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<blockquote data-quote="John Roberts" data-source="post: 145915" data-attributes="member: 126">Re: Damping Factor - Actual listening tests?I really don&#039;t want to go around this old tree again, but the speed of the DC300 was compromised even further by the quasi-complementary output stage topology. Fast and rugged PNPs were not widely available way back then, so the DC300 used NPN power devices to both pull up and pull down. To make the NPN power device act like a PNP, a smaller PNP was connected in a darlington connection to make the compound device behave like a power PNP. This mixed darlington is slower than a same polarity darlington, so the overall amplifier stability compensation had to be slow enough to accommodate the slower half of this quasi-complementary output stage. The DC300 delivered respectable performance when new back in the day...&nbsp; I was not a fan of replicating the old schematic almost verbatim, while using SMD and newer plastic power devices (but using the same old tired topology) to make the CE1000/2000 amps. Some sharp pencil bean counter probably got a raise for that (no actual design engineers were stressed) project.&nbsp; :-(JR</blockquote>

[QUOTE="John Roberts, post: 145915, member: 126"] Re: Damping Factor - Actual listening tests? I really don't want to go around this old tree again, but the speed of the DC300 was compromised even further by the quasi-complementary output stage topology. Fast and rugged PNPs were not widely available way back then, so the DC300 used NPN power devices to both pull up and pull down. To make the NPN power device act like a PNP, a smaller PNP was connected in a darlington connection to make the compound device behave like a power PNP. This mixed darlington is slower than a same polarity darlington, so the overall amplifier stability compensation had to be slow enough to accommodate the slower half of this quasi-complementary output stage. The DC300 delivered respectable performance when new back in the day... I was not a fan of replicating the old schematic almost verbatim, while using SMD and newer plastic power devices (but using the same old tired topology) to make the CE1000/2000 amps. Some sharp pencil bean counter probably got a raise for that (no actual design engineers were stressed) project. :-( JR [/QUOTE]

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