Two Vbe-matched (<1 mV) pairs of ZTX851 NPN transistors for the Moving Coil preamp. Includes two aluminum acorn nuts glued onto the pair to increase thermal mass and improve thermal equilibrium.
The Zetex ZTX851 was designed as a high-current low saturation voltage switch. As a consequence of its device geometry, the ZTX851 also has a low rbb resistance making it suitable for low-noise, low source impedance audio amplifiers.
The suitability of the ZTX851 for low noise amplifiers is discussed in section 8 of the new Third Edition of Horowitz and Hill's "Art of Electronics." "Although its noise voltage is unspecified, we found excellent noise performance good consistency with some Zetex bipolar transistors, notably their ZTX851 (NPN) and ZTX951 (PNP)."
Though it is not specified in the datasheet, the rbb of the ZTX851 was measured by Horowitz and Hill to be about 1.6 Ohms. (Art of Electronics, 3rd Ed. pg. 535.)
Zetex ZTX851 Two Vbe-Matched Pairs for the MC Preamp
- Brand: Zetex Diodes, Inc.
- Product Code: ZTX851-MP2-2
- Availability: 2-3 Days
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$24.95
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