The Broughton Audio Super Stack is a tube boost pedal with a Fender tone stack EQ. Its EQ section is an exact recreation of the Fender tone stack with Mids, the familiar three-band passive network used in classic Fender amplifiers, and Broughton Audio states that the circuit is also the same as the Alembic F-2B, the rack preamp that brought that Fender front end to studio and stage players1. Where most boost pedals are clean solid-state volume lifts, the Super Stack puts a real 12AX7 tube in the path and lets you shape the result with genuine Fender bass, middle and treble controls.
The tube is a new production JJ 12AX7, powered by an internal high voltage charge pump. Broughton Audio says this gives the same gain and response as that found in many classic amps, meaning the tube runs at proper amplifier voltages rather than the low, starved voltages of some tube pedals1. The pedal is a small batch item, limited in production2.
The Fender tone stack and where it came from
The tone stack at the heart of the Super Stack is the passive three-band network used in classic Fender amplifiers, here with a Mids control, which Broughton Audio describes as an exact recreation1. Because it is the same circuit as the Alembic F-2B, the pedal traces its lineage to a well-known approach: taking the preamp and EQ of a Fender amp and packaging it as a standalone unit for bass and guitar players1.
The Fender tone stack has a long history in outboard gear. The Tubeworks Real Tube 903, a tube preamp documented by the Guitar FX Layouts site, shipped with modded tone stack layouts, and its Layout 1 was the Fender variant3. That lineage is worth knowing as a player: the Super Stack's EQ behaves like an amp's EQ, not like the active EQ on a graphic or parametric pedal. The bands interact, and the classic Fender stack has a scooped-mid character at its center positions, which is part of the sound players associate with those amplifiers.
Controls and switching
The Super Stack carries the Fender-style three-band EQ with Mids, plus a true bypass switch1. The true bypass means that when the pedal is off, the signal passes around the tube and tone stack entirely, so the Super Stack can sit on a board and be brought in only when you want its tube character and amp-style EQ shaping.
Power requirements
Power is the one place this pedal asks more of your board than a standard 9V pedal. The requirements, per the maker1:
- The supply must be regulated, and capable of providing at least 300 mA1
- 2.1mm barrel with center negative polarity1
That current demand rules out a standard 9V battery-style supply and makes a daisy chain a poor choice. Broughton Audio lists specific recommended supplies2:
- Dunlop Iso-Brick
- Voodoo Lab Iso-5
- Voodoo Lab Mondo
- Voodoo Lab 4x4
- Voodoo Lab Digital
- Strymon Zuma
- Decibel Eleven Hot Stone Deluxe
- Decibel Eleven SMD
The maker's own product pages give two different figures for the minimum current: at least 300 mA on one page and at least 250 mA on another. Either way, the supply must be regulated, and isolated units from the recommended list are the safe choice.
The Super Stack DI
Broughton Audio also makes a Super Stack DI, and the two share a name but not a format. The Super Stack DI is a tube preamp for musical instruments, based on classic Fender amplifiers that include a three-band tone control, and Broughton Audio describes it as an exact recreation of the preamp section, using the popular passive tone stack found in vintage Fender amps4. Where the Super Stack is a 12V DC pedal, the DI is a mains-powered preamp, not a pedal-sized unit, and it carries upgraded features found in the P1551.
Key differences between the two145:
| Super Stack | Super Stack DI | |
|---|---|---|
| Format | Pedal, 4.77" long1 | Mains-powered preamp, not pedal-sized |
| Power | 12V DC (9V possible), center negative1 | 115VAC model for North America or 230VAC model for Europe, chosen at ordering |
| Outputs | Pedal output | Transformer-coupled balanced XLR plus unbalanced mono 1/4" line output, both usable simultaneously |
| Jacks | Standard | Neutrik audio jacks |
| Extras | True bypass1 | Thru jack to feed a tuner or bass amp; input muted when neither jack is used |
The DI's input is designed for mono instrument level signals via a 1/4" jack, with a Thru jack to feed another device such as a tuner or bass amp, and the input is muted when neither jack is used4. It comes with a power cable for North American orders only4. B-stock units have been offered, described as having a small indent on one edge on the back, touched up with paint and only noticeable up close5.
Warranty, returns and ordering
Broughton Audio covers the Super Stack for one year to the original owner, with warranty repairs handled by emailing sales@broughtonaudio.com1. Returns must be initiated by email within 7 days of receiving the product; the buyer pays return shipping, and a refund is issued minus shipping cost when the pedal is received back in new condition1. The maker ships internationally via Canada Post, with shipping cost shown at check-out2. The Super Stack is a small batch pedal, limited in production, and is priced at US$275.001.
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Questions
Does the Broughton Super Stack use a real tube?
Yes. Broughton Audio fits a new production JJ 12AX7 tube and powers it with an internal high voltage charge pump, which the maker says gives the same gain and response as found in many classic amps. The tube runs at real amplifier voltages rather than the low voltage starved designs found in some tube pedals.
Is the Broughton Super Stack true bypass?
Yes. Broughton Audio states that the Super Stack has a true bypass switch, so when the pedal is off your signal passes through without the circuit, EQ or tube in the path. This suits players who want the boost engaged only at certain moments.
What power supplies does Broughton Audio recommend for the Super Stack?
The pedal requires a 12V DC supply for maximum performance, using a 2.1mm barrel with center negative polarity. It can run on 9V with reduced gain and headroom, but nothing above 12V or below 9V. Recommended supplies include the Voodoo Lab Iso-5, Mondo, 4x4 and Digital, the Strymon Zuma, the Dunlop Iso-Brick and two Decibel Eleven units.
What is the difference between the Super Stack and the Super Stack DI?
The Super Stack is a 12V DC powered boost pedal in a 125B enclosure. The Super Stack DI is a mains-powered tube preamp with a transformer-coupled balanced XLR output plus an unbalanced 1/4 inch line output, Neutrik jacks, and upgraded features shared with the P15. The DI is a rack-style unit rather than a pedalboard pedal.
What warranty does the Broughton Super Stack have?
Broughton Audio covers the Super Stack for one year to the original owner, with warranty repairs handled by emailing sales@broughtonaudio.com. Returns must be initiated by email within 7 days of receiving the product, with the buyer paying return shipping and the refund issued minus shipping cost when the pedal arrives back in new condition.
Sources (5)
- Super Stack, Broughton Audio
- Super Stack, Broughton Audio
- Guitar FX Layouts: Tubeworks Real Tube 903 Modded Tone Stacks, Guitar FX Layouts (tagboardeffects.blogspot.com), 2017-06-18
- Super Stack DI, Broughton Audio
- Super Stack DI (B-stock), Broughton Audio
