MEASURES
-
Rails: +/- 24VDC under load
-
DC offset at speaker teminals: +/- 2mV
-
BIAS: 1.3A (0.61V on R13/R14)
-
Voltage gain: 10 (20dB)
-
THD+N (at 1 Watt into 8 Ohms at 1kHz): 0.08%
-
THD (at 1 Watt into 8 Ohms at 1kHz): 0.04%
MEASURES
-
Rails: +/- 24VDC under load
-
DC offset at speaker teminals: +/- 2mV
-
BIAS: 1.3A (0.61V on R13/R14)
-
Voltage gain: 10 (20dB)
-
THD+N (at 1 Watt into 8 Ohms at 1kHz): 0.08%
-
THD (at 1 Watt into 8 Ohms at 1kHz): 0.04%
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NOTES
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R7 changed to 52.3k to remove excess negative DC offset at the output of the amp
-
R4 changed to 8.2 Ohms and 220uF bipolar capacitor added to remove DC offset at Edcor input (pin 1)
-
Boards, Edcor transformers and MOSFETs from TeaBag
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Harris IRFP9240 MOSFETs
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Matched Toshiba JFETs from FET Audio
-
Dual mono implementation
-
2 x 250VA transformers from Toroidy - 230V primary, 2x18V secondary
-
8 x 22000uF KEMET PEH200 in power supply
-
Deluxe 4U chassis from Hi-Fi 2000
RESOURCES
-
Manual: First Watt M2
-
diyAudio: Official M2 schematic, M2 Clone boards with 120mm UMS spacing
-
Other: Edcor
Last update: 10.03.2019.
NOTES
-
R7 changed to 52.3k to remove excess negative DC offset at the output of the amp
-
R4 changed to 8.2 Ohms and 220uF bipolar capacitor added to remove DC offset at Edcor input (pin 1)
-
Boards, Edcor transformers and MOSFETs from TeaBag
-
Harris IRFP9240 MOSFETs
-
Matched Toshiba JFETs from FET Audio
-
Dual mono implementation
-
2 x 250VA transformers from Toroidy - 230V primary, 2x18V secondary
-
8 x 22000uF KEMET PEH200 in power supply
-
Deluxe 4U chassis from Hi-Fi 2000
RESOURCES
-
Manual: First Watt M2
-
diyAudio: Official M2 schematic, M2 Clone boards with 120mm UMS spacing
-
Other: Edcor
Last update: 10.03.2019.
Burning Amp BA-3 Front End
Designed by Nelson Pass. Class A pre-amplifier without negative feedback loop. More details on First Watt website.
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MEASURES
-
Rails: +/- 25VDC
-
JFETs current: 8mA
-
R10: 1V, R11: 1V
NOTES
-
Complimentary Front End (BA-3) board from diyAudio Store
-
Power supply in a separate chassis shared with Pearl 2 and Technics SL-1200 turntable
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Super Regulator board from diyAudio Store
-
PSU board from diyAudio Store
-
Galaxy 2U chassis from Hi-Fi 2000
-
Matched Toshiba JFETs from FET Audio
-
Matched Toshiba 2SK2013/2SJ313 MOSFETs
-
Ladder type 25k stepped attenuator based on Seiden 4 pole 23 way switch and Nickel-Chromium thin film resistors 1/4W 0.1%
-
ELMA 4 pole 6 way input selector switch
-
Jensen JT-11P-1 line input transformers
ATTENUATION DETAILS
BLOCK DIAGRAM
RESOURCES
-
Manuals: Burning Amp #3, Super Regulator
-
diyAudio: The BA-3 as preamp build guide, BA-3 As Preamp, Burning Amp BA-3b (Balanced)
-
Passive pre-amps: Goldpoint, hifi collective
Last update: 11.06.2023.