The NiWatt

Not Your Grandfather’s 300B

January, 2025: the first batch of production chassis is due in early March.

We've tried to structure the technical narrative below, to be easily understandable for those of you without a background in electronics, while at the same time, conveying the philosophy behind our design decisions.

We respect your intelligence and think you deserve no less!

Old Meets New

Mark I?  Mark II?  Mark X?

You can think of this design as a Mark-10 iteration.  Over the course of development (and after finalizing the circuit), we went through some 50 circuit layout revisions (we lost count).

We once asked a highly revered guitar amplifier designer whether he was his concerned about people stealing his design.  He replied that no one will build the same amplifier from the schematic.

Development of the NiWatt taught us that same lesson.

We're quite proud of the design, and your owners manual comes with a schematic, but the magic comes from the physical construction and attention to detail in layout and build.  The schematic is a small, but important  part of the story.

The Power Supply

Critics of the syrupy sound of most 300B amplifiers are reacting to flaws in the power supply design and driver circuit.

Tonal beauty is one thing (we like that), but an amplifier that can't follow complex, dynamic music is a non-starter for us.

The NiWatt has two independent power supplies:

• One for the output section (the 300B)
• One for the input and driver section

Shared power supplies are a key issue with direct-coupled designs.  For all of their benefits, each successive gain stage in a direct-coupled design robs power from its predecessor.

When passing a Fortissississimo (ffff) passage to your loudspeakers, your output section and its power supply is under extreme duress.  

With an independent supply for the input and driver sections, they remain unfazed - coasting along with power in reserve.

This is a critical point, because the sound of a directly heated triode is the sound of the driver stage.

read.  that.  last.  sentence.  again ...

This is a critical point, because the sound of a directly heated triode is the sound of the driver stage.

The Critical Driver Stage

It's critical to have power in reserve, but without properly specifying the driver stage, an amplifier's dynamics will be severely compromised.  

The challenge increases when driving larger directly heated triodes like the 845 and 211.  300Bs lie somewhere between these tubes and the "flea power" 45s and 2A3s in this regard.

This is one reason why many individuals prefer 45s and 2A3s - not because they're better tubes than 300Bs or their larger siblings, but because they're more forgiving of design errors in the driver stage.

We agree with Sakuma's approach: using an output tube (in this case, a 6V6) to drive an output tube (in this case, a 300B).

The combination of an isolated supply and a driver section capable of delivering ample current to the output under all conditions, contributes to the perception of a dramatic increase in power, dynamics, and control.  

The driver section is never under stress.  

Read about the NiWatts' encounter with a pair of Von Schweikerts.  A 300B amplifier should not be able to drive such an inefficient speaker ... and yet the NiWatts do.

It is for this reason that we encourage you to compare the NiWatt with both push-pull 300B amplifiers as well as “transmitting tube” amplifiers like those based on the 845 tube (20 watts).

We think you’ll be surprised by the NiWatts' authoritative presentation.

Heating the Filaments

There's been considerable controversy over AC vs. DC heating of directly heated triode filaments, and we were previously fans of AC heating for all of the traditional reasons.  

This was in spite of the audible hum that a 5 volt filament produces in a best-case scenario.  We almost didn't try DC heating.

We played with various DC heating solutions.  Quite a few configurations produced what you'd expect:  a bleached, or "sanitized" sound.

Our solution employs a common mode choke in the DC supply, and the winner was the best of both worlds:  quieter, but with no loss of body - having all of the tone colors we sign up for with our triodes.

In case you're wondering, we did not employ Coleman Regulator boards, in spite of their well-deserved reputation.

At the end of the day, this was an philosophical consideration, as we wanted to eliminate as much silicon from the NiWatts as possible.  There's no right or wrong here, and this was an aesthetic choice.

Mirror Imaged Pairs

We go to extra expense in support of implementing the shortest signal path from input jack to speaker terminal.  This further contributes to an optimized layout.

This circuit is so revealing that auditioning various samples of a 3″ length of wire is clearly audible.

Onboard Power Supply

We're turntable guys and are always thinking about vibration.

So while in theory, an outboard supply can reduce both electrical and mechanical (vibration) noise, a well-conceived vibration strategy coupled with intelligent layout can address this on a single chassis.

We considered implementing a 4 chassis design (external power supply for each monoblock), but prototyping showed us there was no free lunch.

Whenever we shortened wire paths, there was a sonic gain.  This led us back to onboard power.

The question remained:  how to reduce self-generated noise in the chassis ...

Going to Extremes - Isolated Tube Sub-chassis

Bonus! The lone coupling cap in the amplifier is also mounted to the sub-chassis.

A Rising Tide Raises all Ships

We have a working theory that great tonearms and great electronics raise the level of their associated components, while paradoxically making them sound more alike.

How can this be?

With high quality tonearms, their bearings and resonant behavior make the job of the cartridge much easier.

Expensive cartridge designs allocate substantial design effort and materials to managing resonance, so the cartridge does some of the tonearm's work.  Yes, there's vibrational energy to deal with, but it gracefully exits the cartridge body.  In contrast, a "lesser" cartridge benefits more from the tonearm's ability to manage energy.

With the NiWatts, we found relatively budget priced tubes sound much better than they have any right to.  A good circuit and careful parts specification matters!

Will the NiWatts sing a sweeter song with a pair of Western 300Bs?  

You betcha, but you'd be very surprised at what they can achieve with more modest tubes.  We think this is a good thing.

"Roadie" Proof Construction

Turret board construction (picture to follow) ensures immunity to physical shock.  

This is the same construction method used in guitar amplifiers which are ruggedized to survive abuse from “roadies”.

Of course (as part of our layout optimization), we went through over a dozen board designs until we were satisfied.

The compact chassis layout does not compromise maintenance.  Quite to the contrary, the direct, intuitive signal path is an amplifier which is easily serviceable.  We expect this amplifier to be in service for multiple decades, and it was designed with this in mind.

Parts Matter

Every part must justify its place in the NiWatt – from a 3″ length of wire, to the smallest resistor, and as noted above, the NiWatt is extremely responsive to parts changes.

The most expensive part was not necessarily the best suited to the task. For example, our NOS supply of Black Gate power supply capacitors did not fare as well as power supply capacitors which could easily have been overlooked if one specified parts based on price or "audiophile reputation".

Of course, there are places in the circuit demanding of premium parts, and it's no surprise that premium transformers justify their place in the NiWatt.  

The power transformer, interstage and output transformers are specified from Monolith Magnetics in Belgium.  Their output transformer has a bandwidth of 7Hz to 151,000Hz.  

You read that correctly:  one-hundred-fifty-one-thousand Hz.

We're happy to build with another capacitor of your choosing, but know that the Jupiters set an extremely high bar.

Circuit Topology

Damper diodes (tubes) are specified in place of conventional rectifiers. Their high current capability conveys rhythmic speed and their reduced switching noise contributes to delicacy and nuance. Refer to the tube section for more details.

Three Stage Design:  Input, Driver, and Output

We are firm believers in separate input and driver stages, because the input tube’s job (voltage gain) and driver tube’s job (current delivery) is very different.

Asking a single tube to perform both functions is like asking your BMW to haul a cord of firewood.

Dual Power Supplies:  we covered the benefits above.

Input Stage (6SN7):  Choke Loaded, RC coupled to the Driver

 A classic circuit topology which has withstood the test of time.

We considered interstage transformers for this section.  Ultimately, we came to appreciate the "tunability" of having one quality capacitor in the signal path.

Driver (6V6):  Interstage Coupled to Output Section

This is a perfect spot for an interstage transformer, and the Monolith iron with its extraordinary bandwidth fits the bill perfectly.

Phase inverting (3 gain stages)

An amplification (gain) stage (either a tube or a transistor) inverts phase, so an even number of stages is non-inverting and an odd number inverts phase. Simple, huh?

Rectification - 4 damper diodes (any of: 6AU4, 6AX4, 6CQ4, or 6DE4)

Traditional rectifiers (5AR4, 5U4G, etc.) are dual diodes (two diodes inside one tube).  Damper diodes have a single diode, so replacing a single 5AR4 requires two damper diodes.

The NiWatts specify one diode pair for the 300B & and a second pair to power both the input and driver section.

Signal tubes

• 1 6SN7 (input tube)
• 1 6V6 in triode mode (driver tube)
• 1 300B (output tube)

The musical benefit of damper diodes

Most individuals are unfamiliar with damper diodes. They have much lower switching noise.  This translates into a less “hashy” sound than even the best new old stock rectifiers.

They also have much higher current capabilities than normal rectifiers. All things being equal, damper diodes follow musical transitions with more finesse and speed.

Damper diodes are in plentiful supply in new old stock, and as an added bonus, they are priced lower than what you’d pay for current production 5AR4’s from Sovtek, JJ etc.

How does it get better than that?

Introductory pricing: $18,995

Price includes:

A $500 travel rebate:

If you visit Galibier to audition and purchase a NiWatt within one year of your visit. Visit Colorful Colorado on our dime!

Free Power and Speaker Cables:

NiWatts are delivered with two Wind River Power Cables and a single-wire set of our Wind River Speaker Cables.

If you have already purchased any Wind River Galibier cables in the past, we’ll credit you for the price you paid for any three cables.  Credit is for the price paid, less tax and shipping.

Cable notes:

These cables are not “throw-ins”. They were instrumental in the prototyping and development of the NiWatts. We needed better tools, so we had to design them.