Stephenson Amplification Stage Hog (Ver 5.0) :

"A tube pedal designed for guitar players!"

The Stage Hog is a 1 watt, all-tube guitar amp that doubles as a distortion pedal and a practice amp. When used as a practice amp, the speaker out jack can be plugged into any type of guitar cabinet, even a 4x12. When used as a distortion pedal, the line out jack can be plugged into any guitar amp input. The Stage Hog’s sound is very reminiscent of a good old hot-rodded vintage tube amp. The voice switch toggles between tweed warmth and plexi crunch.

Features:

• All-tube preamp
• All-tube power amp
• High voltage power supply, so the tubes are run in their “sweet spot”
• Custom 'Made in Canada' transformers
• 120/240vac mains operation
  ***Specify at time of order so the power supply can be wired accordingly.
• Power scale master volume, allows for varying amounts of power tube saturation
• Bypass switching when used as a distortion pedal
• Remote switching pedal allows Stage Hog to be placed on the pedal board or with the guitar amplifier
• Ground switch (avoids hum associated with ground loops)
• Buffered output

Tube Amp Controls:

• Power scale
• Gain control, adjusts preamp level
• Tone control, adjust tone in preamp
• Voice switch, toggles between plexi crunch and tweed warmth
• Mid switch, boosts midrange
• Bright switch

Line out controls (for when SH is used as a pedal):

• Level control, master volume for rhythm tone
• Tone control, master tone
• Lead control, master volume for lead tone

The majority of tube distortion pedals on the market today produce preamp distortion. The Stage Hog is different because it relies on power tube saturation for its distortion. The SH has all the components that a full size guitar amp has, high voltage power supply, tube power section with output transformer, and tube preamp.

I designed the SH to be the second channel of a clean amp (such as a twin), I wanted an all out cranked tube amp sound for my gain channel (cranked plexi), and bypass the pedal for my clean sound, and I wanted to be able to have these sounds at any volume level. So this is the idea behind the SH, and since it is a regular guitar amp (just miniaturized) it will drive a speaker cabinet (great little practice amp).

The power scale feature allows control over the level of power tube saturation, the PS used in conjunction with the gain and mode switches enables tones from dark and saturated to bright and focused and everything in between.

The remote switching feature is a dual button footswitch that detaches from the Stage Hog. The remote switch comes with a 16 foot cable, so the Stage Hog can sit on the amp or can be mounted on the pedal board.

Stage Hog - Size comparison

Stage Hog Operation

• When powering up the unit: first turn the Power Scale control to minimum, then turn the power switch to ‘ON’. After about one minute slowly turn the power scale to the desired setting. This offers the ultimate in soft start (gentle warm-up).
  
  
• SCALE (Power Scale): Controls the amps wattage, as well as the level of power tube coloration (compression and saturation). Lower settings of the power scale control make the Stage Hog sound smoother and warmer. If you need the loudest clearest brightest sound, then keep the power scale set on full.
  
  
• GAIN: Control adjusts the amount of gain from the preamp
  
  
• TONE: Control is voiced to cover a wide sweep of the guitar frequency spectrum (very effective for only a single control)
  

• LINE (Controls):
  
  • Level : Master Level Control for line out signal when Stage Hog is being used as a pedal.
  • Tone: Master Tone Control.

  The Line controls have no affect on the sound when the Stage Hog is being used as a practice amp.
  

• Footswitch: Toggles between straight through signal (bypass) and stage hog signal. The red LED has to be on in order to hear the Stage Hog's sound even when the pedal is being used as a practice amp (connected to a speaker cabinet). When the Stage Hog is being used as a distortion pedal, the LED lets you know when the pedal is on and when it's bypassed.
  
  
• GND(Ground): Switch is used to eliminate ground hums. When used as a practice amp the switch may need to be adjusted one way and when used as a distortion pedal it may need to be set in the opposite way. Just put the switch in the quietest position.
  
  
• MID: Boosts Midrange Voicing.
  
  
• VOICE: switch toggles between a toggles between 'Plexi Crunch' and 'Tweed Warmth'.
  
  
• BRIGHT: Switch adds a large value cap across the gain pot. Best results are achieved when the gain control is adjusted between 12:00 and 3:00.. The bright switch adds clarity and gives the tone a ‘liquid’ feel.

Here are some tips.

• I usually keep the power scale set 1/2 way, gain 3/4's, tone 3/4's, voice switch up, boost down, and the bright up. This is a good starting point and you can tweak from there. The controls are very interactive, if you adjust one thing, try tuning the other control for best tone.
  
  
• When the Stage Hog is being used as a distortion pedal the power scale control has to be turned up high enough to produce a big enough signal to match the bypass volume. If the power scale is set low (around 2 or less), the line control won't have enough range to make the volume loud enough to match the bypassed sound. So keep the power scale over 2 when using the stage hog as a distortion pedal. When using the Stage Hog as a practice amp, you can set the power scale as low as you want (there is no bypass signal to worry about matching).
  
  
• When using the Stage Hog as a distortion pedal and plugging into a guitar amp that has a 'bright' switch, leave the bright switch off. The tone will be fiizzy and bright when the guitar amp’s volume control is adjusted to lower settings (a guitar amp’s bight switch bypasses highs when the volume is turned down).
  
  
• The Stage Hog when used as a pedal is tuned to operate with it's internal dummy load, not an actual speaker. This means that the Stage Hog doesn't sound as good if you use it as a practice amp and a distortion pedal at the same time (plugged into a speaker and also plugged into a guitar amp).

Stage Hog Top View - shown with Bypass Switch

The Stage Hog uses two dual triode tubes:

• 1- 12AX7 type
• 1- 12DW7 type

The 12AX7 is the tube on the left hand side when viewing the amp with the bottom plate removed and the powers switch pointing away from you, and the 12DW7 tube is the one on the right.

Stage Hog - Bottom View - shown with cover removed

Since the amp only has two tubes, changing either one has a major influence on the tone.

The Stage Hog is supplied with current production tubes. A Sovtec 5751 in the 12AX7 position and a JJ ECC832 in the 12DW7 position. I find these tubes to sound very refined and generally work well for all musical styles. Of course it doesn't hurt to experiment so here are some possible tube choices that can be used in the Stage Hog.

• Caution The Stage Hog has over 300vdc inside; ***This is enough voltage to kill***
  
• Do Not Remove the bottom plate unless the Stage Hog is unplugged from the wall socket and has had at least 3 minutes time for the filter caps to discharge. Once the power on the Stage Hog is switched off the filter caps automatically discharge, but it takes a few minutes.
  
• The tubes get hot so be careful.

For Some cleaner tones:

• I like to run a 12AU7 in the 12DW7 location, I find the tone to be very pleasing for low gain situations (try the boost switch for more fatness).
  
• The 5751 is a nice moderate gain candidate in the SH's 12AX7 position for some classic tones, so if you have a 5751 tube on hand, try this out.
  
• 12AU7's in both SH tube locations for the cleanest possible tones, useful for turning the SH into a clean boost pedal.

Other info:

The Power Scale circuit is a variable wattage control, not a typical master volume. The PS is a part of the amp's power supply. As the PS is dialed down the amp gets quieter because the power amp itself becomes a smaller wattage power amp. Lower wattage settings means less headroom, less headroom means more compression and distortion as the amp is pushed. I've designed the SH with no Drive Control (the Drive and Scale work together in keeping the tone uncolored at low wattage settings) so max amounts of power tube saturation are possible.

The SH has a supply transformer that is capable of running from120vac 60hz or 240 50hz. Each pedal is made to order and I wire accordingly for the correct mains voltage. At this time changing the voltage operation is not a user option.

Most of the distortion generated by the SH is from the power section, the preamp is voiced more on the bright and clean side of things and is designed to compress rather than distort, this helps maintain good touch sensitivity. The power section creates a smooth distortion that gets darker and more compressed as the Scale is turned down.

The Stage Hog is very compact (5x7x2).

The dual triode 12DW7 tube type has been selected for the Stage Hog because it uses 1/2 a 12AX7 and 1/2 a 12AU7. The 12AX7 side is used in the preamp section (to get max possible gain), and the 12AU7 section is used in the power amp section (low mu tube well suited as a single ended class A triode running into an output transformer). In a 1 watt amp the 12AU7 has the right properties to be used as a power tube, low voltage gain and high currant capability. A typical power tube does not need a high voltage gain, it does however need the ability to handle heavy currant demands.

 

Contact Info :

STEPHENSON AMPLIFICATION

Mark Stephenson
PO Box 176
Parksville, BC
CANADA
V9P 2G4

Tel: 250-954-2292
Monday to Friday 10:00 AM - 6:00 PM Pacific

stephenson@telus.net