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REVIEW: Pioneer SX-780 Receiver

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Model: SX-780
Category: Receiver
Suggested Retail Price: $unknown
Description: Classy, analog 70's receiver with great sound and good reserves
Manufacturer URL: Pioneer
Manufacturer URL: Pioneer

Review by FRG7SWL ( A ) on July 25, 2004 at 16:08:22
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for the SX-780

"It's A Rock Machine"! "It's A Soul Machine"! "It's A Country Machine"! So proclaimed a mid-70s Fender Stratocaster print ad. Conclusion was the Strat was all of the above, & much more; as apt a description of Pioneer's SX-780 receiver as well! After being treated like an ignoble stepchild, 780s are now finding their sanctified sonic niche in vintage receiverdom(kinda like Fender's Jaguar in axedom, thanks to Kurt Cobain). Oak Tree Vintage Sales theorizes that Pioneer's SX-780 was probably the best selling model of Pioneer's SX-x80 series. They sound a lot more powerful than their stated 45 watts-per-channel, whilst being bereft of that 70s-era midrange-centric Pioneer house sound. Which is probably due to those Darlington STK-0050 Power Pack output devices. Oak Tree sold a 780 whose Darlington Power Packs produced 22 volts-per-channel @ 8 ohms for 60 w.p.c.; & 18 volts-per-channel @ 4 ohms for 81 w.p.c. Unless you're using super-inefficient two-ohm terrors, you'll not lack for volume. There have been complaints that, on some 780s, those aging speaker protection relays impede audio signals. So bypassing those relays(a relatively simple mod,which also converts the 780 into a great studio guitar amp; wouldn't be surprising if the 780's topology was subtly appropriated by every succeeding instrument amp maker utilizing integrated-circuit amp chips for valve-esque solid-state output)will help open up that distinct 780 retro voicing. Which is more akin to Marantz in overall tonal texture, as befits a receiver with retro-cool analog power meters on its' facade. Heck, speaker access is push button activated(as were most Marantz units), rather than click-switched(as on most other Pioneer models). Oak Tree also noted that "all control pots & switches are super quality ALPS brand, the best Pioneer could have picked". They're silky smooth in operation, & not as prone to dust contamination as those on similar-era Marantz units. F.M. reception is crisp & extermely sensitive, though lacking the selectivity of Sony's 6800SD in certain reception situations. Here in Sactown the 780 doesn't reject backwave signals from Nevada City's KNCO(94.1 mhz) as thoroughly as Sony's 6800SD whilst aimed @ Berkeley's KPFA(also 94.1 mhz) via outdoor Weingard antenna. In f.m. audio quality, though, both units are fairly equal. Phono equalization is exemplary, @ least with Shure V-15 Type IV hyper-elliptical & micro-ridge cartridges. As impressive as stock 780s are, they're a modder's dream machine of convenience. Replacing the stock wiring & audio-chain caps will render a unit as ear caressing as any in Marantz' legendary solid-state stable. For a nice retro touch, take a simple diode(like a IN4A), reverse the tail towards the positive lamp bulb feed, & get a cool subdued glow for those late night listening sessions. 780s were probably reviled by audio elitists because they were plentiful & found lacking in ultimate pristine presentation. Now they're beloved by listeners desiring effortless kick-ass sonics coupled with roguish refinement. 780s rock! Plus they got soul! Which suits proletarian country bumpkins just fine!

Product Weakness: F.M. selectivity not on par with top-gun units; More aux inputs should have been incorporated, easily remedied via external aux box add-on
Product Strengths: Sledgehammer amplification which belies its rated 45 watts-per-channel from Darlington STK-0050 Power Packs; Crisp & sensitive F.M. reception; Exemplary phono pre-amp section; Super quality ALPS-brand control pots & switches; Easily modifiable for even more expansive sonics

Associated Equipment for this Review:
Amplifier: Marantz MR-235; Sony STR-6800SD; Sherwood S-7100A; Rotel RX-602
Preamplifier (or None if Integrated): Dynaco PAT-4
Sources (CDP/Turntable): Denon DCM-450 cd player; Yamaha P-07 turntable
Speakers: Celestion Vintage 30s; Electro Voice Forces; ESS Model 10s; Jensen 1204; Pioneer CS-33s; Utah Cadences
Cables/Interconnects: Radio Shack Monster Cables
Music Used (Genre/Selections): Blues, Classical, Folk, Funk, Hip-Hop, Jazz, Reggae, R-N-B, Soul
Room Size (LxWxH): 10 x 10 x 10
Time Period/Length of Audition: Five years plus
Type of Audition/Review: Product Owner

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Topic - REVIEW: Pioneer SX-780 Receiver - FRG7SWL 16:08:22 07/25/04 ( 1)