Just got a 6J1 buffer preamp in the mail. Its the Little Bear preamp that uses 6J1 tubes. Cost was $30.
The Chinese 6J1 tubes are squishy sounding. After replacing them with USA 5654 tubes it came alive and sounds really great going into a solid state amp.
Looking at the schematic, the tube section is above ground, fed with +28 and -28 volts from a split rail supply.
Is this a way of getting a plate voltage of 2 x 28, or 56 volts on the plate? Or does it not work that way?
The Chinese 6J1 tubes are squishy sounding. After replacing them with USA 5654 tubes it came alive and sounds really great going into a solid state amp.
Looking at the schematic, the tube section is above ground, fed with +28 and -28 volts from a split rail supply.
Is this a way of getting a plate voltage of 2 x 28, or 56 volts on the plate? Or does it not work that way?
Attachments
It uses a pair of voltage doublers, one to convert the 12volts to +28v and the other way up for -28v.
Yes 56volts total Anode to Cathode available voltage. As it is only a buffer the power supply is an overkill as it is using a balanced supply and the ripple rejection is excellent without the need for regulation.
Yes 56volts total Anode to Cathode available voltage. As it is only a buffer the power supply is an overkill as it is using a balanced supply and the ripple rejection is excellent without the need for regulation.
You have +/-28 volts on plate available.
Would have thought the half wave filtered power to the filaments would cause more hum/buzz trouble than just the plain AC. Just would have supplied them direct in series or full wave rec.
Would have thought the half wave filtered power to the filaments would cause more hum/buzz trouble than just the plain AC. Just would have supplied them direct in series or full wave rec.
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I am getting some filament noise. Could I bypass D1 and take out C13 and try it with AC?