Crossover Capacitors and Crossovers In General

[captainbeefheart]

I read through what he said in that link from a different thread and I agree. Loudspeaker efficiency as a system and Loudspeaker sensitivity are two different things.

 

 

With Al's network the total system efficiency drops but sensitivity stays the same. That's why I gave the example of a specific amplifier with a specific amount of loop gain, with the volume control at the same exact level the two systems will have the same acoustical output. The amplifier does need to deliver extra current hence the efficiency is reduced.

 

Now people that have experience with the networks know the acoustic output isn't the same but that's not because of the resistor, it's because of the lower chosen output tap. Some people claim the mid-horn is two in your face as it is. When leaving the auto-former at the same output tap as stock, increasing the the 13uF to 48uF and adding the 10 ohm resistor actually increases amplitude to the mid horn at 1kHz. It's just too much mids so the horn is taken from the next tap down on the auto-former putting the amplitude around -1.5db compared to stock. So yes less acoustic output but by choice from the auto-fomer. The swamping resistor isn't stealing any power away from the mid-horn.

 

Think of a 10 ohm resistor as  load connected to a 10v battery. We get 1 amp of current and 10 watts of power through the resistor. Now add another 10 ohm resistor in parallel, The battery sees 5 ohms, and so produces 2 amps of current. Each 10 ohm resistor is dissipating 10 watts of power. The original resistor has not changed, it produced 10 watts before and after adding the second resistor.

 

BTW i got a kick out of that little article about increasing the power handling capability and grossly lowering system efficiency by adding the two resistors to keep the amp seeing a constant impedance. 1200 watts to get the same acoustic output as originally only needing 1 watt🤣

[Curious_George]

9 hours ago, Chief bonehead said:

Because George like to stir it up. No bueno. 

Got your message Chief. However, it's not that I like to stir-up trouble. It sounded like Dean was lamenting spending two-days working with someone, that's all. 

[Deang]

17 hours ago, Crankysoldermeister said:

I’ve just spent the last two days working with a vendor to make sure they use the right steel for their laminations when they build this next series of autotransformers. Now, it seems really odd to me that Klipsch would care about a detail like that, but not care if the polyester caps they choose don’t produce the results they are looking for. 

 

I wasn't "lamenting". It was actually fun and educational. Read it again, I think maybe you missed the point I was trying to make.

 

I don't think you were trying to stir things up. I think we have all become like Pavlov's dogs to some degree - just always expecting to be kicked between the legs by someone, lol.

[Deang]

 

"With Al's network the total system efficiency drops."
 

"The amplifier does need to deliver extra current hence the efficiency is reduced."

 

Check. Also means if you have a flea powered amp, you have less to work with.

 

"When leaving the auto-former at the same output tap as stock, increasing the the 13uF to 48uF and adding the 10 ohm resistor actually increases amplitude to the mid horn at 1kHz."

 

Seems counterintuitive but must be true since the impedance is lower. In actual practice however, with the settings the same, the midrange sounds like it has more attenuation, which is probably due to the 12dB/octave bandpass filter, which the Type AA does not have.  

[Curious_George]

1 hour ago, Crankysoldermeister said:

 

I wasn't "lamenting". It was actually fun and educational. Read it again, I think maybe you missed the point I was trying to make.

 

I don't think you were trying to stir things up. I think we have all become like Pavlov's dogs to some degree - just always expecting to be kicked between the legs by someone, lol.

I understand. It's hard sometimes to get the right context when reading text a lot of times. I apologize anyhow. 

[Curious_George]

Dean, have you done any comparitive listening between the aftermarket autoformer and the T2A? Other than the taps offering different levels of attenuation, do you think there is a sound difference? 

[Deang]

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.

[captainbeefheart]

2 hours ago, Crankysoldermeister said:

Check. Also means if you have a flea powered amp, you have less to work with.

 

Not necessarily. Remember that the flea watt amps are tube amps.

 

The tube needs to see a specific load and we design the amplifier that way. The output transformer reflects back the impedance of the speaker to the tube. So if we design the load impedance for the tube at 5k:8, that means we want the speaker to be as close to 8 ohms as possible to get the optimal results. Once a frequency hits that 30 ohm impedance part of the curve the tube will see a MUCH higher load on the primary which for a Pentode/Tetrode will bring the load line down far below the knee and sound awful by producing nasty sounding distortions. Power through the mid-horn doesn't change but now you have much higher distortion right in the most important part of our hearing.

 

They are much different than solid state amps which is why I broke what happens into two categories. So for a tube amp, it's designed for the 8 ohm load so the resistor is just keeping the tube in it's linear region, not a bad thing at all.

 

 

[captainbeefheart]

@Crankysoldermeister it might be fun to walk through a load line design with you to show how a power tube will behave to a difference in the two different loads.

 

So for a 5k:8 transformer it has an impedance ratio of 625:1  and so with a 30 ohm load on the secondary the tube goes from seeing 5000 ohms to 18750 ohms. That's almost 4x times the resistance. You will certainly get reduced power with that load on the tube and far greater distortion. The swamping resistor keeps the tube seeing the 5000 ohms it wants to see.

[Curious_George]

I know Dean has said his previous experience with a tube amp on Heritage speakers was less than overwhelming, but that is in contrast to my experience. I wonder if the speaker he was using at the time had a flat impedance curve? 

 

Granted, not everyone likes a low power tube amp on speakers. 

[Deang]

Man, you guys missed all of the real fun, back when I had money to spend. Let's see, VAC,  Welborne Apollos, Quad II Forty's, AES Superamp (ran two in a vertical biamp config), Craig's VRD's, and a Canary CA-301 (300B), and probably a thing or two that I just can't remember. The Wright Sound 2A3 was a failed experiment. Probably the most anemic sounding amp I've ever heard.

[Curious_George]

1 minute ago, Crankysoldermeister said:

Man, you guys missed all of the real fun, back when I had money to spend. Let's see, VAC,  Welborne Apollos, Quad II Forty's, AES Superamp (ran two in a vertical biamp config), Craig's VRD's, and a Canary CA-301 (300B), and probably a thing or two that I just can't remember. The Wright Sound 2A3 was a failed experiment. Probably the most anemic sounding amp I've ever heard.

Well, we will help you re-live the glory days! 

 

Since this is my thread, I'll digress, aside from being a Klipsch Heritage speaker fan, I love the opposite end of the spectrum as well, the Original Advent Loudspeaker. I have a set that I restored and even though they represent the antithesis of what a Klipsch loudspeaker is, I love they way they sound and can appreciate both for what they are. 

 

As a HUGE bookshelf speaker, they indeed go down to 30Hz by themselves and sound very natural, but you need some power to drive them. Some people love the tweeter, others hate it. There does not seem to be a middle ground, but I don't think it is that bad. No worse than the original JBL L100 tweeter, which most people think sound OK for what it is. 

[Curious_George]

I do have a replacement tweeter for the Advent, another modern ring radiator, but I have not integrated it into the loudspeaker yet or modified the crossover. Forth coming...

[captainbeefheart]

26 minutes ago, Crankysoldermeister said:

The Wright Sound 2A3 was a failed experiment. Probably the most anemic sounding amp I've ever heard.

 

No surprise there, they will have the hardest time driving most Klipsch speakers. Hardly any damping, maybe a DF of 2, high distortion. That type of amp will gain a lot from a flat load vs frequency. 

 

Welborne Apollos and Canary 300b amps are in the same exact situations as the Wright 2A3.

 

I don't know what the other amps are except the Quad II which should have given probably the best results from all the amps you listed. What did you think of the Quadd II amps?

 

 

[ClaudeJ1]

On 8/31/2022 at 1:19 PM, captainbeefheart said:

 

Exactly why I say construction can have an impact on the variables. The rolled types still are made but for the competitive capacitor manufacturers for high frequency, fast rise time switched currents they have been stacking the layers in different manners and instead of having one lead at the inner foil roll and the other at the outside foil roll they offset each plate to one side of the package and the extended part of the plate is connected to the lead, this give much more uniform characteristics.

 

Here is an image.

Looks to me that the double/reverse type construction in the right column would be for Radial leaded capacitors and not axial.

 

[OO1]

oh , ok 

 

[Deang]

3 hours ago, captainbeefheart said:

Welborne Apollos and Canary 300b amps are in the same exact situations as the Wright 2A3.

 

Really different outcomes with those. The Apollos and Canary were awesome. I really regretted selling the Apollos.

[captainbeefheart]

1 hour ago, Crankysoldermeister said:

The Apollos and Canary were awesome. I really regretted selling the Apollos.

 

Oops my mistake, I was thinking of a different Welborne amp............Moondog I think.

 

I just looked at the Apollo and wow completely different!! The KR 842vhd is a completely different tube able to deliver much more power and it also has about 1/3 the plate impedance of a 2A3.

 

 

I must have interpreted your post incorrectly, or Nick saying your experience with tube amps was less than overwhelming put in my head that you didn't like any of the tube amplifiers that you just listed.

 

I think the first paragraph you listed are amps you enjoyed? And the Wright amp was just an example of one you didn't like?

 

 

Oh well, it really doesn't matter. I just feel bad interpreting others post incorrectly. I'm glad we had this conversation because it brought attention to those Apollo amps which are very interesting and I have never seen before. I can't find any information about them besides subjective reviews. I want cold hard facts and specs lol

 

I always have interest in tubes I have never used before to build with but I hardly see myself building with the KR 842vhd as they are disgustingly expensive. I'll just find some less expensive transmitting tubes to make a high powered SE amplifier.

 

On that note I know a guy that has 150wpc SET amplifiers using the 833c transmitting tube. He spent $10,000 on just having the output transformers wound from Monolith. Those amps are insanely awesome.

 

 

[Curious_George]

19 minutes ago, captainbeefheart said:

 

Oops my mistake, I was thinking of a different Welborne amp............Moondog I think.

 

I just looked at the Apollo and wow completely different!! The KR 842vhd is a completely different tube able to deliver much more power and it also has about 1/3 the plate impedance of a 2A3.

 

 

I must have interpreted your post incorrectly, or Nick saying your experience with tube amps was less than overwhelming put in my head that you didn't like any of the tube amplifiers that you just listed.

 

I think the first paragraph you listed are amps you enjoyed? And the Wright amp was just an example of one you didn't like?

 

 

Oh well, it really doesn't matter. I just feel bad interpreting others post incorrectly. I'm glad we had this conversation because it brought attention to those Apollo amps which are very interesting and I have never seen before. I can't find any information about them besides subjective reviews. I want cold hard facts and specs lol

 

I always have interest in tubes I have never used before to build with but I hardly see myself building with the KR 842vhd as they are disgustingly expensive. I'll just find some less expensive transmitting tubes to make a high powered SE amplifier.

 

On that note I know a guy that has 150wpc SET amplifiers using the 833c transmitting tube. He spent $10,000 on just having the output transformers wound from Monolith. Those amps are insanely awesome.

 

 

I have a pair of 833A's that are waiting for a future SE projects! Looks like you are on my design team Cappy...

[Curious_George]

7 minutes ago, Curious_George said:

I have a pair of 833A's that are waiting for a future SE projects! Looks like you are on my design team Cappy...

BTW, I also have a pair of 872 rectifiers that I am going to use in combination with the 833A's. I know not many people like using mecury vapor rectifiers, but the glow of them would add a visual effect to the amp.