These diminutive Dacs pack quite a punch for their price and size. One of their claims to fame is a battery power supply, which is slowly charged by a trickle charger. This Dac came in for a battery replacement.
This interesting amp was in the workshop for hum reduction. There is a lot of correspondence on the internet about the amp and ways to reduce hum, and in this case the hum was as much mechanical as electrical. We swapped out the input wiring for screened cable and fitted screening cans to the Edcor autoformers all with little effect on the hum levels. The next set is to try a DC blocker on the mains to see if that helps the mechanical noise from the transformer.
Having reviewed the costs of restoration and options with the owner we are going to:
- Turn two into streamers using Google Chromecast Streamers and Class D amplification. Two of the controls will be used for on/off and volume and the tuning dial will be backlit by LEDs.
- The third, the Bush VHF, will be fully restored and a Chromecast model built in and connected to the Aux input.
All three will use the original speakers, in the case of the Bush that’s two 6ins bass /mid units and an electrostatic tweeter.
There’s been a lot of highly positive feedback of my work publicly posted on the Web. Here’s a selection of recommendations and feedback:
‘The upgrade work carried out to the WD Power, Pre and Phono has lifted the system beyond what I had wished for. David gives a reliable, knowledgable cost effective service with good communication and is very accommodating…. What more can you ask for?
The Custom built DACs, hand built and professionally finished in high spec casings are also of a very high standard and sounded utterly wonderful. A great alternative to inferior price point products available in the commercial HIFi world. No Middleman, no BS, No advertising and marketing…It just makes sense!
The picture below shows the completed upgrades. All electrolytics have been replaced. There’s 12 alone in the power supply, and many more across the pre and phono boards. Elena Silmics have been used where space permits, otherwise Panasonic FC and Nichicon Muze. None of these is in the signal path. The main input and output capacitors-originally metallised film have been replaced with foil /film types. All components were mounted as in the original preamp, with the exception of two in the phono stage which were mounted slightly above the board to allow for nearby warm running resistors.
This arrived recently in the workshop.A power supply electrolytic has blown, taking out the fuse. From a visual inspection that appears to be the sum of the problem. Electrolytic failure is very common in these sub woofer amps. A lot of heat in a small sealed box with low temp rated capacitors is a recipe for relatively frequent failure. Capacitors will be replaced with uprated ones.