[sdiy] Tube signal conditioner ?

[Scott Gravenhorst]

I'm having trouble understanding how using vacuum
tubes will improve the performance of a DAC.

Or is this simply a "see if it can be done" challenge?

I understand how tubes add warmth and are of great value in
audio signal path applications and others, but here, I just
don't get it.  Speed?  Accuracy?  Monotonicity?  Noise?  It
seems like a whole lot of heat, power and space.

I think tubes are great, I just don't get this application.

On a different note:
I once had a T-shirt with a silk screened schematic of a two
triode flipflop that was used in the first tube binary
digital computer.  Has anyone here ever used this for a
suboctave generator?

Matt Jones <thereminhd at yahoo.com> wrote:
>
>--- Michael Buchstaller <buchi at takeonetech.de> wrote:
>> Hello friends,
>> 
>> i am on the quest for some kind of Schmitt-Trigger
>> or
>> Comparator that allows me to clean up a possibly
>> noisy
>> signal to an exact 0/1 level.
>> 
>> Purpose of this is for my tube DAC. At this moment,
>> i am using
>> tubes to amplify the TTL output from my digityl
>> circuitry to drive
>> a R/2R ladder. But, TTL seems not to have very exact
>> signal
>> lexels (H is anywhere between 3.9 and 4.4 V, L
>> between 0.4 and
>> 0.9 V) between outputs of different chips.
>> 
>> So, i want to make some kind of "hard switching", by
>> means of a tube.
>> How can i achieve this ? OK, i have the schematics
>> of that old philbrick
>> tube opamp, and could use it as a comparator, but i
>> feel there must be
>> a more simple solution for that.
>> 
>
>Your best bet is to switch the tube drivers to CMOS
>devices - if you keep the load small, they will 
>swing much closer than the TTL gates will.
>
>One problem comes to mind - I don't recall tubes
>having
>a very predictable "saturation" (transistor term) 
>voltage. This may cause problems with driving the 
>ladder.. just a thought.
>
>  --mdj
>
>
>__________________________________________________
>Do You Yahoo!?
>Sign up for SBC Yahoo! Dial - First Month Free
>http://sbc.yahoo.com

=========================================================  
- What good are laws that only lawyers understand?
- Government: The other religion.
- The media's credibility should always be questioned.
- Lambs who lie down with lions are lunch.

-- Scott Gravenhorst | LegoManiac / Lego Trains / RIS 1.5
-- Linux Rex         | RedWebMail by RedStarWare
-- FatMan: home1.GTE.NET/res0658s/FatMan/
-- NonFatMan: home1.GTE.NET/res0658s/electronics/