Cambridge Audio A1 Mk IIISE Power Amp Conversion
These amplifiers in their normal state are extremely good value for money at under £100 from Richer Sounds. What people are probably not aware of is how easy these amplifiers can be improved by bypassing the pre-amp section if you want to use it purely as a power amp.
The amplifier has a separate power amplifier pcb board that is located next to the speaker terminals and the heat sink. The power amp uses two Phillips TDA1514 integrated chips to provide 30 watts into 8 ohms per channel with just a handful of other components.
Connecting the power amp to the pre-amp section is a 6 way cheap white connector strip that sends the +/- voltage and receives the left and right line signal from the pre-amp.
By connecting a line signal direct to the power amp you can bypass the input switching, volume, balance and tone controls providing an extremely clean signal path. All that is needed to do is use a couple of teflon insulated phono sockets and drill two 10mm holes above the speaker terminals at the rear and disconnect the two grey leads that run from the power amp to the pre-amp, leaving the blue and orange power leads still in place and solder these cables to the new phono sockets and that's its done.
Cambridge Audio say the tone controls use audiophile quality caps and close tolerance metal film resistors combined with gold plated sheilding to minimise distortion and colouration caused by this circuitry which it does. However the improvement in sound quality when using the Cambridge Audio A1 Mk IIISE as power amp with a passive pre-amp is quite dramatic. Once you have heard the difference in sound quality, it will put you off integrated amplifiers for the life. I am absolutely convinced that less is better when it comes to the stage between the source and the power amp as the difference is enormous.
Obviously the quality of the pre-amp determines the improvement in sound quality made but nevertheless it is usually substantial. Anyway these amplifiers at under £100 really do make a good choice as a dedicated power amp especially for AV solutions given how easy it is to modify them.
This entry was posted on Monday February 20th, 2006 at 2:51 PM and is filed under Amplifiers, Tweaks. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response.
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3 Responses to Cambridge Audio A1 Mk IIISE Power Amp Conversion
Adrian Says:
October 10th, 2008 at 12:11 PM
hi
Interesting article on making more from a cheap amp. I recently found one of these amps in the dustbin after the TDA1514A's had 'smoked' after being pushed too much - I've got the replacements and am just about to replace them but may do the capacitors too. Any thoughts or experiences of using higher or better quality caps in this unit?
Hi-fi insight Says:
October 10th, 2008 at 12:19 PM
Adrian,
The main priority was to improve sound quality by just using the power output section of the amp and bypassing the pre-amp section which is un-required in my set up.
I am pretty sure superior caps could improve the output stage and no doubt the power supply caps as well.
Paul Says:
February 8th, 2009 at 12:01 PM
Adrian,
I have just got around to looking at one of these after both power rail fuses have blown. Did your blown TDA1514 do the same thing?
Regards
Paul Rowan