Removed the Crossover Circuit Board.
This is it - front & back.
What do you see?
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Ampeg Isovent - Jack Plate Circuit Board.
- Thread starter Nicholas Orick
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Removed the Crossover Circuit Board.
This is it - front & back.
What do you see?
.
There is a common connection between the woofers and the tweeter HPF through ground. But the tweeter on/off switch breaks continuity with the signal side of HPF circuit. Without continuity the HPF is essentially out of the circuit and cannot interact with the woofers.
Your obviously an experiential learner so I don't expect you to believe me. Have fun removing and replacing.
That doesn't look like a true crossover to me. That looks like a high-pass for the tweeter output and a way to wire in the limiter bulb.
What do you hear?
I see this and it doesn't tell me anything new.
What are the results? Have you learned anything new from removing the board?
Yes I believe you, but it also clear the 210s and 215s are connected to the Crossover Circuit Board, and since both independent of each other have the F Bomb, this means a common source of the F Bomb, and this means where both meets, which is at the Crossover Circuit Board.
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I haven't ReWired it yet.
I am going to have to get some 1/4 inch jacks before I ReWire it.
The 210s and 215s are no longer connected to the HPF. Is the F bomb gone?
NO. This means something ON the Crossover Circuit Board is causing the B Bomb problem.
I will have to get separate 1/4 inch jacks before ReWiring it.
Why use the bulb for a Limiter?
What is the purpose of Limiting and the use of the bulb?
What are the other components on this board?
The 1/4 inputs is all that you removed when you removed that board since you had the tweeter already out of it.
- Feb 12, 2006
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- Development Engineer-Mesa Boogie, Development Engineer-Genzler (pedals), Product Support-Genz Benz
I see EXACTLY what I saw before, the LF drivers have NOTHING to do with the crossover. The ONLY thing onbthst board is related to the tweeter. The rest is the connection wiring to the LF drivers... a glorified terminal strip.
What exactly were you hoping to recive from your post asking your questions?
Were you looking for answers from folks who know what they are talking about, or were you looking for strokes for how smart you think you are?
Perhaps we ALL misunderstood your motivation for posting something as a qurstion that wasn't?
What exactly were you hoping to recive from your post asking your questions?
Were you looking for answers from folks who know what they are talking about, or were you looking for strokes for how smart you think you are?
Perhaps we ALL misunderstood your motivation for posting something as a qurstion that wasn't?
This diagram answered a question.
The 210s are in Series, the 215s are in Series, and the two are probably Parallel.
Would I be correct on this?
This is actually all I need to know for sure.
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It's an old-fashioned way of protecting drivers. The bulb is basically a resistor that increases its resistance as you slam it with more power. It's calibrated to the power that speaker system can handle. As you begin to overload the cab, the lightbulb begins to light up. When it lights up, it begins to act like a gigantic resistor in real time to the current being delivered - effectively preventing it from getting to and damaging the speaker.
There are much better ways of doing this now, but as a last resort, it can be a helpful way to protect the speakers.
I see an inductor and a couple of filter caps on the board to remove the bottom end from the side feeding the tweeter - everything else is just wiring up between the jacks and the tweeter control.
With superbly engineered and manufactured modern bass drivers from companies like Eminence and Faital, any advantages and dubious claims of isobariks being ‘faster’ (tee hee) is now irrelevant. Get rid of it before it becomes your white whale.
To add further to why the lightbulb, because tweeters can handle much less power than woofers and often get blown, so the lightbulb is used to protect it. If the circuit diagram is accurate then the tweeter is the only thing it is protecting. This is highly likely.
The bulb protects the tweeter from excess power. It's a fairly common feature in older bass speakers. The other components are a switch, 2 resistors, a capacitor, and an inductor The capacitor and inductor form the HPF so the tweeter only receives frequencies above 5khz. The resistors are used to pad down the signal, so the output of the tweeter matches the output of the woofers. The switch allows you to select between two tweeter levels and off.
Okay this sounds good.
What do Inductors and Caps do?
Also do you see anything which could potentially Intensify the F frequencies?
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