Jump to content

Inherited 6 La Scalas - Need some assistance please


Ed Wolinski

Recommended Posts

  • Moderators
5 hours ago, Edgar said:

I'm not familiar with the particular circuit in question, so I can only answer in generic terms

Sorry, I thought you would have had it memorized by now:

 

The JH is Jim Hunter. The "Approved" I can't quite make out, but I believe that could be a KG (Kerry); or could be RDJ ("Roy"). 

 

image.thumb.png.c52b5ed49d849a36be1cdd23b48a1451.png

Link to comment
Share on other sites

43 minutes ago, Edgar said:

One of the curves is measured while the other is simulated using LTSpice.

 

This confused me 🤔.  Luckily, I found a 245uh and a 345uh inductor, so I ran tests across a K-77M.

 

The blue plot is a 245uh inductor.

The green plot (little hard to see) is the same 245uh inductor with a nail through the middle to bring it up to 345uh.

The red plot is an actual 345uh inductor.

 

Surprised me to find out that the 245uh plus nail isn't even close to the 345uh!

 

Mike 

 

245uh vs 345uh.jpg

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

  • Moderators
1 hour ago, mboxler said:

Surprised me to find out that the 245uh plus nail isn't even close to the 345uh!

 

Mike 

Was the nail Ferrous? Magnetic?  Sorry, I couldn't resist. 

 

39 minutes ago, geoff. said:

…that’s one magic K-77, lol

Well I want whatever the purple line is. Where can I get one of those? (Just kidding)

 

1 hour ago, mboxler said:

Surprised me to find out that the 245uh plus nail isn't even close to the 345uh!

So @edgar, even though the nail go the "target" rise in the impedance (345mH), it doesn't act the same acoustically as a 345uH. I assume this is due to the "side effects" you described in earlier posts like hysteresis and other things going on when you but something magnetic down the center of an air core conductor?  

 

@mboxler which sounded the best to you, or have you gotten that far?

Link to comment
Share on other sites

  • Moderators
2 hours ago, mboxler said:

Surprised me to find out that the 245uh plus nail isn't even close to the 345uh!

How much smoothing do you have going on there? Do you have the raw (dirty) curves?

 

In terms of speaker design and XO configuration (without regard to what part is doing what), which of those three is best? If someone showed you mBoxler's 3 curves, and said "here are three different parts, cost is equal, pick the one you want". Which do you pick? Red looks like a 4800 kHz XO, Green looks like a 4900 XO, and Blue looks like 5500 kHz XO. All three look to have the same slope. I guess you can't tell slope from curves like that? An octave lower would, on average, be about 2500 kHz and the drop is 16 to 20 dB per octave depending on which of the three. Maybe these curves are just the inductor, Not the XO as a whole and so slope can't be determined?

 

Sorry for the basic questions, I know this doesn't help the OP with his questions. But he is going to be busy changing the second XO with the parts he got so hopefully he won't mind. 

 

Travis

Link to comment
Share on other sites

  • Moderators
2 minutes ago, Chief bonehead said:

Any screw that magnetic will not work. And no pwk did not design it that way. Use a non magnetic screw. 

So duct tape isn't the way to go? Are you sure you are from Texas?

 

How the magnetic screws got in there in the first place it appears will be a mystery wrapped up in an enigma as it wasn't PWK's doing. This was before Chief Bonehead (BCB), and Mr. Hunter replied in the other thread he doesn't know how they got there (well in a funny round about way, he didn't deny that happened but didn't admit it either) and said "doubtful" there would be any documentation. 

 

@Ed Wolinski Mr. Ed, there is your answer on the screw. 

 

So now it is paint, etc.?

 

Thanks for the topic, I learned a great deal along the way. 

 

 

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

I may have been one of those that said Klipsch ran out of brass screws and intentionally used steel until stock restored. Could as well have been some newbie or careless veteran just grabbed the wrong box of screws from the supply room. S**t happens. No real harm done, I am sure owner was well satisfied listening with steel screw for decades without an issue. Just replace with brass if found in your network and be more happy with your speakers.  

  • Like 2
Link to comment
Share on other sites

8 hours ago, Travis In Austin said:

How much smoothing do you have going on there? Do you have the raw (dirty) curves?

 

No smoothing.  This is as dirty as it gets.

 

8 hours ago, Travis In Austin said:

In terms of speaker design and XO configuration (without regard to what part is doing what), which of those three is best? If someone showed you mBoxler's 3 curves, and said "here are three different parts, cost is equal, pick the one you want". Which do you pick? Red looks like a 4800 kHz XO, Green looks like a 4900 XO, and Blue looks like 5500 kHz XO. All three look to have the same slope. I guess you can't tell slope from curves like that? An octave lower would, on average, be about 2500 kHz and the drop is 16 to 20 dB per octave depending on which of the three. Maybe these curves are just the inductor, Not the XO as a whole and so slope can't be determined?

 

 

This is the actual voltage across the K-77M.  All of them start out around 18db per octave.  The slope steepens up to the peak voltage point.   I think this is due to the fact that this is an underdamped high pass filter???

 

Mike

  • Like 1
  • Thanks 1
Link to comment
Share on other sites

Thanks for all of the great input. As a new guy here I never expected 5 pages of discussion and the tremendous amount of help that was provided by y'all. Many thanks for the tip on JEM; my first (of many to come) transactions with him was perfect. Now to the screw. This is (to my ears, at least, I hear nuances in music very well, more than most people I know) different with a stainless screw in place. I have to get some brass screws to further my investigation. As I stated before the output is crisper, brighter, but not 'trebly'. Hard to explain; but noticeable. Perhaps more 'presence' is the word I am groping for. Two of the 6 have been recapped and stainless screws are in place. Next in line for those 2 is some light sanding and a good exterior paint job that might match the original finish. Still looking for further advice on that avenue. 

  • Like 3
Link to comment
Share on other sites

12 minutes ago, Ed Wolinski said:

Next in line for those 2 is some light sanding and a good exterior paint job that might match the original finish. Still looking for further advice on that avenue. 

https://www.acrytech.com/product-category/speaker-cabinet-coatings/

 

I'd go with DuraTex in lieu of painting. Much more forgiving and more durable than paint.

 

 

  • Thanks 1
Link to comment
Share on other sites

9 hours ago, Travis In Austin said:

So @edgar, even though the nail go the "target" rise in the impedance (345mH), it doesn't act the same acoustically as a 345uH. I assume this is due to the "side effects" you described in earlier posts like hysteresis and other things going on when you but something magnetic down the center of an air core conductor?

The change is measureable. The specific cause(s) of the change are unknown without more information.

 

However, magnetic hysteresis consumes energy and dissipates it as heat. That means it acts like a resistance. Resistance in an LC circuit reduces the Q, i.e., flattens-out peaks. It's only conjecture, but it seems to fit.

  • Thanks 1
Link to comment
Share on other sites

  • Moderators
1 hour ago, Edgar said:

The change is measureable. The specific cause(s) of the change are unknown without more information.

 

However, magnetic hysteresis consumes energy and dissipates it as heat. That means it acts like a resistance. Resistance in an LC circuit reduces the Q, i.e., flattens-out peaks. It's only conjecture, but it seems to fit.

An ounce of yours or Roy's conjecture, I have found, it worth of pound of general speculation. I learned a great deal, maybe the next bonehead class I will be able to spend more time in class, but it would clearly slow everyone down. 

Link to comment
Share on other sites

  • Moderators
3 hours ago, henry4841 said:

I may have been one of those that said Klipsch ran out of brass screws and intentionally used steel until stock restored.

I had it pegged for industrial sabotage, you know, maybe JBL, Bose, and others slipped in an undercover network builder who poured out the stainless screws (of the non-magnetic variety) and put in plain old steel screws.  I guess doing what I do results in a way over-active imagination. 

 

Kidding aside, that's a pretty logical and probably the simplest explanation and one that would be favored by Occam.

 

 

Link to comment
Share on other sites

1 hour ago, Edgar said:

The change is measurable. The specific cause(s) of the change are unknown without more information.

 

However, magnetic hysteresis consumes energy and dissipates it as heat. That means it acts like a resistance. Resistance in an LC circuit reduces the Q, i.e., flattens-out peaks. It's only conjecture, but it seems to fit.

 

I believe your are correct.  My 245uh air coil measures .1 ohm DCR.  When I switch to resistance at 1 khz, it is .152 ohms.  Placing the nail through the center increases the resistance to .524 ohms.  

 

Likewise, at 10 khz, the resistance increases from 1.75 to 3.59 ohms.  

 

In either case, Q is almost cut in half with the nail, which will flatten the peak.

 

Mike

Link to comment
Share on other sites

1 minute ago, mboxler said:

I believe your are correct.  My 245uh air coil measures .1 ohm DCR.  When I switch to resistance at 1 khz, it is .152 ohms.  Placing the nail through the center increases the resistance to .524 ohms.  

 

Likewise, at 10 khz, the resistance increases from 1.75 to 3.59 ohms.  

 

In either case, Q is almost cut in half with the nail, which will flatten the peak.

I love it when science works!

 

However, make certain that your AC resistance measurements are not also including the inductive reactance magnitude.

Link to comment
Share on other sites

4 minutes ago, Edgar said:

I love it when science works!

 

However, make certain that your AC resistance measurements are not also including the inductive reactance magnitude.

 

I'm assuming it doesn't since the reactance of a 245uh inductor is 15.4 ohms at 10 khz.

  • Like 1
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...