Would anyone talk me out of buying an "AD-20"?

[stonedseven]

Hello All,I'm looking to slowly expand my portable recording rig. The
Denceke AD-20 along with the phantom power supply usng 9-volt
batteries is very attractive to me. I'm going to check one out and
probably buy it tomorrow, unless there's a good-intentioned pro, who
has an objection. I mainly record live shows with DAT and MD, so the
Toslink S/P DIF out, seems like a good option. Open and Grateful for
any help!Thanks, Mark.

[Ron Charles]

The Denecke is a damn good unit, and I would definately recommend it.
Ron Charles
"stonedseven" > wrote in message
om...
> Hello All,I'm looking to slowly expand my portable recording rig. The
> Denceke AD-20 along with the phantom power supply usng 9-volt
> batteries is very attractive to me. I'm going to check one out and
> probably buy it tomorrow, unless there's a good-intentioned pro, who
> has an objection. I mainly record live shows with DAT and MD, so the
> Toslink S/P DIF out, seems like a good option. Open and Grateful for
> any help!Thanks, Mark.

[David Satz]

stonedseven wrote:

> Hello All,I'm looking to slowly expand my portable recording rig.
> The Denceke AD-20 along with the phantom power supply usng 9-volt
> batteries is very attractive to me. I'm going to check one out and
> probably buy it tomorrow, unless there's a good-intentioned pro, who
> has an objection. [ ... ]

It's a good little unit, and so is the Denecke stereo phantom power supply
which works so nicely with it, and saves you the cabling mess--I wish that
all phantom supplies had their output cables attached in the same way.

The only quibbles I have with the AD-20 are these:

[a] It's an absolute bare-bones unit with no low-cut filters or alternate
sampling rates, etc., but it's fine for recordings that are destined for
CD-R after just some basic editing.

[b] If the battery runs down, its noise floor rises considerably. Do
_not_ record with a run-down battery in this unit, even for a few minutes.

[c] Its gain control knobs are tiny and uncalibrated; in dim light you
can't even tell how far up or down they're set.

[d] It will not work at all if phantom power (DC) is present at its inputs.
It is designed to work with a phantom supply such as the matching Denecke
unit that blocks DC at the outputs of the supply. Do not try to use the
AD-20 with other phantom power supplies unless you've tested their outputs
with a meter first. If DC is present, the AD-20's preamp will pass no
audio signal at all and could be damaged.

[e] Its inputs are undithered, so recordings made in extremely quiet
surroundings can have audible quantization distortion at low signal levels.
Frankly, what Denecke's Web site says about this (assuming that it's still
the same as what they had up there for several years) is just ignorant
bull****--they really should know better.

However, by "extremely quiet" I mean "uncannily, eerily quiet." Under
most normal circumstances this should not be an audible problem since the
background noise of most live recording venues is enough to dither the
converters' inputs nicely. Still, for any serious classical recording in
a quiet studio or hall I'd want to use something a step or two higher up
on the evolutionary scale.

Unfortunately, the next step above the AD-20 is a big one. The MindPrint
DI-Port is pretty much unusable due to its terrible implementation of 48V
phantom powering--mine actually put out a small puff of smoke and died
when I plugged in a pair of Schoeps mikes. And after that you've got only
the Grace Lunatec V3 and the Apogee Mini-Me--luxury items in the $1200+
range which still have some problems of their own.

Hmm, I don't seem to have any record of the unit's input overload point.
One moment, I'll measure it ... OK, I see why I have no listing of it.
The preamp doesn't seem to have an input stage clipping problem the way
so many others do. If you set the gain control to its minimum setting,
the converters reach digital full scale output with about a 400 mV signal,
but at that point the preamp hasn't begun to distort audibly yet. For
most purposes that's excellent headroom. The only exception would be if
you're recording very loud sound with extremely sensitive microphones.

Good luck, and please stop by and let us know what you think after you've
used the AD-20 some.

--best regards

[Scott Dorsey]

David Satz > wrote:
>
>[c] Its gain control knobs are tiny and uncalibrated; in dim light you
>can't even tell how far up or down they're set.

THIS is what drives me up the wall with it. I can't deal with that at all
since there is no way to set the two gains so they are the same.

>[e] Its inputs are undithered, so recordings made in extremely quiet
>surroundings can have audible quantization distortion at low signal levels.
>Frankly, what Denecke's Web site says about this (assuming that it's still
>the same as what they had up there for several years) is just ignorant
>bull****--they really should know better.

This is less of a problem than it used to be, because now we have a bunch
of portable systems that will take 20-bit inputs. Even a lot of MD units.
It was a very serious problem when the thing came out and everyone was
recording to DAT, and it was the reason that I eventually sold my unit.

>However, by "extremely quiet" I mean "uncannily, eerily quiet." Under
>most normal circumstances this should not be an audible problem since the
>background noise of most live recording venues is enough to dither the
>converters' inputs nicely. Still, for any serious classical recording in
>a quiet studio or hall I'd want to use something a step or two higher up
>on the evolutionary scale.

I considered it sort of noisy, actually. It was fine with a good condenser
mike but really unusable with a 77DX. Then again, it was very very small.
On the other hand, it was a lot quieter than the stock preamps in the DA P-20,
which were just plain unusable with a 635A.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

[stonedseven]

(Scott Dorsey) wrote in message >...
> David Satz
> wrote:
> >
> >[c] Its gain control knobs are tiny and uncalibrated; in dim light you
> >can't even tell how far up or down they're set.
> > THIS is what drives me up the wall with it. I can't deal with that at all
> since there is no way to set the two gains so they are the same.
> > >[e] Its inputs are undithered, so recordings made in extremely quiet
> >surroundings can have audible quantization distortion at low signal levels. > >Frankly, what Denecke's Web site says about this (assuming that it's still
> >the same as what they had up there for several years) is just ignorant
> >bull****--they really should know better.
> > This is less of a problem than it used to be, because now we have a bunch > of portable systems that will take 20-bit inputs. Even a lot of MD units.
> It was a very serious problem when the thing came out and everyone was
> recording to DAT, and it was the reason that I eventually sold my unit.
> > >However, by "extremely quiet" I mean "uncannily, eerily quiet." Under
> >most normal circumstances this should not be an audible problem since the
> >background noise of most live recording venues is enough to dither the
> >converters' inputs nicely. Still, for any serious classical recording in
> >a quiet studio or hall I'd want to use something a step or two higher up
> >on the evolutionary scale.
> > I considered it sort of noisy, actually. It was fine with a good condenser
> mike but really unusable with a 77DX. Then again, it was very very small.
> On the other hand, it was a lot quieter than the stock preamps in the DA P-20,
> which were just plain unusable with a 635A.
> --scott








I was up in San Francisco today, and picked up the AD-20 from a nice
little sound company, who gave me a good deal. He's giving me time to
check it out to make sure it's what I need. My first impression is
that it's a sturdy unit wth a good quality feel. It's basic, but
that's exactly what I need right now. The small gain knobs may be an
issue, but I'm hoping that after a little experience with them, I'll
get the feel for it. I'm really excited to put this unit to the real
test in a couple of days!Sharing your experiences definately gave me
insight with this unit, and I really appreciate the vital points that
were expressed. I'll let you guys know my impressions in a few days,
after a few experiments with this little unit. Thanks Again!Mark.