Replacement sub amp for Def Tech Supercube ll

[the-bogus-man]

Hi all,

The plate amp in my Definitive Technologies Supercube ll subwoofer has kicked the bucket. I would like to find a suitable replacement external amp with both line-level and speaker-level passthrough inputs, preferably auto power on, and a built in X-over. I'm not picky about sound quality - I just need it to work and not start on fire, haha. So far my searches on Amazon, Aliexpress, and Parts Express have been fruitless, so I'm hoping that someone else has found a similar solution to what I am looking for and can chime in.

Thanks in advance for your help!

 

[antcollinet]

Where are you located?

 

[the-bogus-man]

Where are you located?

I'm in Canada

 

[antcollinet]

I'm in Canada

Don't think I'm going to be much help then.

There is a UK based Sub manufacturer, who also supplies plate amps for subs. But they don't have the passthrough feature you require in any case.

 

[AnalogSteph]

Before starting with bodgery and baby/bathwater type exercises, I would first attempt to get the thing fixed properly. It appears that schematics exist, which is a good start:

Definitive Technology Supercube II

I bought a Supercube II a while back for $75 from shop goodwill and it initially powered on but had no sound. Upon opening 'er up, I did a quick inspection (this thing is jam packed!) And it appears a few parts for a bit hot, to say the least. Can anyone tell me what these two obvious visually...

www.diyaudio.com

Start with visual inspection and see if you can spot anything obvious. I see the unit seems to be full of Su'scon capacitors (and 85°C rated parts at that in a unit that seems to be getting quite warm), which is a relatively low-grade brand of electrolytics if memory serves... a "gets the job done but nothing special" kind of deal. Failing (electrolytic, bipolar) output lowpass filter capacitors in subwoofer BASH amps are kind of a classic at this point (manifesting as low/distorted or no output), so I'd check whether this design sports any... Nope, just film caps there. This'll take some poking around then. Could still be electrolytics, but definitely check for shorted power MOSFETs as well.

 

[Clmrt]

Apex Jr

 

[bogart]

I'm in Canada

To AnalaogSteph's point - are you in a major city? There are some reputable shops around Toronto who can likely repair if you're not a DIYer also.

 

[Roland68]

Hi all,

The plate amp in my Definitive Technologies Supercube ll subwoofer has kicked the bucket. I would like to find a suitable replacement external amp with both line-level and speaker-level passthrough inputs, preferably auto power on, and a built in X-over. I'm not picky about sound quality - I just need it to work and not start on fire, haha. So far my searches on Amazon, Aliexpress, and Parts Express have been fruitless, so I'm hoping that someone else has found a similar solution to what I am looking for and can chime in.

Thanks in advance for your help!

ATOHM S250-MK2-X and ATOHM S500-MK2-X would both meet your basic requirements, as would DAYTON AUDIO SPA250, MONACOR SAM-2, MONACOR SAM-300D, Monacor SAM-500D, Yung International SD300, Yung International SD500.

However, it would be a coincidence if it would physically fit, so you would need an adapter board or a separate housing for the amplifier.

Alternatively, you could consider driving your system actively, e.g. with a cheap SMSL A300 400 watt amplifier and a the t.racks DSP 4x4 Mini.

Power amplifiers from the PA area with crossovers would also be an alternative and can be very cheap second-hand.

But as @AnalogSteph wrote, I would try to repair it first. The subwoofer is old and failed capacitors are normal and not a big problem.
Maybe you can find a DIYer in your area who can help you or contact a Repair Cafe, FabLab/MakerSpace/GarageLab near you.