Specifications:

• ACME Audio Silver Plated IEC connector, ACME Audio Silver Plated fuse holder, ACME Audio Silver Plated ceramic fuse, EI core transformer, He-Fred rectifiers, Jensen four pole capacitors and a Linear Tecnologies regulator. Includes the Nirvana Regulator upgrade.
• Price $950

The application of power supply design is a topic that is frequently not fully appreciated by the typical audio enthusiast. Even individuals who are adventurous enough to pop the hood on their gear may yet have a limited grasp on what they are looking at. It is often assumed that if a piece of equipment has a large transformer and chunky filter caps, then it must have a high-grade power supply. While these two sub-components play an important role in the performance of a power supply, there are several other considerations that must be addressed in the overall architecture of the component layout. Designers must work through an appropriate grounding scheme, and smooth the ripple characteristics of AC current with the bridge rectification assembly. The electrical current needs of the circuit must be taken into account, and the power supply filter capacitance requirements are then generated. A high quality power supply directly affects the sonic characteristics of a component; therefore every part within the power supply has an influence on the overall sound. During the design process, it is necessary to listen to the effects of the parts used within a power supply, and find the appropriate blend of parts to achieve maximum performance. Since the audio circuit of any component manipulates the DC output of a power supply, it can be inferred that the overall performance of a piece is determined by the quality of the power supply stage.

Wayne Wannahan at the Bolder Cable Company has spent several years designing high performance power supplies for the Slimdevices Squeezebox. The Bolder Cable Company offers not only high-end power supplies for the Squeezebox, but also a complete line of modification packages for this digital player. In stock form, the Squeezebox is a respectable digital component, although there are limitations to the sound quality of this unit. The modification packages and custom power supplies that Wayne offers, creates a pathway for tangible performance improvements to the Squeezebox.

The Ultimate IV power supply with the Nirvana regulator circuit is the pinnacle of power supply technology for the Squeezebox.1 State of the art circuitry doesn’t come cheap, and this power supply comes with a $1550 price tag. However, this design incorporates every bit of knowledge that Wayne has gleaned from the countless hours he has invested in modifying the Squeezebox. The parts used within the Ultimate IV are top shelf, and Wayne makes his final parts selection based on the sonic contributions of each individual component. This power supply is not just an exercise in electrical engineering. Instead, the Ultimate IV is a synthesis of technical knowledge, practical experience, and a desire to coax the final shred of sound quality from the Squeezebox.

At the center of the Ultimate IV power supply is a carefully selected EI core transformer. The bridge rectifier is built from discreet HEXFRED diodes. Wayne experimented with several well-known capacitor brands, but in the end chose Jensen capacitors. The IEC connector, fuse holder, and fuse are all sourced from ACME Audio. All of these parts from ACME have undergone cryogenic treatment. Wayne also evaluated the feasibility of a printed circuit board for this iteration of his power supply, but listening sessions determined that a point-to-point wiring layout yielded better performance. The internal wiring used in the Ultimate IV power supply has been upgraded to a solid core silver wire. Wayne also improved the basic circuit contained in the power supply, and has added a pre-regulator stage to the design. The final regulator stage is the Nirvana circuit, which is supplied from Aspen Audio. The Nirvana circuit is a negative impedance regulator, with a feed forward design. This regulation stage enables the circuit to deliver current quickly, and ensures that the power supply will be responsive to the demands of the Squeezebox.

The Bolder modified Squeezebox is an excellent stand-alone digital component. The Squeezebox used in this review has the digital and analog Bolder Cable modification installed. The Ultimate IV power supply sits a few feet from the Squeezebox, and a shielded cord supplies power to the SB3. Amplification duties are taken care of by a Jeff Rowland Consummate pre-amplifier, and a Model 5 power amplifier. An Audio Magic Mini-Reference power conditioner provides clean AC power to the system. The speakers contain a pair of Audio Nirvana Super 12 drivers, which are housed in custom Lovecraft Design cabinets. Audio Magic Illusion 4D cables are used throughout the system. Power cords are sourced from the Audio Magic Extreme line of cables. All components are housed in a set of racks from AV123.

Even in the initial listening sessions, the superiority of the Ultimate IV power supply is clearly evident. The new power supply has a lower noise floor, and this results in an improved presentation of instruments and vocals. The acoustic characteristics of the recording venue are easily heard, and performers are realistically placed within the confines of the sound stage. “Manteca” by the GRP All-Star Band [GRPAll-Star Band; GRP Records GRD 9672] showcases a vibraphone at the beginning of the piece. With the Ultimate IV power supply in place, the vibraphone has wonderful clarity, and the subtle shadings of the instrument can be experienced, due to the lowered noise floor. Actually, all the instruments in this piece are improved by the latest version of the Bolder power supply. Another area where definite improvements are evident is the sound of the saxophones. The previous power supply I used turned in a respectable performance on this track, but lacked the refinement that the Ultimate IV brings to the table. The reed and brass elements of the saxophones are clear; yet blend together in a way that captures the distinctiveness of these instruments. The valueoriented power supplies that are available for the Squeezebox can possibly recreate 80% of the performance of the Ultimate IV power supply.2 Yet Wayne’s latest creation separates itself from the pack of contenders, and unearths the miniscule details in a recording that results in a memorable listening experience.

The previous versions of modified Squeezeboxes often had limitations with their ability to recreate the leading edge of an instrument. In other words, the attack of a powerful trumpet note did not have the bite that it should have. While a smooth presentation is easy to listen to, the final degree of realism becomes lost in the shuffle. Improvements in the power supply address this phenomenon, and it can be minimized to a great extent. Over the years Wayne has made steady progress resolving this issue, and the application of the Nirvana regulator circuit results in a significant improvement to this issue. Recreating the proper attack of a piano is a difficult task. When the notes are played quickly, the leading edge of each note is often obscured by the notes following them. This creates an end result of a piano that just does not sound quite right. In the hands of an accomplished performer the piano is superb at conveying artistic expression. Mary Chapin Carpenter is a highly respected folk singer, and has a gift for creating music that blends introspective lyrics with elegant piano compositions. “Only A Dream” [Come On Come On; Columbia CK 48881] is one of my all time favorites from Carpenter, and I regularly use it to evaluate any component that wanders into my listening room. With the latest version of the Bolder power supply in place, the clarity and definition of the piano on this song is definitely improved. The individual notes now have a distinct leading edge, yet each one resolves cleanly as the melody progresses. The piano also has the proper tonal balance, and the increase in resolution is not due to an alteration of the tonal balance of the music. The benefits of a high quality power supply are easily recognizable, and the Ultimate IV does extract that final degree of resolution out of the Squeezebox.

The bass response of the Squeezebox is also enhanced by the use of the Ultimate IV power supply. My listening sessions reveal not only an increase in bass extension, but also an improvement to the clarity of the lower registers. This clarity adds to the impression of deeper and tighter bass, and an increase in the amount of bass information being provided by this player. Since we are heading into the holiday season, I find myself digging out some excellent Christmas music. “God Rest Ye Merry Gentlemen” [Christmas In the Northwest 6; RBC Dain Rauscher FVCNW 0503SEA] by Gypsy Soul is a jazzy interpretation of this well known song. An electric stand up bass sets a smooth bass line to this song. To one extent or another, the previous power supplies I have used with the Squeezebox did not fully express the bass line on this song. With the Ultimate IV power supply, the bass is easier to follow, and becomes an integral part of the song. Instead of being lost in the mix, the electric bass is now the foundational instrument to the song, and creates a stark contrast against the vocals. Once again, the Ultimate IV power supply documents Wayne’s knowledge and experience regarding the inner workings of the Squeezebox. Another level of resolution and detail is coaxed out of this diminutive back box.

This review is the third installment in a yearlong series about the Squeezebox. The first article appeared in the September 2007 issue of Affordable Audio. The stock Squeezebox and power supply set the baseline for this series of articles, and is the yardstick in which the Bolder Cable Company modifications are measured against. 3 In stock trim, the Squeezebox is, at best, a run of the mill digital player. Fortunately, Wayne had gotten wind that I had a Squeezebox review in the works, and he sent out two linear power supplies for me to evaluate. The stock ELPAC WM-220-1 made a noticeable difference in the sound of the Squeezebox, but the one with Bolder Cable Co. modifications turned the SB3 into a respectable player. Clearly there was no going back; I had started down the slippery slope of Squeezebox upgrades. After completing this review, I packed my Squeezebox up and sent it to Wayne for the Full Enthusiast upgrade package. In the meantime, a friend of mine sold me a cloned version of an Ultimate I power supply that he used with his SB3.4 In May, A$$A published a review of the Bolder Cable Co. modified Squeezebox with the more sophisticated power supply. The Ultimate IV power supply represents the final step in the upgrade process for my Squeezebox. There is a Statement modification package that Wayne has developed, but it must be installed in a stock Squeezebox.5 This journey has come to its end, and I have been fortunate enough to experience the different levels of performance that can be had from the Logitech Squeezebox. The stock unit is a respectable inexpensive player, yet it has the potential to be a high-end machine.

The Bolder Cable Co. Ultimate IV with Nirvana regulator resides on the frontier of power supply design for the Squeezebox. There have been other companies that have developed modification packages and power supplies for the Squeezebox, but all of them have dropped out of the arena. To the best of my knowledge, the Bolder Cable Company is the only entity currently offering Squeezebox modifications. Wayne Wannahan is not content to just install his modifications, but continues to develop and evaluate alternate designs for the Logitech digital players. 6 The latest version of the Ultimate power supply offers improvements to the performance of the Squeezebox that cannot be achieved in any other manner. The Ultimate IV increases the low level detail of the SB3, and also improves the lower registers of this player. The Aspen Sound Nirvana regulator is responsible for the improvement in the attack of the leading edge of the music. A fully modified Squeezebox and an Ultimate IV power supply will perform at a level that is on par with the better conventional digital machines.7 For those individuals looking for the best bang for the buck from a Squeezebox, I would recommend a Bolder Cable Co. modified ELPAC power supply. For audio enthusiasts looking to obtain the finest digital playback available from their Squeezebox, this power supply is a logical choice.

from affordableaudio, By John Hoffman