Frankenstein 300B Stereo Amplifier

Frankenstein 300B Stereo Amplifier ToneAudio Product of the Year

Frankenstein 300B Stereo Amplifier Frankenstein 300B Stereo Amplifier

Coincident is excited to introduce the newest addition to our series of power amplifiers - the Frankenstein 300B Stereo Amplifier. The Frankenstein 300B Stereo amplifier is the stereo version of the highly acclaimed Frankenstein M300B Mono Amps. The two Frankenstein amps share the exact same mirror finish stainless steel chassis, virtually the same design and circuitry and industry breakthrough performance. The differences are the Stereo amp uses the 6SL7 input tube instead of the 6EM7 and utilizes the 5AR4 rectifier instead of the 5U4GB. Both are all hardwired share the vast majority of components. The Frankenstein Stereo 300B will be the best constructed, finest performance and best value of any single ended 300B available. It represents a breakthrough at its reasonable price point.


Output Power - 8 watts RMS SE class A
Output Impedance - 8 ohms
Frequency Response- 10hz- 20khz- +/- 1db
THD- less than 1% 20 hz - 20 kHz
Input Sensitivity - 800 MV full output
Input Impedance - 47K ohms
Power Requirements- AC 115V or 230V 50,60hz ( user selectable on the rear panel)
Dimensioin - 15” W x 12” D x 8.5” H
Net Weight - 17 kgs- 38 lbs.
Tube Compliment - 6SL7 x2, 300B x 2, 5AR4 x 1.

Price - $2499 US, All tubes included except 300B.

Coincident Speaker Technology

The Coincident Frankenstein Stereo SET 300-B Amplifier

Product 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.


Dynamo 34SE MKIII

Replaced By The New Frankenstein Stereo 300B Amplifier

2023 the absolute sound editors choice award

2019 TAS Editors' Choice Awards

Dynamo Mk III Amplifier

2020 the absolute sound - Editors' Choice Awards

2019 TAS Editors' Choice Awards

Dynamo Mk II Amplifier

2019 the absolute sound - Editors' Choice Awards

2018 Positive Feedback Writers' Choice Award

2018 Positive Feedback Writers' Choice Award

Dynamo Mk II Amplifier

2018 Positive Feedback Writers' Choice Award

The Absolute Sound 2019 Annual Edition

Dynamo Mk II

High-End Audio Buyer's Guide Award

Coincident Dynamo MK II Amplifier

2018 The Absolute Sound

Dynamo Mk II Amplifier

2018 the absolute sound - Editors' Choice Awards

The Absolute Sound

Dynamo MK II Amplifier

2018 Buyer's Guide - Top Amplifiers Under $2000

2017 TAS Editors' Choice Awards 2016 TAS Editors' Choice Awards 20/20 Award Best Of 2013 Blue Note Equipment Awards
Coincident speaker - Dynamo 34SE Coincident speaker - Dynamo 34SE Coincident speaker - Dynamo 34SE
Dynamo 34SE MKIII
Dynamo 34SE MKIII

After the overwhelming success of the Coincident Dynamo 34SE MK II amplifier ( Editor’s Choice TAS, Blue Note Award by , Positive Feedback ) we are excited to announce the Dynamo SE 34 MK III. The MK III contains a whole host of significant upgrades that not only enhance performance but dramatically improves reliability, virtually eliminates noise, hum and susceptibility to AC line variation and fluctuation. The end result is taking the already breakthrough performance and build quality of the finest value amplifier in existence and elevating it to a new level of excellence in every parameter. The most noteworthy change offered by the MK III, is the introduction of 2 inputs selectable from the front panel. The improvements include the following:

1. Power Supply - The power transformer has been enlarged by 50%. Much improved insulation and winding techniques result in noiseless operation, and a 40% reduction in generated heat levels.
Filtering and energy storage has been increased by a whopping 70%. The sonic improvement is substantial- deeper, more impactful lower frequencies, wider and the ability to drive a much wider range of speakers without strain. Distortion levels at high SPLs and low frequencies has been reduced by 35%. Furthermore, the large power supply has now been isolated from the sensitive input circuitry resulting in the elimination of electromagnetic interference.

2. Chassis - Not only is the chassis 20% larger in order to accommodate the huge new power transformer, it has been stiffened and braced to reduce unwanted resonances. Sonically this translates to greater purity and transparency. The Dynamo has gone from weighing 22 lbs to 30 lbs.

3. Capacitors - Every single capacitor has been doubled in voltage capacity which provides bullet proof reliability and eliminates potential problems in areas afflicted with high AC line voltage that is prone to surging and/ or fluctuation.

4. Tube Rectifier - The previously used instant on 5U4GB rectifier tube has been replaced with the soft start 5AR4. This provides a safeguard against excessive inrush current upon turn on.

5. Two Inputs - The MK III has now been transformed into a stereo integrated amplifier. Toggle switch selectable on the front panel are the 2 inputs.

The overall improvement wrought by the MK. III is highly significant. From virtually eliminating noise so that the Dynamo can successfully be used with ultra high sensitivity speakers and increasing its power capabilities so that it can mate with a wider range of lower sensitivity speakers to unshakeable reliability in any environment to stunning performance enhancements that include deeper, punchier bass, greater transparency and purity overall, more expansive soundstage and greater extension and air in the treble all combine to create an amplifier that while is hard to surpass at $5000, is unmatched at its value laden price of only $1799 US. While the Dynamo 34SE MKII at $1499 US was considered the finest value in all of high end audio, all the huge and costly improvements incorporated in the MK. III with only a $300 increase in price, make the even more of an audiophile bargain.

For those on a budget but who still demand top flight sonics and build quality, the Dynamo will prove to be a revelation. Single ended triode tube sound that belies its 8 watt power rating. Any 86 db sensitivity speaker can be powered with startling clarity and dynamics. Build quality not seen at twice the price. Perfect for those who want a simple compact set up or as a second system where true musicality is insisted upon. Hard to believe that this much performance and quality can be had for under $1800 US. Volume control and 2 inputs front panel selectable turns the MKIII into a stereo integrated amplifier obviating the need for a line stage and includes a highest performance headphone amp with phono jack conveniently located on front panel.

- All hard wired.
- Huge capacity power supply
- massive power transformer
- output transformers using 6N copper windings
- polypropylene coupling capacitors
- all electrolytic capacitors 50% over rated.
- state of the art headphone amp included
- high gauge stainless steel,mirror finish chassis
- auto bias circuit to automatically optimize tube performance

Inputs: 2 RCA - front panel selectable
Output Power : 8 watts per channel
Tube Compliment : 6H9C (6SL7) -2 input/driver tube, EL 34 (2) output tube, 5AR4(1)soft start rectifier
Output impedance : 8 ohms
Voltage selectable: 115V/230V - switch located on bottom plate
Frequency response: 20 hz- 20khz- flat
Sensitivity: 300 mv full output
Input impedance : 100K ohms
Headphone Amp Output Impedance : 100 ohms
S/N Ratio- 92 db
Weight: 30 lbs
Dimensions : 9.5” W x 12.5” D x 7” H
Price: $1799 US

The Dynamo MKIII is now available on special order optimized for 300B output tubes instead of the EL 34 which is still standard. The Dynamo MKIII will now exhibit all the finest sonic qualities of single ended triode 300B output. Compared to the Dynamo SE34, power output remains the same. Gain is slightly lower which is especially well suited for high sensitivity loudspeakers. The new Dynamo SE 300B MK III will easily exceed the performance of comparable SET amplifiers costing many times its reasonable selling price. For those wanting to buy the M300B Frankenstein amps, but require something more compact in a single chassis with a state of the art headphone amp and a line stage with 2 inputs, at a more affordable price, the new Dynamo 300B is impossible to equal.

Price - $2295US - without 300B tubes.

For owners of Dynamo MKII, converting your unit for 300B output operation, is now available.

Price: $699US without 300B tubes
           $875US with Psvane matched and tested Clear Glass 300B tubes.

Dynamo 34SE MKIII


M300B Frankenstein MK IV

2023 the absolute sound editors choice award

2018 TAS Editors' Choice Awards

2020 the absolute sound - Editors' Choice Awards

2019 TAS Editors' Choice Awards

2019 the absolute sound - Editors' Choice Awards

2018 TAS Editors' Choice Awards

2018 the absolute sound - Editors' Choice Awards

2017 TAS Editors' Choice Awards 2016 TAS Editors' Choice Awards TAS 2013 - The Absolute Sound Editor's Choice Awards Stereomojo Recomendation

M300B Frankenstein MK III - This is , without a doubt, the finest amplifier, overall, I have ever heard. - Arthur Salvatore- High End Audio

Coincident speaker - M300B Frankenstein MK II Coincident speaker - M300B Frankenstein MK II Coincident speaker - M300B Frankenstein MK II Coincident speaker - M300B Frankenstein MK II

As of Aug.1/2022, Coincident is excited to introduce the MK.IV version of the Frankensteins. Improvements include:

- Enlarged power supply capacity- deeper, more impactful bass
- Improved voltage regulation- immune to AC voltage fluctuations
- Improved resistors and capacitors which results in greater revelation of low level detail and airier, more extended high frequencies
- Coincident Quantum Leap internal wiring which enhances purity and transparency.
- Upgraded output transformers with a flat frequency response from 10 hz- 30khz.

The Frankenstein MK IV are even more transparent, with extended frequency range, enhanced dynamics, punchier, tighter bass and are absolutely dead silent.Perfect match with ultra high sensitivity speakers ( 100db or higher) due to the total absence of residual noise.

The M300B Frankenstein MK IV mono amplifiers are ready for pre order with . Built to the absolute highest standard - Stock will be available Oct./2022

- Triangular chassis constructed from high gauge stainless steel -mirror polished finish- maximum non resonant, highest rigidity and non magnetic
- All hardwired with Coincident Quantum Leap cable
- The finest 6N copper interstage (no coupling capacitor), output and power transformers
- Finest Teflon caps
- Massive all polyproylene power supply- no electrolytics
- Precise Auto biasing which maintains optimum operating bias as tubes age
- 3 tube configuration (6EM7 input driver, 300B output, 5U4GB rectifier) for purest sonics
- Input tubes are the best NOS American. Comes standard with the finest quality, tested 6EM7 and 5U4GB tubes.

These amps represent a sonic breakthrough. Their transparency and absence of an electronic sound set new standards. Mated to the appropriate speakers, they will prove to be a revelation. They easily drive every Coincident speaker model.

MK IV Specifications

Output Power: 8 watts RMS -(Triode) / SE Class A
Output Impedance: 8 ohms- Optimized for 8-16 ohms.
Frequency Response: 10hz - 20khz ±1db
T.H.D.: <1%, 20hz-20khz (Ref. Output)
Input Sensitivity: 700mv
Input Impedance: 100k ohm
S/N: >90db
Tubes: (6EM7×1, 300B ×1, 5U4GB ×1) / Channel
Power Requirement: AC 115v Or 230V - 50/60hz (User selectable on back panel)
Dimension: 15" W x 12" D x 8.5" H
Gross Weight: 19 Kgs- 41.8 lbs.
Net Weight: 17.5 Kgs - 38.5 lbs.
Price - $6899 US /pair

Coincident speaker - M300B Frankenstein MK II


211PP Dragon MK. II

211PP Dragon MK. II Mono Amplifiers - This is the finest high power amplifier I've ever heard. In short, my associates and I hear a combination of sonic strengths we've never heard before. - Arthur Salvatore- High End Audio

We are now excited to introduce the MK. II version of the highly acclaimed Dragon amplifiers. The improvements include:

1. Dual power transformers in place of the previously used single unit. The new transformers individually possess the capability of powering the amplifier. In tandem, they are coasting only using less than 25 % of their rated capabilities. The result is a far cooler operating amplifier, thereby improving reliability and long term
stability. Additionally, the Dragon is now virtually noiseless. It is incredibly quiet which is a remarkable feat for an amplifier this powerful operating at such high voltages. Sonically there is an improvement from top to bottom. The bass is tighter, deeper and punchier. The mids and highs are more transparent and the soundstage more expansive. Due to the reduction in noise, overall revelation of low level detail is enhanced.

2. Chassis Rigidity - To accommodate the dual transformers of the MK. II Dragons, the chassis has been enlarged by 20%. The amplifiers are now 2" wider and 2" deeper and 1" higher. They now weigh 85 lbs, which is 20 lbs heavier than the previous model. The chassis is now more rigid which results in the virtual elimination of chassis induced resonances. The MK. II now utilizes 6 ceramic isolating feet to stabilize the unit.

3. The standard supplied 211 tubes will now be the exceptional Shuguang Pevane. They represent a marked sonic improvement over the previously supplied standard Shuguang. The Pevane is also more durable and reliable and runs 15% cooler.

4. AC ground lift is now included. This switch conveniently eliminates hum created by AC ground loops.

The MK. II Dragon is now the finest sounding, high power amplifier in existence. Its purity is within a hair's breath of the finest SET 300B amplifiers (the Frankensteins) yet its power delivery is awe inspiring. It also runs cooler and is exceptionally quiet.

Coincident Speaker - 211PP Dragon Mono Amplifiers Coincident Speaker - 211PP Dragon Mono Amplifiers Coincident Speaker - 211PP Dragon Mono Amplifiers Coincident Speaker - 211PP Dragon Mono Amplifiers

The purity, transparency and continuousness of a DHT SET but with the power, explosive dynamics, weight and impact of a huge push pull pentode amplifier - sounds mutually exclusive, not any longer. The 211PP Dragon mono amplifiers are such a creation. These amplifiers are absolute state of the art in terms of components selected, circuit design and execution and construction quality. This is unique among high power, push pull DHT triode amplifiers. There has never been a high power, DHT amplifier built to this standard with sonic performance at this level. The Dragons are capable of driving even the most difficult speaker loads.

Latest version of the Dragon MK II ( Jan.1/19 shipping) include the following improvements:

-Dual power transformers per amp to ensure low noise, cool operation and unlimited power reserves
-The finest 6N copper interstage (no coupling capacitor), output and dual power transformers
-Tube compliment- 6EM7 super tube for input- So much current capability it has its own power supply
-300B Driver Tube for utmost purity ( no pentode tubes used in this DHT design)
-Dual 211 Shuguang Pevane output tubes in a push pull configuration which dramatically lowers distortion and provides huge power reserves. (over 300 watts of peak power- 80 watts continuous- sounds more like 250 watts)
-Teflon caps use in cathode bias circuit
-Massive power supply- caps are all 1500V polypropylenes- no electrolytics
-Highest quality discrete resistor potentiometer permit the direct connection of a CD player thereby obviating the need for an expensive line stage or for use in a biamped system
-Binding posts are Coincident 6N copper, .25" solid post
-Auto bias maintains optimum bias as tubes age
-All resisters are 1% tolerance and none less than 2 watts
-All meticulously hard wired using Coincident Statement cable

The sonic improvements include:

-Tighter, punchier and more impactful bass and mid bass
-Wider dynamic gradations
-Airier, more extended and smoother high frequencies
-Harmonic completeness that rivals the finest 300B SETs
-Enhanced transparency and purity.


211PP Dragon MK. II Mono Amp
Output Power: 75 watts RMS - 300 watts peak (Triode) / Push-Pull Class A-
Output Impedance: 8ohm
Frequency Response: 20hz-20khz ±1db
T.H.D.: <1%, 20hz-20khz (Ref. Output)
Input Sensitivity: 700 MV
Input Impedance: 100k ohm
S/N: >90db 
Tubes:(6EM7×1, 300B×1, 211×2)/ Channel
Power Requirement: AC 115v Or 230V 50/60hz (User selectable on back panel)
Dimension: 11.5 " W x 20.5 " D x 10 " H
Gross Weight: 90 lbs - 41 Kgs
Net Weight: 85 lbs- 38.5 Kgs
Price - $10,999 US/pair

211PP Dragon Mono Amplifiers


Joules refers to the amount of energy storage that is in the filter capacity of the power supply of an amplifier. The higher the number, the better and the greater the headroom or power reserves that are available to power a given speaker.For example, 2 amplifiers may be rated at 28 watts RMS. However, when the output signal peaks above the 28 watt output, the amplifier with the higher Joule rating will be more resilient in avoiding clipping distortion and will possess the ability to provide greater headroom ( the difference between the signal peak levels and the amplifier’s clipping level). Peak power depends on the amplifier’s power supply ( energy storage). If the amplifier’s power supply has a bank of large filter capacitors, it can store energy that can be released during short peaks and avoid clipping or distortion. Therefore, the 2 amplifiers rated at 28 watts continuous output are not equal in their respective ability to produce the required peak signals.The one with the larger Joule rating will be more capable in accurately reproducing the peak signals without clipping.

Power Supply Energy Storage - Joule

Dynamo MK II - 8 watts RMS - Joule - 52
Frankenstein M300B MK III- 8 watts RMS - Joule -140
Dragon MK II - 75 watts RMS - Joule -920
Turbo Monos - 28 watts RMS - Joule -975

For comparison purposes - Comparable Amplifiers-

8 watts RMS SET tube amplifiers - Joule - 20
75 Watt RMS Triode Tube Amps - Joule -100
28 Watts SET Tube Amps - Joule- 65

As the above clearly demonstrates, Coincident amplifiers are designed with massive energy storage capabilities (significantly using polypropylene filter capacitors exclusively) and as a result, sound much more powerful than their wattage ratings suggest.


Designed By Science Driven By Passion
391 Woodland Acres Crescent, Maple, ON., L6A1G2
Tel: 647-221-1834