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Modular Series
Ultra 4B SE Special Edition
Stereo Phono/Line Preamplifier
User's Manual
Phono Line1 Line2
Balance
Volume
Mapletree Audio Design
Ultra 4B SE Stereo Preamplifier
Rev. Feb. 22/13
Mapletree Audio Design
Lloyd Peppard
R. R. 1, Seeley's Bay, Ontario, Canada, K0H 2N0
(613) 387-3830
www.mapletreeaudio.com
info@mapletreeaudio.com
© Copyright Lloyd Peppard 2002-2013
-Specifications are subject to change without notice-
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Summary of Contents for Mapletree Ultra 4B SE
- Page 1 Modular Series Ultra 4B SE Special Edition Stereo Phono/Line Preamplifier User’s Manual Phono Line1 Line2 Balance Volume Mapletree Audio Design Ultra 4B SE Stereo Preamplifier Rev. Feb. 22/13 Mapletree Audio Design Lloyd Peppard R. R. 1, Seeley's Bay, Ontario, Canada, K0H 2N0 (613) 387-3830 www.mapletreeaudio.com...
- Page 2 Introduction The Mapletree Audio Design Ultra 4B SE Stereo Phono/Line Preamplifier offers the audiophile a number of desirable features: ? ? Compact chassis layout for use with separate power supply for low noise. ? ? Exclusive use of NOS octal tubes, known for low distortion and musicality.
- Page 3 Under normal conditions, it should not be necessary to replace the fuse. If power fails to come on, you can check the fuse and replace with a spare if necessary. If the fuse blows a second time, you should not try to operate the unit. Contact Mapletree Audio Design for information regarding service.
- Page 4 Balance Volume Mapletree Audio Design Ultra 4B SE Stereo Preamplifier The front panel controls are (left to right) the 3-position Source selector switch (Phono- Line1-Line2), the Balance control, and the Volume control, which adjusts the gain of both channels simultaneously. If you find that you hear pops from your speakers when switching between sources, turn down the volume control before switching.
- Page 5 Replacement tubes can be obtained from several suppliers in the U. S. and Canada. Mapletree Audio Design will attempt to provide replacement tubes to customers at cost plus shipping. Some listeners enjoy trying different brands and variants of tubes.
- Page 6 MAD Ultra 4B SE Phono/Line Preamplifier © Copyright Lloyd Peppard 2002-2013 Rev. Jan. 21/13 SW1a L. Line inputs Source R21a R11a 475K 1% R20a 47.5K 1% 12SN7GT 475K 1% 1/200 221K 1% 12SC7 332K 1% 820 pF 2% +55 V 0.1/400...
- Page 7 Parts List______ Reference No. Description C1a,b 0.012uF/160V 2% polystyrene capacitor C2a,b, C4a,b, C8a,b 0.1uF/400 V polypropylene film capacitor C3a,b 820pF/630V 2.5% polystyrene capacitor C5a,b 0.001uF/100 V 5% polypropylene capacitor C7a,b, C9a,b 1uF/200 V polypropylene film capacitor C11a,b, C12a,b 100uF/400V electrolytic capacitor D1a,b 10 mA red LED J1a,b–J5a,b...
- Page 8 Circuit Operation______ Referring to the schematic diagram, both channels are identical. The following description refers to either channel unless otherwise noted. The phono input signal is applied to input jack J1, loaded by resistor R1, then capacitor coupled to the grid of the first section of the 12SC7 which is configured as a common-cathode voltage amplifier.
- Page 9 MAD Ultra 4B Specifications______ Phono Section (100 k? load) Max. RIAA error: 0.5 dB 30–20 kHz Maximum Gain: 50 dB Noise: less than 3mV for gain of 48 dB; less than 1 mV for gain of 40 dB Input resistance at 1 kHz: 47 k? ? Line Section (100 k? load) Frequency response (1 V output, 100K load): 20 Hz–20 kHz –0.5 dB (any volume control setting)
- Page 10 SPST power switch (250 V rated) 230 VAC/25 mA power transformer 14 VAC/1.4 A filament transformer 6.3 VAC/0.9 A filament transformer 6X5GT rectifier tube Mapletree Audio Design Preamplifier Power Supply PS 2 © Copyright Lloyd Peppard 2003-13 Rev. Feb. 17/13 D3, D4 Power 6X5GT 0.5A/250V...
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