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Old 6th September 2012, 11:05 PM   #801
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Default Lots of stuff!

Hello all...

Sorry I have been absent, but.... have been busy moving... Yuk!!

First, thanks to Skip Pack for stepping up and providing info on the Manzanita thing. BTW, S.P., Hope your Altec 605A's in OB trim are serving you well!!

FYI, most Manzanita plants are small to medium hight and brush like. Say 24" to maybe 72" and rangy. However, in the central foothills of CA, there is a large variant, which, can grow to over 40' with trunks up to 40" in diameter. It is this variant that I know and think of as a Manzanita. The "little apple" reference is to the small berry like fruit the Manzanita produces, that is apple shaped and colored.

Pano, thanks for supplying the baffle dimensions for the Ultra!

Concerning the P.Audio 18 coax... I am still refining this project. I have discovered via various emails from others that also have pair(s) of these that there seems to be some variance in the woofer T/S parameters. I am waiting for a trial sample from P.A. before ordering up the minimum 50 pair required for a new factory direct order. So it's going to be a while before I can move forward with the final crossover and a commercial version. Such is life!
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Old 9th September 2012, 11:25 AM   #802
Johno is offline Johno  Australia
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Default Impatient...

So I have finished the baffles, polished and varnished, mounted the drivers and now stored in the lounge room. WAF seems to be OK thank goodness.

Found a guy on eBay selling 25kg of recovered cross-over capacitors for next to nothing. Luck dip. About 10kg were Solens, go figure. Also a bunch of wax blocks that I have yet to explore and about 5kg of MKP types from Phillips and Wima etc. Rest were electrolytics. Asked the guy if he still had the cross-over inductors - no sold for the copper value (grrrr).

Search for inductor suppliers, all too expensive or too high R or iron cored. Thinks - I can wind an inductor. Get out the old text books, re-discovered the Brooks approximation, work out the former sizes and copper length. Buy a reel of 10 gauge wire for $500, smallest reel I could find. Didn't realise copper was so much. Buy the hole-saws for building the formers. $200 (I will line the former and cheeks with nylon for quick release and will impregnate the coils with varnish as I go).

What do I wind it on? Sewing machine has not been used since we were first married so is now missing a motor and foot control (secretly). Or maybe I should use the drill stand with a little phase controller - much more torque and how would I build a horizontal mandrel with half decent bearings anyway. Ah- what about buying a lathe.....

Bloody hell John B, you are costing me a fortune. But it is fun, so many thanks.
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Old 9th September 2012, 12:52 PM   #803
Pano is offline Pano  United States
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Use a big iron core inductor for the woofer. Like the Erse models. Aircore is not right for this part.

Sounds like a great haul on the caps, sure sucks about the inductors. Copper is $$$ these days. Let us know how it comes along.
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Old 9th September 2012, 06:46 PM   #804
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Johno

Boy, you are going all out, that is for sure! Great to know you are having fun with your project.

As for your inductor situation, a 18-20 mh 10 ga air core would be interesting to say the least, but wow, it's going to weigh 20-30 lbs!! I have a couple 2 MH air cores and they are monsters.

I have not done the calculations, but would assume a 10 ga would exhibit around 1.0 ohm or so assuming 18-20 MH and that is close enought to the .8 ohm or so a 15 or 16 ga iron core typically measures.

Of course the Iron core low pass inductor is a concession to size and cost issues. Plus keeping the insertion losses to a minimum. I don't think anyone has attempted the large air core solution your are pursuing.

I'm sorry you are spending so much money on the project, but am confident you will have a great speaker when all is done.

Please let us know when you are done and what you think of the results. A couple pics would be great too!

Best

John
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Old 10th September 2012, 11:30 AM   #805
Johno is offline Johno  Australia
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Default 20mH air core

I calculate 21 turns per layer by 21 layers (plus about 5 extra turns to trim the value).
The Brooks coil formula prescribes a "square" cross section where length = height = 2*ID = 4*OD. My ID is 94mm and OD is 188mm (thats about 7.5 inches OD)
Given the 5.2kg weight of the thing I was going to mount it low down near floor level, in plain view for stability and to teach persistent kids a lesson when it gets hot. Resistance is probably too low at just under an ohm. The 2mH is only a modest 4 inches across and 1.25kg.

While the large diameter air core solenoid may be cute there is a downside, and that is the magnetic losses and also stray field pickup (big coils make good antennae). The other reason for mounting it away from the woofer motor. Just for fun I have also worked out how to wind a toroidal air-core at 20mH. These do not leak or interfere and should be yummy for fidelity. I have yet to check the math or optimise the shape but it looks to be a bit larger at 17 inches OD and 20kg.

Of course I will share some photos, but until then it is burning a hole looking at those 2 silent, one-eyed, yawning sentinels standing at the end of the room.
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Old 10th September 2012, 10:11 PM   #806
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John do you intend to release the full specs of the HE versions for DIYers like with the plain Manzanitas? Or will it remain a commercial product?

Last edited by dimkasta; 10th September 2012 at 10:13 PM.
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Old 16th September 2012, 06:07 PM   #807
dawa is offline dawa  Sweden
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Default Some thoughts on variations

Hi John
I finished my Manzanita’s a couple of weeks ago. Have hooked them up to a Hypex ucd 400st homebuilt amp. Approx 200Watt 8 ohms. And it really makes the Manzanita sing! I have as others had my doubts about the small Vifa driver but it has fulfilled my expectations totally.

Now to my thoughts about the sound from these “no-boxes”. This weekend I visited a really big hifi show in my town. The whole of Scandinavia was there and some of those exotic equipment you only read about was displayed. What I found was that the GRADIENT HELSINKI 1.5, which I think uses the same woofer as the Manzanita, actually sounds very good and is close to the sound from the Manzanitas.
This layout is very interesting as the front area is so small. Could it be done with the Manzanita? I accept that the woofer has to be at the same height but do the Vifa need such a big baffle?
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Old 18th September 2012, 12:52 AM   #808
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Default HE - OB

Dimkasta....

Thank you for your interest in the HE! The original was based on a special Eminence woofer that has been discontinued. Eminence no longer offers any of their professional 15" or 18" woofers with pressed baskets, which unfortunately is what the original version of the HE used. A very special, unique woofer. That woofer had a lot to do with the magic of the H.E.

I have been auditioning a variety of 18" paper cone woofers to replace the original Eminence. To date nothing really fills the bill, if you will.

So.... the original crossover does not mater, and as with most multi-way designs, crossover is key. If I do find something reasonalbly priced in an off the shelf 18 that can replace the original Eminence 18 I will proceed with the project and release a simple DIY version for others to enjoy.

Best

John
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Old 18th September 2012, 01:19 AM   #809
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Default Vifa baffle width

DAWA

Thank you for your impressions and question about the Manzanita, specifically the Vifa.

And.... Nice to know the Manzanita general performance is some what similar to the G.H. 1.5, which from various reveiws has established itself as a state of the art product.

Concerning the baffle width of the Vifa in the Manzanita format...

Like all designs there are concession to simplicity, cost, praticality and all the rest. The relatively large baffle diameter does provide a correct amount of loading as well as the proper OB F= / F peak characteristics.

I must restate the basic goal of the project, and that is to keep every aspect as simple as it can be with out any major performance compromises.

And, as has been stated several times in past posts, I wish to promote, enable if you will experimentation with the base design.

I do suspect radical baffle and wing shapes could, can improve the sonic performance of the base Manzanita design. Again ... that is the wonderful aspect of the base design... it is as simple as it can be, and yet... delivers amazing performance.

So... please experiment. Share what you learn. The closer you get this design to real music for reasonable cost and construction simplicity, the better!!

Best

John
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Old 20th September 2012, 11:11 PM   #810
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Default A new potential frontier

Hello all.....

Trying to take the Manzanita concept to the next level, with out expandanding the baffle and build costs too far.

It seems that a 15 inch woofer is the limit when a stand mounted aesthetically balanced OB format hi fi speaker intended for DIY residential use is the goal. There seems to be a horizion... physical boundry where a baffle wider than 16 inches or so is no longer pleasing and balanced to the eye.

So... working with several 15 inch woofers that may provide the magic balance of low distortion, bass extension, mid range performance, efficiency, cost, Q and flat frequency response. Also working on a mating full range as well.

As the woofer's diameter increases, the lower end demands of the mating HF driver also increase.

All of this is a design project at the moment. And is intended as an FYI, as I am still inovating and learning from all the great feed back I have been receiving.

If anything develops that justifies a post, I will, of course share with all.
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