Coincident Speaker Technology

The Coincident Frankenstein Stereo 300B

Component of the Year - 2023 - ToneAudio


Not a monster at all
$2,495 (output tubes not supplied)

Joni Michell's lovely voice always lends itself to a great match with SET amplifiers and my Heretic AD612 speakers. Tracking through a copy of Court and Spark, a record I've been listening to for a long time starts out great, becoming more sultry with each track as the amplifier warms up from ice cold. By the time the next record (Santana's Abraxas) is up, the big soundfield has become huge and the amplifier gets more control in the low frequencies. By an hour, the tubes are fully warmed up and stable, offering even more tubey goodness.

Coincident's owner, Israel Blume is a clever guy. Instead of selling his Frankenstein 300B stereo SET power amplifier with one 300B or other and have everyone argue about his choice, he's put all the quality into the amplifier, letting you choose your favorite pair. If you've never had the pleasure of experiencing one, they manage to create a special kind of audio magic with a pair of efficient speakers that is nearly impossible not to love.

Blume has built a company and a reputation on building and delivering components delivering high musical involvement at incredibly affordable prices. I've used several of them over the years and they always deliver excellent results. And I'm a big fan of the highly polished casework too. This is a great looking amplifier.

While cliches like "game changer," "giant killer," and the like abound, the reason for the Frankenstein's level of high performance is more practical. Because Coincident has always taken the manufacturer direct route, the 40-80% markup usually taken by dealers and importers is passed on to the customer. Leaving the final output tube choice to the user saves money and lets you decide how far to take things. Think of the Frankenstein stereo as a prepped race car

that you merely need to do the fine tuning on to your preference.

Unboxing and setup

The Frankenstein keeps it simple with a single pair of RCA inputs and an IEC power socket. However in addition to the power switch (tastefully on the back) is a toggle switch to float the ground. When using high sensitivity speakers, a little bit of noise can sneak into the presentation requiring you to float the ground. Having this right at your disposal is a nice touch. Initial listening begins with the supplied 5AR4 rectifier, a pair of 6SL7 driver tubes and a pair of Electro Harmonix 300B power tubes. But this is only where the fun begins. If you've never used 300B tubes, please pay careful attention to the four pins on the bottom - two are slightly bigger in diameter, and if you insert them wrong you will do some damage. As they say on social media, "ask me how I know?" It's a mistake you'll only make once.

The amplifier weighs about 42 pounds, and has a relatively compact chassis. No tube cage is supplied (I never use em anyway, and again another cost saving/value adding measure) so if you have kids or pets, place your Frankenstein accordingly. Because this amplifier has no features to speak of, and requires no adjustments for bias, etc., we don't have much to discuss in this department. Plug it in to your preamplifier, turn it on, and roll.

The relatively stock sound

As the Frankenstein doesn't come with 300Bs, and so many have their favorite, it's tough to describe the out of the box completely. The EH 300Bs were chosen because of their reasonable price and availability. You should be able to find a pair of these at nearly any tube store. There's a certain signature sound that 300B based amplifiers exhibit - more extended at both ends of the frequency spectrum, and a little less liquid than 2A3 or 45 based amplifiers. With 98dB/1-watt speakers, I'll take the dynamics offered by the 300B over a few extra molecules of midrange tonal saturation.

While it might seem unorthodox to play Rush through a 300B system, listening to Neil Peart's drum and percussion work through the Frankenstein is simply breathtaking. Where far more expensive 300B amplifiers I've tried fall down with this test, the Coincident amplifier follows every nuance. In addition to a high level of texture served up, and incredibly dynamic attack, this dense music is served up in a way you can hear everything. No need for more cowbell. All those Rush tunes just fanned the flame for some Yes and King Crimson, this time listening more for bass extension and speed. Again, the Frankenstein does not disappoint. The rapid-fire delivery from both bands comes through clean and with enough weight, you might not think you are listening to an SET.

Great as musical information at the frequency extremes is delivered, the real allure of this amplifier is the natural tonality and enormous soundstage it can generate. This is why so many audiophiles that lean more towards female vocal music lean towards the SET. Passing the signal through a single tube eliminates many of the electronic artifacts that make your brain think you are listening to a hifi system instead of music. Ditto for acoustic instruments.

Even if you're an SET fan, you'll be taken back at how pure stringed instruments and pianos sound - there's so much texture and decay. It's creepy good. Once the tubes are warm, you'll be hard pressed to escape the gravitational pull of your couch or listening chair beyond changing a record if you're a vinylista. Streaming via the dCS Vivaldi kept me on the couch for hours on end nearly every time I fired up the Frankenstein. And I'm keeping the review sample, so I can't pay it a higher compliment.

Tube exploration

Good as this sounds, there's more. Swapping the three tubes in the front for a vintage rectifier, a pair of RCA 5691 "Reds" (the black plate version) and a pair of Western Electric 300Bs brings performance to an entirely different plateau. If you say I'm crazy for putting $2,000 worth of tubes in a $2,500 amplifier, I'd say "guilty as charged." But the increased performance is well worth it.

The WE's bring more extension, bass grip and an overall smoothness that you don't hear as readily until you switch back for a few minutes. It's like going from swimming in a big pool to swimming in the ocean. Bigger everywhere. And again, underscoring how good the basic circuit is.

Listening to the same tracks used for initial listening reveals much more front to back depth. When listening to Joni Mitchell sing "Raised on Robbery," her lead vocal is further out front, and her overdubbed backing vocals are further back than before. This improves even further with the NOS 5691s. Adding these tubes serves up more smoothness and a complete lack of grain. Regardless of the tubes you choose, this amplifier is incredibly quiet, adding to the further sense of dynamic drive. Again, stopping by any audio forum with give you some more info on tubes, or drive you crazy. It's up to you, but know this - the Frankenstein responds well to premium tubes.

Simply wonderful

This amplifier delivers such a high level of musical realism, you might never want to listen to a solid state amplifier again. You may never want to listen to another amplifier again. The key to success with an 8 or 9 watt per channel amplifier is the right speakers. If you find the right speakers for your Frankenstein, you'll be loving it.

The 300B single ended triode amplifier is a model of simplicity. Simple to the point that almost anyone can make one. Getting one to sound great is another movie and getting one to sound great for a reasonable price, still another level of attention to detail. Frank is in the last category, and considering how involving this amplifier is, I can only imagine how good the Frankenstein monoblocks are with even more power supply and fine tuning. Precious few people can make a great 300B amplifier, at any price. I'm happy to go on record saying this is one of the finest 300B amplifiers I've had the pleasure of listening too.

The level of high frequency extension and bass grip offered by this amplifier, even with budget 300Bs reveals major attention to power supply design and transformer choices. Going this route still has you sporting a killer 300B amplifier. At this price I highly suggest spending time on the 300B planet, even if you don't stay there. And don't bother looking for a used one - I've rarely ever seen Coincident gear for sale on the secondary market. People tend to keep them.

In closing, I'm happy to present the Frankenstein with our Product of The Year Award in the low powered amplifier category. And as I like to say? JFBO. (Just F***ing Buy One) You'll be glad you did.

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