The SE44 stereo single ended power amplifier utilizes four horizontal output tubes paralleled in triode mode to produce 22watts per channel in class A. The input stage for each channel utilizes an improved Mu follower design that utilizes a 6LU6 as the voltage amplifier (triode section) and ( pentode) section as the constant current source. This is a true constant current source that has more than enough gain to properly respond to the small signal / voltage changes without a resistor dropping large amounts of voltage typically in standard Mu follower designs. Additionally a driver stage has been included which is a critical factor to ensure excellent low end response and a quick rise time. The driver stage uses a 6/12SN7 of which one triode provides regulation with the other triode directly driving the output tubes in a cathode follower configuration without the need for capacitors. The only capacitors in the signal path are between the input and driver stage which are high quality polypropylene. The output stage for each channel consists of four 6GB5 or EL504/ 27GB5 horizontal sweep tubes paralleled in triode mode with class A operation. This output configuration can pass a large amount of current with harmonic distortion in dB relative fundamental of 2nd -26, 3rd -44, and 4th - 60. A separate and well regulated bias supply with external top mounted chassis adjustment is used- Please note the following comment regarding bias;

Cathode/ automatic/ self biasing amplifiers use a large resistor impedance between the cathodes of the output tubes to ground. This raises the cathodes above the ground potential in effect creating the required negative grid number one voltage on the output tubes that determines the current flow and class of operation. Amplifiers with this type of bias do not require any adjustments when output tubes are replaced and are less expensive to the manufacture as no additional negative power supply or controls are required- just a cathode resistor and by-pass capacitor. With cathode biased amplifiers the speed and rise times are much slower due to the large value cathode resistor that is in series with the audio output. Further a large value electrolytic cap in parallel with this cathode resistor has to be used for a shunt AC path ground return and impedance reduction. Electrolytic capacitors in the signal path further degrade the sound quality. Fixed negative bias supplies connect the output tube cathode to ground and have an additional negative voltage power supply. The negative voltage is adjustable and fed to the control grid of the output tube that determines the current flow and class of operation. All of my power amplifier designs use a fixed bias voltage that eliminates the cathode resistor and electrolytic by-pass cap producing an amplifier with fast rise times, superior dynamics and transparency. Bias adjustments are required whenever output tubes are replaced- I personally prefer to keep my bias controls inside the amplifier requiring the removal of the bottom cover to adjust the bias. As an option on customer demand I will make the bias adjustments accessible on the top chassis.

The output transformers are custom designed and hand wound with four primary and three secondary interleaved sections with each layer varnished prior to insulation. The power supply has over 2,000uf of capacitance by-passed with film capacitors- electrolytic capacitors are only used in the power supply and never directly in the signal path. Plate voltage is delayed 30 seconds to prevent cathode stripping. This automatic system uses a damper diode providing D.C. relay voltage through a controlled warm up. Quality Ceramic tube sockets, point to point wiring, IEC input, 5 way binding posts and NOS tubes complete the package. All tubes are NOS with 13 tube compliment of 2X6LU6, 2X12SN7, 8X6GE5 or EL504/ 27GB5- anode caps required and 1X6AX4 thermal delay tube. This unit comes with a one year warranty parts and labour except the tubes that are covered for 90 days.

Build Features:

The SE32 stereo single ended power amplifier utilizes a pair of horizontal output tubes paralleled in triode mode to produce 15 watts per channel. The input stage for each channel utilizes an improved Mu follower design that combines a 6DJ8 / 6ES8 in parallel as the voltage amplifier with a 6CL6 as the constant current source. This is a true constant current source that has more than enough gain to properly respond to the small signal / voltage changes without a resistor dropping large amounts of voltage typically in standard Mu follower designs. Additionally a driver stage has been included which is a critical factor to ensure excellent low end response and a quick rise time. The driver stage uses a 6/12SN7 of which one triode provides regulation with the other triode directly driving the output tubes in a cathode follower configuration without the need for capacitors. The only capacitors in the signal path are between the input and driver stage which are high quality polypropylene. The output stage for each channel consists of two EL504/PL504 27GB5 horizontal sweep tubes paralleled in triode mode with class A operation. This output configuration can pass a large amount of current with harmonic distortion in dB relative fundamental of 2nd -26, 3rd -44, and 4th - 60. A separate and well regulated bias supply with external top mounted chassis adjustment is used- Please note the following comment regarding bias;

Cathode/ automatic/ self biasing amplifiers use a large resistor impedance between the cathodes of the output tubes to ground. This raises the cathodes above the ground potential in effect creating the required negative grid number one voltage on the output tubes that determines the current flow and class of operation. Amplifiers with this type of bias do not require any adjustments when output tubes are replaced and are less expensive to the manufacture as no additional negative power supply or controls are required- just a cathode resistor and by-pass capacitor. With cathode biased amplifiers the speed and rise times are much slower due to the large value cathode resistor that is in series with the audio output. Further a large value electrolytic cap in parallel with this cathode resistor has to be used for a shunt AC path ground return and impedance reduction. Electrolytic capacitors in the signal path further degrade the sound quality.
Fixed negative bias supplies connect the output tube cathode to ground and have an additional negative voltage power supply. The negative voltage is adjustable and fed to the control grid of the output tube that determines the current flow and class of operation. All of my power amplifier designs use a fixed bias voltage that eliminates the cathode resistor and electrolytic by-pass cap producing an amplifier with fast rise times, superior dynamics and transparency. Bias adjustments are required whenever output tubes are replaced- I personally prefer to keep my bias controls inside the amplifier requiring the removal of the bottom cover to adjust the bias. As an option on customer demand I will make the bias adjustments accessible on the top chassis.

The output transformers are custom designed and hand wound with four primary and three secondary interleaved sections with each layer varnished prior to insulation. The power supply has over 2,000uf of capacitance by-passed with film capacitors- electrolytic capacitors are only used in the power supply and never directly in the signal path. Plate voltage is delayed 30 seconds to prevent cathode stripping. This automatic system uses a damper diode providing D.C. relay voltage through a controlled warm up. Quality Ceramic tube sockets, point to point wiring, IEC input, 5 way binding posts and NOS tubes complete the package. Tube compliment 2X 6DJ8 or 6ES8, 2X 6CL6, 2X6/12SN7, 4x EL504 / PL504 / 27GB5, 1X 6AX4

Here is a custom built line level pre-amp & headphone amplifier. This amplifier is a special proprietary designed mu-follower with a 12SN7 or 6CG7 (both sides paralleled for the lowest noise and output impedance) as the gain tube and a 27GB5 horizontal sweep tube in triode mode as the current source for each channel. This is an extremely stable natural sounding pre-amp that uses no feedback and has no electrolytic capacitors in the signal path- only in the power supply.

The high voltage power supply regulator circuit uses a horizontal sweep tube followed with an oil filled capacitor feeding a large choke coil. Secondary filtration with electrolytics by-passed with film caps. Regulated D.C. filament supplies are used for the 12SN7’s or 6CG7’s and 27GB5’s. The front panel has a four position selector switch, mute switch, volume, balance and two headphone jacks. The back panel has two sets of line out (RCA) four sets of RCA inputs, IEC connector and fuse holder Using as a headphone amplifier there is plenty of headroom with 92 volts peak to peak that will sufficiently drive any headphone from 10 – 2,000 ohm impedance. As a line pre-amp you have 17dB of gain without feedback.

To sum up, this preamp uses no feedback, no transistors; no electrolytic capacitors in the signal path, horizontal sweep tube and choke loaded rectification with D.C. filament supplies. This unit can serve as a high end purity line stage and also a superb headphone amplifier. This unit comes with all new or NOS tubes- 2x 12SN7 or 2x 6CG7, 2x 27GB5 and a 12BQ6 regulator tube, detachable power cord and instructions. One year warranty parts and labor except the tubes that are covered for 90 days.

• Headphone / line front panel selector switch
• Additional inputs / outputs

Here is a custom built state of the art pre-amplifier amplifier that provides the finest sound reproduction with no feedback and an all tube regulation stage with error correction in a separate power supply. The line stage is a modified mu-follower design with a 6CG7 (both sides paralleled for the lowest noise and output impedance) as the gain tube and a 6FQ7 both sides paralleled as the current source in each channel. This is an extremely stable natural sounding line stage that uses no feedback and no electrolytic capacitors in the signal path- only in the power supply. Regulated D.C. filament supply’s for both channels.

The front panel selector switch selects four inputs, with a front panel mute switch (relay operated) that mutes the output and front panel volume and balance controls. There is plenty of headroom with 92 volts peak to peak so a headphone jack is also included. The phono section contains four tubes ( 2X 6DJ8, 2X 12AT7 ) and is one of the finest examples of transparency and accuracy. To sum up this preamp uses no feedback, no transistors, and no electrolytic capacitors in the signal path, vacuum tube regulation with a D.C. filament supply for each channel with a low output impedance output of less than 140 ohms. This unit comes with a detachable power cord and all NOS tubes- 2x 6CG7, 2x6FQ7, 2x6DJ8, 2x 12AT7, 1X6BQ6 and 1X6AX4

The PP150S stereo power amplifier utilizes horizontal output tubes to produce 75 watts per channel. 6EM7 dual triodes are used for the input, phase slitter and driver stages and EL504 / 40KG6 horizontal tubes for the output stage. Bias is derived from a separate source and is well regulated with external top mounted adjustments- please note the following comment regarding bias; Cathode/ automatic/ self biasing amplifiers use a large resistor impedance between the cathodes of the output tubes to ground. This raises the cathodes above the ground potential in effect creating the required negative grid number one voltage on the output tubes that determines the current flow and class of operation. Amplifiers with this type of bias do not require any adjustments when output tubes are replaced and are less expensive to the manufacture as no additional negative power supply or controls are required- just a cathode resistor and by-pass capacitor. With cathode biased amplifiers the speed and rise times are much slower due to the large value cathode resistor that is in series with the audio output. Further a large value electrolytic cap in parallel with this cathode resistor has to be used for a shunt AC path ground return and impedance reduction. Electrolytic capacitors in the signal path further degrade the sound quality. Fixed negative bias supplies connect the output tube cathode to ground and have an additional negative voltage power supply. The negative voltage is adjustable and fed to the control grid of the output tube that determines the current flow and class of operation. All of my power amplifier designs use a fixed bias voltage that eliminates the cathode resistor and electrolytic by-pass cap producing an amplifier with fast rise times, superior dynamics and transparency. The 6EA7 as a dissimilar dual triode with one section like the 6SN7 but with 10 watt plate dissipation and the other similar to theECC83. In each channel the two 6EA7 sections do the first stage gain and phase splitting while the second 10 watt sections accomplish the drive for each output tube. Bias voltage is from a separate supply and well regulated.

The output transformers are custom wound M6 core that have 4 primary and 3 secondary sections with each layer dipped in varnish prior to insulation. Plate voltage is delayed 30 seconds to prevent cathode stripping. This high voltage delay is accomplished with a damper diode rectifying the relay coil voltage through a controlled warm up. The separate power supply uses a massive power transformer system. High speed diodes, regulation and 2x 15,000uf of capacitance paralleled with film capacitors are used in the power supply. Electrolytic capacitors are only used in the power supply and power distribution networks. Distortion and speed are greatly improved with the addition of a drive stage between the front end 1st gain / phase splitter and output stage. The end result is an extremely stable high wattage power amplifier that has a flat frequency response; low distortion and output stage/transformer overshoot of less than 1%. This amplifier comes complete with a detachable power cord, IEC input, ceramic tube sockets, NOS tubes, instruction manual with bias instructions. Tube compliment 4x 6EA7 / 6EM7, 4x PL519 /EL509/ 40KG6 and 6AX4 used as the thermal delay. This unit comes with a one year warranty parts and labour except the tubes that are covered for 90 days.

This model has a stereo volume control added to the front panel with back panel selectable direct inputs, volume inputs and outputs. The PPV150S stereo power amplifier utilizes horizontal output tubes to produce 75 watts per channel. 6EM7 dual triodes are used for the input, phase slitter and driver stages and EL504 / 40KG6 horizontal tubes for the output stage. Bias is derived from a separate source and is well regulated with external top mounted adjustments- please note the following comment regarding bias; Cathode/ automatic/ self biasing amplifiers use a large resistor impedance between the cathodes of the output tubes to ground. This raises the cathodes above the ground potential in effect creating the required negative grid number one voltage on the output tubes that determines the current flow and class of operation. Amplifiers with this type of bias do not require any adjustments when output tubes are replaced and are less expensive to the manufacture as no additional negative power supply or controls are required- just a cathode resistor and by-pass capacitor. With cathode biased amplifiers the speed and rise times are much slower due to the large value cathode resistor that is in series with the audio output. Further a large value electrolytic cap in parallel with this cathode resistor has to be used for a shunt AC path ground return and impedance reduction. Electrolytic capacitors in the signal path further degrade the sound quality. Fixed negative bias supplies connect the output tube cathode to ground and have an additional negative voltage power supply. The negative voltage is adjustable and fed to the control grid of the output tube that determines the current flow and class of operation. All of my power amplifier designs use a fixed bias voltage that eliminates the cathode resistor and electrolytic by-pass cap producing an amplifier with fast rise times, superior dynamics and transparency. The 6EA7 as a dissimilar dual triode with one section like the 6SN7 but with 10 watt plate dissipation and the other similar to the ECC83 In each channel the two 6EA7 sections do the first stage gain and phase splitting while the second 10 watt sections accomplish the drive for each output tube. Bias voltage is from a separate supply and well regulated. The output transformers are custom wound M6 core that have 4 primary and 3 secondary sections with each layer dipped in varnish prior to insulation.

Plate voltage is delayed 30 seconds to prevent cathode stripping. This high voltage delay is accomplished with a damper diode rectifying the relay coil voltage through a controlled warm up. The separate power supply uses a massive power transformer system. High speed diodes, regulation and 2x 15,000uf capacitance paralleled with film capacitors are used in the power supply.

Electrolytic capacitors are only used in the power supply and power distribution networks. Distortion and speed are greatly improved with the addition of a drive stage between the front end 1st gain / phase splitter and output stage. The end result is an extremely stable high wattage power amplifier that has a flat frequency response; low distortion and output stage/transformer overshoot of less than 1%. This amplifier comes complete with a detachable power cord, IEC input, ceramic tube sockets, NOS tubes, instruction manual with bias instructions. Tube compliment 4x 6EA7 / 6EM7, 4x PL519 /EL509/ 40KG6 and 6AX4 used as the thermal delay. This unit comes with a one year warranty parts and labour except the tubes that are covered for 90 days.

Build Features:

• · Point to Point wiring
• Good quality stepped volume adjustment
• No electrolytic capacitors in the signal path
• Separate regulated screen supply
• High quality film capacitors used in the signal path
• Regulated fixed bias
• Horizontal out put tubes EL509/PL519
• Amplifier dimensions: 8”H x 20”W x 12”D Power supply 7”H x 13”W X 8”D

The MB-130 mono block amplifiers share the same circuitry as my PP150 designs but are dual mono with 6 output tubes per channel producing 130 watts per amplifier. 6EM7 dual triodes are used for the input, phase slitter and driver stages and EL504/PL504 27GB5 horizontal tubes for the output stage. Bias is derived from a separate source and is well regulated with external top mounted adjustments- please note the following comment regarding bias;

Cathode/ automatic/ self biasing amplifiers use a large resistor impedance between the cathodes of the output tubes to ground. This raises the cathodes above the ground potential in effect creating the required negative grid number one voltage on the output tubes that determines the current flow and class of operation. Amplifiers with this type of bias do not require any adjustments when output tubes are replaced and are less expensive to the manufacture as no additional negative power supply or controls are required- just a cathode resistor and by-pass capacitor. With cathode biased amplifiers the speed and rise times are much slower due to the large value cathode resistor that is in series with the audio output. Further a large value electrolytic cap in parallel with this cathode resistor has to be used for a shunt AC path ground return and impedance reduction. Electrolytic capacitors in the signal path further degrade the sound quality.

Fixed negative bias supplies connect the output tube cathode to ground and have an additional negative voltage power supply. The negative voltage is adjustable and fed to the control grid of the output tube that determines the current flow and class of operation. All of my power amplifier designs use a fixed bias voltage that eliminates the cathode resistor and electrolytic by-pass cap producing an amplifier with fast rise times, superior dynamics and transparency.

The 6EA7 as a dissimilar dual triode with one section like the 6SN7 but with 10 watt plate dissipation and the other similar to theECC83. In each channel the two 6EA7 sections do the first stage gain and phase splitting while the second 10 watt sections accomplish the drive for each output tube. Bias voltage is from a separate supply and well regulated. The output transformers are custom wound M6 core that have 4 primary and 3 secondary sections with each layer dipped in varnish prior to insulation. Plate voltage is delayed 30 seconds to prevent cathode stripping. This high voltage delay is accomplished with a damper diode rectifying the relay coil voltage through a controlled warm up. The separate power supply uses a massive power transformer system. High speed diodes, regulation and 2 x 15,000uf capacitance paralleled with film capacitors are used in the power supply. Electrolytic capacitors are only used in the power supply and power distribution networks. Distortion and speed are greatly improved with the addition of a drive stage between the front end 1st gain / phase splitter and output stage. The end result is an extremely stable high wattage power amplifier that has a flat frequency response; low distortion and output stage/transformer overshoot of less than 1%. Each mono block power supply comes complete with a detachable power cord and an IEC input. Ceramic tube sockets, NOS tubes, instruction manual with bias instructions. Tube compliment for each mono block 2x 6EA7 / 6EM7, 6x EL504/PL504 27GB5 and 6AX4 used as the thermal delay. This unit comes with a one year warranty parts and labour except the tubes that are covered for 90 days.

Here is the ultimate expression in electrostatic tube amplification. The inputs from your source are routed through the volume / balance controls and into the first dual triode paralleled amplification stage followed by two 6CG7 dual triodes and into 4 x 6EM7 tubes that are a double triode with one section rated at 10 watts (x4 for the differential output) and the second section similar to an ECC82. The power supply uses high speed fast recovery diodes with choke loaded HV rails utilizing film by pass caps on the power supply electrolytes with all D.C. filament supplies. Only HQ film caps are used in the signal path. The front panel has two Stax outputs, one for high bias and one for low bias that will work with virtually all Stax products – high bias, low bias and electret. Tube compliment is 2x ECC82, 2x 6CG7, 4x 6EA7. All tubes are NOS with 10 hours burn in.

The EA-4 has one set of RCA inputs with the addition of XLR inputs that are volume controlled. Customer choice of separate stepped volume controls or a stereo stepped volume with a balance control. These two inputs are controlled by a front panel switch that controls an input relay. The power supply uses high speed fast recovery diodes with choke loaded HV rails utilizing film by pass caps on the power supply electrolytes. Only HQ film caps are used in the signal path. The filament supplies are all D.C. The differential output is accomplished using 6EA7 tubes that are a double triode with one section rated at 10 watts (x4 for the differential output) and the second section similar to a ECC83 but with a much linear gain. The front panel has two Stax outputs that will work with virtually all Stax products - high bias, low bias and electret plus the addition of a Sennheiser HE-90 jack. Tube compliment is 2x ECC82, 2x 6CG7, 4x 6EA7. All tubes are NOS with 10 hours burn in.