Filters and Impedance

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mj90210
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Filters and Impedance

#1 Post by mj90210 »

I recently changed my DR300’s to passive crossover and I am having a problem that was intermittent when running them biamped. I was running the biamp option listed in the plans, low pass on woofer and protection for compression drivers. When running the biamp option once and a while, I can’t really narrow it down but the 12” driver amp would go into protection whenever the input voltage was turned up but would go away at low voltage. I checked the connections, active crossover settings via dcx2496 and the venue 360 and always reminded the same. As crazy as it sounds it seems after a while or shutting down amps, processors, and input source they would all of a sudden act normal. I figured I would get away from the complexity of biamping and run them with a passive crossover per the plans. After completing the crossover they will make mulitiple different amps(class d and a/b) go into protection when the voltage goes up but will play when voltage is very low. I have ohmed out all the drivers and they are good, and they play wonderfully when biamped and bypassing any of the passive filters. Any suggestions on what to check next?
Thank You All for Your Time!!...Really!

Built:
2xDR300's
4xDual-30” Tuba 60’s
Simplex 21" Eminence NSW6021
1x20” THT
TLAH‘S
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SLA pros
TrT 10" Driver-10" Wide
Auto Tuba 10" Driver

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Bill Fitzmaurice
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Re: Filters and Impedance

#2 Post by Bill Fitzmaurice »

The indication is that the impedance load of the woofer amp is low. Are you running more than one cab per channel?

mj90210
Posts: 79
Joined: Fri Feb 03, 2017 2:12 pm
Location: Montana-USA

Re: Filters and Impedance

#3 Post by mj90210 »

I run two on separate channels. I have tried them on a Class D and a Class AB to eliminate an amp problem/setting and it persisted.
Thank You All for Your Time!!...Really!

Built:
2xDR300's
4xDual-30” Tuba 60’s
Simplex 21" Eminence NSW6021
1x20” THT
TLAH‘S
SLA Center-9 driver and Surrounds
SLA pros
TrT 10" Driver-10" Wide
Auto Tuba 10" Driver

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Bill Fitzmaurice
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Re: Filters and Impedance

#4 Post by Bill Fitzmaurice »

Since it's OK without the HP filter something in them must not be right, causing a too low impedance load. Either the inductor values are too low or the cap values are too high, or a combination of both. It takes gear you probably don't have to measure them. Try disconnecting a cap at one end. If that fixes it then the cap value is too low. Replace them with 16uF.

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Seth
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Re: Filters and Impedance

#5 Post by Seth »

Is the problem repeatable for both cabinets individually, if you run only one cabinet (the other completely disconnected), then switch to the other? Same results for each?

How many ohms did the drivers indicate when you checked them?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Seth
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Re: Filters and Impedance

#6 Post by Seth »

mj90210 wrote: Sat Aug 15, 2020 3:24 pm ...I am having a problem that was intermittent when running them biamped...

...they play wonderfully when biamped and bypassing any of the passive filters.
These two statements seem to contradict each other. Did the issue occur before adding the passive crossovers?
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

mj90210
Posts: 79
Joined: Fri Feb 03, 2017 2:12 pm
Location: Montana-USA

Re: Filters and Impedance

#7 Post by mj90210 »

Thanks for the replies. Bill are you talking removing the 10uf cap on the HP filter? Just to be clear the problem was intermittent when I was running the passive low-pass filter and bi-amping per the plans. When I added the passive highpass I could not get them to work at all at volume. If I remember correctly If I actively applied a low pass filter to the woofer of either 1.1-1.3hz (I can't remember), ontop of the passive Chebyshev filter, the woofer amp would come out of protection mode when input was raised. I understand this is bits and pieces but I hope it sparks a thought to help. Also typically my response at the crossover or 1.2khz is down 6-8db but I always figured that was due to the Impero 12A natural response. Let me know if you can think of any other trouble shooting tips.
Thank You All for Your Time!!...Really!

Built:
2xDR300's
4xDual-30” Tuba 60’s
Simplex 21" Eminence NSW6021
1x20” THT
TLAH‘S
SLA Center-9 driver and Surrounds
SLA pros
TrT 10" Driver-10" Wide
Auto Tuba 10" Driver

Bruce Weldy
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Re: Filters and Impedance

#8 Post by Bruce Weldy »

Are the woofers definitely 8 ohm drivers?

6 - T39 3012LF
4 - OT12 2512
1 - T24
1 - SLA Pro
2 - XF210


"A system with a few knobs set up by someone who knows what they are doing is always better than one with a lot of knobs set up by someone who doesn't."

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Bill Fitzmaurice
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Re: Filters and Impedance

#9 Post by Bill Fitzmaurice »

Disconnect the 20uF cap on the low pass filter. I should have written LP filter previously.

mj90210
Posts: 79
Joined: Fri Feb 03, 2017 2:12 pm
Location: Montana-USA

Re: Filters and Impedance

#10 Post by mj90210 »

I disconnected the 20uf cap on the LP and the problem quit. I am installing a 15uf since it is what I have On hand. I will test and measure them again. Should I worry about changing the coil and cap to different values in the future? I figured I would ask before I order replacement parts. Thanks!
Thank You All for Your Time!!...Really!

Built:
2xDR300's
4xDual-30” Tuba 60’s
Simplex 21" Eminence NSW6021
1x20” THT
TLAH‘S
SLA Center-9 driver and Surrounds
SLA pros
TrT 10" Driver-10" Wide
Auto Tuba 10" Driver

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Seth
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Re: Filters and Impedance

#11 Post by Seth »

Great news!

Not sure what you had in there. I'm thinking maybe you got a couple out of a bad batch or they weren't the specified 100v+ caps. I'd replace them with this one which is currently out of stock, although it looks like they expect them in soon. They have the 1% tolerance version in stock at a $5 premium. Could be worth it if you're anxious to get them buttoned up.

That is, unless Bill recommends a different value than is stated in the plans.
Build in process - 2 WH6, one Alpha 6a loaded, one PRV Audio 6MB250-NDY loaded

Two 2x6 shorty SLA Pro's
One T39, 16", 3012LF loaded
Tall AutoTuba, 20" wide, 2x 8" MCM 55-2421
TruckTuba, 8½" wide, 2x 8" MCM 55-2421

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Bill Fitzmaurice
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Re: Filters and Impedance

#12 Post by Bill Fitzmaurice »

I suspect the caps you had were out of spec. In any event if the 15uF work OK use the same brand and value if you add more cabs to the pile.

mj90210
Posts: 79
Joined: Fri Feb 03, 2017 2:12 pm
Location: Montana-USA

Re: Filters and Impedance

#13 Post by mj90210 »

The current caps are the higher end/tighter speced Dayton Dayton Seth posted. I actually have another set that were used for protection on the tweeters when biamping. I will try them and let you know what I come up with.
Thank You All for Your Time!!...Really!

Built:
2xDR300's
4xDual-30” Tuba 60’s
Simplex 21" Eminence NSW6021
1x20” THT
TLAH‘S
SLA Center-9 driver and Surrounds
SLA pros
TrT 10" Driver-10" Wide
Auto Tuba 10" Driver

mj90210
Posts: 79
Joined: Fri Feb 03, 2017 2:12 pm
Location: Montana-USA

Re: Filters and Impedance

#14 Post by mj90210 »

Replaced cap with exact same 250v 20uf Dayton-1% Dayton and problem was present.

Replaced cap with 250v Dayton 15uf-1% and problem was present.

Removed cap and problem is not there with the input well past 50 volts.

The coil visually looks ok. FYI I have tlah’s and sla center I can rob parts from for testing purposes.
Thank You All for Your Time!!...Really!

Built:
2xDR300's
4xDual-30” Tuba 60’s
Simplex 21" Eminence NSW6021
1x20” THT
TLAH‘S
SLA Center-9 driver and Surrounds
SLA pros
TrT 10" Driver-10" Wide
Auto Tuba 10" Driver

User avatar
Bill Fitzmaurice
Site Admin
Posts: 28619
Joined: Tue May 02, 2006 5:59 pm

Re: Filters and Impedance

#15 Post by Bill Fitzmaurice »

I'm stumped. It shouldn't be happening, but it is. Leave the caps out, you'll lose some midrange sensitivity but nothing EQ shouldn't take care of.

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