henry4841

I understand what you are saying. One can get sidetracked and start listening to equipment instead of music. From what you are saying I believe you will be perfectly satisfied with a good receiver or integrated amp. Right now I have a 2nd system in my bedroom using a restored receiver from the 70's and the sound is plenty good enough, enjoyable. That and I had forgot the advantage of having radio to listen to in an all in one device.

It is hard to get away from Chinese components in electronic equipment. Most components in crossover networks are made in China, been that way for a number of years. I seriously doubt you will get Klipsch to provide their source for drivers or horns. Apple products are designed in USA and made in China.

John I did not know what a LK72 was until I googled and now know it is the Scott LK-72. https://www.hifiengine.com/manual_library/hh-scott/lk-72.shtml At the beginning of this thread there is no mention of what you were creating so I just glanced at this thread and moved on thinking it was some boards you bought on Ebay. Now knowing what you are doing has peaked my interest and I am glad to see members here doing such things. Are you using any distortion analyzer software like Arta or either a distortion analyzer to see what kind of harmonics this build has? I have an old distortion analyzer but I have found software like Arta to be as good as the one I have. Being a PP amplifier I would expect to see less 2nd and more 3rd but one never knows until tested. Great instructive build thread, or should I say design thread.

I have many of the class D boards available at the present time except the N-core of which I have heard nothing but praise for. The only Icepower I have experimented with is the 50ASX2SE which is a very respectable D board with a tube kind of sound. The D board I like the best is the Texas Instruments TPA3255 which I could live with if it were the only amplifier I have. Excellent sound lacking nothing in quality of sound. Outstanding bass, smooth mids and vocals with great sound stage. Available cheap on Ebay to try before buying a more expensive receiver. Naturally having someone with D amplifiers to listen to before purchasing would be best but these days very limited for most. I have most of the cheaper offerings available for many years on Ebay and to me they are too thin sounding for my taste. Class D is the wave of the future in amplification in most consumer products. More then likely you al have already heard class D in modern televisions. Some televisions have acceptable sound with the limitations of speakers in a flat screen using class D amplification.

Not so anymore. Class D in a receiver is a very good option with the icepower and hypex N-cores modules among others.

I was a little disappointed also on just the wattage war receivers. As most know on this forum quality is more important then quantity with our speakers. Being from that era though I can remember wanting more and more watts without knowing better then. It is still a driving force with many thinking more watts equate to better sound even today.

I found this interesting especially the prices in todays dollars.

Not sure if Dean is building x-overs anymore. Critesspeakers is probably who you need to contact. https://critesspeakers.com/

Now we will be buying oil from foreign countries because we will not have a surplus to sell. Makes sense to me.

Some may wonder how a push pull amplifier can operate in class A. How it is done is the transistor are run like SE amplifier as high as safely possible all the time instead of like an A/B amplifier where the transistor runs just a little bit and increases when a signal is detected. Most designers in an A/B amplifier just run the transistor high enough to eliminate crossover distortion. Crossover distortion occurs when the positive part of the signal goes to one transistor and then the negative part of the signal transfers to the other transistor. I intentional left out the word bias where it may be better understood in layman terms.

Probably necessary with drivers being used. That and the fact an autotransformer is not used anymore but depend on l-pad networks for attenuation increasing the number of parts. What is usually added to increase the parts count are notch filters to fatten out the frequency response. To correctly add notch filters is not an easy task and is usually done by sound engineers with proper equipment and sound chambers. The early heritage line with their 1st order networks did not get spectacular reviews in the rags of the 70's and 80's being they depended more or frequency response curve and and not their ears to rate speakers. From literature that came with my speakers in 86 PWK says music is dynamics and my speakers are dynamic. My previous speakers were AR3a's with a flat frequency response and were dull and boring. Bought LaScala's next and never looked back. Also I should add I have never experimented with steeper networks for my speakers due to the fact I am satisfied with what my ears hear now. I feel positive about what the engineers at Klipsch are doing now as sounding excellent. Like Nelson Pass they depend on the design to achieve great sound and not gold parts. I cannot speak personally having only use my 86 LaScala's with 1st order networks since 86 but what has been said on this forum by members that have bought the steep ALK networks for their heritage speakers is that you have to increase the volume on said networks to wake the speakers up. I like having big sound at low volumes myself. I am sure the steep ALK networks sound fine though when woke up.

For those not familiar with networks here are some examples of 1st order and 4th order and parts required for each. No specific drivers or speakers. 4th order Parts List Capacitors C1 = 2.12 uF C2 = 4.21 uF C3 = 26.69 uF C4 = 37.7 uF C5 = 5.65 uF C6 = 1.26 uF C7 = 50.3 uF C8 = 11.38 uF Inductors L1 = 0.16 mH L2 = 0.71 mH L3 = 1.01 mH L4 = 5.76 mH L5 = 0.47 mH L6 = 0.22 mH L7 = 3.82 mH L8 = 1.92 mH 1st order Parts List Capacitors C1 = 3.98 uF C2 = 35.85 uF Inductors L1 = 0.23 mH L2 = 2.04

I personally do not think you can wrong with McIntosh. For a different sound I would recommend a tube amplifier. Mc still makes one of those as well and for a very good reason. You could try a cheaper tube amplifier first and sell it if it is not for you.

I am confused. The only reference I made about PWK was that he was aware of other orders of crossovers in the above statement. Are you saying he did not know about other networks like say 2nd or 3rd order? As an electrical engineer I can almost certainly say he was well aware of all the networks used for drivers He chose a 1st order network being the A network for his K-horn? Are you trying to say that was all he knew? The A was used for many years until the delicate tweeter that could not handle frequencies below 6K hz was used. Then Klipsch kept the 1st order between the bass and squawker but used a sharper 3rd order filter with a sharper cutoff to protect that tweeter in the AA for many, many years. Also he did not even use any cutoff network for the squawker but depended on the cutoff of the horn itself to provide this function. Both the A and AA networks are built with just as few components as Paul thought necessary. Which are not many compared to the networks used these days. If I am wrong about the history of this please show where I am wrong. I know of another hi-end manufacturer of horn speakers that believes in using simple 1st order networks and his speakers reach above $100k. You may certainly disagree with me being in the camp of few parts and simple networks. I am aware of the other camp of complicated circuits with lots of parts. The flat button on many amplifiers and receivers are for those in my camp of thought. Nelson Pass built both his companies on the philosophy of simple circuits with only the parts necessary to correct the faults in the active devices. Most tube amplifiers are built around this train of thought as well, simple circuits with few parts.

Class A in the winter, class D in the summer.

Klipsch experimented with notch filters with many components with the AL crossovers which on paper flattens the frequency response. Now not considered a great crossover. PWK was from the school of less is better. Any component added to any crossover is to correct a problem with the driver. A perfect speaker system would be one speaker handling the full audio spectrum. With a knowledge of electronics one can take a crossover and back engineer it to find why a circuit is added. In general terms it is because of the type of network involved 1st order to 6th order. Each has it's advantages and disadvantages. With limited experimentation with big horns I prefer a 1st order crossover network with few parts. Even in the 40's and 50's PWK was aware of other orders of crossover networks but chose a 1st order except for the delicate tweeter, 3rd order in the AA network to protect it. Capacitors, electrolytic mainly, have improved over the decades but film is preferred in the audio path of a crossover network. Not much improvement in other components since then when talking crossover networks. Klipsch is now using an older capacitor design, polyester, thinking they are still plenty good enough even though polypropylene is considered better. I find nothing wrong with a polyester capacitor either and use them myself when price and size is is considered in a restoration or build. The general consensus is the sharper the network used the more you have to crank the volume to wake up your speaker. The more gentler the network produces big sound at low volumes. With a sharper network the problem of phase shifts is more prevalent as well. Each engineer of a speaker system understands these principles and has to chose what is best for his design and the sound he decides is best and hopes enough buyers agrees and purchase his product.

Another explanation Nelson Pass has given in one of his papers is like a relay race. In class A just one runner takes the baton and runs as fast as he can and never passes the baton. In class B the first runner takes the baton and runs as fast as he can and stops and passes the baton. In class A/B it is more like a real relay race where the baton is passed with both runners slowing down and passing the baton.

In class A the transistor is turned on up as high as the designer thinks is safe and operates at it's maximum safe operating point. The audio signal is then fed into the transistor. In B the transistor is turned on only when it sees an audio signal then cuts off. A/B is when the transistor is turned on a small amount always and opens up to it's safe operating point when it sees a signal. This is the reason that class A amplifiers run so hot all the time whereas a class A/B amplifier only gets really warm when playing the music loud. For this reason, the transistor operating fully running as high as safe, class A is considered the most linear operating method of amplification. The reason purist still prefer class A not that other forms of amplification can and do sound excellent when designed properly. Class D is another form which others can better explain then myself. I have a rudimentary understanding of how it works but not enough to go into detail. I hope this helps some. The article posted by Nelson is an excellent one but does require some electronic knowledge to fully appreciate. Class A, AB and D are the ones music lovers generally have to pick from.

Sound is so subjective. Identical spec components can do sound different with my ears and from what I have read. Sound is just too complicated to fully understand everything. Testing and specs are just tools to use with the final verdict determined by listening test. Nelson Pass describes it way better then I ever could in some of his lectures and writings.

Unless a cap has failed which rarely happens in a crossover network the best way I know to describe the difference in caps is just different sounding. The sound that one achieves replacing caps for you may not be what another considers an improvement. I have tried many different caps in crossovers some I like better than others but I would not describe any as bad only different sounding. Naturally if one goes to this trouble trying different caps they will find a particular one that suits his taste which I did. Not for everyone for sure but one that I like. Again if you like the sound you now have why try to fix something that is not broken. There are many on this forum that replaced caps and considered the change too bright for their taste. I have read this many times. Give it a try if you choose to but do not expect any substantial difference, only a different sound.

Klipsch spec caps is a kinda vague comment. A capacitor is a simple device most all manufacturers have outstanding specifications on the capacitors used in crossover networks. You do not need a military grade capacitor in a crossover network. Electrical engineers do not go crazy on picking parts. There as so many manufactures of quality capacitors that making selection of a capacitor childs play. Anyone that can read a specification sheet on capacitors will find this true. I suspect the main Klipsch spec is like all manufacturers of electronic products boils down to price. For those that do not have or have very little knowledge of electronics buying from a Klipsch's authorized dealer is the way to go. That way you will know and your mind be satisfied you have what Klipsch recommends. For all others the field for picking a cap is big and wide being so many good manufacture's out there. Being a lurker on this forum I have seen the subject of capacitors being one of the most controversial subjects with some of the most heated arguments. I rather stay out of heated arguments especially when it comes down to such a simple subject of a film capacitor. Electrical engineers do not get caught up in any specific brand of any component. They just read the spec sheets, do some testing and use what is available at the best price. This is probably the reason the engineers at Klipsch pick a polyester capacitor (trade name 'Myler') for their networks. Most on this forum consider polypropylene to be a better cap, not necessarily so. When the specs of a polyester cap is good enough and the price is much cheaper electrical engineers choose that part saving their employer money making everyone happy including the consumer.

I have never heard a 2A3 tube amplifier. That is one I have not built. The reason being following what George Anderson has to say about it. http://tubelab.com/ His description is like the 45 tube but having 2 45 tubes in one envelope. By the way the 45 tube is one of the best sounding ones you will find but low on power. I have a SS 45 tube amplifier and enjoy the sound it makes. I consider my SE 300b amplifier the best sounding of all the tube amplifiers I own. For all the diy'ers on this forum George's SSE amplifier is one of the best builds out there. I probably listen with it more than my other tube amplifiers. You will not go wrong with the EL34 family of tubes.

Good short answer to question.

I would not expect an electrolytic in a crossover to out of spec that much being so little voltage it sees. Not much chance of breaking down. ESR is a better measurement but there is a lot of misconception of reading the ESR of a capacitor. When the spec is say 2 ohms of ESR and one reads 3 to say 5 ESR it does not mean the cap has failed. Only the ESR, resistance, has increased a slight amount which really has very little effect on the sound. What I call splitting hairs. Most technicians consider a cap is bad when the ESR is stated as 2 and it reads lets say 10 or much higher. Then a technicians determines it needs replacing. Not all technicians mind you there are perfectionist in every field but one really does not require perfection in a piece of entertainment gear. Most consider polypropylene caps superior to polyester but Klipsch generally consider polyester caps plenty good enough in their crossovers and I agree. Who am I to disagree with the electronic engineers working for Klipsch. Nothing wrong with someone spending hundreds of $ for one cap if they want to but the cost vs improvement is going to be very low. Money probably better spent elsewhere if looking for improving sound.

Years ago I experimented with 20 or more different crossovers and caps for my LaScala's. Some I designed myself and all that I could find on the web from other sources. There were some that I liked better then the AA's which were more pleasing to my ears and setup but at the present time the AA's are back in my LaScala's as plenty good enough. The ones that pleased me the most are the ones I designed myself without using the autotransformer. The main reason I put the AA's back in is when my time is over they will be easier to sell being stock for my kids. Paul Klipsch did an excellent job designing the crossovers for his speakers for what he had available way back when. But most here already know that.