DELTA-double regulation worthwhile?

Archived from groups: rec.audio.pro (More info?)

Frank Stearns wrote:

> Another Delta item... skip now if you're bored with these.

I've followed all the Delta threads so far,
no sense stopping now. In case anyone doesn't know
by now - everything applies directly to the Venue
series as well.

> Some higher-end preamps (and a few consoles) distribute higher
voltage DC

.. . . . .

> So, this would be doable for a reasonable amount of hassle and modest
> money -- question is whether this would be worthwhile. Opinions? Am I
Wyle
> E. Coyote just now sprinting off the cliff and hanging in space,
waiting
> to fall into the canyon -- or could this get noticeable performance
> improvements?

My personal feeling on some of these mods is that
it's more hassle than I have time for.
My interest does not diminish in either the mods
or the theory behind them.

I've done a few mods myself, mostly for practical
reasons like signal routing in the monitor path,
and to allow the Venue strips to work in the Delta 8.
How about modding the M1 thru M4 mute switches and
the mute ribbon on the Venue strips to feed 16 subs
instead of the 8 groups I have now ?

> Thanks again,
>
> Frank Stearns, Mobile Audio
>
> PS - I am documenting this overall rebuild/repair project as I go. If
> there's interest, I can post the occasional progress update.
> --

I'm following these carefully.
Good luck.
rd

Archived from groups: rec.audio.pro (More info?)

"Frank Stearns" <franks.pacifier.com@pacifier.net> wrote in message
news:116uhsokqr3u38f@corp.supernews.com...
> Another Delta item... skip now if you're bored with these.
>
> Some higher-end preamps (and a few consoles) distribute higher voltage DC
> rails and then regulate down to the working voltage locally in each
> channel strip. This has some advantages; I wonder if such a scheme would
> benefit the Delta modules over a simple beefed-up version of the present
> RC method (as Jim suggested, moving to 1/2W resistors and upping the local
> power caps to 470 uF).
>
> 317 (and I believe) 339 regulators are available in TO-92 cases delivering
> 100 mA (most Delta modules, even with hungrier ICs installed, draw well
> below that).

You want 317 and 337, not 339 (339s are, if I recall correctly since I'm too
sleepy to get up and look, comparators).

The main advantage is significantly lower supply impedance to the active
devices. Possibly lower noise, too, depending on the central supply, but
this probably won't matter much. Give it a shot on an input strip and an
output strip and see if there's any difference. Do bypass the
voltage-setting resistor with at least 25uF (I use 100uF) and hang a cap on
the output for stability.

Peace,
Paul

Archived from groups: rec.audio.pro (More info?)

"Frank Stearns" <franks.pacifier.com@pacifier.net> wrote:
>
> PS - I am documenting this overall rebuild/repair project as I go. If
> there's interest, I can post the occasional progress update.



There's interest right here. Thanks Frank!

--
"It CAN'T be too loud... some of the red lights aren't even on yet!"
- Lorin David Schultz
in the control room
making even bad news sound good

(Remove spamblock to reply)

Archived from groups: rec.audio.pro (More info?)

Frank,

regulators can be noisy, after all they are just power amps operating
at DC.

while they are great at eliminating 120 Hz, they can add wideband noise

I suggest you add a small RC after the regulator to get rid of the
wideband noise especially for powering preamps.

Before and after measurements are always nice too. Surely we can
agree that improvements to hum and noise can be measured.

Mark

Archived from groups: rec.audio.pro (More info?)

Frank Stearns <franks.pacifier.com@pacifier.net> wrote:
>So, this would be doable for a reasonable amount of hassle and modest
>money -- question is whether this would be worthwhile. Opinions? Am I Wyle
>E. Coyote just now sprinting off the cliff and hanging in space, waiting
>to fall into the canyon -- or could this get noticeable performance
>improvements?

My experiences with local regulation have not really been good ones. I
think you gain more just by relying on brute force than you do with
regulating each individual stage alone.

Perhaps regulating each bucket might be a compromise, but again I really
don't know if you should expect any sonic improvement.

For the most part I have found that heavy regulation of each stage
in a system seems to degrade the sound more than improve it for the
most part. Probably because going to that sort of configuration means
you are forced to limit the capacitance after the regulator.

I think if you _are_ going to take this approach that you are better off
using some higher grade regulators than the usual three-terminal stuff.

For the most part, using minimal bypassing, I have found that the
LM314 seems to result in better sound than the 7815, and the high
speed Linear Technology regulators seem an improvement over either
one. Needless to say, more bypassing is a good idea. And I cannot
give you any good reason for this opinion either, so take it as you will.
--scott

--
"C'est un Nagra. C'est suisse, et tres, tres precis."

Archived from groups: rec.audio.pro (More info?)

"Lorin David Schultz" <Lorin@DAMNSPAM!v5v.ca> wrote in message
news:rsIbe.4937$3V3.3811@edtnps89...
> "Frank Stearns" <franks.pacifier.com@pacifier.net> wrote:
> >
> > PS - I am documenting this overall rebuild/repair project as I go. If
> > there's interest, I can post the occasional progress update.
>
>
>
> There's interest right here. Thanks Frank!


Same here.

Predrag

Archived from groups: rec.audio.pro (More info?)

"Paul Stamler" <pstamlerhell@pobox.com> writes:

>"Frank Stearns" <franks.pacifier.com@pacifier.net> wrote in message
>news:116uhsokqr3u38f@corp.supernews.com...

>> Some higher-end preamps (and a few consoles) distribute higher voltage DC
>> rails and then regulate down to the working voltage locally in each
>> channel strip. This has some advantages; I wonder if such a scheme would

-snip-

>> 317 (and I believe) 339 regulators are available in TO-92 cases delivering
>> 100 mA (most Delta modules, even with hungrier ICs installed, draw well
>> below that).

>You want 317 and 337, not 339 (339s are, if I recall correctly since I'm too
>sleepy to get up and look, comparators).

D'oh! You're right; 337s.

>The main advantage is significantly lower supply impedance to the active
>devices. Possibly lower noise, too, depending on the central supply, but
>this probably won't matter much. Give it a shot on an input strip and an
>output strip and see if there's any difference. Do bypass the
>voltage-setting resistor with at least 25uF (I use 100uF) and hang a cap on
>the output for stability.

Okay -- the usual and customary+ for these regs.

It's an all or nothing kind of thing, as once I run the distribution rails
up I can't put in regular modules for direct comparison/"daily use"
evaluation.

I'm reasonably sure some improvements will result; the chin-rubbing
question of the day is whether the sonic gains are large enough to justify
the effort.

Thanks for your help, Paul.

Frank Stearns
Mobile Audio

--
.

Archived from groups: rec.audio.pro (More info?)

On Wed, 27 Apr 2005 08:04:40 -0000, Frank Stearns
<franks.pacifier.com@pacifier.net> wrote:

>Some higher-end preamps (and a few consoles) distribute higher voltage DC
>rails and then regulate down to the working voltage locally in each
>channel strip. This has some advantages; I wonder if such a scheme would
>benefit the Delta modules over a simple beefed-up version of the present
>RC method (as Jim suggested, moving to 1/2W resistors and upping the local
>power caps to 470 uF).

One real issue is getting a proper ground for the regulator to
reference from. Pardon my dangling participle.

Unless the regulator's ground reference is clean, you may end up
with higher impedance and/or noise than a brute-force solution.

Good fortune, and good soldering,

Chris Hornbeck
"Don't panic."

Archived from groups: rec.audio.pro (More info?)

"Chris Hornbeck" <chrishornbeckremovethis@att.net> wrote in message
news:9e90719aldt4mjn44q2ukmk2i5o5iddpjr@4ax.com...
> On Wed, 27 Apr 2005 08:04:40 -0000, Frank Stearns
> <franks.pacifier.com@pacifier.net> wrote:
>
> >Some higher-end preamps (and a few consoles) distribute higher voltage DC
> >rails and then regulate down to the working voltage locally in each
> >channel strip. This has some advantages; I wonder if such a scheme would
> >benefit the Delta modules over a simple beefed-up version of the present
> >RC method (as Jim suggested, moving to 1/2W resistors and upping the
local
> >power caps to 470 uF).
>
> One real issue is getting a proper ground for the regulator to
> reference from. Pardon my dangling participle.
>
> Unless the regulator's ground reference is clean, you may end up
> with higher impedance and/or noise than a brute-force solution.

One way to make this work: the reference point of the regulators (where the
ADJ resistors meet, usually) goes to the load ground, which goes to the main
system ground. The regulator reference point does NOT go back to the power
supply.

Peace,
Paul

Archived from groups: rec.audio.pro (More info?)

Frank Stearns wrote:

> Another Delta item... skip now if you're bored with these.
>
> Some higher-end preamps (and a few consoles) distribute higher voltage DC
> rails and then regulate down to the working voltage locally in each
> channel strip. This has some advantages; I wonder if such a scheme would
> benefit the Delta modules over a simple beefed-up version of the present
> RC method (as Jim suggested, moving to 1/2W resistors and upping the local
> power caps to 470 uF).
>
> 317 (and I believe) 339

337

> regulators are available in TO-92 cases delivering
> 100 mA (most Delta modules, even with hungrier ICs installed, draw well
> below that).

It's *not* the current rating that's the problem - it's the *package
dissipation* !

Thermal considerations 101.


> I could get some small daughter boards made up with down leads that would
> mount right into the present holes of the physically paired 10 ohm
> decouplers. These little boards would hold the + and - regulators plus the
> few other support Rs and Cs. The TO-92s should not require heatsinks, but
> I could be wrong on that.
>
> Most of the Delta modules have roughly the same mechanical spacings for
> these decoupling resistors, so these add-on regulator boards could be
> "universal". My new PS could deliver up to 24V for the distribution, and
> the V adjust R values on the 317/339s in the old shoebox supply could be
> altered to get a few more volts.
>
> So, this would be doable for a reasonable amount of hassle and modest
> money -- question is whether this would be worthwhile. Opinions? Am I Wyle
> E. Coyote just now sprinting off the cliff and hanging in space, waiting
> to fall into the canyon -- or could this get noticeable performance
> improvements?

I doubt it frankly. What makes you think it'll sound any better ?


Graham