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Reviewer: Paul Candy
Source: Eastern Electric Minimax CD player with NOS Philips Miniwatt 6DJ8s, Pro-Ject 1 Xpression turntable w/Ortofon 540 Mk II cartridge, Pro-Ject RPM 5 turntable w/Ortofon Rondo Red cartridge [in for review]
Preamp/Integrated: Manley Labs Stingray, Audio Zone AMP-1, JAS Audio Array 2.1 [in for review], Pro-Ject Tube Box phono stage
Speakers: Green Mountain Audio Callisto (on sand filled Skylan stands), Zu Cable Tone [in for review], REL Q108 Mk II subwoofer
Cables: Zu Libtec speaker cable [on loan for review], Zu Gede interconnects [on loan for review], Audience Maestro interconnects and speaker cables, DH Labs Air Matrix and Revelation interconnects, JPS Labs Superconductor+ interconnects, Auditorium 23 speaker cables, BPT IC-SL interconnects and SC-7.5L speaker cables [in for review]
Power Cables: Zu Birth [on loan for review], BPT L-10 [in for review], Gut Wire Power Clef 2, Power Clef SE, Audience powerChord
Stands: Premier three-tier, filled with sand
Powerline conditioning: BPT Pure Power Center w/Wattgate 381 outlets w/ Bybee Quantum Purifiers and ERS cloth, Blue Circle BC86 MkII Power Line Pillow, GutWire MaxCon
Sundry accessories: Grado SR-60 headphones, Pro-Ject Speed Box, Gingko Audio Cloud 11 platform, Skylan isolation platforms [in for review], Grand Prix Audio APEX footers, Isoclean fuses, Walker Audio SST contact enhancer, Walker Audio Ultra Vivid, GutWire Notepads and SoundPads, HAL-O Tube Dampers, Herbie's Way Excellent Turntable Mat, Herbie's Grungebuster2 CD Mat, dedicated AC line with Wattgate 381 outlet, Echo Busters acoustic room treatments
Room size: 11' x 18' x 8', short wall setup, hardwood floors with large area rug
Review Components Retail: Mahi $2,500/pr, Shrimp $1,880
Two years ago I reviewed and subsequently bought the Manley Labs Stingray integrated amplifier. During that time, it has faced off against every amp I've had in for review - plus a few others I borrowed from either friends or dealers. With few exceptions, the Stinger has come out on top for me. It's not the be all and end all of integrated amplifiers but in terms of price, build, functionality, performance and emotional engagement, it is a stellar piece and one that I continue to enjoy listening to music through. Since the Mahi amplifier is essentially a monoblock version of the Stingray, I wanted to hear what improvements separate power supplies and additional storage capacitance would offer. And since the Stingray features a passive linestage, I wanted to try an affordable separate active preamp. I was confident that the Shrimp/Mahi would prove sonically superior to the Stingray. But would I enjoy music more? Quite often with other amps I've sampled, the answer was no. Sure, some sonic traits might have been superior but they didn't necessarily get me closer to the music and the musicians' intent. How would the Mahi and Shrimp fare?


The Mahi monos or Mahi Mahi and Shrimp arrived impeccably encased in cleverly shaped foam inserts packed inside sturdy cardboard boxes for maximum protection. As with the Stingray, the manuals were excellent and full of useful information. Also included in one of the Mahi boxes was a multimeter for checking the bias settings of the output tubes. What a nice touch. Build quality and appearance were first rate. All three pieces looked stunning in their black wrinkle powder coat and blue-grey anodized (also called pewter gray) livery.

The Shrimp preamplifier -- of course, eh? -- is an all-tube minimalist design i.e. with no remote nor balanced connections but with single-ended non-inverting circuitry built around a pair of EI 12AT7 input valves and a pair of NOS GE 7044s in the output stage. There is no global negative feedback. Instead of the more common cathode follower output circuit, the Shrimp incorporates a White follower, which offers less distortion, greater overload margin, and ultimately, a remarkably low output impedance of 50 ohms [schematics below, White follower to left]. Therefore, the Shrimp should have little problem driving flaky power amps or typical high-capacitance audiophile approved interconnects.


Apart from the four valves, the innards include lots of MIT/MultiCap polypropylene caps plus two humongous 30uF MultiCaps in the output. Volume and balance controls are audiophile-grade Noble pots. This Shrimp sits upon four heavy-duty soft rubber-like footers, presumably to reduce vibration and resonance. There are five controls on the front panel. From left to right, those are input selection, volume, balance, mute and power on/off. Engaging the mute illuminates the button, which also flashes for 30 seconds during the Shrimp's soft-start power up sequence. On the rear panel are five line level unbalanced RCA inputs, a tape loop, two sets of outputs, a mains fuse and the IEC connector. The outputs are paralleled for connecting two stereo amps or four monoblocks. Before you pooh-pooh the lack of balanced connections, I quote from Manley's Shrimp page:

"Shrimp FAQ #1: The Shrimp is unbalanced. Why can't I have balanced inputs and outputs?"
"Yes, the Shrimp is entirely a single-ended design. The circuitry uses single-ended topology. In order to be able to provide balanced inputs or outputs, we would have to convert the signal to balanced using something like ICs or transformers. Both these options would add more "stuff" to the signal and be certainly audible detracting from the pure sound the Shrimp provides. If you are dealing with balanced source outputs or driving a balanced amplifier with the Shrimp, check to see if you also have unbalanced connections on that gear. Change your cables and go with that. You might be pleasantly surprised that they too added extra audible "stuff" in order to provide balanced XLRs. The RCAs that don't have that extra "stuff" in the signal path actually sound better (depends on a given unit's specific design). Or use some RCA-to-XLR adaptors. Most balanced gear has no problem being driven single-ended but check with the manufacturer if they are going to want the negative pin 3 of the XLR grounded or floating. Transformer-coupled XLR jacks always can be driven single-ended by running HOT into Pin 2 and grounding pin 3 to pin 1. Some IC-coupled XLR inputs will want pin 3 floating, others will require it to be grounded when running single-ended into it. Check with the manufacturer of your gear to see how to hook it up single-ended."

The Mahi Mahi are more or less mono versions of the Stingray with increased B+ capacity (180 Joules) plus variable negative feedback and Triode/Ultralinear switching. The Mahi monos are cute little amps and will easily fit onto the palm of your hand. As with the Shrimp and Stingray, Manley's customary LED backlit logo dominates the chassis front. The top deck features four Russian EL84M pentodes, an EI 12AT7 input and a NOS GE 6414 driver tube. Also on the chassis top are two toggles: one for switching between ultralinear and triode modes while the other adjusts the amount of negative feedback. There are three choices: MAX (10dB), STD (6dB) and MIN (3dB). For triode operation, the screen grid of the EL84 is connected or 'strapped' to the anode, whereas for ultralinear operation the screen is connected to a dedicated tap on the output transformer. The reason for all this?

Each mode has a different sound. UL is generally punchier while triode is sweeter. Think of UL/triode switching as a tone control and negative feedback adjustment as a presence control. More on those switches anon. Bias adjustment is a snap. The bias points are mounted behind the power tubes while the ground is front and center. Use the included multimeter and follow the detailed instructions regarding biasing. Trust me; it's almost as easy as changing a light bulb and a heckuva lot easier than programming a VCR or TV. Behind the power and output trannies are a single RCA input jack and a pair of WBT multi-way binding posts. The power on/off switch resides on the rear panel next to the mains fuse and IEC connection.


The Mahi sits on four nicely machined pointed corner posts. All in all, the Mahi Mahi and Shrimp are quite beautiful in a distinctly American retro-chic kinda way. Indeed they are as American as baseball, apple pie and Howard Stern. The Mahi's power rating varies from 14 to 46 watts depending upon feedback and UL/triode settings. On average, expect about 20 watts in triode and double that in UL. The Mahi's output transformer -- as well as those in Manley's other amps -- is optimized for 5-ohm loads which happened to be ideal for my Green Mountain Audio Callistos since their impedance ranges between 4.1 to 5.3 ohms from 100Hz to 20kHz. Lucky me. One might loose a little power with vastly different impedances. However, I didn't notice anything amiss when I used Zu's 12-ohm Tones.

The EL84 is a great little power tube and I've become quite fond of it. It doesn't quite have the rich midrange of the more popular EL34 pentode but this little firecracker has delightfully airy, sparkling highs allied to a quick, incisive snap-your-fingers toe-tapping vibe. However, it won't be to everyone's liking especially if you lust for a warmer, lusher presentation. To me, EL34 amps can seem a little fuzzy and thick. Granted, these are broad generalizations and the chosen output tube is only as good as its attendant circuitry but each tube type does have a unique character. Heck, that's what makes tubes so much fun. There's something for everyone. Right now, I'm on an '84 kick. Some say the EL84 lacks bass but pair it with a suitable output transformer as in the Stingray and Mahi and that claim will evaporate.

Manley possesses one of the most interesting manufacturer websites as well as a delightful sense of whimsy; after all, they name their products after sea creatures! Stingray, Mahi, Snapper, Shrimp and soon, Prawn and Manta Ray. How about Pogy, Finback, Guppy and Hammerhead for future product names? Seriously, you can spend hours drilling through the various layers on this site and you will find plenty of valuable info, pics, links (some very disturbing), insights, wisecracks and the most useful yet sarcastic (but in a fun way) FAQs in cyberspace. Therefore, rather than prattle on about specs, design history and such, point your browser here and here.
I should note that Manley's products are designed and assembled in the United States. In this day of outsourcing nearly everything to countries lagging behind Western standards of pay, benefits, working conditions and environmental controls largely for greater profit margins, it's refreshing to see a firm supporting its local community and suppliers.