ISLETA • Battery Powered Mic Preamp
Scheduled for a September 2026 release, ISLETA is a two channel, battery power preamp for portable, off-the-grid recording. Its signal path is fully balanced from the transformer-less inputs to the massive, transformer-coupled Main Outputs. Complimenting these is an unbalanced Stereo Auxiliary Output on a 1/4" TRS jack. All outputs are separately buffered and work simultaneously. For example, the Main Outputs could feed a dedicated pro-audio rig while the Aux Output feeds a video camera.
Standard features include switchable Hi/Low Input Impedance, High Pass Filters and Phantom Power. The Precision Rotary Gain controls range from +7.5dB to +65dB in 2.5dB steps. Every channel is matched within ±0.1dB. The Stereo Aux Out has a -12dB switch for interfacing to -10dBv "prosumer" level devices.
ISLETA is designed to be powered by rechargeable LiPo batteries. These batteries (available world-wide) provide flexibility, high current, and long operational life per charge. For example, 1300mAh batteries could power ISLETA and a pair of Schoeps microphones for 20 hours. With passive ribbon or dynamic mics the duration could be up to 30 hours. Most portable preamps use hashy switching circuits to synthesize the elevated voltages required for microphone & preamp operation. Not ISLETA. Pueblo Audio's design sources pure DC power directly from the batteries, natively.
Capture engaging, sumptuous sonics anywhere you wish without concern of running out of juice. That's freedom.
Standard features include switchable Hi/Low Input Impedance, High Pass Filters and Phantom Power. The Precision Rotary Gain controls range from +7.5dB to +65dB in 2.5dB steps. Every channel is matched within ±0.1dB. The Stereo Aux Out has a -12dB switch for interfacing to -10dBv "prosumer" level devices.
ISLETA is designed to be powered by rechargeable LiPo batteries. These batteries (available world-wide) provide flexibility, high current, and long operational life per charge. For example, 1300mAh batteries could power ISLETA and a pair of Schoeps microphones for 20 hours. With passive ribbon or dynamic mics the duration could be up to 30 hours. Most portable preamps use hashy switching circuits to synthesize the elevated voltages required for microphone & preamp operation. Not ISLETA. Pueblo Audio's design sources pure DC power directly from the batteries, natively.
Capture engaging, sumptuous sonics anywhere you wish without concern of running out of juice. That's freedom.
Block Diagram
Preliminary Specifications
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Input Impedance: 3kΩ / 26kΩ
HPF: -3dB @ 47Hz (min. phase) Channel Crosstalk: <-140dB [1kHz] CMRR: -128dB [60 Hz, +60dB gain] CMRR: -100dB [10kHz, +60dB gain] |
Distortion: 0.0006% [1kHz, +4dBu out]
Distortion: 0.0013% [1kHz, +24dBu out] SMPTE IMD: 0.0032% [250Hz+8kHz, 4:1] Max. Input: +22dBu [+7.5dB gain] Max. Output: +31dBu [10kΩ load, ≤ 0.0024% thd] |
Bandwidth: 1Hz to 500kHz [+0/-3dB]
Spectral Accuracy: ±0.1dB [20Hz-20kHz] Linear Phase Deviation: 0.30˚ [20Hz] EIN: -137dBv [Rs=0Ω, 20-22kHz, A-weighted] EIN: -130dBu [Rs=50Ω, 20-22kHz, unweighted] |
Price: $1990 (batteries and charger sold separately)
Dimensions: 8.7"x 8.4"x 2.1", 5lbs.
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Battery Power
ISLETA is powered by two lithium polymer (LiPo) batteries. Specifically: 22.2v, 6S LiPo Batteries with XT60 connectors in capacities up to 1300mAh. Smaller capacities (mAh) may be used but the operational life will, of course, be shorter. As long as the batteries will fit in the battery compartment, you can use which ever 6S battery is on hand. The battery compartment internal dimensions are 7.9" x 1.9" x 1.6". The batteries are easily installed/removed by hand from the battery compartment via a door with captive thumb screws. For charging, the batteries are removed and should be recharged in a fire proof area. ISLETA has a battery management system which provides LED indicators for charge level and will power down ISLETA well before the batteries drop below their minimum safe voltage.
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When battery capacity is between 40% and 100% the Green LED will be lit.
When battery capacity is between 25% and 40% both Green & Red LEDs will be lit.
There is a slow transition from green-only to red-only, helping indicate the state. When battery capacity is 25% or lower the Red LED will be lit.
This may be considered as operating in "Battery Reserves". Though there is likely a few hours of life left, it's a good time to consider recharging the batteries at the earliest convenience. No LEDs lit indicates the battery management system has powered down ISLETA to prevent the batteries from dropping below their safe minimum voltage. ISLETA must be switched off & batteries removed for safe charging.
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LiPo batteries and LiPo chargers (with balance function) can readily be purchased, world wide, from various Hobby Outlets, Amazon, etc.. There are even dual charger models available that allow recharging two batteries at the same time. Having a spare set of batteries is sensible when working in the field. Observe all safety precautions when using, charging and storing LiPo batteries.
• The Blue Star Edition •
ISLETA is also being offered in a "Blue Star" edition. In this version key components are upgraded to more exotic versions (read tangible/real benefit, not audiophile hyperbole). The stock ISLETA is like a Ferrari. Blue Star is a hot-rodded Ferrari. Stock is already amazing; hot-rodded is gilded. So it is with ISLETA. When budgets can accommodate a further $500, the additional fidelity and resolution is a joy. Stock models can be upgraded down the road, if desired.