What is the Difference between the old Innersound ESL amp and the new Sanders ESL amp?

  • The chassis is now aluminum.
  • All chassis parts are thicker to eliminate resonances.
  • XLR connectors are genuine Neutrik. They use professional metal sockets with locking devices.
  • RCA connectors are Cardas with Rhodium plating.
  • The power transformer is larger and more powerful. This has increased the amplifier's power from 300 watts to 360 watts/channel.
  • The power transformer is now fully shielded in an aluminum cylinder and potted in epoxy.
  • A new power supply circuit board is more compact and all wire has been eliminated (except for a 2" piece connecting the circuit board to the speaker binding post).
  • The amplifier is now completely modular in construction.

  • The face plate is "cleaner" and less cluttered.

  • The low-level, input amplifier circuitry has been redesigned to use the latest and best transistors.

  • The bias circuitry has been upgraded to provide more stable operation.

  • More powerful and linear output transistors are used to handle even more power and reduce distortion.
  • The new circuitry and transistors allow the use of less bias so that the amplifier runs even cooler than the original amp.
  • The speaker binding posts are placed at 45 degrees for ease of routing stiff speaker cables.



I believe that most high-end, audio products are priced at unconscionably high levels. Not only is this unfair to consumers, it is damaging the reputation of the entire industry.

Examples of this include tiny amplifiers selling for prices in excess of $20,000 and speaker cables selling for thousands of dollars. There is no way that the parts, performance, or design costs of these amplifiers or cables justify such prices.  This is particularly true in the case of small amplifiers, because they cannot drive loudspeakers in a typical home environment to realistic levels without clipping.

I believe in designing and selling products of real value for a reasonable price. We design, manufacture, and sell electrostatic speakers, amplifiers, preamplifiers, speaker cables and interconnects.

Great listening,

Price List

Electrostatic Speakers Model 10c $14,000
  Model 10d $15,000
  Model 11 $12.000
Amplifiers ESL Stereo $  4,500
  ESL Mono $ 9,000 pair
  Magtech Stereo $  5,500
  Magtech Mono $  11,000 pair
Preamplifier Combined Line Stage & Phono $  4,500
EROS Upgrade Kit Innersound EROS Panel and Crossover upgrade kit $  3,000




Service and Support

Sanders Sound Systems offers world class support to its customers. This support includes repairs, upgrades and service. Please feel free to contact us for troubleshooting assistance and we will work together to meet your needs.


Sanders Sound Systems Manuals 

  acrobut.gifModel 10b Speakers

acrobut.gif  Model 10c Speakers


 Model 10e Speakers

acrobut.gif  Programming Crossover for 10C Speakers

acrobut.gif  ESL Mark II Amplifier

acrobut.gif  Preamplifier


Sanders Sound Systems Videos

  LMS Recommended Adjustments (click image to view video)












LMS Essential Adjustments (click image to view video)












Assembling 10e Speaker System (click image to view video)10e assembly













 Sanders Sound Systems Legacy Products Manuals

acrobut.gif Phono Preamplifier

acrobut.gif Line Stage Preamplifer



Sanders electronics are warranted to be free from defects in material and workmanship for as long as the original purchaser owns them.

The warranty applies only to the original owner. It is non-transferable.

During this period, Sanders will, at its option and without charges, either repair any part or assembly of parts that is found defective in material or workmanship or replace the product with one of comparable quality, subject to the following limitations and exclusions:

This warranty shall not apply to any product which has been subject to misuse, abuse, modification, negligence, or accident.To obtain warranty service, the owner need only contact the factory using the information below. The owner is responsible for paying shipping costs to return the faulty component to the Sanders factory.

Sanders Sound Systems
12054 Deer Trail Road
Conifer, CO 80433
Phone: (303) 838-83=130
Email: This email address is being protected from spambots. You need JavaScript enabled to view it. or This email address is being protected from spambots. You need JavaScript enabled to view it.

Innersound Legacy Products Supported


  • Eros Mk1, Mk2, Mk3 Hybrid Electrostatic Loudspeakers and related crossover amplifier

  • Isis Mk1, Mk2


  • Electrostatic Loudspeaker Amplifier

  • Monoblock Electrostatic Loudspeaker Amplifier

  • Kilowatt Monoblock Amplifier

  • Home Theater Amplifier

Pre Amplifiers

  • Remote Control Preamplifier

  • Phono Preamplifier

Innersound Legacy Products Manuals




Conventional amplifiers have serious problems when forced to drive electrostatic loudspeakers. Roger Sanders has developed the first amplifier specifically designed to drive these unusual speakers.
•    .
Conventional amplifiers have serious problems when forced to drive electrostatic loudspeakers. Roger Sanders has developed the first amplifier specifically designed to drive these unusual speakers.
Electrostatic loudspeakers (ESLs) are very different from conventional magnetic speakers and place unusual and difficult demands on the way amplifiers deliver power to them.
A magnetic speaker presents a resistive/inductive load to an amplifier, while an ESL appears mostly as a capacitor.
We have developed both the ESL amplifier and the Magtech amplifier to meet these demands. Our pre-amplifier has been designed to match the faceplates of our amplifiers.  

silvercombo Amplifier and Preamplifier in Silver





Sanders Sound Systems Amplifier and Preamplifier - Black

 Both the ESL and Magtech amps use the same special amplifier modules that Roger designed to drive electrostatic speakers.  The difference between the two is that ESL amps use a conventional, free-floating, unregulated power supply while Magtech amps use Roger's unique, 100% efficient, linear, regulated power supply.  
Magnetic speakers draw tremendous current from an amplifier and that causes the internal power supply voltages to fluctuate dramatically in response to the music (typically by about 30%).  This reduces the power from the amp and causes the distortion and bias to be modulated by the music.
A regulated power supply maintains stable internal voltages at all times.  This is a tremendous improvement over a free-floating power supply.  All amplifiers should use regulators, but virtually none do because their designers have not figured out how to make a powerful regulator that doesn't waste vast amounts of heat.  Our regulator is unique in that it runs cold and wastes no heat.  So we offer virtually the only regulated power supply amplifier on today's market.
Electrostatic speakers operate on voltage, not current.  So they don't cause major fluctuations in the internal voltages like magnetic speakers do.  But they will still cause some voltage modulation and mains voltage is not stable either.  So even electrostatic speakers will benefit from an amplifier with a regulated power supply.

A regulated power supply will provide the best performance, so most of our customers (even our electrostatic speaker customers) opt for the Magtech. We  keep the ESL amp in our line-up because it costs less than a Magtech and so represents a tremendous value.  So those customers for whom money is a major concern, use the ESL amp instead of the Magtech.
In summary, the Magtech amp is the best for all speakers because it not only has the electrostatic amplifier modules, but it also includes a regulated power supply.  So unless money is a major concern where the value of the ESL amp is essential, Roger recommends the Magtech.






Price: $4,500

The preamplifier is the control center of your system. This preamplifier is designed to provide the finest and most transparent acoustic performance available while increasing the value to our customers. Specifically, the new Sanders Preamplifier combines the performance and features of our previous Line Stage and Phono preamps into one.



  Click to enlarge

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.

Additionally, more modern circuit design technology has reduced distortion and noise figures from those in the earlier preamps.  The styling has been redesigned to better match our amplifiers.  A video processor pass through also is included in the new preamp.  All the previous ergonomic and performance features of the earlier preamps have been retained.

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.

Controls are available both by remote control and on the front panel.  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 comparitor 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.

Most components come with a remote control transmitter that only controls that particular component.  Therefore you end up adding that remote transmitter to the pile of remotes you have for all your other electronics.

Rather than contribute to "remote clutter", the Sanders Preamp comes with a programmable remote that can be used to operate all your components.  You will then no longer have to dig through a pile of remotes every time you want to adjust something in your audio/video system.

The phono preamp offers exceptional flexibility and features, including virtually all the features of the most expensive, dedicated phono preamps.  These include switchable gain for both moving magnet and moving coil cartridges, and user-adjustable cartridge loading for both resistance and capacitance so that users can match their cartridge manufacturer's specifications for optimum performance.  The phono circuit has the benefit of extremely low distortion and an ultra-quiet noise floor.


Click to enlarge 



Sanders Sound Systems Preamplifier Back

Click to enlarge


Electrical Specifications


  • 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.


  •  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

 Frequency Response

-3 dB at 5 Hz and 200 kHz


Greater than 100 dB below 1 volt reference


Less than 0.002% from 10 Hz to 40 KHz @ 5 volts peak into  600 ohms or higher, shunted by 1,000 pF or less

Output Impedance

50 ohms, non-reactive, balanced or single-ended

Phono Input Impedance  

User adjustable between 47,000 and 100 ohms.  Default  setting is 47,000 ohms

Phono Input Capacitance  

User adjustable between 50 pf and 1,200 pF.  Default setting is 50 pF.

Input Impedance

47 kohms, balanced or single-ended 


User adjustable up to 18 dB.  Default setting is +8 dB

 Maximum Output   

 10 volts peak


Greater than 70 dB from 20 Hz to 20 KHz 

Power Supply

Independently regulated with shielded toroidal transformer and 20,000 uF of capacitance

Power Consumption

10 watts


Voltage is user selectable for use world-wide



Weight and Dimensions


Net Weight:  8 pounds (3.6 KG)
Shipping Weight:  13 pounds  (5.9 KG)



17" wide x 2.5" tall x 10.5" deep (43cm x 6.35cm x 27cm)


Speakers and Electronics are manufactured in Conifer, Colorado.

We sell Direct World-Wide  (along with select dealers) - Prices apply World-Wide - 30 Day In-Home Risk Free Trial 

We are so confident in the design and build quality of our products, that we offer a

Sanders Sound Systems Lifetime Warranty

All Rights Reserved 2018 Sanders Sound Systems