{"product_id":"ram-labs-low-noise-tested-ge-5751","title":"RAM Labs Low Noise GE 5751","description":"\u003ch1\u003eRAM Labs Low Noise GE 5751\u003c\/h1\u003e\n\u003ch3\u003eComputer-graded to within 4 dB of the tube’s theoretical noise limit for quiet performance in high-quality line stages. A buy-out from the legendary RAM Labs\u003c\/h3\u003e\n\u003cp\u003eThe GE 5751 is a nine-pin, high-mu dual triode developed for dependable voltage-amplifier service. Each triode section has its own cathode connection, while the center-tapped heater allows operation from either a 6.3 V or 12.6 V supply. GE’s original design emphasizes sturdy, vibration-resistant construction and reliable operation under demanding conditions.\u003c\/p\u003e\n\u003cp\u003eWith a nominal amplification factor of 70, the 5751 provides less gain than a 12AX7, which is typically rated at 100. It shares the familiar 12AX7-family pin configuration but has different electrical characteristics. In equipment designed or approved for it, the 5751 can reduce overall stage gain while retaining the high-mu dual-triode architecture used in many preamplifier circuits.\u003c\/p\u003e\n\u003cp\u003eCompatibility should always be confirmed with the equipment manufacturer. A 5751 should not be treated as a universal replacement for every 12AX7 application.\u003c\/p\u003e\n\u003ch4\u003eRAM Labs Low Noise Selection\u003c\/h4\u003e\n\u003cp\u003eRAM Labs’ Low Noise grade is selected to measure within 4 dB of the theoretical noise limit for the tube. RAM identifies this grade as particularly suitable for high-quality line stages and other applications in which low noise is important but the exceptionally stringent selection required for a high-gain phonostage may not be necessary.\u003c\/p\u003e\n\u003cp\u003eEvery dual triode is tested and graded using RAM Labs’ proprietary computer-based system. Measurements are taken separately for both sections, with the results recorded on the tube box. These include noise voltage over a bandwidth of 400 Hz to 20 kHz, RAM Labs’ proprietary RAM Factor, susceptibility to microphonics, AC gain at 1 kHz, and a DC plate value used to identify operating variations.\u003c\/p\u003e\n\u003cp\u003eThe published distinction between the Low Noise and Super Low Noise versions is the measured noise threshold. The underlying tube type remains the same, but the Super Low Noise grade must meet a substantially tighter selection standard.\u003c\/p\u003e\n\u003ch4\u003eAbout RAM Labs\u003c\/h4\u003e\n\u003cp\u003eRoger A. Modjeski founded RAM Labs in 1981 after working as a design consultant and chief engineer for Harold Beveridge Inc. Modjeski was known both for his Music Reference amplifiers and preamplifiers and for his extensive research into the measurement, selection, and application of vacuum tubes.\u003c\/p\u003e\n\u003cp\u003eAt RAM Labs, Modjeski developed a computer-based signal-tube tester using proprietary software originally written for an Apple II computer. He later expanded the system to test power tubes, establishing methods for evaluating both bias and transconductance under relevant operating conditions. RAM Tubes continues to use his research and testing principles following his death in 2019.\u003c\/p\u003e\n\u003ch3\u003eFeatures\u003c\/h3\u003e\n\u003cul\u003e\n\u003cli\u003eVintage GE-manufactured 5751 dual triode\u003c\/li\u003e\n\u003cli\u003eRAM Labs Low Noise grade\u003c\/li\u003e\n\u003cli\u003eSelected to within 4 dB of the theoretical noise limit\u003c\/li\u003e\n\u003cli\u003eRecommended for high-quality line stages and other noise-sensitive applications\u003c\/li\u003e\n\u003cli\u003eComputer tested for noise, microphonics, gain, and operating variation\u003c\/li\u003e\n\u003cli\u003eSeparate test data recorded for both triode sections\u003c\/li\u003e\n\u003cli\u003eLower nominal gain than a 12AX7\u003c\/li\u003e\n\u003cli\u003eCenter-tapped heater for 6.3 V or 12.6 V operation\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch3\u003eSpecifications\u003c\/h3\u003e\n\u003cp\u003e\u003cb\u003eManufacturer:\u003c\/b\u003e General Electric\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eTube Type:\u003c\/b\u003e 5751\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eConstruction:\u003c\/b\u003e High-mu dual triode with separate cathode connections\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eBase:\u003c\/b\u003e 9-pin miniature\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eMounting Position:\u003c\/b\u003e Any\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eNoise Grade:\u003c\/b\u003e Low Noise (LN)\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003ePublished Noise Selection:\u003c\/b\u003e Within 4 dB of the theoretical noise limit\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eMeasured Parameters:\u003c\/b\u003e Noise voltage, RAM Factor, microphonics, AC gain, and DC plate value for each triode section\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eNoise Measurement Bandwidth:\u003c\/b\u003e 400 Hz–20 kHz\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eHeater Voltage:\u003c\/b\u003e 6.3 V parallel or 12.6 V series\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eHeater Current:\u003c\/b\u003e 350 mA parallel or 175 mA series\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eNominal Amplification Factor:\u003c\/b\u003e 70\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003ePlate Resistance:\u003c\/b\u003e 58,000 ohms\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eTransconductance:\u003c\/b\u003e 1,200 micromhos (1.2 mA\/V)\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eMaximum Plate Voltage (Design Center):\u003c\/b\u003e 300 V\u003c\/p\u003e\n\u003cp\u003e\u003cb\u003eMaximum Plate Dissipation (Each Section, Design Center):\u003c\/b\u003e 1 W\u003c\/p\u003e\n\u003cp\u003e \u003c\/p\u003e","brand":"RAM","offers":[{"title":"Platinum Grade \/ No Cryo","offer_id":53806219264184,"sku":"RAM-5751-P","price":99.0,"currency_code":"USD","in_stock":true},{"title":"Platinum Grade \/ Yes Cryo","offer_id":53806219296952,"sku":"RAM-5751-P-C","price":99.0,"currency_code":"USD","in_stock":true},{"title":"Kevin's Stash \/ No Cryo","offer_id":53806219329720,"sku":"RAM-5751-KS","price":109.0,"currency_code":"USD","in_stock":true},{"title":"Kevin's Stash \/ Yes Cryo","offer_id":53806219362488,"sku":"RAM-5751-KS-C","price":109.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1564\/1247\/files\/GE_5751_Tube_Thumbnailcopy.jpg?v=1784940344","url":"https:\/\/upscaleaudio.com\/products\/ram-labs-low-noise-tested-ge-5751","provider":"Upscale Audio","version":"1.0","type":"link"}