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Subaru
1-3-2-4
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join:2001-05-31
Greenwich, CT
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1 edit

Logitech Z-680 Subwoofer to a receiver

I have a Denon AVR 1612 on the way today from Amazon and if I can I would like to figure a way to get the sub connected as a temporary fix until I can get the correct sub in about 2 weeks.. it's just painful without any bass to fill any musical stuff out.

The Logitech interfaces with the control pod but the plate amp is on the subwoofer it's a 8" driver

*edit found this

If any people are (like I was) looking for a way to use the amplifier with out the control pod heres my little guide..

1. Take the amplifer off the subwoofer. (I needed to cut some wires here to get it off enough)

2. Take off the back plate (lots of screws to undo here including some with bolts on the other side)

3. Take off the panel on the rear side which has the plug to the control panel. (once you've removed the bolts it just pulls off)

4. Now using the pin labels that you will find on the panel that you pulled off identify the VREGDD, MUTE AMP and STANDBY AMP pins (they are all in a line), use some single core wire to connect mute and standby to the vregdd (or put switches on) This will allow the amp to be turned on with out the control pod being attached.

5. connect the inputs (eg RF AMP etc) to some sort of connectors ie 3mm or coax connections.

And Thats it, make sure if you cut any wires to ease the amp off you fix them back up and cover with electrical tape

Now the amp can be turned on/off by the switch on the back or if you put switches on the STANDBY AMP Wire. One thing to note though is that the Amp now has no Pre-Amp which means no onbard volume control or crossovers so make sure you turn the volume right down on the source before you plug it in!!



Subaru
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Ok I took the amp out I did it without having to cut wires but you have to be sure not to tug on it, anyways I see these connections but most receivers have a Subwoofer RCA cable being as I have a left over cable and looking at these pins wont the wire be a bit too thick to make the connections?

I might do the switch connection since when I do get the proper sub this whole system is just going out to the living room.

I still have a lot of single core wire that would do but I hate doing stuff like that.
--
It's NOT Ni-kon It's NE-KON!




LG is NOT Lifes Good It's Lucky Goldstar!



Subaru
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reply to Subaru

Click for full size
Click for full size
Click for full size
pictures

The amount of dust inside was crazy.. coughing at least 5 min


Subaru
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1 edit
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dump question.. since the RCA has two wires inside should the shield be connected to ground?

ohh nevermind the other wire is a shield



Subaru
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reply to Subaru

Magic smoke has been released!

Blew one of the tda7293 chips



Subaru
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reply to Subaru

Click for full size
Click for full size
It was covered in heatsrink so more pressure on the shielding wire
Ah I bet this had something to do with it.. and a little bit of aftermath..

never work on a project when getting home from a party :P

I'm going to guess here this was the cause.. but the funny thing was while the shield and the pin are touching here the shield was not connected on the amp PCB maybe some type of imbalance was going on?

redoing the leads now and going to tie to shield ground.


Subaru
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I did a ohm test of the RCA at least I'm seeing a reading this time, granted I should of taken a reading before testing at least that way I would of known something was amiss..

now about this IC amp chip, from looking at at least 40 different threads on like 5 different sites, it seems it does not take much to really send this chip to an early death.. I know on DIY audio one thread felt like the so call circuit protection maybe only lasts a few seconds or is really not up to handling any short circuit of any type.

I did find 5 of the TDA7293 are for the satellite speakers and 2 are bridged for the subwoofer, it just took out just one of the 7293's so.. things are grounded now and the leads are separate now, I understand this amp IC has a mute/standby but in my case since I bypassed it now it's going to thump, but the last time I tried the switch it was not bad.. what would scare the crap out of you was if the power went out it sounded like a gun shot

After this I need to make sure I get a uni-drill bit.
--
It's NOT Ni-kon It's NE-KON!




LG is NOT Lifes Good It's Lucky Goldstar!



drjim
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Long Beach, CA
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reply to Subaru

You let the smoke out with a BANG!



Subaru
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said by drjim:

You let the smoke out with a BANG!

From what I read line voltage I think hits the chip, I know very little about this audio chip I just know from searching it's used in a lot of amps..

One thing I don't know much about or can't find much info.. say a chip is oscillating how long does it take to overheat?


drjim
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join:2000-06-13
Long Beach, CA
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Depends on what frequency and amplitude the frequency of oscillation is.

Could run forever, could go POOF! in seconds.
--
One man's Magic is another man's Engineering.



Subaru
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reply to Subaru

Post office finally delivered the backed up mail so the chip came but now I have no power at home lol



Subaru
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1 edit
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Ok make sure I had no more shorts but something else.. I can hear it (music) or at least the bass parts in the subwoofer but I'm at +8.0d dB and it's not loud at all I kinda have to put my hear to it to hear anything.

Doh.. I'm going to have to run auto setup few things I forgot to change on the receiver :P

Here is a little quick video.. chips got pretty hot in 30 seconds, 110 F hot.

»www.youtube.com/watch?v=y9lmIIu-···youtu.be


Subaru
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Friken done pretty much :P I have a crap load of screws left for some reason :P as long as the chips are pressed on the heatsink and the board is screwed down and the speaker is screwed in then it's fine for now, next I have to calibrate it since the level are really off and I used the Audyssey setup.

»www.youtube.com/watch?v=iv9kemlv···youtu.be


Subaru
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reply to Subaru

Only thing is the sub makes a slight 60 Hz hum that is heard regardless of the receiver being on or off, not sure I can do much about that?



rjackal
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Plymouth, MI

Do you often talk to yourself on the internet?



Camelot One
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Greenwood, IN
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said by rjackal:

Do you often talk to yourself on the internet?

Some days those are the best conversations on the internet!


Subaru
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I assumed people here did not know what I was talking about, little to no info on this system since its custom, I found info on the chips elsewhere.



Camelot One
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Greenwood, IN
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With 507 unique views as of right now, people are following the thread, even if they aren't posting.



Subaru
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I see



Subaru
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reply to Subaru

Ok must be a ground loop, but a little confused if I remove the subwoofer cable the hum stops, which I expected that but say if I touch a metal part of the heatsink or the RCA jack it's self I can get hum again.

would that mean a bad ground? I wonder if I put the ground wire in between the wrong spot/



Subaru
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reply to Subaru

I wish I could add some type of gain on this I have to crank the receiver to about -16dB to get enough fill in. Music is a little different because I don't need to have it so loud and it fills out well. The other day I did a 18 h 22Hz test for the sub to see how hot the heatsinks got and the side where I replaced the IC chip was 135F not sure what the thermal cut-off was I think it was 75c


thexman

join:2012-11-12

hey there, no self conversation anymore

i followed your topic and also your video on youtube, i'm very interessted in your modification of the z680 subwoofer, because also have such a logitech system and want to use it with an av receiver like you.

but there are still some questions left open (wiring the rca with pcb and also the wiring within the pins of the pcb).

I hope i correctly understood what you did (please correct me if not):
-you connected MUTE AMP and STANDBY AMP with separated wires over a switch with VREGDD?
- you connected RF AMP with the RCA Cable ?
- what you did exactly with the shield ? connected with the ground next to the RF AMP?
- did you already bypass the humble of the woofer?

Hope you can answer my question, that will help me very much, setting up my speakers and the woofer without the annonying pod.

regards


thexman

join:2012-11-12

1 edit
reply to Subaru

double post, nevermind!



Subaru
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reply to thexman

said by thexman:

hey there, no self conversation anymore

i followed your topic and also your video on youtube, i'm very interessted in your modification of the z680 subwoofer, because also have such a logitech system and want to use it with an av receiver like you.

but there are still some questions left open (wiring the rca with pcb and also the wiring within the pins of the pcb).

I hope i correctly understood what you did (please correct me if not):
-you connected MUTE AMP and STANDBY AMP with separated wires over a switch with VREGDD?
- you connected RF AMP with the RCA Cable ?
- what you did exactly with the shield ? connected with the ground next to the RF AMP?
- did you already bypass the humble of the woofer?

Hope you can answer my question, that will help me very much, setting up my speakers and the woofer without the annonying pod.

regards

yep that's how you wire it to work without the pod with the switch just make sure you don't make a solder bridge because how close the pins are and the single core wire.

For the RCA jack I used a drill but it's better if you have a uni-drill so you can get the right hole size, for the jack since I did not have the normal RCA jack I ripped one out of my Xbox 1 AV connection box that had the optical out. That ended up having a good back of rubber that would mount flush and to mount I used 2 part epoxy and let that set over 5 hours.

making the connection the center wire went to Sub AMP or it could be any of them as long as it says AMP.. the shield, depending on what jack you are going to use will be a wire wrapped around foil or a separate connection if you get a ready to mount type jack, for the ground to shield I think I connected it to signal ground.

And bypassing the humble of the woofer? What's that? You mean hum? I still have hum but I haven't got around to fixing that yet I don't think I'm making a good ground connection with the ground wire I put back.
--
It's NOT Ni-kon It's NE-KON!




LG is NOT Lifes Good It's Lucky Goldstar!


thexman

join:2012-11-12

1 edit
reply to Subaru


rca female
thanks for the detailed reply to my question(s), yes i meant hum not humble, english is not my main language so I choose the wrong word, but you nevertheless got it

with the "ready to mount type jack" you mean a jack without cables like that on the picture that i attached right?

I am not sure if i should give that modification a try, because I took a closer look on the pcb and the distance between the pins and there's not very much space for untrained soldering

my actual solution is a direct wiring between the sub pre-out of the amp and the pod input for the different channels which works fine, but requires the pod to be turned on, which is kind of annoying

once again thanks for your detailed reply


Subaru
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Yeah pretty much like you posted, now if you have another speaker model that's not a z680 then I don't know what the PCB layout is and if things are labled, I know they started scratching off the model numbers of the chips after mine


thexman

join:2012-11-12
reply to thexman

no doubt, its exactly the z680 model not z5500 or one of the newer ones, so labeling and layout positioning should be the same like with your model (even though i bought it in europe )



Subaru
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ok In that case yes it will look the same, now the one things that are missing is something to increase the gain. In movies this can be a issue, I'm still using the satellite speakers from the Z680 so they are a smaller then the main speakers I will be getting, I ran a auto setup on my Denon and it raised the sub level up to +11.dB

To really get it to fill in you have to run near 0 dB and that's loud! Music it's fine, I'm playing some Celtic music on it now and it fills in fine at -32.5 dB

But like I said this was just something I wanted to try, I don't know if it's possible to add a gain to it it might cause some issues.
--
It's NOT Ni-kon It's NE-KON!




LG is NOT Lifes Good It's Lucky Goldstar!


utopian999

join:2013-01-09

Hi,
I have a z680 sub with a control pod that doesn't work so I've been looking for a way to use the sub without the pod. I came across this forum and I used the instructions posted to re-wire the sub. It appears to work, however the sub puts out very little sound. I have it connected to my Yamaha htr-5950 and I set the sub out volume to +10 and yet the sub still puts out minimal volume. I noticed on the video you posted that your sub seems to play appropriately.

What can I do to increase the sub volume so it fills in the music properly?

Is it possible that I'm not using the correct single core wires in the pin pads?

Your assistance is appreciated!

ACP



Subaru
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I think in the video I stuck the video camera in or very close to the port so that's not a good test, and yes like I said before the Sub has no gain like a standalone one would so the sub volume is dependent on how loud your receiver is.. My auto EQ set the sub to like +11

Funny thing is music it's not much of an issue and movies I tend to run at -14db so the sub balances it out.. I ran it once at that but running a 10 Hz sound test for 8 min to warm up the new chip and to check to make sure the thermal paste had time to set and check temps.

I'm not too sure if it's possible to get the sub have some type of gain volume setting.

I should do another video this time not right at the port :P
--
It's NOT Ni-kon It's NE-KON!




LG is NOT Lifes Good It's Lucky Goldstar!