Circuit Topology
Amplification technology identifies whether the audio signal path uses tubes, solid-state devices or both.
Also called: Amplification Technology, Output Stage
Tube means vacuum-tube gain and output stages; solid state uses semiconductors. Hybrid combines both in the relevant audio path. Supply or display tubes do not count, and amplifier class is a separate property.
Circuit Topology — Power Amp
This describes the active devices in the audio gain and speaker-output stages. It identifies how the audio signal is amplified or buffered.
A tube input followed by a transistor output is hybrid; the output stage’s operating class is a separate description. Compare the stated signal-path design, rather than a general product tagline.
Circuit Topology — Optical Equalizer
This describes the active devices in the optical-cartridge audio gain and output stages. It identifies how the audio signal is amplified or buffered.
The circuitry supplying the optical cartridge is not, by itself, the audio amplification technology. Compare the stated signal-path design, rather than a general product tagline.
Circuit Topology — DAC
For a DAC, the classification applies to the analogue stage after conversion, not the converter chip or digital processing. Op-amp current-to-voltage conversion followed by a tube buffer uses both technologies.
Selectable tube and solid-state analogue paths also constitute a hybrid arrangement here. A passive output has no active-stage technology to classify; the presence of semiconductor digital circuitry does not make that stage solid state.
Circuit Topology — Crossover
This describes the active devices in the audio gain and output stages around the crossover processing. It identifies how the audio signal is amplified or buffered.
Combining discrete transistors and op-amps remains solid state; digital processing does not make a tube-and-transistor hybrid. Compare the stated signal-path design, rather than a general product tagline.
Circuit Topology — Phono Preamp
This describes the active devices in the cartridge-signal gain and equalized output stages. It identifies how the audio signal is amplified or buffered.
A tube stage combined with semiconductor gain or buffering is hybrid; a tube rectifier in the supply is not sufficient. Compare the stated signal-path design, rather than a general product tagline.
Circuit Topology — Preamp
For a preamplifier, the classification covers its audio gain and output stages. A tube gain stage with a semiconductor buffer is hybrid, whereas an entirely semiconductor audio path is solid state.
A passive preamplifier without an active gain or buffer stage has no active-device technology to classify. Supply rectifiers, indicators and remote-control electronics do not decide the audio-path classification.
Circuit Topology — Headphone Amp
This describes the active devices in the audio gain and headphone-output stages. It identifies how the audio signal is amplified or buffered.
A tube voltage-gain stage feeding a transistor output is hybrid; this is separate from whether the output is balanced. Compare the stated signal-path design, rather than a general product tagline.
Circuit Topology — Reel-to-Reel
This describes the active devices in the audio amplification stages in the tape signal path. It identifies how the audio signal is amplified or buffered.
Transport motors and control electronics do not determine this classification of the audio circuit. Compare the stated signal-path design, rather than a general product tagline.
Circuit Topology — Tuner
This describes the active devices in the audio gain and output stages. It identifies how the audio signal is amplified or buffered.
Tuning and display circuitry are separate; a valve indicator does not turn a solid-state audio path into a tube design. Compare the stated signal-path design, rather than a general product tagline.
Circuit Topology — Equalizer
This describes the active devices in the audio gain and output stages in the equalizer. It identifies how the audio signal is amplified or buffered.
A mix of discrete transistors and integrated analogue circuits is still solid state, rather than tube-and-transistor hybrid. Compare the stated signal-path design, rather than a general product tagline.
Circuit Topology — MC Head Amp
This describes the active devices in the low-level cartridge gain and output stages. It identifies how the audio signal is amplified or buffered.
A semiconductor input combined with a tube audio stage is hybrid; cartridge gain and loading remain separate specifications. Compare the stated signal-path design, rather than a general product tagline.