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OLA crossover help please


drmoron

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Well, Pete, decided to go for the gusto and use the good inductors. Getting braver ;) What the heck--only paid $50 for the speakers. Figuring in the refoam kit, new caps, resistors, inductors and misc these are still costing me well under $200. So even if I decide not to keep them I can probably sell them and at least break even.

Here's what I ordered from Erseaudio:

(2) EAC32-18-450 0.45mH 18ga EQ -Perfect Lay High Bond Air Core Inductor $9.30

(2) EAC31-18-070 .07mH 18ga EQ - EQ – Perfect Lay High Bond Air Core Inductor $4.80

(2) EAV75-14-1500 1.5mH 14ga XQ - Perfect Lay Air Core Inductor $44.60

Subtotal $58.70

Shipping $9.25

Total $67.95

So while I wait, think I'll make some cabinet braces per Carl's suggestion and clean up the veneer.

I've decided that, except in extreme cases, it's better to just clean the cabinets with Howard Restor-a-Finish, leaving minor dings and scratches as "patina."

Sanding and veneer do not make a good combination.

Kent

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The refoam job is finished. Came out quite well if I do say so. Still don't agree that the Masonite-ring version is "easy" compared to more conventional designs, but not as bad as I had feared.

Kent

Hi Kent

Glad your refoaming went well for you.

I see an optical illusion, it looks like to 1/2 roll is outward, rather than inward.

I've seen this before on ebuy, dunno why it appears that way.

Maybe I should eaze up on my meds. LOL

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Hi Vern!

The same thing happens to me too with masonites. I usually have to take a second or third look to let the "correct" way lock in to my vision.

I take meds too but they shouldn't be any of the kind to make me hallucinate (just blood pressure and anti-cholesteral drugs).

Unless, of course, Kent has discovered a new, superior, half-and-half Advent refoaming method.

\:^)

Doug

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I see an optical illusion, it looks like to 1/2 roll is outward, rather than inward.

What?! You mean that's not how they go? :lol:

Yes, they are inverted per originals.

Finished the bracing: 2 oak braces front-to-back.

Kent

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Separated at birth? Never noticed this before but the OLA looks a LOT like the KLH Model Five: Bull nose frame, trim between the bull nose and grille, even the size. OLA is 14 ¼ x 25 5/8 x 11 ½. KLH Five is 13 3/4 x 26 x 11 ½

post-101828-0-56999100-1313603254_thumb.

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Separated at birth? Never noticed this before but the OLA looks a LOT like the KLH Model Five: Bull nose frame, trim between the bull nose and grille, even the size. OLA is 14 ¼ x 25 5/8 x 11 ½. KLH Five is 13 3/4 x 26 x 11 ½

Hi Kent

Small section of cabinets but both are attractive in appearance.

You'd almost think that the same designer was involved with both of their design. LOL

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They are pretty Kloss in appearence.

:lol: :lol: :lol:

Funny (to those who know how Henry pronounced his name).

Built one new XO today. Thanks Pete for the encouragement and advice. Those new inductors are BIG and HEAVY compared to the weenie ones in there originally. Used Carli capacitors and stuck a bypass cap on the tweeter. Doubt it helps but it couldn't hurt. New Dayton "Audio Grade" resistor.

Can't wait to get these finished now! But I'm dividing my time between these and the Pinnacle PN6+ Sally find.

Kent

post-101828-0-53986600-1313786912_thumb.

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:lol: :lol: :lol:

Funny (to those who know how Henry pronounced his name).

Built one new XO today. Thanks Pete for the encouragement and advice. Those new inductors are BIG and HEAVY compared to the weenie ones in there originally. Used Carli capacitors and stuck a bypass cap on the tweeter. Doubt it helps but it couldn't hurt. New Dayton "Audio Grade" resistor.

Can't wait to get these finished now! But I'm dividing my time between these and the Pinnacle PN6+ Sally find.

Kent

Hi Kent

When I was a subscriber to, The Audio Amateur magazine, there was a Walt Jung who wrote several articles.

A Dynaco C-100 electrolytic capacitor type bank for the Dynaco 400, but it could be used for others.

Almost every electrolytic capacitors that he wrote about had a small, such as 0.47uf capacitor, across it.

I would need to review all my old back issues to be absolutely certain of this.

Not too long ago I read something about this, it allows higher frequencies to pass.

Maybe it is, AVA, Van Alstynes (spel) web site.

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Not too long ago I read something about this, it allows higher frequencies to pass

Yes Vern, that's the theory. I'm skeptical but the bypass caps are very cheap so why not?

Kent

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Hi Kent

When I was a subscriber to, The Audio Amateur magazine, there was a Walt Jung who wrote several articles.

A Dynaco C-100 electrolytic capacitor type bank for the Dynaco 400, but it could be used for others.

Almost every electrolytic capacitors that he wrote about had a small, such as 0.47uf capacitor, across it.

I would need to review all my old back issues to be absolutely certain of this.

Not too long ago I read something about this, it allows higher frequencies to pass.

Maybe it is, AVA, Van Alstynes (spel) web site.

Hi Vern,

Walt Jung is the author of "The OP Amp Cookbook" and I believe

that he has written application notes for Analog devices. His web site:

http://waltjung.org/

He was somewhat involved in the old TIM debate, or is at least mentioned

by John Curl on DIY Audio when he brings it up.

Jung also did this excellent history of OP amps paper:

http://www.analog.com/library/analogDialogue/archives/39-05/Web_ChH_final.pdf

I noticed prior art involving Deane Jensen's patent for the inductors

used in his 990 OP amp. I'm PB2 here:

http://www.diyaudio.com/forums/solid-state/107404-simulation-je-990-op-amp-deane-jensen.html#post1289112'>http://www.diyaudio.com/forums/solid-state/107404-simulation-je-990-op-amp-deane-jensen.html#post1289112

I really admired Jensen's work on the JE-990:

http://www.diyaudio.com/forums/solid-state/107404-simulation-je-990-op-amp-deane-jensen.html

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:lol: :lol: :lol:

Funny (to those who know how Henry pronounced his name).

Built one new XO today. Thanks Pete for the encouragement and advice. Those new inductors are BIG and HEAVY compared to the weenie ones in there originally. Used Carli capacitors and stuck a bypass cap on the tweeter. Doubt it helps but it couldn't hurt. New Dayton "Audio Grade" resistor.

Can't wait to get these finished now! But I'm dividing my time between these and the Pinnacle PN6+ Sally find.

Kent

I'm really curious to hear your opinion of the LA, did you consider

comparing one with the crossover upgrade and one without? You're

welcome to try the BSC circuit if you'd like. They're rather forward

sounding without it and they really "lock in" with it. I would not

hesitate to give them some power also, I've run 200W/ch keeping it

below clipping. You would not want to drive them hard with that much

power, especially originals without ferro fluid in the tweeter.

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Hi Pete

Unfortunately I did not keep a "stock" xo, so I can't compare them. I'm betting those heavy new inductors will affect the sound, but have no idea how. I doubt the Carli caps will have an audible effect, since I've been told they have ESRs closest to the original NPE caps. And yes--I'd like to give the BSC circuit a try.

Hope to finish the other speaker soon, then stuff the cabinets with 2.1 pounds of fiberglass (according to Carl) and fire them up. The foam is gone--used it as packing material!

Here's a shot of the new and old inductors. Big difference!

Kent

post-101828-0-03448400-1313946574_thumb.

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That inductor is so much bigger because it is air core and requires thicker wire.

There are very large differences in iron core inductor saturation (distortion)

characteristics. Laminated iron for woofer inductors are usually best but there

are also newer Ferrites that are fairly good. I've not seen any measurements

on the old Advent inductor but there is a good chance that there will be an

improvement with the air core when pushed hard. I don't expect a large difference.

Let me know when you have them finished and are ready for the BSC.

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Laminated iron for woofer inductors are usually best but there are also newer Ferrites that are fairly good. . . .

I've not seen any measurements on the old Advent inductor . . . .

OK. Now I'm confused (again). Didn't you recommend that specific air core woofer inductor? And.. Didn't YOU measure the old Advent inductors? I must be missing something :(

Kent

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OK. Now I'm confused (again). Didn't you recommend that specific air core woofer inductor? And.. Didn't YOU measure the old Advent inductors? I must be missing something :(

Kent

That was me Kent. So, you have me to blame if things don't work out to your liking. I found the voicing with the compliment of coils I used changed a bit to the lower side which, if the same occurs for you, you may not need BSC.

I have some WT2 woofer coil measurement scans of the old and new but haven't had the time to post them yet.

I just summarized the results in an earlier post #19.

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Hi Carl

No "blame". I was referring to Pete's page that shows measurements of the inductors: http://baselaudiolab...VENT_LA_XO.html

and here, http://www.classicsp...?showtopic=4919 in Post #3 he recommended a Dayton Air Core Perfect Lay inductor that seems identical to the Erse: http://www.parts-exp...tnumber=266-360

Hence my confusion.

Kent

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I measured the linear inductance value.

I did not measure the non-linear distortion characteristics.

All iron core inductors saturate at some current level.

Usually it is at mid to high current levels, but there are

some with odd non-linear characteristics even small signal.

All air core inductors do not saturate at all, they have

virtually no distortion.

I did repeatedly say that they would probably only make

a difference at high levels above 50W. The air core inductors

will certainly not sound worse, only better.

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I measured the linear inductance value. I did not measure the non-linear distortion characteristics.

All iron core inductors saturate at some current level. Usually it is at mid to high current levels, but there are some with odd non-linear characteristics even small signal.

All air core inductors do not saturate at all, they have virtually no distortion.

I did repeatedly say that they would probably only make a difference at high levels above 50W. The air core inductors will certainly not sound worse, only better.

Here's one of the things that confused me: I understand that "air core inductors...have virtually no distortion" but earlier you wrote " Laminated iron for woofer inductors are usually best but there are also newer Ferrites that are fairly good" (Post #39). So my confusion involves which is "best" for woofers--air core or laminated iron.

Thanks for all the guidance

Kent

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I think Pete meant, of the iron core inductors, laminated is best.

Not of all inductors.

So, air core would still be better.

Doug

Right, there is no question about air core, they are best.

Properly designed laminated steel have been considered best

in woofer applications for many years. From memory, I seem

to remember the OLA woofer inductor being a Ferrite type,

not laminated steel. Their was a test of inductor distortion in

Speaker Builder or AA many years ago and most cored types did

not do well.

Erse, for example has some huge cored inductors rated for 500W

that do not look to be laminated that they claim are low distortion.

I'd like to see some independent tests of them.

I stick to all air core whenever possible in my best designs.

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I think Pete meant, of the iron core inductors, laminated is best. Not of all inductors. So, air core would still be better.

Doug

Oh. Duh :blink:

That clears it up

Kent

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:lol: :lol: :lol:

Funny (to those who know how Henry pronounced his name).

Built one new XO today. Thanks Pete for the encouragement and advice. Those new inductors are BIG and HEAVY compared to the weenie ones in there originally. Used Carli capacitors and stuck a bypass cap on the tweeter. Doubt it helps but it couldn't hurt. New Dayton "Audio Grade" resistor.

Can't wait to get these finished now! But I'm dividing my time between these and the Pinnacle PN6+ Sally find.

Kent

Hi Kent

Where did this type of cabinet bracing originate?

I've seen the original AR-1W prototype with it's front baffle radial bridging and the usual AR-3 and 3A cabinet

with it's horizontal bracing but never front baffleboard to back panel bracing.

Is this a new technique for strength?

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Where did this type of cabinet bracing originate? . . . Is this a new technique for strength?

Originate? I dunno. I basically copied Carl's technique. See attachment to Post #12:

http://www.classicsp...?showtopic=2895

Front-to back certainly adds strength, it's easy to do and the screw heads are on the front baffle and back panel so there's no "screwing up" :lol: the veneer. Seems to work well. I just added bracing to a small Pinnacle speaker, too.

Also check the Human Speakers site

http://www.humanspea...wto/bracing.htm

Huw Powell writes: "Places where the baffle is cut for the drivers, and hence weakened, are also ideal candidates - since not only is the material weakened by the cutouts, but this is where the "equal and opposite reaction" energy of the drivers enters the cabinet material directly. Often you will find that these two become one and the same - the rear panel is the largest, and putting in front-to-back braces around the woofer, say, will stiffen it nicely. "

Kent

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Finished the crossovers, put one speaker together. I used 33oz of fiberglass, consistent with Carl's write-up but although they sound "good" they seem a bit bass heavy compared to the AR91s.

Any suggestions?

Kent

[edit] OOPS. Nevermind. It's not the bass. I have one bad tweeter. Sounds like a tissue paper & comb kazoo :angry:

Can someone tell me if the offset fried egg tweeters in the OLA were the same as the ones in the Smaller Advent? They look the same but I know the Smaller Advent was a 4 ohm system.

post-101828-0-05506000-1314210970_thumb.

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