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Type AA crossover rectangular capacitor replacement


Tizman
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1 minute ago, captainbeefheart said:

 

They purchase parts knowing the specification needed so that the inductor will not saturate under normal use, say up to 100 watts. The iron core vs air core was a no brainer for them really, the price is cheaper and there is less DCR for better damping. If they did get an air core with the same DCR and inductance it would be huge and expensive for no benefit.

 

The problem is someone reads somewhere that air core does not suffer the same core interaction problems and so they are superior. Although this is true, it is much more prudent to just use an iron core inductor where it is sized appropriately to not saturate the core. You end up with the same low distortion signal but with lower DCR and for less money which the savings is passed onto the consumer.

 

It's the same as someone reading that silver has a lower resistance vs copper. Yes this is true but instead of purchasing a silver cable it is much more prudent to just increase the size of the copper conductor and you will lower the resistance much more than just using silver. So a 14awg copper speaker cable, non-engineer says I know more than everyone because silver has less resistance so I am going to use 12awg silver. Besides even the cost of silver going with a 12awg copper will yield a lower resistance than 14awg silver. I know, why not just use 12awg silver cable, here is where price comes in, it is cheaper to just go down to 10awg copper. And don't say you will purchase 10awg silver cables, that is ridiculous but the same argument keeps going in circles, just go to an 8 or even 6awg copper conductor. Jumping up a size in copper is always better than switching conductor material. The layman says silver has lower resistance vs copper so it is better, you can't tell me otherwise. An engineer asks what are we trying to do? Lower resistance. Ok, well we could use silver but that is expensive and doesn't gain us much or we can just jump up a size in copper conductor and lower the resistance. The latter is the better way of doing it of course but don't tell an audiophile that, silver is always best so if you don't use silver you are not hearing your stereo at it's best.

I am sure you are like me and get a laugh out of some of these post about something as simple as a capacitor. I still say manufacturing technics and quality control is more important then dielectric used. I stock a large assortment of capacitors for repairs and test them before installing and find differences of specs in brands for value and ESR with same dielectric. If I had my choice with price no object it would be Nichicon. When price is a consideration I have found Wurth Elektronik brand to be adequate and I buy in quantities of 50 at a time. German brand but made in China as most all electronic parts these days. 

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On 11/27/2021 at 7:14 AM, KT88 said:

Perhaps the lascala is simply better than the klipschorn when it comes to connecting the mids to the bass.

I suggest the following test: Build all the parts from one of the Lascalas, squaker, xover and tweeter into one of your Khorns.

Then you can compare...

1) Khorn original against Khorn with Lascala parts. If you hear differences, there is potential here.

2) Khorn (with Lascala parts in midrange, treble and xover) against the second Lascala that you have not dismantled.

If you still hear a difference here basically in the same way you have not liked and mentioned as such before then it is 100% due to the fact that they are different bass horns. There are no other influences.

If you still don't like what the Klipschhorn reproduces in it‘s midrange and treble compared to the Lascala, then it's probably the worse connection in the 400 Hz region of the Khorn from bass to midrange (which also affects the perception of treble).

 

BTW are both, the Lascala and Khorn the first of their kind which you experience?


 

I have three pairs of La Scalas.  My daily drivers are a

pair of ‘74s with AA networks.  I also have two pairs from 1989 with AL-3 networks.  I prefer the ‘74s.  The Khorn is my first.  I hope it’s not an issue with the match between bass bin and the HF section.  I have switched the tweeter portion of the crossover from the original 2uF/.245mH/2uF to 2.2 uF/.16mH/6.7uF on the original board, and have an extra outboard tweeter section that uses the original values to compare.  I am currently burning in the speakers as they haven’t been used for a long time.  This may be part of the problem.

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Leaving the speakers playing music overnight greatly improved the sound.  They sound much better.  The ‘74 La Scalas still sound more cohesive in comparison, and more “real”.  The Khorns have much more and better bass.  Perhaps I’m just not used to the more full range character of the Khorns?  I haven’t tried going back to the original 2uF/.245mH/2uF tweeter crossover section.  I am using the higher Q 2.2uF/.16mH/6.7uF recommended by ALK.  Any opinions on this modification to the AA?

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12 hours ago, Tizman said:

 I haven’t tried going back to the original 2uF/.245mH/2uF tweeter crossover section.  I am using the higher Q 2.2uF/.16mH/6.7uF recommended by ALK.  Any opinions on this modification to the AA?

 

Many prefer the older AA crossover network including myself. The more advanced crossovers become the more they try and filter "unwanted" frequencies from a specific driver. But with Klipsch heritage models many of us just prefer the AA network vs the steeper AL network.

 

Try the AA filter

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The steeper slopes pretty much require a greater listening distance before there is a cohesive sound.

 

I also think (my opinion) the LS sounds more cohesive because of the way the horn is constucted. The khorn and LS each have a bifurcated horn, but the LS,  coming to a point, sounds more like a single horn. 

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2.22uF / 0.21mH / 6.65uF = 5200 Hz @ 9.2 (impedance). This is what the filter would be doing "electrically". Acoustically is a different matter and what really counts because you want a smooth transition (frequncy response) to your other drivers. 

 

If you know the impedance of your tweeter at the desired crossover frequency, you can "easily" (yes, easily...) calculate your new crossover point. 

 

You can use many online crossover calculators to tweak your AA tweeter section. 

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1 hour ago, Deang said:

The online calculators don't factor in the reactance of the components and how they effect each other.

 

Which alignment?

 

I personally don't find much "easily" about it.

 

Butterworth for the values previously posted. 

 

Bessel - 1.65uF / 0.18mH / 8.24uF = 6000 Hz @ 8 (impedance)

 

Today, if you have some technical or even computer skills, most hobbyist can use DATS to measure impedance and REW for room measurements. Both DATS and a good microphone for REW will only set you back $250. Not a lot of money for very powerful tools if you are into speakers or the DIY speaker hobby. 

 

If for some reason, you are not skilled, there is always another hobbyist willing to help. 

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5 hours ago, Deang said:

 

.20mH, not .16mH -- and I'm pretty sure Al has never recommended this for the AA, since the tweeter filter is in series with the 13uF. If you do it, lift the connection from Tap 5, and move it to input connection. What you will hear is obnoxiously bright.

 

Somehow you misquoted something Tizman said as something I said. Is there anyway to correct this.

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12 minutes ago, captainbeefheart said:

 

Ask and ye shall receive

 

First image is values posted by tizman: 2.2uF/160uH/6.8uF

 

Second is the stock values:   2uF/245uH/2uF

 

 

 

alk.png

stock.png

 

Those constant "k" filters were not the best for audio filters, but they worked in the Heritage line for a long time. 

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20 minutes ago, captainbeefheart said:

 

Ask and ye shall receive

 

First image is values posted by tizman: 2.2uF/160uH/6.8uF

 

Second is the stock values:   2uF/245uH/2uF

 

 

 

alk.png

stock.png

 

Would you please post one of the LTspice models?   Also, I'm not a bat 🦇.  Could you end your simulation at 20000 hz?  My simulation is quite a bit different.

 

Thanks, Mike

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