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Have not listened to it long enough..running them in..in my computer room ..but boy is this thing silent...amazing. No Hum whatsoever..
The d3a has been made a pseude triode by 2 * 200R resistors on from screen 2 and 3 to plate (I.e. pin 8 and 9 via the resistors to pin7)
I added a humm pot just for good measure. I think I might that that might just be the only part that is superfluous. Also comtemplated adding the dc filter in the the center tap of the toroidal..but it is so quiet..mechanically and electrically that it is not necessary.
Thanks to Thorsten/KYW for the inspiration for this particular design. It is an extract from one of his schematics (the one pictured below
One of T's amps:
Slightly related question. I noticed you used the MQ Ex01 100H as an anode load choke on the driver. Brian also lists an S&B "Anode Load Choke for driver tubes" on his site - anyone know what inductance that choke is and could it be used in this Bas/T Lady Day?
> Brian also lists an S&B "Anode Load Choke for driver tubes"
> on his site - anyone know what inductance that choke is and
> could it be used in this Bas/T Lady Day?
This choke was designed for me and can be used in my own design, I measured 160H @ 12mA DC with around 10V @ 20Hz.
CSS FR125's on a makeshift open baffle. Just one channel playing
I was pretty amazed at how much bass this little driver produces in an open baffle (and so was my son as you can hear early on in the film )
there was no subwoofer somewhere in the room ;-)
Source..computer soundcard playing an mp3.
Amplifier DiyHiFiSupply Ladyday SE amp.. wired as schematic.
To infinity and beyond!!!
Nice one Bas, just a few notes....
1) The 12R resistor pair are heater balancers, so use these or the Humpot/Resistor combo instead, not both. My own use with two sets of resistors on each side of the heater balances the Cathode currents out of each side of the heater.
2) The 0.47uF X 2 Capacitors after the rectifier are really "tuning" capacitors, set so you get the kind of HT you want. I was operating the 300B with 350V/60mA with effectively 6K nominal Load (3K OPT Mismatched). Add a few uF to get the HT up to around 450V.
Also the RC circuit across the choke should be adjusted for lowest ripple.
and went to bed.
and my Dragonfly's are out on loan...I have the LD's connected to the pc for running in. With little speakersdrivers on the floor. My CSS FR 125'S also on loan.
But I'll add a little switch to the first 2uF C to try it when I have my Prometheus up and running..and will report my findings.
1.) Thanks...yes..stupid of me..
2.) Do you think it will sound better with 450VDC? I also chose the lower voltage and lower current you aimed for because I think you wrote somewhere that you actually prefer lower voltage and lower current for the 300b soundwize.
> I think you wrote somewhere that you actually prefer lower
> voltage and lower current for the 300b soundwize
Actually, I prefer Higher Load, Higher Voltage, Lower Current.
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