I agree. But my 1980's and 1960's amps have been serviced/recapped and had transistors replaced. I think 20 years without service is what I would expect from 2000-era Sony, Denon, Marantz, Parasound etc.
【開発者に聞く】マランツ「PM-10」は、“録音現場の音”を目指してスイッチングアンプを選んだ (1/6) - PHILE WEB
【開発者に聞く】マランツ「PM-10」は、“録音現場の音”を目指してスイッチングアンプを選んだ
@dualazmak can do a real translation, but the auto-translation seems reasonable
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■スピーカーリレーの排除によって音の純度をさらに高めた
The purity of the sound has been further improved by eliminating the speaker relay
ーー PM-10の発売は、SA-10より約半年、延びることになりました。
The announcement of the PM-10 was half-a-year behind the SA-10.
村山氏 発表が遅れた理由は、主にスピーカーリレーに関連する部分に時間がかかったためです。一般的なアンプにはスピーカーリレーが使われることが多いですが、PM-10にはありません。スイッチングアンプの出力段は電流のオン／オフのスイッチのようなものなので、リレーと同じ役割が担えるからです。
The reason for the delay in the announcement was that it took more time, mainly for the part related to the speaker relay. Speaker relays are often used in general amplifiers, but the PM-10 does not. This is because the output stage of a switching amplifier is like a current on/off switch, so it can perform the same role as a relay.
[my commentary: "mainly" not exclusively -- they are trying to hype up the delay as a feature not a bug]
スピーカーリレーは保護回路の役割も果たしますが、音質を第一に考えるとないにこしたことはありません。しかし、スイッチングアンプなら単純にリレーを外すことができるというわけではなく、様々なケアが必要になり、ここに時間がかかったのです。
Speaker relays also play the role of protection circuits, but if you put sound quality first, you will never be disappointed. However, switching amplifiers did not simply allow the relay to be removed, and various care was required, which took a long time.
澤田氏 理屈の上では、Hypexのモジュールはスピーカーリレーが必要ありません。しかし、購入していただいて10年・20年と経った後、部品が経年変化しても大丈夫という保証までするためには、Hypexの仕様だけに頼るわけにはいきません。この点について社内の基準をクリアするのに苦労しました。
In theory, Hypex modules do not require speaker relays. However, in order to guarantee that parts will be safe even if they age after 10 or 20 years of purchase, we cannot rely only on Hypex specifications. We struggled to meet internal standards in this regard.
[my commentary: Marantz shipped a ton of HypeX UcD amps and they even bragged about making a Class D amp for B&W subwoofers in the past, so they aren't new to Class D. If you read the whole interview, they really "hint" that the European division is why they went with Class D instead of Class AB for the new reference, but that they did work really hard to make it work. I think they talk about relays since that fits in with the audiophile marketing story of less-in-the-signal path, but it's the first time I see something with specific years and an OEM saying they don't rely on Hypex specifications.]
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And if you look at the protection circuit on the PM-10, they seem to run the NC500OEM in software mode.
