Amp Fan

Amp Fan
$15 Kit


Click for larger photo

Build info:
Schematic

You don't need the thrust of a 747 to cool your amp. You'd be surprised at the benefit of just a little bit of airflow over your output bottles. This fan provides 12 CFM of airlflow and is two speed, switch selectable. It's quiet and has no detectable hum. It is powered from your 6.3V filament supply and requires less current on high speed than a typical 12AX7 filament. Because all amps and their topology are different, I don't have any suggestions for implementation on any particular amp other than to say it is better not to have the air flowing directly on an area of a tube. To do so could cause high thermal currents in the glass due to one area being hot and another area being cooled. So, it could cause cracking in the glass. Best thing to do is make some small metal vanes or a plenum and direct the air so it flows in a wide pattern around all of the tubes and then exits the other end of the line or quad of tubes. If you have the reserve power in your PT, it's no problem at all using two or even three fans if you are really going to pound the output circuit. This kit is supplied with the fan, the circuit board, two brass or nylon standoffs, and hardware. The electrolytics that appear to be missing on the circuit board are mounted on the back of the board so the slide switch may be mounted on a rear panel or other convenient place.

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   Bias Rite Head Kit

$16
Bias Rite Head kit.


Kit includes all parts to build one octal Bias Rite head. Measures cathode current and plate voltage.

Build info:

#1 Step By Step Instructions
by Ted Weber

#2 Diagram (PDF file)
by Rob Hull

#3 Build Photograph
by Matt W.

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TEMPORARILY OUT OF STOCK

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   Bias Monitor Cable Kit

$15
Bias Monitor Cable Kit


Got a BF amp or a clone of one? Got an amp with some extra holes in the back panel? Got a decent voltmeter? If so, no need to spend 100 bucks on a bias rite. You can install this kit and measure the idle current in the outputs. For BF amps, you install the jack provided in the hole that has the ground switch. That way, you don't have to muck up a vintage amp by drilling a hole in the chassis.

Here are instructions that may be applied to just about any amp. The cathode of most octal power tubes is on pin 8 and for most 9 pin tubes it is on pin 3. You install 1 ohm 1% resistors between the cathode of the output tubes and ground, then take a sample of the voltage across those resistors to the jack you installed. Anytime you want to check the idle current, you simply plug your voltmeter into the jack using the cable you'll build with the parts we provide in the kit.

It couldn't be simpler. The kit includes a stereo jack and plug, so you can do one, two (independently), or the two sets in a quad, and on up. In other words, both sides of a push pull. The kit includes stereo jack, stereo plug, two 1 ohm 1% 2 watt resistors, banana plugs, wire, and three conductor cable.



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TEMPORARILY OUT OF STOCK

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   Bias Meter

Bias Meter
$30


Click for larger photo

Build info:
Schematic

This kit is a combination of our PM128 LCD panel mount voltmeter and a small circuit board that attaches to the meter and contains a power supply for the meter. It also has a resistor network for monitoring the B+. This kit is a no brainer as far as installation goes, because the meter and circuit board are preassembled. All you have to do is run wires from it to certain points in the amp and it's ready to go. The small power supply runs on 120VAC, or you can remove a capacitor on the board, put a jumper in its place, and run the board from the 6.3V filament supply. The board has 1% resistors to take a sample of the high voltage (B+) and feed it to the meter. You install a 1 ohm, 1% resistor (2 supplied) between the cathode of the output tube and ground, and then run a wire from the high side of that resistor to the display board. Or, you can install a swtich to switch between multiple tubes. Additionally, there are three holes on the edge of the board to connect to a small SPDT switch so you can switch the meter between reading B+ and cathode current. It's a great way to check for tube drift or resetting the bias due to low or high line voltage. Another cool thing you can do is monitor the line voltage. If the filament winding has a grounded centertap, you can take one side, rectify it, filter it, and then divide it down with a resistor divider before feeding it into the meter. By calibrating the reading with the values of the resistor divider using a known good voltmeter, the reading should track variations in the line voltage by reading the filament voltage. I've done it, and it is surprisingly linear and proportional. This same circuitry and devices are used in our 6M45 Rack Mount kit.
Now, although I have made this kit look really easy to implement, keep in mind that, as with all of our kits, instructions are not provided. The circuit board is labeled for the inputs, and to anyone with an understanding of electronics, biasing, etc, it is rather intuitive and a snap to install. Please make sure you understand what this thing is all about before you consider buying one.

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   Bias Board

Bias Board
Dual $15   Quad $25


Click for larger photo

Build info:
Schematic
Layout

Want to match your own tubes? With this board, you can adjust the idle current in the output tubes independently. With a little more work by monitoring the control grid and plate voltages, you can match your output tubes. This board has two or four adjustable bias outputs, and may be operated from 40 to over 350 VAC. The bias supply is regulated to 62 volts.
The kit includes board and all parts, with four nylon standoffs and hardware.


Dual Bias Board
Temporarily Out Of Stock
Bias board, kit, two adjustment pots. $15
Quad Bias Board
Temporarily Out Of Stock
Bias board, kit, four adjustment pots. $25
 


   Analog Bias and High Voltage Monitor



$22
Analog Bias and High Voltage Monitor Kit

Cool looking vintage style analog meters with all the components to monitor bias in two tubes and the high voltage. The meters have backlighting that can be powered from the filament supply. Choice of 100mA or 200mA meter for the current monitor. The high voltage meter reads to 1,000 VDC.

Build info:
Suggested Implementation

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Full Scale Current Reading On Meter


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   Master Volume Control



$8
Master Volume Mod Kit

Dual 1 meg pot with knob and coupling capacitors so you can install a Master Volume control in your amp.

Suggested Implementations

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Knob

Coupling Capacitors (4 pieces)

Capacitor Type

A La Carte

No Capacitors -$2

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   Hi-Lo Power Switch



$15
Hi-Lo Power Switch

This kit allows you to go to half power in a cathode biased amp by changing the cathode resistor and ungrounding two of the output tubes. It can also be used for fixed biased amps by just ungrounding two of the output tube cathodes.

Build info:
Suggested Implementations

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Cathode Resistor

For this kit, there are two resistors in the output tubes cathode circuit. If you calculate that you need 50 ohms for 4 EL84's, for instance, you would order 50 Ohms. Then, when you flip the switch to the low power mode, it puts two 50 ohm resistors in series for 100 ohms, and also disconnects two of the cathodes.

A La Carte

No Switch -$2

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   EF86 Preamp Circuit



$45
EF86 Preamp Circuit

Includes EF86, all parts including a 12 position rotary switch and capacitors for drive selection, and a volume potentiometer. Also included in the kit is a right angle mounting plate punched for two 9 pin tubes. Allows you to install an EF86 stage with minimum intrusion in your amp.

Build info:
Suggested Implementations

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Knob

A La Carte

No Capacitors -$2
No Resistors -$2
No Tube -$10
No Knob -$1
No Drive Selection parts, just the EF86 preamp parts -$6. Includes the mounting plate and tube socket, resistors, capacitors, and EF86 (if you didn't opt out of those).

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   Cascode Preamp Circuit




$39
Cascode Preamp Circuit

Add a cascode preamp circuit for a new pallet of tones. Includes two dual triode tubes, all parts, and a right angle mounting plate punched for two 9 pin tubes so you can add more gain, a buffer, etc.

Build info:
Suggested Implementations

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Tube 1

Tube 2

A La Carte

No Tubes -$7

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   Tone Control Amplifier Circuit



$45
Tone Control Amplifier

This is an active tone control. In other words, it is a tone stack with gain. A dual triode and all other parts are included in the kit. Using an active tone stack will give you a lot more range on the bass, mids, and treble control.

Build info:
Suggested Implementations

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Tube

Knob

A La Carte

No Tube -$3
No Pots -$3
No Capacitors -$2
No Resistors -$2

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   General Purpose Gain Stage



$40
General Purpose Gain Stage

Dual triode gain stage with all the parts, including a mounting bracket for the tube. An assortment of R's and C's are provided to tweak the stage.

Build info:
Suggested Implementations

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Knob

Tube

A La Carte

No Tube -$3

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   Tube Effects Loop



$40
Tube Effects Loop Kit

Add an effects loop to your amp. Includes all the parts to implement a buffered effects loop --- tube, resistors, capacitors, tube mounting bracket, hardware, jacks. The way this circuit is configured, you can plug into the SEND jack and have a line out signal without disrupting the signal flow in the amp.

Build info:
Suggested Implementations

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Tube

Capacitor Type

A La Carte

No Tube -$3
No Capacitors -$2
No Jacks -$2

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   Balanced/Unbalanced Line Out



$30
Balanced/Unbalanced Line Out Kit

Add a balanced and/or unbalanced line out to your amp. Takes a sample of the speaker output, knocks it down, puts it into a pot and then a transformer. From there, it connects to a standard XLR connector. The input to the transformer is an unbalanced signal that may be taken to a standard 1/4" panel jack. Kit includes XLR and 1/4" jack, pot, knob, resistors, and wire.

Build info:
Suggested Implementations

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Potentiometer Value

Knob

A La Carte

No Pot or Knob -$3

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   Channel Switching Kit



$50
Channel Switching kit

Add channel switching to your amp. Includes an optoisolator board, a tube, the mounting bracket for the tube, the footswitch, and all necessary parts.

Build info:
Suggested Implementations

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Tube

A La Carte

No Tube -$3
No Footswitch -$10
Temporarily Out Of Stock

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   Push Pull Raw Control



$5
Push Pull Raw Control

Better known as a tone stack bypass control, this allows you to lift the tone stack to effectively reduce its effect on the tone. This gives you more of a raw, un-eq'd tone. The kit includes the pot with a push-pull switch, and a knob. We show just one way to implement a raw control. Experimenting with other methods is encouraged.

Build info:
Suggested Implementations

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Knob

A La Carte

No Knob -$1
No Pot -$2

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  Pedal Pump™ Effects Power Supply



$30
Pedal Pump™  Effects Power Supply Kit

Variable 6VDC to 12VDC, with a 9VAC@2A output included. If you use our transformer, you are limited to about 300mA per board. However, if you heatsink the regulator adequately, the board will handle up to 1 Amp. The boards for the variable supply are breakaway type boards, so you can have as many as you want on the same main circuit board. If that makes any sense..? Each board has the regulator, rectifier, filters, adjustment pot, and output jack. Of course, you can use different pots and jacks and remote them to a control panel, etc. The kit is supplied with 4 regulator boards and the power transformer. The power transformer is our WPDLXFMR-2, which has 8 isolated outputs, each good for 300mA, and one 9VAC output good for 2A. The input is 125, 220, and 240. Incidentally, since all of these boards are isolated, you can electrically stack them for higher voltages. For instance, if you need 36 volts at 300mA, you got it. The board requires assembly.

Build info:
Suggested Implementations

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How Many Regulator/Power Supply Boards?

A La Carte

No Transformer -$15

Temporarily Out Of Stock

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   Solid State Rectifier Module



$10
Solid State Rectifier Module Kit

Build your own nice looking solid state rectifier. Includes octal plug, four 3 amp, 1000 volt diodes, and a copper cover.

Build info:
Suggested Implementations

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   Solid State Rectifier Module (tall)



$15
Solid State Rectifier Module Kit (tall)

Same as our Solid State Rectifier Module Kit above, but has a 2-3/4" tall copper cover so you can stuff it with power resistors or other secret recipe parts to emulate a tube rectifier. Includes octal plug, four 3 amp, 1000 volt diodes, and a tall copper cover.

Build info:
Suggested Implementations

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   Solid State Rectifier Module (7 and 9 Pin)



$15
Solid State Rectifier Module Kit (7 and 9 pin)

Same as our Solid State Rectifier Module Kit above, but has a 9 pin plug with 2-1/4" tall copper cover, so you can stuff it with power resistors or other secret recipe parts to emulate a tube rectifier. Includes 7 and 9 pin tube base circuit board, 9 gold plated pins, four 1 amp, 1000 volt diodes, and the copper cover. The tube base board looks a little screwy at first, but after you stare at it for awhile, you'll see the 7 and 9 pin tube base layouts. They are laid out 180 from each other for convenience. The easiest way to stuff the board with the pins is to load the pins into a socket, then set the board over the pins, wiggling it until all the pins find their holes. Then, you solder the pin tops in place. You can use thick gel super glue to hold the board in place in the end of the copper cover. I like to push the board inside the tube about 1/32", then you have a ridge to apply a nice bead of glue to. It will find its way past the edge of the board and attach really well to the inside wall of the copper cover. If you want to put a power resistor in series with the diodes, you can get up to about a 10 watt round metal film resistor it that size cover.

Build info:
Suggested Implementations

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