Brick wall made of capacitors

kazumasamurai2007-06-13


I have made another power supply for the balanced-output preamplifier.
There are 2 major improvements:
(1) Electrolytic capacitors replaced with ceramic ones
(2) Connection of the audio transformers as chokes modified.
Some enthusiasts in Japan use surface mount ceramic capacitors instead of electrolytic ones for power supply. Each of the ceramic capacitor looks like a brick, and quite a number of chips must be piled up to archive sufficient capacitance, it is called “brick wall.”

In my case, it is parallel lanes rather than the brick walls. I have curved 2 trenches on cupper surface of PCB, and soldered over 100 chip of caps along each lane. Total capacitance should be around 700uF each, which is little more than 1/10 of the previous one. I am planning to increase the capacitance by making 3rd and 4th “lanes.”

Telecom transformer that I have used is about 1:1, primary and secondary circuits are connected to each of cathode (positive) and anode (i.e. plate and grid, for negative). DC component is canceled with this connection, and yielding more effective inductance.

I expect that this 2 transformer, tube rectified, choke-input and non-electrolytic filtering is the combination of best available. But, its performance is not as good as expected, I have observed considerable ripple (about 500mV peak to peak), and sound quality is not as good as the electrolytic one, electrolytic one is more “stable” & “confident” sound
than new one, and ceramic one has somewhat “weaker” sound. But I expect that would be better with 2 other streets and as it burns in.

「壁」を作りました
部品が有ったのでもう1つ真空管整流の電源を作りました。今度は「壁」を作り、チョークの配線を変えました。生基板にカッターでスリットを2つ切り込み、積セラを片側100個少々づつ並べて半田付け。容量は片側700uF位、電界コンデンサ版の1/10強です。外観上は「壁」ではなく平行線で、近々に3丁目、4丁目を追加する予定です。他に、電話用のオーディオトランスも、1:1なので正電源では、カソードごとに、負電源ではアノード(プレート+グリッド)ごとに1回路を割り当ててDC成分をキャンセルするように配線しました。これで、実効のインダクタンスは増えているはずです。
正負別トランス、真空管整流、チョークインプット、壁平滑は「最強」になる予定だったんですが、さにあらず。リップルが500mv(p-p)ぐらいあり、音も電解バージョンは安定してどっしりとした感じに対して、新作は弱々しい感じ。エージングして容量を増やせばまともになるのではないかと考えているのですが…
(すいません。だんだん日本語がおぼつか無くなってきているようで、日本語のスペルチェックが引っかかっていますが…)