Audio Note Conquest Upgrade

An Audio Note Conquest 300B PSE power amplifier came in for repair and upgrade. Smoke rose from this unit when it was in operation. Upon inspection, the cathode bypass capacitor was blown, together with the 300B tube where the filament was broken and the spring came loose. It is either the defective 300B tube damaged the amplifier or vice versa.

Since this unit has been used for quite some time, the owner agreed to recap all the electrolytic capacitors. We checked all the capacitors and found that some had already leaked and some are busted, including some resistors that showed sign of overheating.

Some mounting that we do not like was also modified - electrolytic capacitors being placed directly beside a vacuum tube. Such capacitors will be operating at high temperature and will have shortened lifespan.

The stock ceramic tube sockets were of low quality types and were replaced with Teflon or high grade ceramic with gold plated copper pins. The new sockets provides a much better contact, mechanically stable, and less resonant compared to the stock sockets. There are several other changes and modifications that we do not mention here but is beneficial to the sound or build of the Audio Note Conquest amplifier.

The owner wanted to upgrade the EI output transformer to J&K Level 3 Nanocrystalline Output Transformer too but unfortunately the cavity was too small to fit the Level 3 OPT. The owner will be saving that for a future new tube amplifier.

Audio Note Conquest

Teflon tube sockets with gold plated copper pins

Tube rectification board before modification

Top view after completing the modifications - note all the new high quality tube sockets.

All the Rubycon capacitors are changed to Nichicon

The low quality rectifier tube socket

Modifications made to provide 5X4G compatibility. Capacitors are upgraded too.

Comparison of high quality versus low quality tube sockets.

Worn capacitors and tube sockets

Some doctor scribblings on what to change.

Side view of the high quality Teflon 300B tube sockets

Teflon 300B tube sockets

Nichicon Capacitors for B+

It was found that some of the components are not matching between the 2 mono-blocks. It might have been some poor repair jobs done previously. The soldering job was badly done to as you can see from the pictures.

The Audio Note Conquest will go through several checks before being powered on. After that, it will go through some burn-in test before being passed back to the original owner.

Due to the busy schedule we have, we shall be limiting our modification and repair services to focus on our core business. Apologies for not taking in all work from now onwards. This may be our last repair and modifications service job unless there are some that are really worth our attention for analysis or study purposes.

J&K Audio Design
1/7/2015

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