Foundation v3 Tube Linestage 2025

The 6922 based Foundation is a single ended tube preamplifier designed around the 6922 (footnote 1) dual triode. The design goal of the Foundation preamplifier was to provide an audiophile quality at an affordable price.

Remaining amplifiers have two large vent holes on the top of the chassis with pure copper mesh for ventilation. 

The Foundation line preamplifier is designed to complement most power amplifiers available including tube or solid state design. The new capacitor selection allows you to choose the coupling capacitor size to best match your amplifier or provide a high pass filter to take the load off your power amplifier when using a powered subwoofer.

The power supply is of usual Response Audio quality. A high quality toroidal transformer feeds a solid state CLC (choke filtered) design utilizing polypropylene filter capacitors. Tube filaments are powered by a separate regulated DC supply.

The circuit is designed  in such a way as to have a maximum tube life for the 6922 tubes.

The preamplifier has more than enough output for any power amplifier, transistor or valve, and is ideal for driving long interconnect cables to remotely located power amplifiers due to its low output impedance.

Standard Chassis is black anodized aluminum 16" x 16" x 5.5" with laser engraved aluminum front panel.

All Foundation products are housed in an all aluminum chassis with aluminum front backing plate with a laser engraved acrylic front panel. The chassis itself uses extensive bracing to help eliminate any resonance from the chassis to get into the signal. We have decided to not pursue expensive, custom CNC'ed aluminum chassis for the Foundation Series to keep our pricing reasonable. Do you want to spend an extra couple of thousands of dollars for a fancy chassis only to get the same performance? 

See pricing below.

• Aluminum chassis with laser engraved acrylic front panels
• Neutrik RCA connectors
• Remote volume control w/Mute
• Tape Monitor Loop
• Capacitor selector switch
• DC Offset Protection
• Enhanced ground scheme
• Polypropylene power supply filter capacitors
•  Solid state choke filtered power supply employing a high current toroidal transformer with a separate transformer used to drive the remote volume control and input selector

• Tube Complement: (2) 6922 driver tubes
• Three sets of RCA line inputs 
• Two sets RCA main outputs - Effected by CAP mode (see below)
• One set of full range Preamp outputs. Can be used to power any other external power amp including subwoofers
• One set Tape input
• One set of Tape output
• Gain: 10dB
• Input Impedance: 100Kohms.
• Output Impedance: 
• Frequency Response: 
• Dimensions: 16Wx16Dx4.5H w/footers
• Weight: 
• Direct Selling Price: $3,995 Bronze or Dark Gray Acrylic

• Warranty: 2 years parts and labor. 90 days on tubes.

Footnote 1: The Foundation circuit is applied in a way that allows the use of the 6DJ8 tube without any abnormalities. 

 CAP - This feature allows you to choose the output coupling capacitor arrangement

• Full - This setting utilizes the single output capacitor for full range response
• High Pass - This setting utilizes a single, small value, high quality capacitor providing a high pass filter output. High pass frequency is based on the input impedance of your amplifier.
• Combine - This setting allows the full range capacitor to be fitted with the High Pass capacitor as a bypass.

TAPE - Allows the use of an EQ, Processor, Tape unit, and of course our Harmonia v3 DHT tube stage