Preamplifier
ENJOY THE MUSIC - Preamplifiier Review Feb 2012
World Premiere!
Roger Sanders Preamplifier
Resolving micro detail from a music and painting it beyond the outer edges.
Review By Ron Nagle
CLICK ABOVE TO VISIT ENJOY THE MUSIC'S SITE AND READ THE REVIEW
The sound was as I hoped; music filled the room and seemed to energize the air in a way different from any driver driven source. Serendipitously this visit coincided with the d�but of a new Sanders Preamplifier. Prior to this show Roger Sanders offered two separate components, a Line Preamplifier and a Phono Amplifier. This new component is a preamplifier with a phono stage; it has no model number because it replaces the two older components. It remains now as the only Sanders Preamplifier in their line.
Note: There was a time when describing how a thing like an audio preamplifier worked was fairly easy, those days are gone. Now we can find audio components that have single controls that can perform multiple functions.
Description
My review sample arrived broken in and came directly from the Sanders demo room at the Marriott Tech Center. The chassis body is constructed of black painted sheet steel. The overall appearance is that of a low profile rectangular box. The box measurers, 2.5" high by 17" wide by 10.5 "deep and weights 8 pounds.
The Sanders Preamplifier is available with two different front panels made from 3/8 inch thick aluminum stock.Choose either a black anodized fascia or the version I received that has a brushed satin aluminum face. At the center of the front panel is a horizontal elliptical depression that compliments the design of the Sanders line of power amplifiers. Within this elliptical (scooped out) depression, there is a line of seven source/input select push buttons. They are labeled from left to right, Balanced (input), Phono, CD, Video, Aux, Processor (loop) and a very unusual Mono select function. This function is useful for checking phase and channel balance. A blue LED lights up just above each of the five main push buttons when one of these sources are selected. Continuing to the right side of the front panel is an elliptically shaped blue LED display containing a two digit numeric readout. Scaled in decibels, this two-digit display normally indicates volume (main) for the source you have selected.
Starting at the left side of the front panel there is an unusual multi function volume control. The shape of this control reminds me of a dresser draw knob. When the volume control is turned, it feels as though it has soft detents. Each detent represents a one-dB change in volume with a maximum range of one hundred Decibels. This control is unique in several ways. It is actually a three function optically encoding volume control sent to a microprocessor. Unlike a mechanical control, it does not have stops when rotated either fully clockwise or counterclockwise. The first function of this control knob is as a standard two-channel volume adjustment. However, this same control knob performs two additional and separate functions. These are indicated by the words, "Main-Left-Right" (channels). When the knob is pushed inward, you can lower the level/gain of the left channel. A white LED to the left side of the two-digit decibel (gain) display will indicate when this function has been selected. A second push of the same knob will allow you to lower and adjust the right channel volume level as indicated now by a red colored LED. This channel adjustment can also be used to shift and center the performance between the speakers by lowering the volume of the louder channel.
Let us say you want to lower the right speaker and by so doing move the soundstages center a bit to the left. To get to the right channel you will need to push in the volume control knob two times. When you start out the display will read the decibel level of the right channel as double zeros. The red led comes on to indicate you have selected the right channel adjustment. Now turning the control knob counterclockwise will decrease the right channel gain. The readout will change from the zero starting point to a minus (-) decibels number. The thing to remember is by pushing in the control knob once and then a second time you can access first the left and then the right channels separately. However, adjusting the level of each source input is done differently. Specifically, to adjust the level of a source input, you must press the appropriate source button simultaneously. Following this procedure will allow you to equalize every separate input source to play at the same comparative level. Then you will be able to change the level of that input up (by as much as 18 dB) or down (by as much as 99 dB) to get it to match the levels of the other inputs. Remember the loudness for both stereo speakers is controlled using the volume control knob just like any standard two channel potentiometer.
At The Back Panel
Roger Sanders PreamplifierWe see a line up of eight pairs RCA female jacks. These correspond to the sources selected by the eight front panel push buttons. Additionally, and a very welcome addition are pairs of balanced XLR input and output connections. Listing the connections from left to right, they are The IEC power cord socket, a fuse holder, an AC power on/off rocker switch. Farther toward the right we find the Output connections, these consist of a pair of right and left XLR balanced output jacks, in addition, there are two pairs of RCA outputs that can facilitate system bi-amp'ing. What is unique is the fact that you can feed my Sanders power amplifier simultaneously with both balanced and unbalanced preamplifier interconnects cables. In fact, whether you use either cable connection separately or both at the same time makes no difference.
The volume control adjusts the levels of all the output connections simultaneously with one exception. There is a processor button that toggles between a video processor and whatever main input is selected. Therefore, you have one set of unbalanced fixed level outputs available. These can be used to feed a recording device or digital processor. This processor input is a special "Pass Through" device at unity gain; the volume control has no effect on it. Whichever input you select will appear at this processor output and can be recorded. You can use the level control to adjust the loudness of the preamplifier system without it affecting the recording level.
Farther to the right are the Input connections. These are pairs of Gold Plated RCA female jacks labeled: Out, In, AUX, Video, CD, PHONO, and one pair of XLR connectors and lastly a chassis grounding lug.
Not Least
The supplied Sanders remote control is one helluva over kill remote. You can program the MX-350 Universal Remote Control to control almost every component in a complex audio video system. It has a full numeric key pad along with all the functions you would need to control a television set CD and DVD player and most cable boxes. Lucky for Moi I only have to tell you about the part that controls the Sanders Preamplifier. At the business end of the remote control, there is a Liquid Crystal display. The display consists of eight pages, the first two pages are devoted too the preamplifier functions. Page one, at the top is the word AUDIO below that is a list Of the input functions. In order they are, Balanced (input) Phono, CD, Video, Balanced (left, right speakers). Page two, Aux, Processor (video) Mono. The last two functions on page two of the remote are, Ampon and Ampin. The owner's Preamplifier manual does not describe these last two selections neither does the separate instruction booklet that accompanies the remote control.
The Engine Inside
The one and only main printed circuit board covers ninety percent of the chassis interior. It is extremely neat, logical and economically designed. I can see sets of Op-Amplifiers and switching relays positioned near each of the rear panel jacks. Selecting one of the front panel buttons will activate the corresponding relay and deactivate any other. As is usual, the right side holds the component power supply, transformer, rectifiers and storage capacitors. At the left side of the main board, there is a circuit, which allows Phono Cartridge loading adjustments. I wanted to put this cartridge optimizing circuit to a test because I had just received my rebuilt Blue Point Special cartridge back from Peter Ledermann at the Soundsmith Company.
This is a Sumiko Blue Point Special with a solid ruby cantilever and Microridge diamond stylus. Eventually, that is after a few hours and a break to rest my weary eyes. I managed to position a nearly transparent Ruby cantilever and an invisible diamond where they should go.
Thank you Jim Fosgate for your wonderful Fozgometer!
The Diagram of the cartridge loading circuit looks like this.
There are DIP switch adjustments to vary the amount of resistive and capacitive loading presented to the cartridge. The circuit is dived into two halves, Right Channel and Left Channel. The first adjustment would be to select either High Gain or low Gain to match the voltage output your cartridge. In my case, I chose Hi-Gain to amplify the output of my Sumiko moving coil cartridge. The next step is subjective, using this circuit will adjust the sound of any cartridge however, this is done by ear and may vary according to your personal preferences. And it may not agree with the specifications provided by the manufacturer. In the diagram above, I added small arrows to show the ON positions of the DIP switches I chose. By trial and error, I set both channels of my moving coil cartridge at 1,000 pf. and 1000 Ohms. Lastly, the manufacturer suggests you leave the preamplifier on to prolong its life.
To Ear Is Human To Forgive Fatigue
Sitting down to listen, my very first ear felt impression is one of a very clean and transparent sound with frequency extension without any limitation. To better illustrate my point let me describe my primary test CD. The main purpose of this CD is a test of sound field detail resolution/retrieval. I use the recorded sound track from the Las Vegas show LOVE [Capital EMI 0946 8 79606]. It is the Cirque du Soleil performance to the music of the Beatles. The very first track on this disk is a remix of the Beatles song Because. At a very low level buried deep under the crystal clear vocal track are the faint sounds of life. At intervals through out the recording, you can hear sounds made by birds, the sound of wings flapping, Doves cooing. Only 32 seconds into the track, you will hear a bird chirping. At 54 seconds Doves cooing, and then at 106 seconds we get to the killer resolution cut. Faintly and now at an even lower volume there is the faint buzzing sound of insect wings. At first it sounds like a Bee but resolution will reveal it as a Fly. Now if you listen using the cutting edge of the audio art you will not only hear it you can follow its flight. Starting just inside the right speaker the Fly quickly moves in a receding diagonal direction across the center stage ending far field behind the left speaker. The Sanders Preamplifier lays it all out there for you to hear, the lateral stage is wide and surgically precise.
Let us inject the human factor; my reference has always been the sound of a human voice, because this I know intimately. Let's listen then to Eva Cassidy, if you look for human emotion turned into music this is the place to go. The first track is the Sting song Fields of Gold, from the Songbird [CD-G210045]. Her words convey a breathless plaintive pleading and longing for a time that has passed. The detail is such that I can pick out the sound of the strings from two different guitars. The sharpest transients are obviously from steel guitar strings. Less obvious is the signature sound of Nylon strings from a second guitar. The strings transient attack and the warmer harmonic overtone reveal the resonating wooden guitars. It is all cutting edge detail and emotion clear for you to hear.
The Phono Stage
Roger Sanders PreamplifierIt was with a strong sense of curiosity and anticipation that I began this part of the evaluation. The following narrative details the results after a meticulous set up of my moving coil cartridge. A wonderful opportunity presents itself with the Sanders Preamplifier. It is the ability to alter the response of your cartridge to optimize your entire systems strengths, the bass, treble and midrange response. This is what this audiophile hobby is all about. Of course, it is vital to get cartage-loading spot on. However, the end result is like selecting a fine wine the sound must complement your pallet. At random I pulled out a Japanese vinyl pressing of Judy At Carnegie Hall, Capitol Full Dimension Stereo [ECS-40207-08]. Recorded Live April 23, 1961.
From the first few bars of the opening overture, I could hear that the Carnegie Hall space on this recording was huge. I realized that my four way AV Strata Mini speakers could not reproduce the expansive stage width of this classic recording. Of necessity I swapped out the speakers with a pair of two way Aurum Cantus. Leisure 2SE Monitors. Sitting on top of these stand-mounted speakers are a pair of Mark Daniels Omni Harmonizers. These are an add on tweeter with a 360 degree dispersion pattern and a frequency response out to 40 kHz. With the added treble extension, the effect will push, back all of the room boundaries.
The transformation was complete; my room now holds Carnegie Hall and Judy Garland. All of the micro details of Judy's signature lisping pronunciation and taunting timing are with me again. The scale of this performance is wonderful. You hear a tiny figure inhabiting a vast space controlling it all with an impossibly huge voice. On the track The Man That Got Away, you can hear Judy's lips quiver with sibilance when she pronounces the word, away. The audience anticipates her every word and she plays with them and teases them as she delays a breathless millisecond between words. She holds the gathered throng in rapt anticipation at every pause; they hang, lips moving, waiting for the next phrase. I shake my head once again remembering the incredible performer she was.
CODA
So what about the innovative Sanders Preamplifier? It is in every respect a thoroughly modern cutting edge audio preamplifier. I did not utilize, the Audio Video, recorder/processor pass through. This circuit is at Unity Gain and bypasses all of the internal controls; it is essentially just a straight wire that has no sound of its own. The active circuits of the Sanders Preamplifier have a stunning ability to resolve every micro detail from a music source and paint it beyond the outer edges of my speakers. I was able to clearly resolve differences I made with every component, cable swap, tuner, CD and Vinyl recording. Even moving the preamplifier to sit on three high bounce balls I got out of a gumball machine made a slight improvement. My intention is to convey performance not in technical prosaic but rather to tell you the way the music flows through the Sanders preamplifier and its ability to touch your emotions. I hope I got that across, not inexpensive but the state of the art is never cheap. Highly recommended.
Semper Hi-Fi
Reference System
Source Components: SOTA turntable with Grado Signature tone arm and Blue Point Special moving coil cartridge, Marantz 8400 Universal CD, Player, ART DI/O Up sampling D/A and A/D processor, Magnum Dynalab FT 101a and Dynalab Signal Sleuth.
Amplification: Sanders Preamplifier, Audio Research SP-9 MK 3 Preamplifier, Sanders ESL Power Amplifier.
Speakers: Onix Rocket Strata Mini and Aurum Cantus Leisure 2 SE two way monitors on 24-inch stands.
Speaker Cables: Kimber 12 TC
Interconnect Cables: Monster Reference 4 pairs, two-1/2 meter, 1 meter and 1-1/2meters
Nordost Red Dawn, 1 meter
Wire World Eclipse-2, 3meters
Audio Research Litzlink 2 pairs, 1 1/2 meter
Chord Silver Siren, 1 meter
Home made Teflon 1 meter
Audiobhan 1/2-meter digital
AC Power: Islatrol Industrial 20 Ampere ac line conditioner
Richard Gray 20amp Sub Station
Alpha Core Balanced Transformer Power Supply
Audio Power PE-1 power enhancer
Triad 2-ampere isolation transformer
Accessories: VPI Magic bricks, Room Tunes Panels, Argent Room lenn
Rives test CD, Fozgometer, Digital Stylus Force gauge.
Specifications
Type: Solid-state stereo preamplifier with phonostage
Frequency Response: 5 Hz to 200 kHz (-3dB)
Inputs: Five unbalanced inputs at line level using RCA connectors. One balanced input using XLR connectors. One unbalanced, RCA phono input with switchable gain, adjustable input loading, and RIAA equalization. One unbalanced video processor input with fixed level at unity gain for "pass-through" use.
Outputs: Two pair of adjustable, unbalanced, outputs at line level using RCA connectors. One pair of adjustable, balanced, outputs using XLR connectors (Pin 2 "hot"). One unbalanced, fixed level output at unity gain for recording using RCA connectors. All outputs may be used simultaneously.
Phono Input Impedance: Adjustable between 47 kOhms and 100 Ohms.
Phono Input Capacitance: Adjustable between 50 pf and 1,200 pF.
Noise: Greater than 90 dB below 1 Volt reference
Distortion: Less than 0.002% from 10 Hz to 40 kHz
Output Impedance: 50Q, non-reactive, balanced or single-ended
Input Impedance: 47kOhms balanced or single-ended
Gain: 28 dB
Maximum Output: 10 Volts peak
Crosstalk: Greater than 70 dB from 20 Hz to 20 KHz
Dimensions: 2.5 x 17 x 10.5 (HxWxD in inches)
WEIGHT: 8 lbs.
Price: $4000
Company Information
Sanders Sound Systems
12054 Deer Trail Road
Conifer, CO 80433
Voice: (303) 838-8130
E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Website: www.sanderssoundsystems.com
Dagogo - Preamplifier Review - March 2012
Sanders Preamplifier Review
Slide rules and pocket protectors
In the subjective audio universe, where gross amounts of 2nd harmonic distortion, horrendous phase shift, and totally inadequate frequency response gets euphemistically labeled “bloom” and “harmonic richness,” the purveyors of audio accuracy must hide their devotion to truthfulness like it’s a cardinal sin. “Zero phase shift?! Grab the matches and gasoline, we have a scientist in our midst.” There are negative connotations to marketing with specifications. Anyone old enough to have heard the first transistor amps will agree they sucked, regardless of what the specs said. Engineers in the ‘60s, ‘70s, and ‘80s, with their use of feedback as a blunt-force-instrument, forever tainted integrated circuits, feedback, and solid state. Though the equipment measured good, it sounded bad. Real bad. In a way, we should be thankful the big corporations made bad sounding equipment. Had they not, we wouldn’t have the audio underground and cottage industries that sprung up to satiate the appetite for good sound.
So, what’s wrong with electronics that have no audible distortion, no audible phase or frequency response issues, no oscillations, no noise and no problem driving any set of cables or amps or speakers? Nothing. Nothing is wrong with that. Are you so hung up on tube rolling and tweaking that you reject the hypothetical existence of an integrated circuit that would do a better job, and keep doing it the same way for 20 or 30 years? Are you that afraid of your music collection?
Though I admit to enjoying tubes, analog, open reel tape, and single driver loudspeakers, I will be the first to admit that there are significant limitations with all the above. If the primary job of an audio system is to be truthful, then does the current crop of high performance digital, and high performance integrated circuits deliver the goods? Increasingly, the answer is yes. We are advancing the state of the art in baby steps. Some of the advancements come from improved manufacturing techniques, giving us higher performance through better matched transistors and purer materials. Some of it has been new ways to accurately measure distortion, or the discovery that the ear can hear things that are hard to measure with simple harmonic distortion analyzers. Some of it is trickling down from medical, aerospace and military technology. The same circuits used to hunt down submarines or find tiny tumors have applications in audio. Billions of dollars have been spent to beat the competition, whether it is another chip manufacturer, stage IV cancer, or enemy combatants.
For all audio, I ask a few simple questions. Is the frequency response wide enough, and flat enough, to allow us to hear all the fundamentals and overtones, and in the correct relationship? Is there audible distortion? Does it have enough power to avoid clipping? After those criteria are met, can it recreate an acoustic space (imaging)? Finally, is it reliable? Those criteria are hard to satisfy, and when a piece meets the criteria, it usually satisfies musically. Sure, there are very subtle nuances, almost impossible to measure, that are the difference between the good and the great, but I have a hard time hearing those nuances over audible harmonic distortion and hum. Almost all the equipment I’ve reviewed had issues, usually minor ones, in one or more categories. Some people don’t mind scads of harmonic distortion, limited power or limited bandwidth, and you know who you are. I do mind, but there is a niche product for everyone.
The Goal
So, what has that to do with the latest preamplifier from Sanders Sound Systems? Everything. Roger is an actual engineer, in an industry with many “gurus” and copycats. Let me offer a few interesting excerpts from the Sanders website in the following:
“Our previous preamps (line stage and phono) were $4,000 each, for a total cost of $8,000 for our customers who needed a phono preamp. Since both preamps are now combined, customers who need a full-function preamp can now save several thousand dollars as the new preamp sells for half the price of the previous two.
The goal of a true audiophile grade preamplifier is to offer gain, switching, and other conveniences, while at the same time passing the original signal downstream without adding distortion, noise, or a sonic signature of its own. The Sanders Preamp does exactly that but includes many ergonomic features for convenience and ease of use that are not available on even far more expensive preamps.
The levels of each individual input can be adjusted to get them all matched so that you don’t get “blasted” or have to turn up the main level each time you switch sources. A stereo/mono switch remains standard equipment. The overall gain, individual gain between devices, and channel balance can be adjusted in precise, 1 dB increments. Muting by remote control is standard. A video readout makes it easy to monitor the levels.
… Front panel controls are done through micro-touch electronic switches. Internal switching is done by miniature, sealed, gold relays. Conventional rotary volume controls have channel matching error of around 20%, which causes the left/right balance to shift as you change the level. To solve this problem, some preamp manufacturers use discrete, precision resistors on a multi-step switch.
While this solves the channel tracking problem, they introduce new ones. Specifically, they have very limited resolution due to too few steps (typically 31 steps of 2 dB each). These “stepped attenuators” produce very annoying switching transients at each step.
The Sanders Preamp solves these problems by using the “volume control” knob to drive an optical comparator circuit. The optical circuit operates a microprocessor that controls an electronic gain system. This controls the level using one hundred, one dB steps, with precision of greater than 0.1% between channels.
The microprocessor monitors the signal voltage and waits for it to cross the zero voltage point between waves before switching to the next level. This prevents any switching transients. The volume control knob has detents at each 1 dB point and it rotates continually. So it as an infinite number of detents and you can feel each 1 dB change in level.
There is a digital display with beautiful, blue, light emitting diodes (LEDs). The display continually shows the output level of the unit and switches automatically to show level differences between channels, when you adjust the balance, or when you adjust the input levels. You no longer have to guess at the levels or try to see fine gradations on a knob to know the levels, since you can see them from several feet away.”
The heart of the new preamp is an extremely sophisticated chip that matches the gain to within .1dB and can remember the various level adjustments for each input. I asked Roger to elaborate:
“The volume control in my preamp is an electronic level control designed and manufactured by Burr-Brown (now owned by Texas Instruments). This chip has many excellent features. It is actually built like a stepped attenuator (using 400 microscopic resistors to obtain 200, 1/2 dB steps, in stereo).
The accuracy of the channel balance is determined by the precision of the resistors. Modern chip-manufacturing technology can now produce resistors with tolerances of better then 0.1% — which is far better than discrete resistors, which are limited to about 1%. Therefore, these Burr-Brown chips offer essentially perfect channel balance.
Conventional stepped attenuators often make “pop” sounds as the circuit changes to different resistors. This is due to the short delay as the switch moves to the next set of resistors, and during this delay, the voltage from the music changes. If the voltage change is significant, you will hear a “pop” when the next contact is made.
The Burr Brown chip solves this problem by constantly monitoring the voltage of the signal. When a change in volume is requested, the electronic resistor switching circuit waits until the voltage monitor shows that the voltage crosses the zero point. It then switches. Since there is no voltage present when the next step in the chain occurs, there is no “pop.”
Of course, music is changing voltage very rapidly, so any delay only lasts a few microseconds at worst. As a result, no human can detect any delay in the process, even when switching through the resistors very rapidly.
The chip has a video driver circuit so that I can have it show its levels on an LED digital display. It also has a microprocessor so that it can be programmed to operate in many different ways. It includes an opamp so that the gain can be controlled.
In my preamp, I control the microprocessor using an optical comparator “pot.” Therefore there are no conventional analog potentiometers to wear out and fail. This also makes it possible to operate the unit by remote control.”
The rest of the preamp includes input and output buffers (discreet) along with regulators. The parts quality is excellent including silver mica caps for the RIAA, Mills wire wound resistors and Mundorf caps. The thickness and quality of metal work are first rate: The top cover of the preamp is very heavy, good for damping vibrations and blocking EMI/RFI. Everything is of very high quality, whether a passive device, cutting edge integrated circuitry, potted toroidal transformer, faceplate, controls with good tactile “feel”, etc. All the components are mounted on one board, with a minimum of connectors and wires that would add noise.
I’ve been researching the dreaded op-amp lately, and it’s kind of a blanket term that should be avoided. You should rather think “integrated circuit”. When I asked Roger about using ICs he responded this way:
“Of course, audiophiles generally believe that ICs sound horrible. Like most audiophile beliefs, this is a myth. The truth is that modern ICs easily outperform any discrete circuit.
If you doubt that, just look at the IC’s measurements and specifications. Don’t believe the specifications? Then listen to ICs using valid listening tests. You will quickly discover that they sound absolutely transparent and that you cannot hear any difference between a modern IC and the perfect reference (a short, straight piece of wire)… I have abandoned discrete circuits like I used in my dedicated phono preamp because they simply could not match the performance of a modern IC.
This should not be surprising. After all, there is no magic. A transistor is a transistor regardless of where it is housed.
The sound of what?
The Sanders Preamplifier is a piece that many reviewers will hate, because it doesn’t have much sound of its own. Cartridges and speakers are easy to review. All mechanical transducers have ridiculous failings, though we are accustomed to those artifacts. Electronics, though, can be difficult to describe, and the Sanders Preamp (and the rest of Sanders electronics) is near the top of the list. It’s hard to describe any peculiar sounds or character produced by the Sanders Preamplifier.
So, what does it sound like? As a preamp, it has zero noise, and zero audible distortion. Whatever distortion is there, is so low that it’s impossible to point to it and say “A-Ha”! Take, for example, the fine tube preamp from Melody that I just finished reviewing. While I loved the looks and sunny disposition, it wasn’t as quick as the Sanders, plus it had audible 2nd harmonic distortion, audible noise and phase shift. Many listeners might not notice these but if you switch between the Sanders and Melody preamps, and if your speakers have good frequency extension, you can hear the difference. Plus, the Melody doesn’t have the perfect channel-to-channel match and volume tracking of the Sanders.
When I say perfect channel match and volume tracking, I mean it. This isn’t reviewer hyperbole. The volume tracking offered by the precision chipset gives .1dB accuracy, something a traditional volume control or unconventional transformer volume control can’t match. The frequency response of the two channels sounded indistinguishable: a nearly impossible feat by a tube preamp. Regardless of volume setting, the two channels were exactly the same. What that gives you is a world class center image “lock” and stereo spread better than anything I’ve used. In that regard, there might be products that are as good as the Sanders Preamplifier, but I doubt you’ll find anything audibly better. There might be other preamps with better imaging outside the speakers due to an even lower level of distortion or better transparency, but I don’t know of one; and it wouldn’t be because they had better volume tracking. It would be interesting to hear the Sanders compared to other transistor preamps using a similar volume control setup. I’ve always heard similar strengths when comparing transistor with tube pieces, but this preamp takes it to a new level.
The phono stage is as accurate, tonally, as any I’ve heard. There are hundreds of phono stages that have enough RIAA accuracy that I expect all phono stages to be similar. If they aren’t, it’s because the designer goofed. I’ll argue that perfect RIAA deemphasis is a waste of time, for a number of reasons that will make up a separate article of the subject. But, it’s not a bad thing to be accurate to less than a dB. What is more audible and more important is matching the EQ of the two channels. It’s the Achilles heel of tube phono stages. The Sanders LP playback channel-balance is as good as other transistor units.
When compared to tube phono stages, mono records don’t sound as smeared, left-to-right. Playing back mono records with tubes can give you a misshapen center image, with the highs stretched to one channel, the mids to the other channel, and the bass back to the other channel, making them sound like they were recorded in a house of mirrors. With the Sanders, mono records were locked in the center. I recommend using the mono switch if you are using a stereo cartridge to play mono recordings. Stereo cartridges will smear mono images for a number of reasons: skating forces, unequal coil windings, cartridge misalignment, warps and off-center pressings. Also, if it’s a mono recording cut with a stereo cutter head driven by stereo electronics, the two channels will be slightly different because cutting heads aren’t perfect; the cutting electronics and tape machines aren’t perfect either. Roger should be thanked for including the mono button. Thanks Roger.
There is enough flexibility in cartridge loading and gain to make a good match for the majority of cartridges. Is it my favorite? Not quite, but it is more linear, with less noise, than my favorite phono stages. This comes down to personal preference because LP playback will never be as “perfect” as playing back a CD. There are too many variables with vinyl play that can affect the sound. The added noise and distortion of my favorite tube LCR phono stages might be covering up mastering deficiencies, cartridge mistracking and/or misadjustment, along with the possibility of complex interactions of cartridge, tonearm, tonearm cable and phono loading which serves to “enhance” the music.
Compared to my favorite LCR phono stages, the Sanders didn’t have as much image depth (see my caveat below), and large scale dynamics seemed to be slightly suppressed. There are records that sound better on the Sanders. There are records that sound better on a tube LCR. The odd thing is that there are records that sound better on the budget Rek-O-Kut Professional Moving Magnet Preamp and, on a few rare occasions, there are records that sound better on a Dynaco PAS, although the PAS is not accurate). What does it mean? Vinyl mastering and playback is as much art as science, so it cannot be “perfected.” I suppose a company could master and press the vinyl, then put together a package of cartridge, tonearm, tonearm cable, and phono preamp, comparing and tweaking things to sound as close to the master tape as possible, but I don’t know of any such setup.
