call this the "Mortifier" section?

 

I agree, it's not exactly portable, so binding posts would seem an unnecessary expense and headache. Glands would be more in your style, but would a soft filler, like Fullers, seal and protect the cables just as well? (Could turn your cannons into glorified spud guns though).

 

I like the tensioning bolts on the side of each cannon - is that one end normal, the other end reverse thread? Amazing.

 

Still can't get my head around the acoustic side of these tubes, and the way you have 8 the same, multiplying the 'qualities' of them - hopefully to good end.

 

Keep up the great work!

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acg you do realise that you are not only creating an over the top system, but you are creating a benchmark by which every other SNA member will get their projects green lighted by the missus.... Well I could build a system like this... ok you can have your idea :D 

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2 hours ago, acg said:

So, I roughly threw together a half height Bass Cannon just to make sure that my concept works and to see if it will be stable and strong enough for the job.

 

As you can see below, I have not bothered to align anything plus I have only half tightened the double ended studs because I have not used the 2mm cork gasket between the braces and the cannons (don't want to bend anything in the mockup phase!).  Also I have not bothered to install a third line of braces whose job is to damp the steel ringing.  It works!  Rock solid...no issues...good to go.  To be honest I was a less shocked by the "look" than I thought I would be, in fact I quite like how they present themselves.  Sure, 8 cannons tall will be imposing but the is no reason that I could not make it 6 or 7 high if helped the overall aesthetic.

 

593f2972f41a7_CannonMockup2.jpg.f42987fb893878eb4af7d265ca45b7eb.jpg

 

593f2974d63d5_CannonMockup1.thumb.jpg.7f8cb49ec86730d69a80b644b21d4907.jpg

 

Except...

 

593f297404336_CannonMockup3.thumb.jpg.ae49b485d9694b90508dff1560d458f6.jpg

 

...I was going to use binding posts at the back end and have already drilled the holes through the 10mm rear plate, but I have realised that I won't be able to solder wire to the back of the binding post and do up the nut to hold the binding post in place (it is one or the other).  Binding posts are not really required in that position, they were just a convenience.  I could reverse them and the system would work:  solder wire between the driver and clamp-down-side of the binding post then push the BP through the hole in the cannon from the inside (reverse the normal direction, so clamp-down-side is inside the cannon), tighten the nut on the outside of the cannon and then solder wire behind the nut.  That plan is a bit arse-about-face so I would like to come up with another idea.

 

One thing that I have thought of is to use a simple cable gland instead of the binding post which will allow the wire through without solder connection...might be a win-win assuming the gland is able to seal properly and not create a pseudo port.  

Image result for cable gland

Does anybody have other ideas? 

 

If you use a pair of conductors with an outer sheath to seal with a single gland entry or, 2 glands one for each pos. and neg. I can absolutely guarantee a good seal for the enclosure, through using the same gland types and IP Rated  Seal against decades of weather on a roof. 

Tight as a fish Mate, water and air tight.

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If you use a pair of conductors with an outer sheath to seal with a single gland entry or, 2 glands one for each pos. and neg. I can absolutely guarantee a good seal for the enclosure, through using the same gland types and IP Rated  Seal against decades of weather on a roof. 
Tight as a fish Mate, water and air tight.

2 would be perfect. Spot on Matt.
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Well, I've ordered some cable glands.  Was a bit of an issue finding some with a long lead-in thread so I can get them through 10mm of steel but I found some for about $1.60 each delivered (IP68).  They even fit the holes I have drilled.

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Just dropped a ute load of stuff to the powdercoater with another load to go in the morning and hopefully some more to go in the next week or so.

 

Feels good to get that stuff away...I'm up to 128 hours on this steel work and starting to get a bit over it, but I have left the best stuff till last...am looking forward to building the amplifier chassis'.

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6 hours ago, Silent Screamer said:

acg you do realise that you are not only creating an over the top system, but you are creating a benchmark by which every other SNA member will get their projects green lighted by the missus.... Well I could build a system like this... ok you can have your idea :D 

 

I do have a cracker of a wife, that's for sure.  She is pretty keen for me to finish the steel work though...

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6 hours ago, BioBrian said:

Still following this build, with more and more incredulity. Will you call this the "Mortifier" section?

 

I agree, it's not exactly portable, so binding posts would seem an unnecessary expense and headache. Glands would be more in your style, but would a soft filler, like Fullers, seal and protect the cables just as well? (Could turn your cannons into glorified spud guns though).

 

I like the tensioning bolts on the side of each cannon - is that one end normal, the other end reverse thread? Amazing.

 

Still can't get my head around the acoustic side of these tubes, and the way you have 8 the same, multiplying the 'qualities' of them - hopefully to good end.

 

Keep up the great work!

 

Yes, the studs are M6 doubled ended, reverse threaded, that I had custom made through Alibaba.  I just twist them and it pulls the opposing brackets together.

 

The Bass Cannons will have an external box so that I can play with series and parallel connections of the 8 drivers and get the impedance to best suit the application.  The bass OPT is designed to drive 1R but I will try a few different configurations in order to get the best result.  

 

Currently I am trying to decide whether to directly wire the OPT to the the bass cannons or to use binding posts at the amplifier...I am a bit torn either way but I do have some Eichman Posts here that I found second hand.

 

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