November 2015

SST Son of Ampzilla II Power Amplifier And Thoebe II Preamplifier
A remarkable sound with excellent soundscape.
Review By Ron Nagle

  Spread Spectrum Technologies (SST) Son of Ampzilla II power amplifier and Thoebe II preamplifier ($3500 each) reviewed here are a continued effort to improve on the original designs by audio engineer James Bongiorno. There was a time when I knew the man. His aura was different, like his appearance, sometimes red, sometimes he was, as I remember, green. He could make a box of wires talk and he could make that box of wires sing. He could play the piano and somewhere his CD is still buried in my stacks. Alas he is no more now due to passing on January 10, 2013, and gone with him is his rainbow colored clothing. He was James Bongiorno audio engineer, entrepreneur extraordinaire. You can trace his professional life through Marantz, Dynaco, SAE, Sumo Electric, GAS (Great American Sound Company), and lastly to our test subjects manufacturer, Spread Spectrum Technologies. Before Jim's passing he formed a partnership with EJ Sarmento of wyred4sound.com. As of this report wyerd4 sound has purchased the SST company in full. It was EJ Sarmento who streamlined and improved the quality control and the manufacturing process that James Bongiorno began.

Years ago in Las Vegas I went to a dinner at the Rio hotels, All American Barand Grill with some friends. At this dinner there was JB and another acclaimed audio innovator, Bob Carver. During dinner they chatted as friends would reminiscing about old times. With one ear wide I shamelessly eves dropped on bits of their conversation, at one point they joked about pulling late nights winding transformer coils with an electric drill. Remembering JB I could not help but reflect on his somewhat closed continence. It was as though he weighed everything I said. But of course all that is very subjective. Intimidated? Yes very possibly, after all his life represented so many things I had not done.

Thoebe II Preamplifier
Let us start upfront with the smaller signal preamplifier. My reasoning is that its character will season the sound of whatever flows through it and pass that on to the power amplifier. First we need to get the obligatory list of nuts and bolts hardware out of the way! You can order the Thoebe II with four different configurations. First configuration would be standard as a line amplifier with a Class A headphone output for $3500. A second option would be to add an ESS Sabre (9018) 32-bit DAC chip that supports 32-bit/384kHz sample rates including DSD 64/128 and that will be an additional $500, thus bringing the overall price to $4000. The third option would be to just add a Class A moving magnet (MM) phono stage, again the total asking price is $4000. Last configuration includes both the DAC and the Phono stage for a grand total of $4250. This is the way the review sample was sent to me as it had all the options.

The Control Panel
The review sample front panel is black in color and somewhat non-standard in its layout. The aluminum face plate is 17.5 inches wide and 0.25" thick. The chassis cover is made of steel and measures, 14.675" deep and is 4.175" high. On the left side are not one, but two 1/4" inch headphone jacks. The left side jack is a standard live output whereas the right side jack will mute the preamplifier output so the speakers are turned off. Side by side under a Green florescent display, is an array of ten small black push buttons. In my system the buttons are hard to see from my chair. First on the left is a Standby/Power button, Next are two push buttons with white up and down arrow symbols silk screened under them. They allow you to scroll/step through the available inputs so you can select your music source. As you do this the Green display changes to indicate which input is active. Positioned directly under the display is the remote control receiver.

Continuing on the right there are seven additional push buttons, they are: Bass and Treble (adjustment 1 to 5), Balance (range 1 to10), Phase (0 and 180), Gain (high or low) Dim (Display 3 choices, normal, dim, off) and Mute. Note: The phase control inverts all of the inputs going into the Thoebe II. These push button functions should be familiar to most audiophiles. Last but no least is the dual function front panel volume control knob. The volume control is different in that it has no detents therefor no starting point and no stop to let you know it is at maximum volume. The volume control spins very freely in either direction and so it seems to function more like a digital encoder. Now everything on the front panel is duplicated by the functions of the remote control. Unusually the remote control is not supplied with the preamplifier. But it is available as a $175 option.

Non-intuitive, the front panel volume control knob serves two purposes. As you should expect it will increase and decrease the speakers loudness. But it is also used to adjust other functions. As an example let us say you want to shift the center image between your speakers more to the left of center. First depress the Balance button. The display changes to show what looks like a closed parenthesis symbol. To shift the audio image more to the left you rotate the volume control knob counter-clockwise. As you so the displays numerical readout (Starts blank no number) will increase up to a maximum of #10. Conversely you would move the volume control clockwise to shift the center image to the right.  If you would like to adjust the bass level or reset the amount of treble you would first press either the Bass or Treble button on the front panel (the display has no numbers). After you make your selection you can use the volume control knob to increase or decrease the Bass or Treble up to a maximum numerical level of #5. If you decrease Treble or Bass the (-) minus symbol will be a prefix before the number setting. Increasing a setting will show a (+) plus prefix before the numerical display.

Or maybe in plain speak it is far easier to say, choose a function and you can adjust the amount with a Clockwise or Counterclockwise twist of the volume control. Every adjustment you dial in will time out after 8 seconds and the display will revert to the last source you were listening to. Also a very nice feature is the initial power up sequence. It always begins with the preamplifier in a quiet standby mode. There are two remaining functions they are Phase and Gain. Previously I have seen digital to analogue converters (DACs) and CD players that had a phase flipping control. These were primarily because some CD's were (rumored) to be out of phase. Incidentally I have found phase inversion most useful with self powered subwoofers. Last we take a look at that Gain button controlling thing. I assume it's primary purpose has to do with the Moving Magnet Phono amplifier in the Thoebe. But additionally it may be used to match other manufacturers' power amplifiers. This seems likely because both of these functions are not device specific because they affect all of the input sources equally. Finally we have reached the end of the button flipping functions!

Thoebe's Rear End
Here is when we look at Thoebe's gray back panel. There are three stereo pairs iof RCA input connections at the rear of the preamplifier and one pair of XLR inputs, so that's a total of 4 analog inputs. The first RCA pair on the left side is on this review sample configured as the optional phono amplifier connection. Otherwise it would be used as RCA #4 and it will serve for any line level input. Next, lined up side by side there are three pairs of RCA jacks. They are designated as RCA #1 to #3 as shown by the front panel display. I know they do this to provide flexibility but. Call me old fashioned, but I would prefer that they were labeled more conventionally as Tuner, Tape, etc: So that the front panel display would tell me in words what was plugged into these three RCA connections. In my case I do have the word phono amplifier appear in what might otherwise be called RCA #4. All the other front panel displays are spelled out by their active connections, such as the three digital rear panel inputs:  Coax, TOS, USB including the Phono, XLR. The XLR input was connected to my Music Hall DAC 25.3. The XLR output was the connection to the Ampzilla II Power Amplifier. Oh! and of course there is an IEC power cord socket  in back.

The Son OfAmpzilla II
Don't panic, it's not really organic! I believe this power amplifier is genealogically speaking number five in the Zilla line. Of course the original Amp Zilla-Killa nut crushing power amplifier (is still in production as a monoblock) was James's first born child. This may be a smaller edition and great great grandson amplifier but still it is an imposing chunk of iron. Dimensions are 9.875" X 17.25" X 5.675 (LxWxH) and the SST Ampzilla weights 40lbs. Power output is rated at 220 wpc into 8 Ohms. Again, shoot me Editor if I didn't tell everyone the way its laid out. (Editor's Note: I've been busy editing this to sound more fluid... and think I failed miserably at it due to flat-tire English.)

Like the Thoebe II the power amplifier front is black in color. The front panel has left and right channel power status LED diodes. There are three grouped horizontally on the left side and three on the right. The center red Led is labeled Status, this indicates normal operation. On either side straddling the Status LED are two more LED's. The left side is labeled B+ the right side is labeled B-. This refers to the Plus or Minus amplifiers 'B" power rails. If either Led is illuminated chances are one of the power rails fuses has blown/opened. The same is true for the other power status LED diodes on the right side. Logically they can quickly tell us the Left and Right channels operational status. Dead center is the round power button, and directly above it is a small red LED labeled Thermal. And that may be very useful because, dear reader, this amplifier cries Ventilate Me because it runs mucho caliente. Let us look at the layout of the power pushing rear panel.

In back I find there are two small ergonomic features that should/needs be more user friendly. O.K. it's nothing that will affect the amplifier performance. However, this is a 'Whats up with that" observation. As you would expect on either side are a pair of five-way speaker cable binding posts for the left and right channels. Question one:  Why are they placed close together and arranged vertically one above the other. My Kimber 12TC speaker cables have locking WBT banana plugs that are laying on top of each other. Consequently I wedged a thin piece of cardboard between the WBT plugs, just for my peace of mind. Most amplifiers have speaker cable binding posts logically laid out horizontally next to each other because cables hang down. Let's look at a very nice feature and this is the provision made available to use either unbalanced RCA or balanced XLR preamplifier input connections. The manufacturer tells us the Ampzilla II circuit is completely balanced from input to output. These two types of preamplifier input connections are grouped at the top center of the rear panel. (Editor's Note: Are we there yet? Oh, guess not.)

The XLR connections are positioned on either side of the RCA jacks like this: --> XLR RCA-RCA XLR. Question two: Directly in between these connections is another squintingly small black push button located on the power amplifiers dark gray back panel. It is used to select between either of the two preamplifier inputs. This RCA/XLR selection switch on the back of the amplifier only grounds the XLR input connection. It doesn't actually switch between the two connection types. So either type of connection will work, but if the switch isn't set correctly, the amp will sound noisy and the gain will be off. True you shouldn't need to use it very often. But, if it was a small toggle type switch all you would need to do is look at it to see what position it was in.

Methodology
Logic dictates that each of the SST preamplifiers and power amplifiers first be evaluated separately and then combined as a system. My reference system amplification at this time is solid-state, with the system being cycled on via a single button from my APC (American Power Company) S15 power conditioner. There is a Parasound P5 preamp feeding a Sanders ESL muscle amplifier. Cables are Kimber 12TC feeding my two-way Arum Cantus SES speakers on 24" stands. Mark & Daniel Omni Harmonizers sitting on top of the speakers. The Harmonizers are really add on Oskar Heil tweeters that reach out to 40kHz. Thus the first order of business is to run the SST Thoebe preamplifier for about six hours then swap out my Parasound P5 preamplifier and slot in the Thoebe II. Before I get to my ‘what it sounds like' part, let me share my very first impressions. The SST preamp is quite hefty in weight and feels more like a power amplifier built into a smaller preamplifiers form factor. I have a Marantz 8400 CD, DVD, SACD player feeding an outboard Music Hall upsampling DAC 25.3. So I have connected the Music Hall DAC directly to the Thoebe II preamplifier via balanced XLR cables. The Marantz universal CD deck is connected via optical TosLink.

And now, finally, let me tell you about Thoebe's voice as it is time to play music. SST's Thoebe II preamplifier has a warmer presentation than my Parasound P5. Thoebe II presents instrumental sonorities on a more expansive and deeper center stage and, for me, am very much into music and imaging so this is paramount for me. All the hardware bells and buttons and whistles are only a means to an end. So I dim the lights and let the walls recede, to a broad liquid soundscape and there I can reside quite contented.

SST Ampzilla II
Let's make a system from these two halves. We remove the Sanders muscle amplifier and replace it with the $3500 Son of Ampzilla II. Is this a match made in heaven? Well I haven't been to heaven, yet it certainly compliments the preamplifier with even more hollow state tube dimensionality. Especially at the low end of the spectrum were the bass provides a fundamental foundation to our stage. Combining the Thoebe II and the Son of Ampzilla II forms an synergistic combination that presents a lifelike flesh and blood realism. Not too fuzzy warm and not too cool either. With a variety of music played through this system, it produces music that sounds very approachable. The power part of this pairing adds more depth and dimensionality exceeding the much more powerful Sanders amplifier. Let's get specific and cue up The Absolute Sound Reference CD [STD Digital-6111142]. This is a compilation of 12 different music samples. Track #9 titled 'Works for Harpsichord" by J.S. Bach is the perfect test medium for transient speed and attack. Listening the rapid tempo of this composition and the lingering sustain causes every reverberant note to hang in space long enough so that the following notes reverberant sounds overlap. At one point the rear soundstage reverberated with an echo that built up to mimic something similar to a humming sound. I had never experienced this effect with any other system. It was a continuance painted on a remarkably deep center stage. The Ampzilla II turns out to complement all the flavors and nuance painted by the Thoebe II. Via two different mid-priced sets of headphones, track #9 was clean and clear yet could not quite match the ability of the Thoebe II preamplifier to delineate subtle details.

Denouement
Let us try what has to be the acid test as at this point everything in the SST system comes into play. What conclusions can, and should be made, are now clearly evident now. So at this juncture we need to feed Thoebe II and the Ampzilla II some really small millivolts. If done correctly, there will be nothing extraneous riding the musical soundscape. Of my six cartridges the Moving Magnet Shure V-15 type 3 V-MR with a 3.5 mV output should be an ideal match. During the recent THE Show Newport I purchased Crystal Visions' The Best Of Stevie Nicks Greatest Hits [Reprize-1000363-2], which is a two LP album on clear vinyl mastered by Stan Ricker. Color me very happy to find the SST preamplifier was dead quite with the volume cranked up with the tonearm and cartridge lifted up off of the record. Very highly qualified people were involved in making this recording, with a very mixed outcome. One of my favorite songs, "Dreams," was backed up by something called "Deep Dish". In this version the tempo was twice as fast as the original Fleetwood Mac recording. The bass and the multi-track mix effects simply overpowered Stevie Nicks lead voice. On the track "Landslide" it is Stevie accompanied by the Melbourne Symphony. Wow! What you hear is a vast soundscape pushing the wall behind my loudspeakers out into the street. Massed violins with a swirling sound deep center threading through and riding above the stage. You might think this confused multi-element recording is a bad thing, yet this tells a powerful story as it requires a very quiet amplifier with superior resolving power to pick apart the rapidly shifting image floating between your speakers.

Last Word
The combination of the Thoebe II and the Son of Ampzilla II encapsulates a very unique sound. It reproduces music like a hybridization cross between a Class A solid-state amplifier with the harmonic structure of ultra-linear vacuum tubes. It manages to capture some of the best traits of each design yet it stands alone. If like me you love to wander in a field of sound, then let this be your doorway.

Semper Hi-Fi

Review System Components
Sota Sapphire 2  turntable
Grado Laboratory Standard tonearm
Shure V15 3 VMR Cartridge
Sangean Digital tuner
Marantz 8400 Universal disc player
Music Hall Up sampling DAC 25.3 and headphone amplifier.
Sanders ESL power Amplifier, Parasound Halo P5 Preamplifier.
Aurum Cantus Leisure 2 SE two way ribbon tweeter monitors on 24" stands
Mark Daniels Omni Harmonizer panoramic tweeters
Onyx Rocket Strata Mini 3.5 way speakers.
Kimber Kable 12tc 11ft. Kimber Kable 8TC Jumpers
Monster Reference Four pairs, two 0.5-meter, 1 meter and 1.5 meters Nordost Red Dawn, 1meter
Chord Silver Siren 1 meter, Homemade Teflon 1 meter, Autobahn ½ meter digital
Wire World 10 gauge IEC line cord,  Power Cords: Kaplan Cables 12 gauge IEC
Islatrol Industrial 20 amp ac line conditioner, Richard Gray 20 amp Sub Station
Alpha Core Balanced Transformer Power Supply, Audio Power PE-1 power enhancer,
APC Power Block, Triad 2-ampere isolation transformer
And a comfortable chair.

Specifications
Thoebe II Solid-State Preamplifier
Optional DAC and/or phonostage: 
DAC, ESS Sabre (9018) 32-bit Asynchronous, galvanically isolated USB input supports up to 32-bit 384kHz PCM and DSD64 + DSD128
Phonostage: Moving magnet discrete Class A design 
Class A headphone amplifier, standard
Digitally-controlled, channel independent tone control
Resistive-ladder type volume control
High/low gain setting
Phase and balance controls
Dimmable) LED display
Internal USB connection for any future software updates
Optional solid billet aluminum full-function remote control
Line (balanced and unbalanced): 19dB high gain, 16dB low gain
Tone Controls: ± 5dB nominal, Turnover points: Bass 300Hz; Treble 3kHz.
Maximum Output: 10V RMS unbalanced, 20V RMS balanced
Input Impedance: 62kOhm unbalanced, 100kOhm balanced
Output Impedance: 50 Ohm, all outputs
Headphone Output: 1 Ohm, 388mW (300 Ohm)
Noise (A wt): MM: 70µV (22µV with 400-20kHz filter)
Line: 10µV unbalanced, 18µV balanced
THD: 0.006% max inputs to main outputs @ 1V RMS rated output
Frequency Response
Phono: 20 Hz to 20 kHz +/- 1.2dB
Line: 20 Hz to 20 kHz (+/- 0.25dB)
Dimensions: 14.675" x 17.5" x 4.175 (LxWxH)
Weight: Without phonostage: 25 lbs., with phonostage: 28 lbs.
Price: $3500; with DAC $4000; with phono $4000; with both $4,250
Custom accessory, all-aluminum remote control $175

Son Of Ampzilla II
Power Output: 220 wpc @ 8 Ohms, 350 wpc @ 4 Ohms
Frequency Response 20 Hz to 20 kHz (+/-0.1dB)
THD: < 0.03%
Input Impedance: 130kOhm balanced, 65kOhm unbalanced
SNR: 110 dB
Gain: 27.5dB, 1.76v RMS for 220 watts 8Ω (either input)
Sensitivity: 1.76 V
Weight 40 lbs.
Dimensions: 9.875" x 17.25 x 5.675 (LxWxH)
Price: $3500

Company Information
Spread Spectrum Technologies
4235 Traffic Way
Atascadero, CA 93422

Voice: (805) 466-9973
Fax: (805) 462-8962
E-mail: support@sst.audio
Web Site: www.SST.Audio