Cheapest way to repair the amp in a Genelec subwoofer.

[datapata]

Howdie! I spilled a glass of water all over my table and unfortunately some of it got into my Genelec 7040 that's under my table. It is now broken and spews out magic smoke when I plug it in. I checked the amp board and there are no fuses so I guess the board is fried, but I assume the speaker itself is still functioning.

Now to my question. I have a MiniDSP and do all my crossover stuff there, so all I have going into it is a mono signal so I don't need any crossover or eq functionality. All I need is a 50w mono block with XLR input, I think? What would be a good option? Preferably something cheap.

 

[Wayne A. Pflughaupt]

To clarify, you intend to use an outboard amp and not a plate amp?

Regards,
Wayne A. Pflughaupt

Equipment List | Tech Articles and Reviews

 

[datapata]

Either is fine honestly, I just want it up and running as cheaply as possible. Plate amp would require me to build a housing box which would add to the cost though.

 

[MCH]

Datapata, I went through a couple of "sub passivations". I am a complete noob, but this is what I learned from ASR members, I hope others will chime in: the original plate amp most likely applies DSP to the signal, that could be even a dynamic one, what I did is to measure the FR of the original plate amp and take it from there.
See around this post:
Post in thread 'My quest to eliminate the noise/rumble of my SVS SB-1000' https://audiosciencereview.com/foru...e-rumble-of-my-svs-sb-1000.46977/post-1861814

 

[Wayne A. Pflughaupt]

You can find a DIY article in the “Tech Articles” link below on how to convert an active sub to passive. However, on-line pictures of the 7040 show it’ll be a challenge adding binding posts. You might have to just run a long speaker wire directly to the driver somehow.

Regards,
Wayne A. Pflughaupt

Equipment List | Tech Articles and Reviews

 

[datapata]

You can find a DIY article in the “Tech Articles” link below on how to convert an active sub to passive. However, on-line pictures of the 7040 show it’ll be a challenge adding binding posts. You might have to just run a long speaker wire directly to the driver somehow.

Regards,
Wayne A. Pflughaupt

Equipment List | Tech Articles and Reviews

Brilliant thanks. Removing the amp enclosure exposes the speaker wire!

 

[somebodyelse]

I'd check with Genelec first so you have a baseline repair cost. Beyond that I'd look for a suitable class D amp board - mono, differential input since you said XLR, enough power - and mount inside the sub. Distortion from the speaker is likely at least an order of magnitude more than from ant amp so long as you don't push it to clipping. Maybe try something ridiculously cheap first?

 

[datapata]

Reached out to a service center and it would essentially be 250 our to replace the board.. In the meantime I found this, https://www.thomann.de/intl/the_tamp_pm40c_endstufenmodul.htm

Think I will just order that and try it out!

 

[DVDdoug]

I'm going to agree with MCH... I probably has some built-in and unknown DSP/EQ.

 

[datapata]

I'm going to agree with MCH... I probably has some built-in and unknown DSP/EQ.

Since I EQ myself with MiniDSP does it matter?

 

[somebodyelse]

I'm going to agree with MCH... I probably has some built-in and unknown DSP/EQ.

That's probably true, but since it's dead measuring it won't be possible. It's going to be crossed over externally, and (I assume) EQ'd for in-room response anyway. Port output can be checked with a mic so it can be high passed at a suitable frequency to stop the cone flapping below tuning. The only thing missing will be driver protection, assuming that's present anyway.

 

[holdingpants01]

Reached out to a service center and it would essentially be 250 our to replace the board..

great price, I would do it, also it's the only way to keep any value of this sub in case you'll want to sell it in the future

 

[datapata]

https://imgur.com/1zFbreQ

Here is a picture (click three dots and download for better view) of the amp and daughter board. Im pretty sure there are no DSP chips present.

 

[somebodyelse]

There's a 5A fuse F1 soldered next to the power inlet. From the residue on the board it looks like the water bridged the high and low voltage sides of the SMPS under what I guess is an optoisolator, as well as a couple of the opamps etc. I don't imagine that ended well. It looks all analog for signal processing. The TPA3118 amp chip should give an idea of the performance level you're trying to replace.

 

[datapata]

There's a 5A fuse F1 soldered next to the power inlet. From the residue on the board it looks like the water bridged the high and low voltage sides of the SMPS under what I guess is an optoisolator, as well as a couple of the opamps etc. I don't imagine that ended well. It looks all analog for signal processing. The TPA3118 amp chip should give an idea of the performance level you're trying to replace.

Aha, for some reason I expected to see a "normal" round glass fuse. Thanks for the info!