La Scala crossover upgrades-ALK network-bass driver

[Randy Bey]

I spoke with Mr. Cooper of Universal Transformer and he says the transformer is 'an upgrade'.

I think Al K. had a hand in defining it's specifications.

Maybe Al can say what changes, if any, he described.

[edwardre]

The Type A looks interesting to me for it's low cost simplicity. Am I correct in interpretation that the xover relies upon the bass and mid driver's natural rolloff (upper), and that the xover establishes the 'cut-in' point?

Guy - As I look at the picture of the network, looks like there are 3 caps. Is this a result of the need to parallel two caps to make the 13uF? (Great pic by the way, thanks MH) Are all three caps Hovlands?

Thanks!

[Guy Landau]

Ed,

I have used 6+7mf MIT Multicap ppmfx capacitors in parallel for the 13mf value and Hovland 2.2mf from my ALK.

[mobile homeless]

Guy,

Two questions:

1. Did you consider the MIT PPFXS Film & Foil Polypropylene over the Metalized Poly? Seems the Film and foil almost always sound smoother than the Metalized, given other equals.

2. Did you ever try modern oils to compare?

kh

[Chris Robinson]

Al, just double-checking on this, but do 1989 La Scalas use the K-77 tweeters? If they don't, are they compatible with your networks? I know the modern Cornwall "II's" aren't ...

Perhaps I missed something in this thread ??

[Erik Mandaville]

Got Mark Cooper's number - thanks lots for that information. I may go ahead and buy a new transformer in order to keep the original as, well, original as possible. A network from 1989 is virtually new in that sense, but I'd rather spend an extra $50 for two new trannies than cutting out the old ones from the original divider. Just sentimental, I guess!

I'll report when I get the parts and the crossover built. I'll probably get this stuff from Madisound and/or Antique Electronics Supply -- hopefully save some time from waiting clearance from Canada. I've got very, very inexpensive Mylar coupling caps in my amps right now (which replaced Hovlands-- yeah, I still have those), and honestly prefer them to the far more expensive (too expensive!) Hovlands. People are surprised when I say the mylars are more transparent than the Hovlands which to Me (probly 'cuz I'm losing my high frequency hearing ability!).

Friendly Regards,

Erik M.

[Al Klappenberger]

The transformer is supposed to be an upgrade. If Mark Cooper say it is, then it IS becasue I think he desinged it. I specified that it should have more core area than the T2A and be bifilar wound of heavier wire than the t2A for tighter coupleing. It also has an additional tap (marked X). Universal Transformer also makes the T2 for Klipsch so Mr Cooper should know.

I ran tests on it compared to the T2A and could find very little difference in the measurments. I found no ringing and frequency response well beyond 20 KHz on either transformer. The 3619 was capable of going lower and both would easily handle the full 50W output of my McIntoh MC50 power amp without saturating.

Al K.

[Al Klappenberger]

mistake

Al K.

[Al Klappenberger]

mistake

Al K.

[John Warren]

Never mind, I took a closer look at the schematic.

[Guy Landau]

----------------

On 10/23/2002 4:48:50 PM mobile homeless wrote:

Guy,

Two questions:

1. Did you consider the MIT PPFXS Film & Foil Polypropylene over the Metalized Poly? Seems the Film and foil almost always sound smoother than the Metalized, given other equals.

2. Did you ever try modern oils to compare?

kh

----------------

Kelly,

I have bought the capacitors at Audiocom UK and wanted to order the ppfxs but they were'nt available at that time,so I've settled for the ppmfx.Since I've built the type A only for experimental reasons and did'nt think that I will like them that much.

I have decided to build them after listening to my father's JBL 375 and thought that I am missing something and thought that the simplicity of that design can improve things (as it did).

I still have the original oils and might experiment with them too,but I am about to be married and relocate to the US in six weeks so I don't know if I'll have enough time for another experiment.

[Erik Mandaville]

Guy -

It sounds like some congratulations are in order here! Getting married and re-locating to a new country are pretty big alterations to one's life -- and at the same time, as well.

On the audio side, the type A network on paper looks to be very good, with a minimum of components. This is one area that obviously benefits the speakers of my other system -- Lowthers in rear-loaded horns. No crossover is used whatever, as I'm sure you know. But this fact can't but help impart some of the sense of immediacy and presence that Lowthers are known for. The La Scalas come close to that, and have other advantages in the bass frquency range, and are much more able to handle complex kinds of material. Lowthers are outstanding for small ensemble classical and jazz, but sound congested and vague when called upon to reproduce symphonic/orchestral types of material. I am by no means what some might be described as a 'bass fanatic' but the La Scalas illustrated how much low end information I was missing.

Regards and best of luck!

Erik

[Guy Landau]

Thanks Erik.

I think that you will like the type A very much and especially for the improved sense of immediacy.

Guy

[Al Klappenberger]

Hi Guys,

Guy's experiment with the original Klipsch type "A" is interesting. The "A" is a

simple 6 dB / Octave network. There is one advantage to this type network over

my design and a few major disadvantages. The main negative is the total lack of

any tweeter protection. The main advantage is a more correct phase relationship

between the two drivers being crossed. It's my opinion that this factor is

overrated though.

The Klipsch type "A" is not a constant impedance network. To do that takes more

parts. That's a disadvantage for a manufacturer like Klipsch. I have designed a

constant impedance network that is 6 dB / Octave and constant impedance too. The schematic is attached for anybody who might be interested. Like the network I

build, the squawker level is also adjustable. You can't change the level on the

Klipsch "A" by moving the taps without changing the value of the 13 uF cap as

well.

The woofer inductor should be of solid wire. The use of Litz here is ok, but a

waste of money. If you want to spend more money to improve it, go to a thicker

solid wire, like #12 rather then #14.

The 39 + 1 uF cap consists of a Polypropylene cap in parallel with a high

quality bypass cap like the North Creek Music "Harmony" I use. This cap nulls

out the inductance of the 2.5 mHy woofer inductor keeping the load to the amp

resistive at the 400 Hz crossover.

The .2 mHy inductor should actually be .21 mHy but that is not a standard value

Solen makes and it's not that critical anyhow. It should be of #14 Litz wire.

You could buy a .22 mHy and remove some turns if you have the equipment to

measure inductance.

The 10 Ohm swamping resistor brings the squawker impedance back to 8 Ohms and

absorbs the changes in load when you move transformer taps to set the level.

The transformer can be Universal Transformer Co 3619 or the Klipsch T2A. If you

use the T2A you will be somewhat limited in your level choices since it does not

have the "X" tap.

For the 3.3 uFd tweeter cap, any good polypropylene cap is fine. I still believe

totally that the paper in oil cap (Jensen) are BAD NEWS! They have 10 times the

loss of the Hovland Musicaps. If you really want to loose some of your highs

(and you actually might), then consider the paper in oil caps.

Al K.

[Guy Landau]

AL,

Your new crossover seems quite interesting and I guess that I will try it real soon.

I can use most of the parts from my original ALK crossover.

Do you think that it would be ok to use the 2.2mf Hovland and the 1mf harmony in parallel instead of the 3.3mf capacitor?

Thanks

[mobile homeless]

Please note, I respect what Al has done with his crossovers for Klipsch and I think he is very fair and straightforward here. He offers a QUALITY product. He also offers the schematic and parts list for the DIY prone to do their own version, something that many manufacturers surely do not do. He must be commended for this.

On the other hand, please note the following when reading his opinions. Al and I exchanged quite a few email awhile back when I was FIRST interested in his crossover right after I got my Cornwalls. During the email exchange, this is what I found:

1. Al does not like tube amplifiers per say. He believes the entire genre to be colored and not a good nor neutral representation of the music/recording.

2. Al believes that Single-Ended tube amplifiers are pure distortion devices, and as a result are even worse than that average PP tube amp. This, again, based on distortion figures and other measurements. In my emails shared with him on the subject, he writes off ALL SET amps. Al does not take into account the different types of distortion nor the negatives of solid state wars where a reduction in THD and IMD were brought about by heavy feedback, thus affecting the sonics in poor way, but bringing about better measurements.

3. Al derives his opinions of sonics mainly by MEASUREMENTS. I do not believe he has done the proper hands on research involving his own two ears in relating how these measurements correlate with the actual sound of the gear/components. I think it is imperative to combine the two when designing products or deciding on parts within.

4. Al MEASURED some Aluminum Jensen oil caps in relation to the losses and because of these findings in comparison with polypropylenes, he deduced they were POOR. Al has NEVER heard a modern oil cap in his crossovers or system and has not used listening tests to derive his judgment or opinions.

Again, this is in no way meant to discredit Al. I am just trying to show where his views are coming from. Again, I think AL has done a GREAT deal with his crossovers with MANY happy Klipsch users. Indeed, I am hoping to work out an audition and possible review of his Type B for Cornwall crossover some day. Al would like this as well and is open for the results, again, showing his sincerity and honesty. I am looking forward to hearing his crossovers some day in the near future. Again, I know he makes a QUALITY product. He has countless users that have been VERY happy with his crossover with very few complaints (I think only ONE return in ALL).

I do think it important to know where he is coming from however.

Kelly

[Guy Landau]

Kelly and Erik,

I've just finished rebuilding my type A crossovers with the original oil capacitors.(picture attached)

I can only briefly comment on their sound since they were just installed but from first impression they seem a little bit more relaxed and with better weight.I have played a Stephane Grappelli cd and the violin sound just great and doesn't sound too offensive.They are darker sounding but it is fine with me for now.

I can detect more hiss that is coming from the tweeters but I think that I need to burn in the capacitors because they were not been installed for more than 2 years.

I'll keep you all posted.

Guy

[Al Klappenberger]

Mobile,

I don't think that you should be summarizing my opinions without the benefit of

my particular experience on each point. You don't know the entire story. Since

you have done so however, I might summarize my point of view. It is this:

Only an instrument can make a totally unbiased evaluation of a parameter. The

human is to subject to perception. People hear with their BRAIN, not their EARS.

A human must also remember when he has heard to make a comparison at a leter

time. A persons memeory is a very imperfect thing. The only real test to compare

to things is a direct - blind - A / B test. You must also hold ALL OTHER FACTORS

equal when you do the test. Most people have not done this. They will usually

have preconceived notions about what they want to hear and they will hear it! An

instrument has no such problem. If you spend $500 for a set of cables, they will

sound better to you even though they are not!

The Jensen oil caps is a good example. Oil caps have been around for years. They

have a reputation and people like them because they have always used them.

Instruments show they have considerable loss. Anyone who does not believe this

is simply wrong! This is a major concern when used in a filter. What does a high

loss capacitor sound like? It attenuates everything that goes through it. If

it's in the tweeter filter it will make the sound "mellow" because the highs

have been lost. Another word for "mellow" might be "dull". Again, your point of

view takes over. You might also be compensating for a room with reflective walls

making a good speaker sound bright. The high loss cap may compensate. The

instrument tells you like it is! The only trick is making sure you are measuring

the right thing. This is where you ears come into play. If it measures bad, it's

BAD. If it measure good, something else might be wrong. You may simply be using

the wrong instument. If you room is distorting the sound, fix the room by adding

some drapes or a rug. Don't assume it's the "plastic" capacitors that are

"bright"! Once all the instrument tests have been passed it's time to start

listening. Even then no single person can call himself the final judge of what

sound right or wrong.

Another point about oil caps. I don't want to hear about linearity. BIG DEAL! If

one of your loved ones has cancer and a head cold at the same time, how would

the doctor treat him? Would he prescribe surgery and radiation, or chicken soup!

As for SET amps, I suggest you count up all the people who sware by SET amps and

all the other people who sware by solid state amps. Just who is in the majority

and who is it that makes all the noise about them? We Klipsch hounds are simply

lackey that our high efficiency speakers can tolerate them. Put one on a speaker

that requires 50W to hear anything and the average SET amp will pop a gasket!

Most speaker are like that, so most all modern amps are made to put out clean

audio at HIGH power. We need clean LOW power! I beleive it was PWK who said

"it's the first watt that counts". To get clean low power from an amp that will

also put out clean high power is not easy and you will PAY for it! It is not

WHAT you do that counts, it's how well you do it!

Another example is "burning in components". I used to work at a company that

makes filters. To burn one it takes a dual chamber machine that has a shelf that

alternates between a freezer and an oven every hour for about a week! Running a

crossover for several days or even weeks at 2 or 3 watts peak power does

nothing! What burns in is your brain getting used to the sound! After a filter

has been run through a temperature cycling machine you can measure a difference

in it's performance. You can't measure a difference in a loudspeaker network no

matter how long it is used in a speaker. I have tried. I can resolve to about

1/10 of a dB with my instruments. Can you do that with your ears over a period

of a week? I really doubt it.

Do not criticize instrument measurements until you have made them. It may open

an entire new world for you. It is also foolish for someone who probably doesn't

even understand the meaning of component "Q", the difference between group delay

and time alignment, fourier analysis with respect to waveform or the difference

between capacitive and inductive reactance and it's relation to impedance to run

down the opinions of someone who has some technical theory under his belt!

Al K.

[Hardhead]

Here, here, Al!

[Al Klappenberger]

Guy,

Sorry I didn't answer your question about the 2.2 versus 3.3 uFd cap. I was too busy taking the wheels off a certain mibile home! A 6 dB / octave network is an extremely gradual crossover, but I think 2.2 uFd is not quite high enough. A 2.2 uFd + a 1 uF bypass would be 3.2 uFd. which would be ok though. Please don't tell me you stole more parts off my network. I am already fealing the pain!

Al K.