Andy Evans wrote:

What sort of long term plans do you have for a balanced preamp? I've
been using balanced line stages for a while, and while it is heavier
on parts (double everything) it is easier on the volume control in the
sense you can use a simple shunt stepped attenuator on the output - I
personally don't mind a 12 step one for domestic listening, though
others are more demanding.

Motorised Alps volume pot with IR control. Volume indication by means of one
LED in the middle of the knob, and a different one for the 'pointer' - can
thus tell at a glance what the setting is by the angle from the centre LED
to the pointer.

IR-selectable sources with complementary front panel momentary switches. Row
of indicator LEDs for sources: all LEDs are lit dimly, except selected
source, which is brighter - can tell from a glance at the row of LEDs which
source is active.

Sources are CD, cable TV box, computer, DVD player, ANOther random device.
No RIAA, no tape loop. Reusing existing black box Cambridge C75 preamp's
case (with a new front panel) and PSU, probably the volume knob and
circuitry.

Possible circuit tweaks (aside from balanced o/p) include trimmers on the
inputs to match levels (DAC is louder than everything else), and probably
some sort of mute or attenuator function.



I happen to use directly heated triodes,
but you can build it or buy it any way you want. One use of a
balanced tube line stage is that it can function as a tube output
stage for a differential DAC board, which is how I use it. The signal
from the DAC, with DC on it, goes direct into the grids of the line
stage, which is a differential pair with a constant current sink
under it. This arrangement works very well and can be made to sound
excellent - after the tube stage choice is cap coupling, transformer
Push Pull or parafeed. All can give you good results. Something to
ponder on. Andy

What sort of HT should I use on NE5532s?


--
Wally
www.wally.myby.co.uk