JBL G-733
The JBL G-733 is a surround sound receiver from the late 1980s, and it's one of those units that seems to have flown under the radar when new but has since earned what one enthusiast called "justifiable cult status among vintage A/V enthusiasts." It's relatively rare — if you wait around, one comes up for sale every month or two. The record on this model is thin on production years and original pricing, but what's documented is genuinely interesting.
This is an all-discrete, fully analog design. The amplifier section uses mirror-image symmetrical L/R channel blocks with Darlington triple parallel push-pull output transistors — no monolithic ICs, and no op-amps in the audio path. The signal path goes from selector to volume straight into the discrete amplifier section. It's a class A/B, direct-coupled design rated at 75 watts per channel into 8 ohms, or 100 watts into 4 ohms. The build quality backs up the engineering: the cabinet is very dense fiberboard, the front face is an aluminum extrusion, and the power transformer alone weighs about 20 lbs. Mix Magazine (October 1987, p.270) covered the G-733 in its new products section, noting the efficiency of bass-reflex design for live performance as well as home installations.
On the surround side, it uses earlier Dolby Pro Logic processing. Inputs cover Phono, Tuner, CD, Video1, and Video2; outputs include Tape1, Tape2, front and surround speakers, plus a center channel. There are front pre-outs and a subwoofer pre-out for system expansion. The phono stage is there, though input sensitivity specs aren't documented.
Reported specs are strong for the era: frequency response of 5Hz–100kHz (+0 dB, -1 dB), signal-to-noise ratio of 110 dB, and THD of 0.005%. One owner's comment sums up the listening experience: "Sounds fantastic with just a 2.0 setup." Another called it "extremely musical." Powering it up is, in the words of one user, "a reminder of the ultra high quality and build of this generation of JBL consumer gear."
Known specifications:
- Power output: 75 WPC into 8 ohms; 100 WPC into 4 ohms
- Amplifier type: all-discrete, class A/B, direct-coupled; Darlington triple parallel push-pull outputs
- Surround processing: Dolby Pro Logic
- Frequency response: 5 Hz – 100 kHz (+0 dB, -1 dB)
- Signal-to-noise ratio: 110 dB
- THD: 0.005%
- Inputs: Phono, Tuner, CD, Video1, Video2
- Outputs: Tape1, Tape2, front speakers, surround speakers, center channel, front pre-outs, subwoofer pre-out
No production years, original price, weight, or dimensions have surfaced in the available documentation. No common failure points or service notes are recorded either. What's known is that this is a well-built, musical receiver from JBL's late-80s consumer lineup — one that rewards patience if you're hunting one down.
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