Author Topic: Crispy Tangent Evo E8 subwoofer - bin or rebuild?  (Read 304 times)

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Offline LomaxTopic starter

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Crispy Tangent Evo E8 subwoofer - bin or rebuild?
« on: November 23, 2024, 08:54:43 pm »
Friend of mine asked me if I could take a look at his Tangent Evo E8 8" subwoofer which had gone silent. Found that both main filter caps (6800uF 50V "Chang" brand) had spewed their guts and the PCB had been burned to a crisp, with the heat seemingly coming from two zeners (ZD4 and ZD3 vertically below it in photo). Even if I was able to figure out the values of burnt resistors and diodes, the FR4 itself has been carbonised to the point where it falls to pieces when you poke at it.

So not really possible to repair, as such - but I could install a new amplifier in the enclosure. He's got no need for the low-pass filter since he's feeding it from an AV amplifier with a dedicated subwoofer line output. There's a beefy 27-0-27V transformer and a nice switched mains input socket that could be reused, by adding a new rectifier board with a couple of filter caps. I'm just not sure if it's worth the cost & effort!

What say the forum? Bin it - or McGyver it?

 

Offline themadhippy

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Re: Crispy Tangent Evo E8 subwoofer - bin or rebuild?
« Reply #1 on: November 23, 2024, 09:17:02 pm »
Quote
here's a beefy 27-0-27V transformer and a nice switched mains input socket that could be reused,
Any decent heatsinks? recently threw one of these together https://quasarelectronics.co.uk/Item/velleman-k8060-discrete-power-amplifier-200w-kit so far its done wot it said on the tin,only mod i made was upgrading the 2 psu caps from the 50v  supplied to 63V  as with a 30-0-30 transformer it was bit close for comfort
 
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Offline LomaxTopic starter

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Re: Crispy Tangent Evo E8 subwoofer - bin or rebuild?
« Reply #2 on: November 23, 2024, 09:33:57 pm »
Quote
here's a beefy 27-0-27V transformer and a nice switched mains input socket that could be reused,
Any decent heatsinks? recently threw one of these together https://quasarelectronics.co.uk/Item/velleman-k8060-discrete-power-amplifier-200w-kit so far its done wot it said on the tin,only mod i made was upgrading the 2 psu caps from the 50v  supplied to 63V  as with a 30-0-30 transformer it was bit close for comfort

Yeah! I forgot to mention that there's a very substantial black anodised heatsink on the back of the enclosure, which I would certainly want to keep for something. That Velleman kit is very attractively priced, and probably at least as good as the Wun Hung Lo boards I've so far been able to find on eBay... Looks like it would fit nicely on the existing heatsink as well.

 

Offline LomaxTopic starter

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Re: Crispy Tangent Evo E8 subwoofer - bin or rebuild?
« Reply #3 on: November 23, 2024, 10:00:28 pm »
so far its done wot it said on the tin,only mod i made was upgrading the 2 psu caps from the 50v  supplied to 63V  as with a 30-0-30 transformer it was bit close for comfort

I note the absence of a relay; does it make a loud pop when switching on/off? Did you add a volume control pot? The assembly instructions fail to mention this.
 

Offline Audiorepair

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Re: Crispy Tangent Evo E8 subwoofer - bin or rebuild?
« Reply #4 on: November 23, 2024, 10:10:04 pm »
Yes, it looks like failure of the Power Amp means DC to the speaker and nothing to prevent it melting.

I guess it is down to the designer of the end product to incorporate some kind of DC protection circuitry.
 

Offline themadhippy

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Re: Crispy Tangent Evo E8 subwoofer - bin or rebuild?
« Reply #5 on: November 23, 2024, 11:28:54 pm »
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I note the absence of a relay; does it make a loud pop when switching on/off?
thers a small pop but nothing that concerns me
Quote
Did you add a volume control pot? The assembly instructions fail to mention this.
Its just a power amp,no volume pot included,but its simple to add one if needed.
 


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