[Lkdog]

My friend's ACI Titan subwoofer started going crazy in middle of night. A loud pulsating noise.
It is probably 15-20 years old.

Here is video of it. This with no music playing- just powered on and connected to a Jolida integrated amp variable output. Has worked great for years.
Not static or popping on amp. The monitors (ACI Sapphires) sound great.
https://photos.app.goo.gl/mkqUB28r2yPx3yqA9

I checked cable, reinserted cable, swapped cable, checked inputs, etc.
The speaker itself looks great- but maybe I am missing something obvious.

Any help on this appreciated as to next steps.
Is there a drop in replacement?
Is there an obvious part that is failing?
Is it worth trying to fix?

THANKS!

[Bemopti123]

Something in the plate is failing. Either take it out and take it to a tech, or find a drop in replacement or seal the sub and run a rack sub amplifier. 

[Stercom]

Something in the plate is failing. Either take it out and take it to a tech, or find a drop in replacement or seal the sub and run a rack sub amplifier.

I agree its the plate amp in the sub. I would unplug it before it does damage the woofer.  Should be easy to replace if you can find the right size to fit the opening. Cheap ones can be had for less $100 - its worth trying.

[Lkdog]

Tech guy in town says he can't look at it for 12 weeks.
Very few places around here to actually service electronics anymore.
By the time he charges hourly rate, and they order part(s) I am sure the cost would be about same as other options.
The amp is 22 years based upon sticker on one of the caps.

Am interested in either option at a reasonable cost. Preferably the drop in plate amp.

1) Rack amp
2) Plate amp drop in.

Opening is 8.5" X 6".

[avahifi]

Check with Madison.com.

They supply lots of subwoofers and plate amps and usually are very helpful and quite inexpensive.

I agree that the problem is a defect with the old plate amp and it should not be used again.

Frank Van Alstine

[JakeJ]

Did you mean Madisound.com?

https://www.madisoundspeakerstore.com/index.php?p=home

Pats Express and Dayton have some as well.

[rockadanny]

I had to replace  one of my Titan plate amps a while back. Mike Dzurko (ACI owner) recommended getting it from Triad Speakers.
It was an exact duplicate - very happy with the replacement.

Triad Speakers, Inc.
15835 NE Cameron Blvd
Portland, OR 97230

877-264-6315
www.triadspeakers.com

[Doublej]

I would remove the plate amplifier and look for any obvious signs of issues like bulging caps, burn marks, discoloration. If it appears to be something obvious, it's probably worth a shot at a repair.


Good luck with finding a drop in replacement.

[Lkdog]

Thanks for all of the replies.

It is indeed a TRIAD amp.
There is sticker that says TRIAD 9.1 Amp serial #1161. Dated 12/7/99.


No obvious signs of failure, but it clearly needs repair or replacement.
I contacted the TRIAD company and will see what they have to say.

[Lkdog]

Triad states they do not have any of these amps.

They did send me the schematics and identified the probable parts that were bad (large caps and certain transistors).

Very hard to find anywhere around here to work on it. Only place said 12 weeks to even look at it.
I can't find a plate amp that will fit in the enclosure opening of 8.5" X 6".

Right now it is a very heavy paperweight.

[WGH]

Borrow a saber saw and make the hole for the plate amp bigger, the cuts don't even have to be pretty because the wide flange will hide all the flaws.

Parts Express has a bunch of sub plate amps to choose from $59 - $450.

https://www.parts-express.com/search?keywords=sub%20plate%20amp&order=relevance:desc

[Doublej]

I'd buy all of the probable parts that are bad and replace them myself. Generally subwoofer amps are very easy to work on.

Although I will say physically this looks very close in size to the Triad.


https://www.parts-express.com/Dayton-Audio-SPA250DSP-250W-Subwoofer-Plate-Amplifier-with-DSP-300-8010

 The Amplifier dimensions are 10.25" H x 7.25" W x 2.125" D; Amplifier cutout: 9.25" H x 6.25" W.

[CAGCTG]

Lkdog, can you please send me the schematics of the Triad amplifier from your ACI Titan II subwoofer?

[Jeff_From_Michigan]

I have a Titan with a similar issue.  It has been replaced by dual SVS subs running with Maggies, but I'd sure like to get it fixed and put it back in a system with my Sapphires (one of the very best bargains in the history of my audio experience) fed by the conrad-johnson CAV-50.  The sound I was getting out of that combination with my Wadia 830 over 20 years ago was beyond belief. I'm also very interested in trying it with the LUMIN D2 that is sitting idle.

Can anyone offer advice on what parts/components I should be looking for in the plate amp if I want to try replacing mine? By that I mean components that will have the most impact on SQ?

To the OP, please let us know what route you end up taking.

[drmike]

i'd be interested in the schematic also. mine is still fine after 20 + years. great sub!
thanks,
drmike

[VinceT]

I have a pair of ACI's, I have seen those old plate amps pop up for sale here and there in the used market. That being said if mine ever failed I would probably just remove the old amp and retrofit a new plate amp, or seal the opening and use something external.

[philhjobim]

Triad states they do not have any of these amps.

They did send me the schematics and identified the probable parts that were bad (large caps and certain transistors).

Very hard to find anywhere around here to work on it. Only place said 12 weeks to even look at it.
I can't find a plate amp that will fit in the enclosure opening of 8.5" X 6".

Right now it is a very heavy paperweight.

I would be interested in the schematics and common fail parts list if anyone has them.  I pinged Triad for them, but they said they were not available.

Power supply cap on one side looks suspect, unregulated voltage waveform from the rectifier across it so hopefully its just that and an easy fix but the schematic would help if I need to go deeper.  New Nichicon LLS caps on order from RS part number LLS1J682MELB as the LLQ 6300 microfarads are now obsolete.  Amp has a mains hum and no signal gain.

Mine is dated Jan 2002 and has a Triad 11.0 label on.  I built the sub in 2002 with a kit shipped from ACI.  22 years perfect service until the power cables were being worked on and there was a big spike from the  temporary generator blowing up.  Oh I did have to superglue the cone back to the rubber suspension a few years back after it started breaking away on one side and making a horrible flapping noise, but that seems to work perfectly after the repair despite the energy that gets put through it.  Runs with Copland CSA28 amp / B&W CDM1SE monitors / B&W stands / Transparent cables.  Just had to change the amp valves as well - Russian tank valves ran for 15 years in an always on amplifier!  New ones are a bit pricier now, ouch!

Phil

[Lkdog]

Here is what I have.