considering SM tranmitter gain increase

[Larry Fisher]

To the Group:
After some 6 months or so of field experience with the SM transmitter,
we are strongly considering increasing the overall gain of the SM and
SM series transmitters by 10 dB. This would increase all input
configurations including line level input. The display would now show
10 to 54 dB of gain rather than the current 0 to 44 dB. The same
displayed numbers for gain would represent the same gain on either
version, i.e., a setting of 30 dB would be the same on either version.
Equivalent input noise, response, limiting and so forth would not
change.

From what I've read on RAMPS and various emails, indicates we are a
little light on gain. Also, I think some users don't like running the
gain at maximum levels even if that is the best setting in a given
case. Any and all feedback from the real world would be appreciated.

Best Regards,
Larry Fisher
Lectrosonics

[Larry Fisher]

Thanks Scott,
You are within 6 dB of full current gain (44). You would still set the
transmitter to 38. What is the lowest you remeber setting the
transmitter?
LarryF
Lectro

On 6 Sep 2006 09:27:34 -0700, "Scott Farr" <sc...@farroutpro.com>
wrote:

>I run my SM transmitters at 38 on the gain setting never any higher and
>I am using TRAM TR50's
>
>Scott

[wyatt]

I am using 8 SM transmitters on my current production. I am using an
assortment of lavs, and my gain settings varry accordingly. The lowest
gain I have used to date would be 24 using a cos-11, outdoor scene,
times square. the highest would be 44, indoors, using either a b6 (grey
band) or a TR-50 (i dont quite recall which at the moment). My normal
operating gain for a cos-11 has been between 29 and 31.
I think a gain increase would a beneficial improvement, especially
considering that you can get most of the lavs that we, as soud mixers,
employ daily with attenuated output levels. I have yet go below 24db on
my transmitter gain.

Wyatt Tuzo

[Larry Fisher]

Thanks Wyatt,
More good info.
LarryF
Lectro

[Scott Smiith]

Larry,

This is something I have noticed as well (although the output of the
mike used definately plays into the equation). I would say at least 6
db would be helpful, and there is certainly nothing wrong with 10 db,
as long as it doesn't risk overloading the front end preamp.

Scott D. Smith C.A.S.

[Larry Fisher]

Hi Scott,
When the gain is set to minimum, even with the additional gain, the SM
will still require 250 uA of peak current from the mic before the
limiter even begins to engage. This would require a lavaliere that
pulled 500uA of bias. This is higher than any pro mics we have
measured. Another way of saying this is that at minimum gain, any known
lavalliere will run out of bias (clip) before the limiter starts to
limit let alone overdrive the preamp. Further, even at minimum gain
there is still more than 30 dB of limiting before the limiter gives up
and allows the preamp to overload. As I said earlier, I think we were
being way too conservative on gain. Field experience seems to be
bearing this out.
Best Regards,
LarryF
Lectro

[LaFayette]

Greetings Larry,

Would this be an upgrade mod on existing units or only for new
versions?

I've set mine from 30 w/ Sankens outdoors to 38 w/ Sonotrims indoors.
It has been suggested to go w/ red dot Sankens since the regular ones
tend to be hot w/ SM's. Although, I also hear that the Sankens wired
specifically for the SM sound better anyway, more low end. Should I
save my money on new Sankens and just buy the upgrade on the SM?

Cheers, S.L.

[Larry Fisher]

Hi,
There is no downside to running the current SM at maximum gain or close
to it. Performance of the current units at 44dB gain (wide open) will
be exactly the same as the new units at 44 dB gain (10 dB left). So if
you have sufficient gain now to handle the mics you have, then it is
not necessary to change the units. This is not a necessary "upgrade"
and won't be automatically done to units in for other repairs unless
the customer requests it, unlike mandatory upgrades that we always make
to repairs. Mandatory upgrades are due to a mistake we made and are
done at no charge.

Older units can be changed to the new gain structure and corresponding
firmware. There will be a $70 charge to open, test and reseal the unit.
This is the same as for the RM addition mentioned earlier on RAMPS. On
the other hand, you can get both done at once for the same charge.
Depending on the age of the SM you may also pickup a new emulation
also.There is no charge for the firmware and new value resistor
themselves; just the work involved in opening, closing, sealing and
testing the unit. If we are already inside a unit for other reasons,
there will be no additional charge for the gain change. As I said
above, the customer must request the change since if they are happy
with the current gain structure, we are very satisfied to leave it
alone.
Best Regards,
LarryF
Lectro

[morantzsound (Steve Morantz, C.A.S.)]

I was told when I bought my SM's anywhere form 24 to 30 was average. I
usually stay around 27 or 28 and make adjustments at the board or
Deva. It has worked pretty well for me, but will start experimenting
with higher outputs.

Steve Morantz C.A.S.

[Fernando]

Hi Larry, you know I'm one asking for more gain, but I own UM400.
Could this be implemented on that model too (I mean as a mod)
Thanks,
Fernando

[Larry Fisher]

Hi Fernando,
It could be done as a custom modification. We do those sometimes just
to gain some info. I'm curious as to what mics need more gain and how
they are wired. The UM400 is already hotter than our other
transmitters.
Best,
LarryF