Inherited 6 La Scalas - Need some assistance please

[Deang]

I’ve already submitted the question. 
 

This somehow went from “some”, to most AA’s built in the 70’s, to every AA built in PK’s adult life, lol!

[Travis In Austin]

I’m pulling for the duck tape.

 

@Edgar Greg, does a conductive screw, brass or aluminum also create potential for change in this application?

 

Does the higher inductance measured with the ferrous screw correspond with the 1kHZ change in the crossover that was measured? Does the change match up with what one would expect on paper/XO calculator?

 

if the lab standard had a brass/non-ferrous screw it would seem that this could get by for a long time, depending on how sensitive the “Tested by” equipment was at the time.

[Klipschguy]

8 hours ago, Deang said:

I’ve already submitted the question. 
 

This somehow went from “some”, to most AA’s built in the 70’s, to every AA built in PK’s adult life, lol!

Hmm….I never said “every AA built”, I said “widespread use in the 70s”; there is a big difference in the meaning.
 

The AA came around in ‘71 and went out of production in early ‘83, so the 70s is indeed a big chunk of the life of that particular network. My ‘81 KH had brass while all 6 of Ed W’s La Scalas have ferrous as a “stock configuration” - just a couple of examples. 
 

As Travis states, maybe “Tested by” equipment may or may not have been capable of catching “the error” but I do know knowledgeable, hardworking people were certifying each speaker then signing their names with pride (representing the Klipsch name). 

 

I will be interested in what JRH has to say.  Whatever the case, these “flawed AA networks” sound quite good in my opinion. 😉

 

Respectfully,

 

Andy

 

[Klipschguy]

Travis,

 

Thank goodness I didn’t have coffee in my mouth when I read your “duck tape” comment!

 

Andy

[Deang]

I should have just went to bed last night! Why was I posting about a screw at three in the morning! 

[DizRotus]

21 hours ago, Deang said:

I didn’t see a reference to an autoformer or “transformer” issue - I stock these parts. 

 

Dean,

 

He mentioned a need for a transformer for a mixing board.  Michael is heavily involved with such things, so I thought he might be a good source of info for @Klipschguy.

[Edgar]

10 hours ago, Travis In Austin said:

@Edgar Greg, does a conductive screw, brass or aluminum also create potential for change in this application?

No, only ferrous (iron-based) or other magnetic materials.

 

EDIT: Well, there might be potential for some eddy currents in other conductive materials, but I think the current in the coil would have to be unrealistically high.

 

Quote

Does the higher inductance measured with the ferrous screw correspond with the 1kHZ change in the crossover that was measured? Does the change match up with what one would expect on paper/XO calculator?

It's hard to say. The cores for iron-core inductors have size, shape, and magnetic properties that are well-characterized before the coil is even wound, so the results are predictable (within tolerances). Just putting an iron bolt of unknown size, orientation, and magnetic properties into the magnetic field will change the inductance in ways that are hard to predict.

 

Bottom line: It's simply not a good idea, but in certain circumstances one might get away with it.

[henry4841]

Back to screws used in AA networks again. Circles around regularly on the forum. The truth is the difference between ferrous and non-ferrous screw in circuit is not enough to really be a serious concern. Probably the real reason steel was used was when there was a supply problem with the brass screw. Leave be or replace if concerned engineers did not know what they were doing. 

 

As far as iron core saturation, will not ever be a problem in a Klipsch designed crossover. Iron core is plenty good enough, at least true  electronic engineers believe so. Design of an electronic component is far more important than resorting to expensive non-needed parts for improvement. What many call improvement is just different sounding. Bench testing with someone that knows what they are doing is the only true test. That and listening panel with trained ears. 

 

But back to OP finding LaScala's. Great score. Replace what needs replacing and leave rest alone for now. 

[veloceleste]

On 1/20/2023 at 9:49 AM, Ed Wolinski said:

On the other 4, a light sand and repaint with a highly recommended good grade of paint (paint brand yet to be found out, any thoughts?)

Hi,

I painted my kitchen cabinets last year and found a very durable paint that a professional painter recommended and it is holding up beautifully and is easy to clean. It is expensive and only available at Sherwin Williams stores and not available at other retailers. It is Sherwin Williams Emerald Urethane Trim Enamel Interior/Exterior. It was about $80.00 a gallon on sale! Also recommended to use with it is an high adhesion or extreme adhesion primer which is available at various regular retailers. I know it’s a lot of money for paint but as I said it is holding up very well and cleans up easily even around the areas where I am doing a lot of cooking.

 

[the real Duke Spinner]

13 hours ago, veloceleste said:

about $80.00 a gallon on sale! s. I know it’s a lot of money for paint Some Auto Paints how are $700/ gal. 🙄

 

 

.

 

[OO1]

  the Engineers + the Staff knew about it    since 1 designated screw in the   AA's  assembly  jig  was a brass screw ., but they ran out  . all klipsch   crossovers were tested  at the Hope Plant   , no exceptions  , with the ferrous  screw or  the  AA would not have shipped out    .  

[henry4841]

The early Heritage crossovers were not that critical of tolerances in the parts being mostly 1st order with little steeper 3rd order on the tweeter. Mainly to protect that delicate tweeter because of tweeter failure by idiots playing too loud. This topic comes up again and again like it was the most terrible thing in the world having a steel screw instead of a brass one.  It would take someone with extraordinary hearing to tell the difference in a blind test. 

[Ed Wolinski]

Recapped the first AA crossover with parts ordered from Jim from JEM per advice form this thread. .

 

First, a shout out to JEM. Ordered on kits Friday, received them on Saturday. VERY Securely Packaged. Can't say enough good about the entire transaction with JEM. Clear and concise instructions were provided. PLUS a "call if you cannot figure it out or have problems phone number". Cool. 

 

Installed the caps. My three cans were a tiny but damp on top, but not leaking. Measuring the uF, they were actually not that far off. Maybe .3 uF on each. 

 

In any case, fired two up (one with new caps AND a stainless steel crew in the inductor) and a stock uncapped one.

 

Results: The recapped speaker (WITH the stainless steel inductor screw in place) is noticeably brighter sounding. Not 'trebly', but more of a crisper, cleaner sound.  Will do the other xover in the next couple day and then do the screw swaps. Will advise if any improvement/detraction is noted with various screws. 

[Edgar]

4 hours ago, henry4841 said:

It would take someone with extraordinary hearing to tell the difference in a blind test. 

 

Let me start with the disclaimer that I agree with your statement.

 

That said, here we are on a forum that has seen long discussions about the sonic signatures not only of different capacitor dielectric materials, but of different capacitor manufacturers using the same dielectric materials. In that context, we are now dismissing as "negligible" the measurable distortion, not to mention the change in inductance, resulting from an iron bolt inserted into the magnetic field of an air-core inductor.

 

I just sit back and grin. We audiophiles are an amusing bunch. And please take this comment in the light-hearted nature with which it was written.

 

[billybob]

Indeed!

Nylon screw!

[Travis In Austin]

7 hours ago, OO1 said:

  the Engineers + the Staff knew about it    since THE designated screw in the   AA's  assembly  jig  was a brass screw ., but they ran out  . all klipsch   crossovers were tested  at the Hope Plant   , no exceptions  , the AA had to pass the critical tests with the ferrous  screw  or it would not have shipped out    .  

What’s your basis for this? Where is the brass screw designated? Who said they ran out of brass screws? Who told you all crossovers were tested at the plant? How were they tested? At what point in production?

 

Are you implying that they ran out or f brass screws and then switched to ferrous, tested it and approved it?

 

Is anything you have stated based on fact(s) or is it simply your keen deductive reasoning resulting in optimistic assumptions?

 

Prey tell?

[Travis In Austin]

1 hour ago, Edgar said:

 

Let me start with the disclaimer that I agree with your statement.

 

That said, here we are on a forum that has seen long discussions about the sonic signatures not only of different capacitor dielectric materials, but of different capacitor manufacturers using the same dielectric materials. In that context, we are now dismissing as "negligible" the measurable distortion, not to mention the change in inductance, resulting from an iron bolt inserted into the magnetic field of an air-core inductor.

 

I just sit back and grin. We audiophiles are an amusing bunch. And please take this comment in the light-hearted nature with which it was written.

 

I insist on some hard data (inductance measurements) with my duct tape idea. I think I’m on to something here. Normally my fall back is bailing wire, however, even I realize this would throw the whole thing out whack (need to research if they make bronze bailing wire, would have to be special order as they don’t carry it at my farm co-op).

 

Duct tape is your friend.

 

On a serious note, will a multimeter with inductance function properly measure the amount of change (if any) caused by a ferrous screw, non-magnetic stainless, brass, aluminum, nylon, hot glue to base, nylon zip ties or (my favorite) duct tape? 
 

Is a multimeter enough or does it require more (freq oscillator with a scope?). I’m trying to understand the iff what others have measured on a multimeter is solid engendering/science, like a resister, or if some critical steps were needed overlooked in deriving conclusions.

[Travis In Austin]

5 hours ago, Ed Wolinski said:

Recapped the first AA crossover with parts ordered from Jim from JEM per advice form this thread. .

 

First, a shout out to JEM. Ordered on kits Friday, received them on Saturday. VERY Securely Packaged. Can't say enough good about the entire transaction with JEM. Clear and concise instructions were provided. PLUS a "call if you cannot figure it out or have problems phone number". Cool. 

 

Installed the caps. My three cans were a tiny but damp on top, but not leaking. Measuring the uF, they were actually not that far off. Maybe .3 uF on each. 

 

In any case, fired two up (one with new caps AND a stainless steel crew in the inductor) and a stock uncapped one.

 

Results: The recapped speaker (WITH the stainless steel inductor screw in place) is noticeably brighter sounding. Not 'trebly', but more of a crisper, cleaner sound.  Will do the other xover in the next couple day and then do the screw swaps. Will advise if any improvement/detraction is noted with various screws. 

Awesome post. Do you have a meter that measures inductance like for an air core (I’m not up to speed on what is required to do that)?

 

 

[Edgar]

38 minutes ago, Travis In Austin said:

On a serious note, will a multimeter with inductance function properly measure the amount of change (if any) caused by a ferrous screw, non-magnetic stainless, brass, aluminum, nylon, hot glue to base, nylon zip ties or (my favorite) duct tape? 

I'm sure that it would, if sufficiently sensitive. I think that someone earlier in this thread measured some significant change, didn't they?

 

But that's just the inductance change. Other effects include magnetic hysteresis and saturation. And now we're getting into the more exotic stuff with which I have only theoretical experience.

[Travis In Austin]

6 hours ago, Edgar said:

I'm sure that it would, if sufficiently sensitive. I think that someone earlier in this thread measured some significant change, didn't they?

I’m seeking a bump up from .245 to .300 per DaveA. I recall others measured higher inductance as well but can’t remember the numbers they got.

 

In that circuit, forgetting the screw for a second, if you put in a 300 rated air core inductor what would you expect to see in the crossover frequency? A rise, a drop. Any way to predict how much change to expect? What are the typical tolerances and these kind of conductors? 1% 5% 10% 20?

 

I’m trying to understand the very basics here from someone who knows what they are doing. Since everything is relative I’m trying to get an idea (again forgetting the screw) of whether these differences (245 vs. 300) on paper would expect to see a change of 1khz, 10, 100, 1000, 10,000 or n the XO. 
 

I guess I really even need to learn something more basic. Does the air core inductor, in that circuit relate to what the XO frequency will be. (If so, is that because it is acting as a [Edit] high pass filter, only allowing frequencies above a certain cross-over frequency pass to the tweeter). Or

maybe It’s doing none of these, or all of them. Is there a corresponding [Edit: Low pass] filter in the Squaker XO circuit?  

 

DaveA stated this in another thread:

 

I can tell you that the value of the air core coil is changed with the steel screw. I had two AA crossovers and measured the 245uH coils on each with a B&K 885 and one was right at 245 and the other was over 300. My question at the time was why did they measure different and the answer was a steel screw. I have no way or knowledge on measuring the output of a crossover but  the coils value most definitely changes with a steel vs brass screw.

 

What