tubehunter
10-10-2014, 13:47
Here we have my recently built Valve Dac/Preamp.
I haven't built any valve dacs for awhile now but with the fortune of acquiring some very high quality Majestic Transformers manufactured in Pool, Dorset, I thought why not.
The transformers had been stored since 2007 but in mint condition.
They have a copper screen and are quite expensive to produce.
I put this together as a prototype with the intension of building myself another, but going all out with mono block power supplies and high end components if successful.
So to fund that, here it is.
SRPP topology using Russian military 6n6p valves running at 20ma per tube. Bias at -3.8v
Elevated AC heaters.
Polypropylene coupling capacitors, Nichicon quality capacitors in the power supply.
Aluminium case.
3 stereo RCA Silver phono inputs
1 stereo RCA Silver phono output
USB input (uses 3rd input) accepts 16bit 44.1/48khz
Very good signal to noise.
£200
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8059_zpsad5fb3af.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8059_zpsad5fb3af.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8058_zps380ae62d.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8058_zps380ae62d.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8057_zpseac1c470.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8057_zpseac1c470.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8056_zps0f99f094.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8056_zps0f99f094.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8055_zpsbaaf5ac5.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8055_zpsbaaf5ac5.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8054_zps74941a15.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8054_zps74941a15.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8053_zps460f6df5.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8053_zps460f6df5.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8052_zpsbe57d5fb.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8052_zpsbe57d5fb.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8051_zps46031a1b.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8051_zps46031a1b.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8050_zpsdb8e7253.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8050_zpsdb8e7253.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8049_zps0727ac05.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8049_zps0727ac05.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8048_zpsb863c34c.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8048_zpsb863c34c.jpg.html)
I haven't built any valve dacs for awhile now but with the fortune of acquiring some very high quality Majestic Transformers manufactured in Pool, Dorset, I thought why not.
The transformers had been stored since 2007 but in mint condition.
They have a copper screen and are quite expensive to produce.
I put this together as a prototype with the intension of building myself another, but going all out with mono block power supplies and high end components if successful.
So to fund that, here it is.
SRPP topology using Russian military 6n6p valves running at 20ma per tube. Bias at -3.8v
Elevated AC heaters.
Polypropylene coupling capacitors, Nichicon quality capacitors in the power supply.
Aluminium case.
3 stereo RCA Silver phono inputs
1 stereo RCA Silver phono output
USB input (uses 3rd input) accepts 16bit 44.1/48khz
Very good signal to noise.
£200
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8059_zpsad5fb3af.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8059_zpsad5fb3af.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8058_zps380ae62d.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8058_zps380ae62d.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8057_zpseac1c470.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8057_zpseac1c470.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8056_zps0f99f094.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8056_zps0f99f094.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8055_zpsbaaf5ac5.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8055_zpsbaaf5ac5.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8054_zps74941a15.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8054_zps74941a15.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8053_zps460f6df5.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8053_zps460f6df5.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8052_zpsbe57d5fb.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8052_zpsbe57d5fb.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8051_zps46031a1b.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8051_zps46031a1b.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8050_zpsdb8e7253.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8050_zpsdb8e7253.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8049_zps0727ac05.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8049_zps0727ac05.jpg.html)
http://i514.photobucket.com/albums/t350/halx00/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8048_zpsb863c34c.jpg (http://s514.photobucket.com/user/halx00/media/SRPP%20Valve%20Preamp%20with%20DAC/IMG_8048_zpsb863c34c.jpg.html)