henry4841

Just thought I would add that it took me years to come around to all what Roger was talking about at the BAF 2015. I watched it in 2015 as I do most all the presenters at the BAF held every year. It comes down to the voltage you have to swing the sinusoidal signal in. Most all know what a sinusoidal signal looks like with a positive and negative swing. You can swing a lot more sinusoidal in 600v's than say 200V's where most PP EL84 amps have to work in. You are going to drop approximately 50V's across an output tube so in a PP amplifier you are going to lose 100V's of your B+ across the output tubes. When you start out at 700V's you have 600V's left to swing a signal in. A normal PP EL84 uses roughly 300V's B+ and you are left with 200V's to swing the signal in after the loss in the output tubes. That is how Roger got so much power out of EL84 tubes without shorting tube life. The watts used by the tubes are the same being a normal PP EL84 runs more current. The EL84 is rated for app 12 to 12.5 watts and as long as you only use 80% of that number you will not harm the tube life. Roger runs his output tubes at app 10.5 watts in his RM10 for 35W to 40W power on the outputs. The man was a genius in amplifier design. Wound his own transformers as well.

You will not lower the life of the tube if you use a high B+ voltage if you lower the current running through the tube. It is a misconception that tube life will be effected. One has to be careful of the screen voltage to accomplish this though. The wattage rating of the tube is the number you have to watch if you do not want to shorten tube life. Modjeski designed amplifiers have long tube life and seldom need replacing. Working just from my memory he got 35 or 40 watts running 15ma with 720 V's on EL84 tubes in PP on his RM10. At least I believe it was the RM10. Give this some thought and you will see Modjeski was right. The guy taught electronics at Stanford so I would say he knew what he was doing. If you want to learn more about Modjeski this video is outstanding. https://www.youtube.com/watch?v=io_yZENYlxY&t=8s Start at the 28.14 mark for discussion on how he did it.

Should never be used as described without horn attached and a cap to prevent low notes that could overdrive the diaphragm.

Not sure on that claim but Roger Modjeski got 40 watts out of the little EL84 tubes by increasing the B+ and running less current. Like 700V's on those EL84 plates. The higher the voltage the more you have to swing the signal in.

Over hyped is the term I would use. There are schematics out there of the circuit and believe me nothing special in it. Decent parts and reputable dealer make it desirable for someone wanting to experience the SET sound but do not expect anything earth shaking over the many other SET amplifiers out there. I built the Zen from the available schematic that use to be on their website many years ago. To my ears Maynard's Little Sweetie outshines it. That is not to say anything wrong with Zen, just as good or better out there.

It all depends on how critical the person is. When younger I tried to find faults in program. Now I just try and enjoy the music without digging too deep into quality. Let's just say good enough.

Price is my reason. https://www.mp3million.com/artists May not be the best but at least I get to hear the music.

My go to source for serious listening is my LP collection but I have a lot of MP3's at 320 that I can just enjoy the music without being choosy. I have compared a CD to 320 and there is a difference that is noticeable in an A/B comparison but I can still enjoy my music downloaded at 320. Anything less than 320 does does not cut it for me though. As a good friend of mine with a huge music collection always said to me, musicians listen to music audiophiles listen to equipment. If I really like a 320 download I may buy the CD but for me a 320 MP3 is most of the time acceptable. For serious critical audiophiles I can understand their view of 320 MP3's though. Lacking some detail for sure.

It appears rightly so.

Appears so with 3 notch circuits. IMHO sound can be improved by removing notch filters and leave rest alone. Different autotransfomer in the AL than A or AA.

The price of old Heritage speaker asking prices have sure risen in the last couple of years. The price increase of new ones probably has a lot to do with it as well as fewer being offered on the market. That and the inflation we all are experiencing now. It was not that long ago, for me being 73 years old, that the price of an old pair of LaScala's hovered in the $500 range. Good for owners of old Heritage speakers but limits others from hearing great horn sound.

Just curious if Klipsch ever thought of a rotating top part of the K-horn. From what little I know even the closed back K-horns should be placed in a corner. Just seems to me that having a rotating mid and high section would make good sense for adjusting the sound to ones room making the speaker more versatile. I am sure the engineers have considered this and just wonder what their thoughts were for not doing it. Heavy duty lazy susan and a bottom sheet of MDF for the top section is all that would be required. Aesthetic reasons or technical?

I think like you, not fair comparison. Big difference in sound, for me, between SE and PP. Preference depend on preferred music and environment. I like and enjoy them both but my preference for my music taste leans towards SE. That and the Prima is a much more expensive amp. The little Zen, I assume this is the one being discussed, is what it is. An American built SE tube amplifier built at the cheapest cost using decent parts. For me, not a lot of difference between a PP tube amp and a good SS PP amp.

Guys one thing for sure about those old R-R's. They sure are cool looking. Some people buy old non-working ones just for their look sitting next to their audio gear.

I am staying out of serious capacitor discussion. Any brand of capacitor you change to is going to produce a different sound if you hearing is good enough to notice. Change if one must but doubtful if any of the caps in OP speakers are actually what a technician would call bad.

One of my best friends was a serious reel to reel guy. Bug never bit me. I asked him how some of those old recordings he made 50 years ago still sound and he proclaimed as good as when recorded. Not so sure of that being the earths magnetisms does effect magnetic tape. At least an instructor at an electronic class I occasionally watch says it does. The teacher was a EE on submarines in the navy and he said that submarines have to be demagnetized on a regular basis to prevent detection. A tidbit I did not know. Makes sense when you think about it. As far as reel to reel tape, probably not enough degradation to ever be noticeable in the recorders lifetime.

Then why change anything? The old "if it ain't broke why fix it."

I believe he has solved the problem by tightening all connections from his above post 001.

Looks good. I think having a built in generator is nice. Probably works well.

Unhook drivers from wires and use ohmmeter to check continuity between driver leads. Being a mechanic you probably already know a lot of electronic problems in a car, motorcycle, are usually just a bad connection somewhere. As others have said unhook and re-hook all connections and if possible take a soldering iron and go over all the solder connections on the X-over boards. Swapping X-overs is an excellent starting point to see if problem persist on the same speaker after doing so.

Xover problem more than likely, bad connection most likely suspect. Failed parts in crossover rare but possible.

Probably still within spec's but most here think film caps should be replaced but technically I doubt any of the caps have actually failed. Guarantee to sound different if replaced but whether you like the new sound is debatable. Keep old caps to be safe if you decide to replace.

Still have mine dated 1985. Also envelope they came in. My guess is they are not that rare and Klipsch should already have some left over stored somewhere.

I like this kind of stuff, thanks.

The AL crossover has a bad reputation on this forum, not actually deserved in my opinion. I enjoyed listening to my AL crossovers for decades without an issue. Most do consider the AA better sounding. All those other parts are just notch filters flattening out the signal. Apparently at the time it was introduced a flat frequency response was the in thing in all the magazines promoting products.