Adcom GFA-565SE High Current Power Amplifier by Greg Voth

 

 

Like it says in this Adcom amp’s instruction manual, read the manual first. Had I not, there was a chance, albeit small, that I’d have only heard the left channel of the new Adcom GFA-565SE High Current Power Amplifier. The rear selector switch for bridged or stereo output came preset to the bridged position. The manual is full of tips and cautions, the being but one of them, with no drawings or photographs of the amplifier tube seen, so familiarizing oneself with the unit’s front and rear and perusing the informative manual first is highly recommended.

The Adcom GFA-565SE, a compact, handle-free version of the more powerful GFA-575SE, offers considerable power – in stereo, 250 watts continuous average power into 8 Ohms any frequency between 20Hz and 20kHz with both channels driven at less than 0.04% T.H.D. and 350 watts continuous average power into 4 Ohms with both channels driven at less than 0.05 THD. When bridged, the unit provides 700 watts of continuous average power into 8 Ohms at less than 0.1% T.H.D. Of course, if bridged, you’ll need two for stereo.

Adcom L.L.C. describes the GFA-565SE as “a powerhouse” for its ability to provide full power output into any loudspeaker load – “unconditionally.” The GFA-565SE is notably heavy at 51 lbs. unboxed (55 lbs. boxed). Measuring 7 1/4″ x 17″ x 14 3/16”, this unit has two heat sinks running front to back, one on each side of the chassis. Its front panel is carefully finished with heavy-gauge, high-grade aluminum extrusion and anodized for durability. 

 

The amp’s chassis, top cover, and rear panel are of heavy-gauge steel, painted and baked. The power button resides on the front side left, and there are L.E.D. indicators for “high current power amplifier instantaneous distortion alert” for each channel and an L.E.D. indicator to alert the owner should the thermal protection kick in. There are both balanced and unbalanced inputs on the chassis rear, with selection toggles as well as a bridged/stereo switch, two pairs of 5-way binding posts, an I.E.C. power connector, and fuse housing. A power cable is included.

 

The GFA-565SE’s construction

Paraphrasing the GFA-565SE’s construction and feature list in the manual, this amplifier’s point-to-point wiring consists of oxygen-free copper and the highest-grade parts, consistent with their application and voltage requirement. In especially critical circuits, the finest quality film capacitors have been used. A larger potted transformer provides better overall regulation for driving lower impedances at high power levels (it also provides more excellent peak-current capability into loudspeaker loads). No electrolytic capacitors were used in the low-frequency signal path or feedback-loop path. Only non-polarized capacitors are used. A servo circuit minimizes DC-offset voltage at the loudspeaker outputs, ensuring no woofer “biasing” with attendant low-frequency distortion. Larger outside double heatsinks for each channel run along each side of the chassis to ensure greater thermal stability. Additional cooling vents permeate the chassis top plate for greater cooling efficiency and operation into lower impedances. High-quality-gold plated brass R.C.A. input jacks with Teflon insulators are used. Lastly, the front plate sports a thermal overload indicator L.E.D.

In addition, as per the manual, “no protection or current-limiting circuitry is used in the GFA-565SE which could degrade the signal. The driver stages are designed to provide all the current required by the output devices without limiting, compressing, or otherwise distorting the signal coming into the amplifier.” 

Thermal Protection, Cautions, and Warranty

Per the manual, the GFA-565SE “… requires the use of loudspeakers the nominal impedance of which does not drop below 4 Ohms. It is not recommended that the GFA-565SE be used in the bridged mono mode into loudspeakers, or multiple loads, which drop substantially below 4 Ohms.”

The GFA-565SE comes with a limited 2-year warranty (available within the U.S.A. only) – the warranty limitations are spelled out on the unit’s enclosed warranty card. If service is required, the owner must take the amplifier to their dealer or request a return authorization from J & B Distribution for service (not Adcom L.L.C. as mentioned in the manual/warranty card).

Additionally, the manual cautions that “The GFA-565SE has a massive power supply which remains charged for up to five minutes after the amplifier is turned off and the POWER LED ceases to glow.” Do exercise caution when connecting or disconnecting speakers and output cables.

Recent History and J & B Distribution

I spoke with Boris Meitsner, the owner of J B Distribution), who shared that, up through 2001, J & B Distribution was the primary distributor of Adcom products in the U.S.A. In 2001, the Adcom L.L.C. company changed ownership, and In 2006, Adcom’s distribution in the U.S.A. was shut down. Everest World Co., Ltd. still owns the Adcom L.L.C. brand name.

Three months ago, the son of the original owner contacted Meltsner about bringing the Adcom brand back to life, with Meltsner’s J and B Distribution handling all sales, service, and advertising for the U.S.A. The son is interested in J & B creating new Adcom products, but Meltsner convinced that the future power is Class D, doesn’t want to do transistor products. Meltsner speculated that there may be a Class D Adcom integrated in the next couple of years.

J & B Distribution maintains strict control over the sale of Adcom products to maintain consistent pricing. J & B has no qualms about yanking the brand from any dealer who sells any Adcom product via the Internet at a lower price. Adcom service and new product construction will be handled at J & B’s Arizona warehouse. Meltsner shared that the new S.E. version uses a different transistor than the original GFA-565 mono amplifier (circa 1991).

Listening

At the first power on, when playing Kurt Elling’s “Endless Lawns” from the album The Questions (Okeh Records 2018), my wife said, “Sounds amazing!” Bass handling was impressive and solid, with taught imaging on a well-defined stage. With a play of Anat Cohen’s “Boa Tarde Povo” from 2022’s Quartetinho (Anzic Records, L.L.C.), the GFA-565SE presented that foot-tapping tune well, maintaining the groove with punchy bass and solid keys and rendered Cohen’s woody clarinet play quite well, as it weaved its way through the song.

Next, a play of a 24-96 download of Trio Grande’s “Oberkamph,” from their self-titled 2020 debut (Whirlwind Recordings) double L.P. (download included) was duly impressive, with drive and the exceptional handling of both low-frequencies and drum dynamics, allowing each member of this talented trio’s musical abilities to shine brightly.

Lee Pardini’s latest release, “August Scorched Earth” (2023 GroundUp Records), seemed a touch darker and more introspective than his 2021 debut, “Home Bodies.” There were great grooves in this shorter sophomore effort, ID3-tagged as Jazz + Funk. It was pretty spacey, too, as The Universe is a House Party bobbed and weaved through its ’ ’70s-style arrangement.

Playing a 24-96 download of Modul 29_14, from Nik Bärtsch’s Mobile’s “Continuum” (2016 E.C.M. Records GMBH), had the same weight and heft heard in previous listens through my reference S.V.S. S2 Pro amplifier. Percussive transients were well-defined, and instrumentation was dimensional, with nice air around the players and imaging that was taught but softened a bit. Stage depth was accented through the languishing passage, Modul 12, with delectable brushes on skins, soft, distant bass drum beats, sharp taps on cymbal edges, and delicate Kalimba accents. What the GFA-565SE presented drew me near as I enjoyed every note.

Ocean Wide, Canyon Deep, from Jacob Collier’s “Djesse Vol. 1″ (2018 Geffen Records), flowed powerfully into the room, dynamic, resonant and rich with textures. As this song ebbed and flowed from the Tekton Design Double Impact, Collier’s smooth, rich baritone captivated with its warmth and textures. Low frequencies were both powerful and exciting. “Djesse” was such fun, as Colier’s playful orchestration presented interesting twists and turns… his arrangements always shine brightly. The GFA-565SE delighted my ears as it delivered dynamic and transient content effortlessly.

Marc Copland’s trio cover of Herbie Hancock’s “Cantaloupe Island,’ with Drew Gress and Joey Baron on their 2018 “And I Love Her” (Illusions Mirage) effort, Cymbals were smooth, Gress’ bass was dominant and impactful, and Copland’s piano rang warm, with very well-defined body. The near-physical presence of Baron’s drum kit was impossible to miss during his brief but exciting drum solo during this tune.

psaudiobox.jpgThe title track from Randy Weston’s Night In Medina (1972 C.T.I. Records) presented a perfect canvas to judge the abilities of the Adcom GFA-565SE. Always enjoyable, this laid-back track is loaded with a wide assortment of textures and wonderful loose interplay. The stage was rendered as an undeniably dimensional and physical space, and the instruments were well-delineated. The GFA-565SE presented a big window into the expert musicianship that crafted this wonderful tune. Night In Medina never fails to deliver.

I needed to rattle some rafters with Sting’s A Thousand Years1999’s “Brand New Day” (A&M Records) and Adcom’s low-frequency handling proved impressive. Big gobs of bass frequencies permitted the loft, as taught transients were presented with snap. If I didn’t know better, I’d swear a subwoofer was hidden in this good-sized space. This Adcom amp is not at all bass-shy.

The Wrap

It’s been a good while since I spent time with an Adcom component, and the GFA-565SE did not disappoint! It presented a wonderful sense of musicality and rendered my song choices with notable body and heft. If you’re looking for an amplifier that’s musical and packs a punch at a reasonable price, look no further than the GFA-565SE!

With a pair of original GFA-565 mono amps costing $1600 in 1991 ($3,606 in today’s dollars), Adcom again offers a highly competitive option for those looking for big power for the buck, should you need a pair to bridge for massive output.

 

Specifications & Features

Product reviewed: Adcom GFA-565SE High Current Power Amplifier $1899.00US

250 watts per channel, 8 ohms

325 watts per channel, 4 ohms

700 watts, 8 ohms BRIDGED

Balanced and Single-Ended Inputs

Discrete metal cased bipolar output transistors

Custom toroidal transformer

72,000uF total storage capacitance

Ultra-Stable Bias Circuitry

Direct-Coupled Input & Output Circuitry

No Current Limiting to cause signal degradation

Fuse-protected DC rails

120 VAC 50/60 Hz

Max Dimensions: 7 1/4″ x 17″ x 14 3/16″ 

 Warranty: 2 yr. limited manufacturer

Rack mounting: Rack mounting brackets are NOT available for this amplifier.

Adcom L.L.C.

Website: www.adcom.com

Email: info@adcom.com

Everest World Co., Ltd owns the Adcom brand.

U.S.A. Distributor: J&B Distribution Inc.

Dealer, service center, and technician support go through J&B

 Boris Meltsner,

 216 route 206 suite 15

 Hillsborough, NJ 08844

 PH: 480-607-2277

 EM: borism@jbd-usa.com

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