mboxler
-
Posts
574 -
Joined
-
Last visited
Content Type
Forums
Events
Gallery
Posts posted by mboxler
-
-
On 10/6/2022 at 12:02 PM, rmlowz said:
I ordered some from JEM they are only a little over 100.00 with shipping. I am going to see if I can hear a difference with these 65 old ears.
Again I ask...how does one know if a capacitor is out of spec when we don't know the factory specs to begin with?
It would be interesting if you could measure the capacitance of the old caps vs new ones. It would very interesting if you could measure the ESR of the old vs new caps, at various frequencies.
-
Selling a pair of ALK ES5800's. Includes 3-Wire cable to connect to ES400 thru ES700.
$375 shipped (ConUS) includes PP fees.
Mike
-
On 9/1/2022 at 10:40 AM, 001 said:
@Crankysoldermeister any ideas why an electrolytic was used here? What's the advantage to using a lytic when most other models use a film cap for the mid? its a smaller 7 or 6 for ch2, figured it would have used a "better" PE cap.
This would seem to been a good example of whether capacitor ESR really matters. In the Chorus I circuit, the 15 ohm resistor is in series with the capacitor's ESR. If the capacitor's tolorance is 5%, it would be anywhere from 14.25 to 15.75 ohms. Couldn't the value of the resistor have a greater impact on the total impedance than the ESR of the capacitor?
-
2
-
-
I find myself fortunate to have joined this forum years ago.
The Klipsch crossovers fascinated me, and I really wanted to learn what the capacitors, inductors, and autoformers did in a circuit. It was through modifying, measuring, and listening that I was able to learn.
I will always be grateful for those types of discussions, and to all those that contributed to them.
-
4
-
-
28 minutes ago, Jay Grantland said:
One of the caps are leaking on my daughters KSB's and I was going to replace all 4 since I'll have them apart. But the MFD is throwing me off and it's probably something simple and I'm over thinking it. I need a 20 mfd, 40 mfd, 6 mfd and a 3 mfd all 100v. When I googled to convert those values to uf I get 40000uf for the 40 mfd. is that right?
mfd is the same as µF...microfarad. As I understand it, some companies had trouble printing µF on their capacitors so they went with mfd.
-
1 hour ago, Schu said:
where is this leading us?
Starting to wonder that myself.
1 hour ago, deang said:Would actually be result of VC and filter combined, right?
This is the voltage across the K-33E installed in my Khorn, connected to various filters. Wouldn't the horn loading also come into play?
1 hour ago, Trey Cannon said:You need to use a 4 Ohm resistor in place of the woofer to see the VT of the net...
Dean is right, you have VC and filter.
Am I wrong thinking that the driver is a part of the network? If I were to use a 4 ohm resistor in series with a 2.5mh inductor, the plot would end up with a corner frequency of 255Hz, and then drop by 6db per octave after that. That's not what happens across the woofer terminals when using an A or AA, as the voltage drops less than 3db per octave due to the inductance of the voice coil. For some reason I found this interesting.
-
2
-
-
I was interested in the voltage transfers of various filters across the K-33E mounted in my Khorn. I was surprised how much the voice coil affected the A and AA transfers.
Green A and AA
Black AK-2
Red AK-3
Brown AK-4If anyone knows the difference, if any, between the AK-4 and AK-5 I can measure that as well.
Mike
-
2
-
-
1 hour ago, deang said:
That’s where I can help, but wait a while first. Part of it will involve a rewire, and I’m in the process of working on a rewiring kit, and I promise it will be painless (no soldering).
As for the networks, they can be recapped or you can buy replacements from me (I’m Klipsch Authorized).
Hey Dean
The Mid Range Horn picture shows a T5A autoformer, indicating this is an AK-2 crossover. Will you bother just recapping these or will you upgrade them to
AK-3's?
Mike
-
I know nothing about professional recording studios, but do they use cable lifters? Seems to me that if not doing so caused an issue it would end up on the original recording.
-
1
-
-
17 minutes ago, Crankysoldermeister said:
Hi Mike, why do you think it has higher sensitivity?
I assumed the K-55-M was around 3db hotter that the K-33-E, so I added that to approximate the SPL. Probably not a good idea?
-
Added a plot of the AK-3 voltage across the K-33-E. I added 3db to the voltage across the K-55-M to simulate it's higher sensitivity.
-
1
-
-
15 minutes ago, Schu said:
isn't the little 'bark' in this area an issue?
I can only assume that the high pass to the K-55-M was overdamped (if that's the bark you are referring to) to compensate for the new low pass to the woofer. The AK-3 voltage to the woofer is down 3db around 350hz and drops quickly (12db per octave) after that.
-
On 6/20/2022 at 8:19 PM, mboxler said:
I mentioned in another thread that it appears Klipsch liked to have around 3mh inductance across the K-55M, hence the different parallel inductor values for the T4A and T5A. Seems to me that, in order to get the same 3mh using a 3636, one would need to use a 3.5mh inductor in parallel with taps 0-3 of the 3636??? I measure 20mh between taps 0-3 on my 3636.
Dean said it well...I'm full of plots 🙂
I didn't have a 3.5mh inductor, but did have a 3.3mh air core. I cheated and used a ferrous screw of just the right length to place in the center of the inductor and raise the inductance to 3.5mh.
As I thought, the 3.5mh inductor in parallel with the inductance between taps 0 - 3 of the 3636 got me to my target 3mh. The brown plot is that voltage across my K-55-M. I then replaced the 3.5mh with a 5.2mh (no 5mh per the schematic in my stash), resulting in the blue plot. Tried to get rid of the 60hz spikes and the harmonics, but failed. The path to the -4db point differs, but not sure the difference is audible.
-
4 hours ago, captainbeefheart said:
ESR = tan / 2πfc
When two caps are parallel the ESR is also in parallel
If you crunch the numbers with capacitors that have the same tangent (loss angle) and you put them in parallel you'll see ESR hasn't really changed from just one single capacitor.
And no there is no issue paralleling any capacitor values no matter how far apart they are in value.
Tangent of say .06 for a film
8.2uF and 4.7uF vs 13uF
13uF
.06 / 2*π*1000*.000013 = .7 ohms ESR
8.2uF
.06 / 2*π*1000*.0000082 = 1.16 ohms ESR
4.7uF
.06 / 2*π*1000*.0000047 = 2 ohms ESR
Since the two ESR's are in parallel, that's 1.16 ohms and 2 ohms in parallel
1 / ((1/1.16)+(1/2)) = .73 ohms ESR
I thought one had to calculate the Impedance |Z| and the Phase φ of each capacitor and then add those two results in parallel. Using a few online calculators I came up with a combined ESR of around .92 ohms doing so.
-
Congrats, Dean
-
1
-
-
26 minutes ago, KT88 said:
I love following this thread, btw now its more the coils than the caps.
It's all about caps, taps, and coils 🙂
26 minutes ago, KT88 said:A layman's question. I have had AA crossovers from Crites since 2009 but with polyester caps for a year, not the real stuff from JEM but ok for now, even though for me 13 = 2x 6.8 and 2 is 2.2.
Would it make a difference if I use the Autoformer from the original Xover? Were its properties very different from those on the Crites AA switch from 2009?If your Crite's AA came with a 3636, then there will be a subtle change as shown in the plots I attached. A little more voltage to the squawker between 300 and 500hz and a little less after that. I doubt I would hear that.
The T2A inductance values on the spec sheet are +/- 15%. It would be interesting if you could measure the inductance on both T2A's just to see how far off, if any, they are from spec. Again, I'd measure between taps 0 - 3 and multiply that by 4, or between taps 0 - 1 and multiply that by 16.
-
2
-
-
21 minutes ago, captainbeefheart said:
Make sense?
I figured out how to simulate autoformers in LTspice a while back. At that point I realized that the inductance does matter, unless you use the "swamping" resistor. My point is that I wish I could have been a part of that conversation knowing what I know now.
Another case in point is the 5mh value of the shunt inductor on the AK-3. It's in parallel with the 7.3mh inductance between taps 0 - 3 of the T4A, resulting in a 3mh shunt inductor across the K55M. On the AK-2, the inductance between taps 0 - 3 is 11.4mh, therefore a 4mh shunt inductor was used to reach that 3mh target. Coincidence???
-
1
-
-
I remember reading this thread started by @Crankysoldermeister when Dean was having trouble measuring the 3636 inductance. Both Al and Bob chimed in, but their point was that the inductance meant nothing...the level of attenuation is all that matters. I can understand Al's point only because his resistor "swamps" out the autoformer inductance anyway.
It's my understanding that the large inductance between taps 0 - 5 may make measurements difficult. Another way to measure is across taps 0 - 1, which is 25% of the total windings. That inductance times 16 should be the inductance across 0 - 5. I do worry that my numbers are off no matter how I measure.
-
1
-
-
According to the specs, the T2A's total inductance is 45.6mh (11.4 *4).
The inductance of the 3636's is pretty high, and I think that messes with my LCR meter, so I measure the inductance between taps 0 and 3, then multiply that by 4. I end up with one at 88.8mh and the other at 76.8mh.
-
10 hours ago, Crankysoldermeister said:
You mean like, take a stock pair of AA's, and just replace the T2A with one of the others -- no, I have never done that. See, I have left work for you guys to do.
Got a feeling you knew I'd react to this 🙂
Here are LTspice plots of the voltage across the squawker (in this case a 14.6 ohm resistor) in an AA crossover.
The green is tap 3 of a T2A, the red tap 3 of a 3636. The lower inductance of the T2A contributes to the difference in slopes. Noticeable???
I have always found it interesting that the impedance of the tweeter circuit attached to tap 0 increases the attenuation to the squawker by nearly 1.5db.
-
33 minutes ago, Crankysoldermeister said:
My questions have always been more about what the amp is doing. I didn't mention anything about sound pressure, but about sensitivity.
Whether there is a loss or not depends on how you define sensitivity. Is it at 1 watt or at 2.83 volts? If you use 2.83 volts, then the resistor will not change sensitivity, it will just double the current draw from the amp. I believe that's Al's argument on the subject.
If you consider the K55 driver 16 ohms, then same outcome can be reached by placing a 16 ohm resistor across the driver, and placing an 8 ohm Lpad before the resistor/driver combo.
-
32 minutes ago, ClaudeJ1 said:
NoBody means most people. But some do understand it to various degrees based on requirements beyond Audio frequencies.
Although I don't consider myself part of the "understanding" group, here's my take on capacitors. I'll focus on the 2uf value since that's the value of choice in the Heritage tweeter circuit.
I bought some 2uf polyester caps off the Bay to play with.
I feel that ESR isn't important at audio frequencies, and because the dissipation factor of all dielectrics changes with frequency, ESR actually decreases as frequency increases. Here are my measurements of these caps...
1000hz, reactive impedance 80 ohms, ESR .37 ohms.
10000hz reactive impedance 8 ohms, ESR .07 ohms.
In either case, the reactive impedance overwhelms the ESR, making it irrelevant???
Again, I'm no EE, so please correct me if I'm wrong.
Mike
-
1
-
-
17 minutes ago, Crankysoldermeister said:
There you are. I was starting to worry a little.
Getting new carpet installed today. You don't realize how much crap you have until you have to move it out of the way 😥
-
1
-
-
18 hours ago, Crankysoldermeister said:
All of the new builds are done using aftermarket autotransformers. They are wound by the same company but are different than the originals. Inductance between taps is quite different. @mboxler has done quite a bit with this but it's difficult to decipher what the effect might be.
Someone I have a high degree of respect for sent me this on the topic:
"Differences in the reactance at both ends of the impedance modulus are likely but are they significant? The 13uF cap in the circuit will determine the impedance response in the LF side of the modulus, it dominates totally. The high end of the response is determined by the mutual inductance of the windings but even here, I'd be surprised if there were any significant differences to the second decimal."
I, too, wonder at what point a measured difference is audible. Below is an LTspice plot of the voltage across a K55 (simulated by a 14.6 ohm resistor) in an AA circuit. The green plot is with a T2A autoformer, the red, a 3636. Even though the T2A's tap 3 is -3.3db vs the -3db on the 3636, the T2A is "hotter" at the crossover point due to it's lower inductance. As frequency rises, however, the shunt impedance of either autoformer is so high that it becomes irrelevant.
-
4
-
.png.ed028bdb0eb4951091002b4342156166.png)
.png.6617da365b3a6b1d060693aed8d18e78.png)
Update 1977 Klipsch LaScala crossover.
in Technical/Restorations
Posted
If you have the original crossover's T2A, it would be interesting to replace the 3654 with it. I don't have a 3654, but it's supposed to be the same as the
3636 that I do have, less the extra taps.
Here are plots of the 3636 (orange) and T2A (blue). I used a 13uf capacitor and tap 4 is connected to the K-55-M in my Khorn.
Even though tap 4 of the T2A is -3.35db vs the 3636's -3db, the voltage across the K-55-M is actually a little higher in the 400-600hz range. This is due to the difference in inductance between the two autoformers.
Not sure I would hear the difference, but interesting nonetheless.
Mike