Ampeg Isovent - Jack Plate Circuit Board.

[two fingers]

I hear you.

I am NOT discounting what you are all saying.

What I am saying is, I am in the process of ruling out possibilities towards narrowing and zeroing in on the more exact root of the problem.

If the 210s are on one line, and the 215s are on a second, and when testing just the 215s entirely outside of the cabinet, and independently separate from each other, the F Bomb is there, then this rules out the cabinet, this rules out the 210s specifically, and this rules out the 215s specifically. A process of elimination.

At that point this told me the problem had to come from a centrally located Conjoining point, the juncture where both sets of speakers met, and this happens to be at the Jack Plate Circuit Board.

Here is where things get confusing.

Most of you said the Crossover can NOT be the cause when the Tweeter is disengaged. Okay this sounds good, but the F Bomb was still there, the Crossover is still the conjoining juncture point, and I can't help but notice the F Bomb is still there. To further eliminate this possibility would mean ReWiring the Jack Plate by fully removing the Crossover, and just to be sure Nothing in the Crossover is causing the problem, testing the cab WITHOUT the Crossover at all.

If the F Bomb is still there afterwards, then something else has to be the cause of the F Bomb, and this would mean something else very unusual has to be the cause.

Now I understand there are options which could be used to Dial Out the F Bomb, for example the HPF, or Parametric EQ, and Severe Compression maybe, but what I am saying is, before I go to using these options, I first want to see what eliminating the Crossover does.

From there I want to see what I see, and then make up my mind on what I want to do with the Isovent cabinet.

I like the Isovent Concept but I am NOT sure Ampeg got it right when designing this D50 HE cab.

So DON'T think I am discounting what you all are saying.

I am NOT!!!

I am listening to all of you.

In fact you all were helpful in explaining what the Crossover is and how it works and this led me to conclude Removing it all together and testing it that way is the next step in the process of elimination.

Before talking with all of you I had No Idea what to do next.

So if you think I am NOT listening to you, you are Wrong, because I am listening, and I am learning.

What I am saying is, via the process of elimination, I want to make absolutely sure there is Nothing UnForeSeen going on with this Crossover Circuit Board, which happens to be the one point where the 215s, 210s, and the stupid Tweeter, ALL Meet.

If the F Bomb were just in the 210s, or just the 215s, this would probably make more sense, but the fact it is in both actually doesn't make sense, and the one thing that does make sense is the juncture point conjoining the two, which happens to be at the Crossover Board.

How can both the 210s and the 215s both have the F Bomb when independently tested separately they both have the F Bomb?

This means the F Bomb is coming from elsewhere.

Yes the F Bomb is there with different amplifers, and different basses, and the F Bomb is NOT present when playing any of my basses through any of my other systems.

This narrows the problem down to the Isovent.

.

Edit. I realized you answered the questions.

 

[BigBigGuy44]

This narrows the problem down to the Is Isovent.

@agedhorse told you this on the second and fifth post of this thread yet you continue to ramble on about nothing.

 

[Coolhandjjl]

... This narrows the problem down to the Isovent.

I believe it was early in the thread were several commented to the effect that the isobarik wasn’t Ampeg’s best effort, IOW a sucky design, and isobariks in general have dubious claims of being worth it. You just didn’t want to believe it. Do you believe us now?

There’s a reason no one makes these designs anymore (with the exception of Orange, I believe). And just perhaps you’ve discovered that reason.

 

[thetragichero]

Knowing what it isn't is some of the most important and useful information available. When troubleshooting, it's part of a technique called "differential diagnostics". The more you can eliminate, the less there is left that could be the problem.

this and maybe learning to read a schematic legit changed my life wrt trying to fix things. instead of just thinking thinks with my superior intelligence and usually 1. shotgunning a lot of unnecessary parts and 2. ending up frustrated, i can now rule out what it's not and instead of chasing red herrings focus on what it 'might be'
helped a friend about an hour away "revive" his "dead" v4 via text by suggesting the steps I'd use to troubleshoot before even busting out a screwdriver. saved him a bench fee on what turned out to be a dirty shorting jack or somesuch.

 

[Redbrangus]

I have no way of knowing whether it's true or not, but I read this in an actual book way back when there was no Internet. It was a biography of Tesla (not the band), in which it was said that in the early days when Tesla was working in Edison's lab, that he privately expressed frustration with Edison's lack of understanding of basic physics. He notes, with disdain, Edison's technique of just trying every different possible substance in an electrical experiment, when he could have ruled out many of the possibilities with a simple understanding of the phenomenon involved. That technique had served Edison well enough in developing the incandescent lamp, so he continued it his whole professional life. Someone once told me, although I don't think I've ever read it anywhere, that Edison didn't understand Ohm's Law, which was still a relatively new concept when he was doing his early experiments with electricity. I've always thought his steadfast resistance to AC was rooted, at least in part, in the fact that he just plain didn't understand it.

And yes, I know I said I was un-following...I came back out of curiosity. It's kind of like how you try to not look at an accident site when you drive by, but then you just HAVE to grab a glance when the opportunity presents itself.

 

[mexicanyella]

Once we have learned what happens when you try the cab with no crossover board in place, then all of us can move past the crossover board and continue trying to help isolate the so-called F-bomb’s cause (assuming it’s still there) and if not eliminate it, at least try the suggested solutions to work around or minimize it, which might allow you to keep using the cab without the annoying resonance being a problem.

Get some jacks and wire it up, man!

 

[Bassdirty]

Okay if it is NOT the problem then what is it?

It can't be the enclosure because the problem exists when I test the speaker cones in a Free Standing state separately and apart form the cabinet.

The F Intensity F Bomb exists in both the 210s and the 215s.

Again there must be a common sourse where the problem is crated prior to reaching the speaker cones.

I figure at the Jack Plate Circuit Board, but now you say NOT, and If NOT, then Where From?

It is beginning to sound to me like I can just bipass the Circuit Board, in fact Remove It altogether, and ReWire the cabinet Direct to the Input Receptacles.

Or is it - Input Jacks on the Jack Plate?

Would this be a fair assumption?

I mean this would be a whole lot simpler, because all I would have to do is Remove Something, instead of having to Go Get Something, and this of course would save me time, money, and effort.

What do you say?

.

No offense meant , but I feel like agedhorse answered your question/concerns already.. maybe a few times now. I think you should maybe try a more... "modern" cabinet, for your needs.
YMMV
IMO
etc..

T$

 

[seamonkey]

I have no way of knowing whether it's true or not, but I read this in an actual book way back when there was no Internet. It was a biography of Tesla (not the band), in which it was said that in the early days when Tesla was working in Edison's lab, that he privately expressed frustration with Edison's lack of understanding of basic physics. He notes, with disdain, Edison's technique of just trying every different possible substance in an electrical experiment, when he could have ruled out many of the possibilities with a simple understanding of the phenomenon involved. That technique had served Edison well enough in developing the incandescent lamp, so he continued it his whole professional life. Someone once told me, although I don't think I've ever read it anywhere, that Edison didn't understand Ohm's Law, which was still a relatively new concept when he was doing his early experiments with electricity. I've always thought his steadfast resistance to AC was rooted, at least in part, because he just plain didn't understand it.

And yes, I know I said I was un-following...I came back out of curiosity. It's kind of like how you try to not look at an accident site when you drive by, but then you just HAVE to grab a glance when the opportunity presents itself.

Wiki's has a write up on the War of the Currents War of the currents - Wikipedia
And there was a movie that came our recently but I haven't seen it.

An interesting fact is the High Voltage DC transmission lines still have their place. China just installed 1.1Million Volt UHVDC transmission line that spans 3000 Kilometers! Overall this can be cheaper and span farther than AC. In things like underwater cable the DC helps to prevent impedance loss that AC would have in the same cable. It's an interesting world!

For ohms law, think of the light bulb in the crossover. It's not linear, it's not exactly following ohms law.
Maybe people who understand light bulbs have problems understanding Ohms law.

 

[BassmanPaul]

Outstanding.

Now we are starting to get somewhere with the problem.

Actually no we are not. You are arguing the toss with a Gentleman who designs amplification and speaker systems for a living.

I hope you get your problem sorted out but you’d do better by listening to what you are being advised and not hang on for dear life to a faulty premise!

 

[Redbrangus]

Wiki's has a write up on the War of the Currents War of the currents - Wikipedia
And there was a movie that came our recently but I haven't seen it.

An interesting fact is the High Voltage DC transmission lines still have their place. China just installed 1.1Million Volt UHVDC transmission line that spans 3000 Kilometers! Overall this can be cheaper and span farther than AC. In things like underwater cable the DC helps to prevent impedance loss that AC would have in the same cable. It's an interesting world!

For ohms law, think of the light bulb in the crossover. It's not linear, it's not exactly following ohms law.
Maybe people who understand light bulbs have problems understanding Ohms law.

Apparently, just as he famously 'hired mathematicians', Edison was able to hire someone who understood the implications of Ohm's law; the success of Edison's method of electrical distribution depended on the high inherent resistance of the incandescent lamp.

Sorry, @seamonkey, but I don't understand in what way the lamp in a light bulb limiter circuit doesn't adhere to Ohm's law...I need some explaining.

 

[agedhorse]

The non-linear resistance still adheres to Ohm's lab, BUT there is an added time variable. None of the parameters are static, they vary with time (temperature varies with time until it reaches a steady state condition) as the filament heats up. The light bulb limiter actually exploits this non-linearity and thus behaves as a variable.

 

[seamonkey]

Sorry, @seamonkey, but I don't understand in what way the lamp in a light bulb limiter circuit doesn't adhere to Ohm's law...I need some explaining.

For example:
Red Line is a resistor (control), Blue line is a light bulb.

The light bulb isn't ohmic because it's not a straight linear line.

Semiconductors also aren't linear, they have a knee voltage.

 

[Nicholas Orick]

The non-linear resistance still adheres to Ohm's lab, BUT there is an added time variable. None of the parameters are static, they vary with time (temperature varies with time until it reaches a steady state condition) as the filament heats up. The light bulb limiter actually exploits this non-linearity and thus behaves as a variable.

In other words the brighter the bulb gets the greater the limiting.

 

[Nicholas Orick]

Apparently, just as he famously 'hired mathematicians', Edison was able to hire someone who understood the implications of Ohm's law; the success of Edison's method of electrical distribution depended on the high inherent resistance of the incandescent lamp.

Sorry, @seamonkey, but I don't understand in what way the lamp in a light bulb limiter circuit doesn't adhere to Ohm's law...I need some explaining.

What about Edison turning Tesla down.

That wasn't one of his brighter moments.

 

[Redbrangus]

… not one of his 'brighter' moments.

I see what you did there....

 

[DJ Bebop]

I hear you.

I am NOT discounting what you are all saying.

What I am saying is, I am in the process of ruling out possibilities towards narrowing and zeroing in on the more exact root of the problem.

If the 210s are on one line, and the 215s are on a second, and when testing just the 215s entirely outside of the cabinet, and independently separate from each other, the F Bomb is there, then this rules out the cabinet, this rules out the 210s specifically, and this rules out the 215s specifically.

When you 'test' the speakers outside the cabinet, are they still connected to the other speakers via the crossover you are not testing? And if so, are the other speakers still in the cabinet producing sound?

 

[agedhorse]

For example:
Red Line is a resistor (control), Blue line is a light bulb.
View attachment 3675559

The light bulb isn't ohmic because it's not a straight linear line.

Semiconductors also aren't linear, they have a knee voltage.

Each point on the curve follows ohms law.

In other words the brighter the bulb gets the greater the limiting.

Yes

 

[Redbrangus]

For example:
Red Line is a resistor (control), Blue line is a light bulb.

The light bulb isn't ohmic because it's not a straight linear line.

@agedhorse has already said this in a couple of different ways, but just to be clear, an incandescent lamp conforms to Ohm's law at any given point in time.

 

[seamonkey]

Nope, the incandescent varies in voltage with temperature.
Well known
Semiconductors also don't follow the ohms law rules - for different reasons

 

[Redbrangus]

Actually, an incandescent lamp varies in resistance with temperature, which causes the voltage/current change. But at any point in time, the ratio of resistance to voltage conforms to Ohm's law. Just because a circuit doesn't exhibit a linear transfer function doesn't mean it doesn't conform to the laws of physics.