Super-T. Where's all the bass gone?

[spikeyfaz]

In another thread I recently mentioned how impressed I was with my Super-T amp. Well perhaps I shouldn't have tempted fate as it appears that my Super-T no longer seems capable of producing any bass .

I've had a feeling it's been on the way out for a month or two but it wasn't something I could put my finger on as I live this amp on a daily basis. I gues this 'problem' has kinda crept up on me. To compensate for the lack of bass it's also developed rather wirey shrill sound.

It's not my ears as I've borrowed my mate's Yamaha DSP A1000 and whilst this amp is not renowned for prodigious bass, it does show me what I've been missing.

I can't say I'm impressed as I've had the Super-T from new for just over a year.

Before I bin it anyone got anysuggestions as to what's wrong?

 

[DocLorren]

Guessing a little bit here but fact is that capacitors do not live forever. Maybe the caps in the PSU section have slowly gone. I cannot think of another simple diagnosis. Usually takes a decade or more for quality caps to degrade that much by the way.

 

[zBuff]

could be cold solder joints, are both channels lacking bass or just one of them?

 

[Pano]

I'm guessing caps too. But a bad solder or even loose connection may be at fault.

Does the bass come back if you shake it or thump it?

 

[spikeyfaz]

Sound is the same from both channels. I've shaken/thumped the poor old amp but no joy. I had a quick look inside but no obvious faults.

My diy skills are not up to replacing surface mount components but I figure replacing the capacitors shouldn't be too hard. Could someone perhaps post a picture of the board showing which caps I should consider replacing and with what, or at least point me in the right direction?

Thanks.

 

[Pano]

Sorry, my reply yesterday got lost in the forum glitch.

There are 3 power electrlytic caps on the board (and 2 input).

What you want to replace is the big cap near the power switch and the medium size caps near the chip. You can use the same values or larger, if they will fit. 16V minimum.