Carvin DCA 800

Carvin DCA 800

The Carvin DCA 800 rated power output is 300W into 4Ω and 200W into 8Ω. Over the years,she has gained a reputation for being solidly build, reliable and a power house. She is used in Live Sound Reinforcement and to power subwoofers. Let’s take a closer look at what she is all about.

Carvin DCA 800Fig 1 – Carvin DCA 800 Amplifier Schematic

Right at the front is an op-amp, a LM318, that drives the bases of the VAS. In other words, the op-amp replaces the input differential that is often seen in the discrete version. Collector load is 680Ω with a standing current of 3.5mA that’s derived from a 70V rails. With such a high current, there’s little danger of the VAS “loading” the op-amp output, hence no darlingtons are needed. The VAS drives a single RCA medium power transistor which in turn drives four power output transistors (MJ15003/4). Outputs are arranged in a Full Complementary fashion which possibly enhanced her reliability.

Summary

The Carvin DCA 800 transistors are rather elderly by today’s standards.That can’t be helped as this amplifier was developed in the late 80s, reportedly at about 1987. So we are looking at 50yrs since inception.

For those that are fortunate enough to own this amplifier, she can be easily upgraded by replacing her transistors with modern ones. The amplifier will obviously need to be re-tuned for stability but that is a minor issue. Once completed, she’ll sound fantastic.