Mark_Seaton Show full post »
lrc
Thanks loather.  I can measure as well (with fair amount of effort to access the output jack in the back of my receiver - it's an adventure to pull the receiver out for back panel access) but am hoping there might be a simple spec Mark could provide.  FYI he told me previously that the Mk2 does not use a relay on it's 12V trigger input,  due to the fact that "it's complicated" by the auto sensing capability on the audio input.  Not having a relay is why the trigger input on Mk2 is not fully isolated from the amplifier's main ground,  and this is why in my setup a small ground loop occurs (causing small but noticeable and thus irritating hum) when I try to connect both the audio and the 12V trigger signals from my receiver to the subwoofer.  Likely the root issue is in the receiver:  the subwoofer audio out and 12V trigger grounds are not truly common or something like that.

I'm actually using the Mk2's auto-sense capability right now and it works great,  but I'm adding another piece of equipment to my system which requires the 12V trigger from the receiver,  this is why I'm designing a small device which will take the 12V trigger signal from the receiver and create up to 4 totally isolated 12V trigger outputs.  I figure I might as well design it to be compatible with the Mk2 as well, thus my original question...
LRC
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loather
If it's not a relay and it's not isolated from the main ground (eesh, optoisolators are cheap, y'all!) then it's probably a voltage device like a mosfet. If so the input impedance on those is on the order of megohms, so whatever you throw at it would probably be fine. And, back to the topic of measurement - if your sub is in a better position to take the measurement from, then do it there instead of ripping your receiver out of the cabinet 🙂 Grab your bench supply, multimeter, and a spare 3.5mm connector and you'll be good to go!

Since the MK2 isn't earth grounded (kinda sketchy, honestly) then lifting the 12V trigger ground could be detrimental to the life of your system, so I wouldn't do that... the only other thing I can suggest is using a shielded trigger cable in case it's picking up transients from coiled up power cables or whatever else it might be running over.

As a side note, I received my mkII a week ago and really, this is what it should have had from the factory. This sub has *never* sounded better (and it sounded pretty damned good before!)
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lrc
Thanks for the comments loather,  good idea on the power supply I'll think about doing that.

I'm pretty sure the issue is just a simple ground loop:  two cables running from receiver to Mk2 each with a ground connection/signal.  I suspect the ground on the receiver's trigger output is not a very "good" ground,  and thus there's some current flowing back and forth on the ground signals of the two cables (the ground "loop"), thus disturbing the audio signal.  I thought about (and might have even experimented - can't remember) cutting the trigger ground signal (in the cable) but then this would cause whatever current needs to flow into the trigger input,  to return through the audio ground and thus back to same problem (unwanted current running through the audio cable's ground). 

As I mentioned use of the trigger is not really required,  the Mk2 does a great job auto-sensing the audio to turn on.  I'm building this little isolation circuit/device because I want to isolate another piece of equipment and it's easy to get multiple individually isolated outputs from the circuit.  So it's more of an academic project relative to the Mk2 but will be nice to see if it works.
LRC
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soundofrockets
Mark_Seaton wrote:


We have amplifier metalwork back in stock at our OEM and amplifiers arriving at the end of the month with plenty more available in months to come.  The Turbo woofer is based on the same updates I'm doing for the next generation SubMersive driver, so it largely will get done around the same time.  Until I post here that we have delivery week targeted, it's going to be 2-3 months away.


any news of this?  Haven’t seen any activity for some time.  Hope that Mark is ok.
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calentz
Occasionally Mark posts over on AVS; have seen nothing over here. 
Carl
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AcroReaper
Hi Mark or anyone on this forum. Looking for some installation support on the MK2 Amp. I'm clear on the two red wires - simple enough. However, my MFW-15 has a male connector with 7 wires (purple, thin tan, thin red, black, green brown, tan) while the Amp has two female connectors - one with 8 pins, and one with 4 pins. I'm not an electrician and am unclear on what to do with these. I've been unable to find any instructions, let alone any that reconcile the wiring mismatch I'm experiencing. I've emailed and left a message. A little help?
Ivan Belen
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loather
The 7-connector cable is not used with the new amplifier. That's the cable that goes up to gain/freq/phase panel with the three pots at the top of the woofer. You should have received a delete plate for that particular control panel with the kit. Remove the six screws holding in the panel and pull the wires through (there will be foam holding them in). Install the blank plate in its place.

The connectors on the amp are likely for some internal/testing function and we won't be using them.

You'll love this new amp when you get it installed. I thought it sounded pretty good with the original amp, but with the new DSP it really takes this thing to the next level. It's capable of some *really* earth-shattering lows now, combined with phase correction and an eq program that practically flattens it. Worth every penny.
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AcroReaper
Loather, thanks so much. That was my other question - saw the blank-out plate and naturally assumed it meant we'd not be using those anymore, but wasn't sure. I never got as far as pulling it, clearly. You've got me straightened out. I'm really excited. My MFW-15 died so many years ago that I don't even remember what it sounded like with the original amp. One day it just burnt to a crisp, and has sat there sadly and silently next to my Rocket 850s. I appreciate your help. Can't wait to get home and fire it up!
Ivan Belen
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loather
No problem 🙂 glad to help! 
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mac442000
 On 10-21-19 I ordered/paid for an MFW-15 MK2 Amplifier - Original MFW-15 Woofer. I have not heard anything from anyone although I did see that shipping should resume November 28.
I have sent several emails and phone calls with no reply? Are these people still in business?  have I lost my money??  Was going to buy some new speakers from Mark but dont know now??
chuck mcdonald
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calentz
To say that Mark is SLOW to do the things that he says hi going to do would be an understatement, but he responded to someone over on AVS last Sat. The green indicator on his postings is showing that he has been there today. 
Carl
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Mark_Seaton

mac442000 wrote:
On 10-21-19 I ordered/paid for an MFW-15 MK2 Amplifier - Original MFW-15 Woofer. I have not heard anything from anyone although I did see that shipping should resume November 28.
I have sent several emails and phone calls with no reply? Are these people still in business?  have I lost my money??  Was going to buy some new speakers from Mark but dont know now?? 

Hi Chuck,

I don't see any e-mails other than the one requesting and update on the amplifiers shipping which was received December 2nd (Monday morning), which I replied to within 90 minutes of receiving.

Amplifiers finally arrived late yesterday and your amplifiers are waiting for our FedEx pickup this afternoon.  Your order is the oldest of those waiting for MFW-15 amplifiers with all others less than 30 days.  You will see tracking from FedEx this afternoon.

Mark Seaton
Seaton Sound, Inc.
sales@seatonsound.net
773-290-8436
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