| Stephenson Amplification
30 Watt Reverb Combo:
Features:
- Single channel preamp
- Single channel power amp
- 6SN7 tube driven reverb circuit
- Power scale master volume
- FAT control (feedback attenuation circuit)
- Ultra linear / pentode operation
- Footswitchable boost (preamp gain boost)
- 3 way bright switch (front panel)
- Gain switch (front panel)
- Cut switch (front panel)
- Power tube select switches (back panel)
- EQ bypass (back Panel)
30 Watt Combo with Reverb in Black Tolex
Specifications:
- Custom made in Canada toroidal supply transformer with dual primary (120/240 vac operation)
- Custom made in Canada output transformer
- Two 12AX7 tubes in preamp
- One 6SN7 tube in power amp section
- One 6SN7 tube in reverb section (reverb model only)
- Four tube dissimilar power amp, 2 EL84’s blended with 2 octal type tubes for 30 watts of power (peak power of 85 watts when running 6L6 tubes)
- Any of the common octals can be used in the octal tube location (6V6, 6L6, EL34, etc.)
- Heavy aluminum chassis with welded corners
Dimensions:
24 inches wide
9 inches deep
21 inches high (including feet and handle)
Weight:
50 lbs. Equipped with Eminence Tonker Lite
Front Panel
Gain Mode Switch
- Switch in the up position produces more gain and more mids from the preamp.
- Switch in the down position is cleaner tone, great when using booster pedals for the OD tone
Bright Switch (3way switch)
- Switch in up position produces the brightest tones. With the gain potentiometer set lower this position acts like a gain boost on all frequencies except the lower frequencies. This position is a great way to control the bottom tightness when the gain is dialed back.
- Middle position = Off
- Down position is a sparkle boost
Gain Potentiometer
Controls preamp gain. This control used with the bright and gain mode switches, can dial in clean and punchy to saturated distorted tones.
Treble, Bass, and Mid Potentiometers.
These are the amps EQ controls.
Reverb
The 30 watt reverb amps use a unique circuit that incorporates a 6SN7 tube
to handle the duties of producing beautiful lush 3D reverb.
Drive
The Drive works together with the power Scale control to keep the amps tone at any wattage. In other words cranked tone at any volume. When the Scale is set to maximum the power amp produces full wattage, any other Scale setting will produce less than full wattage. Scale set to minimum is the amps standby mode.
The Drive control determines the amount of saturation and compression that the power amp produces. As the amp is Scaled down the Drive should also be turned down to keep the amps natural full volume tone. A good rule of thumb is: adjust the Drive and Scale controls together. In other words: if you adjust one, then adjust the other to dial in the best tone. Of coarse there are no right or wrong settings, dial these controls in to achieve the tone your looking for.
Just keep these points in mind:
- High drive settings and low scale settings will produce a saturated/compressed tone.
- Low drive settings and high scale settings will produce the cleanest tone.
Cut Switch
The Cut switch works in conjunction with the Drive control. With the Cut ON (switch in the Up position) there are less highs and upper mids.
To keep the tone more focused and the bottom tighter, keep the Cut Off (switch in the Down position) and the Drive controlled dialed back.
FAT
Feedback Attenuation – Controls the amount of negative feedback that is employed in the power amp. Negative feedback is a common guitar amplifier method to control the tightness and gain of the power amp. Too much negative feedback can cause a thin constricted sounding amp and too little can cause a bloated sounding amp. With the Fat set to minimum a great deal of negative feedback is employed, which keeps the power amp tight with less body and gain. With the Fat set to maximum the power amp is running open loop (no negative feedback), for maximum gain, body and wattage from the power amp.
Power Scale
This is the amp’s wattage control. This technology was developed by Kevin O’Connor at London Power and is used under Licensed Agreement.
Lower settings produce less wattage, and hHigher settings produce more wattage.
Back Panel
Pentode/UltraLinear
This switch selects what mode the power tubes are running in.
Ultra Linear is a 50’s hi-fi deal that requires a custom output transformer with an extra set of taps that run the power tube screen grids at near the same potential as the plates. Ultra Linear has a smooth warm sound and the lower internal resistance of the power tube allows the Fat control to be set higher.
Pentode is the classic guitar amp method of power tube operation. Pentode produces more wattage and generally more grind. This mode prefers the Fat control be dialed back to keep the bottom tight.
Power-Amp
V1 – V4 Switches
- V1 controls the power tube socket labelled V1. This socket accepts an EL84 tube
- V2 controls the power tube socket labeled V2. This socket accepts any of the common octal tubes (6V6 etc.)
- V3 controls the power tube socket labeled V2. This socket accepts any of the common octal tubes (6V6 etc.)
- V4 controls the power tube socket labelled V1. This socket accepts an EL84 tube.
These switches are used to turn the power amp tubes on or off. Since each power tube (or Valve) has it’s own switch, any combination of settings can be used. There are many possible power tube combinations with these switches.
Here are some examples:
- Any tube can run all by itself producing a single ended low wattage amp
- Any two tubes can be run together, V1 and V2 (or V3 and V4) can be run together for a 10 watt single ended dissimilar tube amp. V1 and V3 (or V2 and V4) can be run together as a push/pull 15 watt dissimilar tube power amp.
- Any 3 tubes can be run together (this is still a 15 watt amp)
- All 4 tubes can be run together for a 30 watt amp
*Note. If all switches are Off then the amp will not produce any sound.
Output
This is the speaker output section.
The impedance selector is labelled 1- 2 -3 because any setting can be used with a 4ohm 8ohm or 16ohm speaker cabinet.
Use the setting that you like the best. When using different output tube combinations, listen to the different impedance settings to see what one you like best.
30 watt reverb tubes:
- 2 x 12AX7
- 2 x 6SN7
- 2 x EL84
- 2-octal power tubes (6V6, 6L6, EL34,etc.)
30 Watt Reverb Combo in Black
30 Watt Reverb Combo in Red
30 Watt Reverb Combo in Purple
Back view of 30 watt reverb combo, equipped with Eminence Tonker Lite
|
