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Lectrosonics SRa (or any UniSlot Receiver) Universal Audio and Powering Loom


john.e.perkin

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Hello guys, I've another cable designed to make your equipment work for you a little bit better.

More and more wireless receivers are coming with slot in options or adapters for use with full size cameras and also use them in their receiver racks, this has lead to some slightly poor design in terms of cabling, so I've designed a cable to work around these design flaws and provide a much more convenient design and operation for you, the end user.

http://bluecowcables.com/product.php?id_product=120

Two of these with two SRa would be a thinking mans Lectrosonic Quadpack. - Lighter, cheaper, smaller and splittable.

They would also be great for use on a camera which has an aux power output but no Unislot.

Also available with TA3 audio outputs upon request.

Many Thanks,

John Perkin

www.bluecowcables.com

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Hey John,

I see on the product page that each adapter contains "jack screws" to allow connecting the locking connectors on your adapter to the SRUNI plate.  I'm not sure that I understand that term, and how that works, but I'm guessing that the thumbscrews on the DB25 connector replace those small screws?  I guess my question is whether the SRUNI will remain structurally rigid once your adapter is DETACHED from the SR. 

My plan would be to purchase a set of these for my ENG Kit, and then use an Octopack for my bigger multitrack rig.  When switching between the two, would I have to return the original screws to the SRUNI when going to the Octopack, or would these "jack screws" permanently replace those screws.

Sorry if this is a long-winded question, but I think this is an important consideration, as I think it would speed up my prep time considerably if it worked the way I wanted it to.

e.

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Yes, just as you described.

They are low profile and are designed to replace the scews on the SRUNI adapter and should still mate in an Octopack or in  camera. I've not seen every single Unislot to see how much clearance there is but it should still work in them all, if it doesn't just swap the screws back, it's gonna be easier than the alternative of having to swap different bottom plate and more cables and connectors.

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Thanks Larry, I believe I spoke with you (or somebody at Lectro) over the phone regarding the concept of this a few months ago to get a yes/no on if it would work.

I'm a very big fan of the Lectro 606 kit here in the UK and I'm hearing good feedback from the UK recordists who've bought it through Everything Audio who I work closely with, it would be nice to see a power in pin on the TA5 of the SM TX's so that a single Line level powered cable could be used for wireless camera links. The UK market tends to dislike wireless kit which has cables coming out more than one side and recordists are very keen to avoid using disposables.

Thanks,

John Perkin

www.bluecowcables.com

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Thanks for the good words, John.

The input power pin would be pretty easy to do on the older 9 Volt units (just a small linear regulator) but much harder on the SM series since the battery voltages are 1.5 Volts and would require a switcher to drop the external 12 Volts down to 1.5 Volts. We would also need to dedicate another pin to a power ground to keep ground loop currents off the audio ground. The final straw is this: if I even thought about changing the 5 pin connector pin outs, there wouldn't be enough wholesale tar and feathers to meet the demand. It is one of those great ideas that needed to be done from the beginning, like in the previous century. When we change the connector wiring again, slated for 2035, it'll be at the top of the list.

Best Regards,

Larry Fisher

Lectrosonics

Thanks Larry, I believe I spoke with you (or somebody at Lectro) over the phone regarding the concept of this a few months ago to get a yes/no on if it would work.

I'm a very big fan of the Lectro 606 kit here in the UK and I'm hearing good feedback from the UK recordists who've bought it through Everything Audio who I work closely with, it would be nice to see a power in pin on the TA5 of the SM TX's so that a single Line level powered cable could be used for wireless camera links. The UK market tends to dislike wireless kit which has cables coming out more than one side and recordists are very keen to avoid using disposables.

Thanks,

John Perkin

www.bluecowcables.com

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Yes, the switcher is in the eliminator and transforms the 12 to 18 Volts to a little less than 1.5 Volts. Then switchers in the SM generate +3.3 Volts from that 1.5 Volts for most circuity, 1.8 Volts for the DSP core, plus and minus 3 Volts for some audio amps and 6 Volts for the limiter. The 6 Volts is regulated to a clean 5 Volts for mic bias and further dropped to 2 or 4 Volts in the servo bias section. Additionally, 4 Volts is generated in another switcher for the output stage at 250 mW, and 3+ Volts for 100 mW operation and less than that for 50 mW operation. Then there are about 4 FETs used as switches to put the SM into sleep mode without turning everything off. Really, there is nothing major inside an SM but power supply stuff. The rest of is just left over Mr. Microphones that we got years ago as surplus.

Best Regards,

Larry Fisher

Lectrosonics

Would I be right in thinking that the SM battery eliminators house the regulator rather than the regulator being in the SM's?

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So just how much physically smaller could you make an SM transmitter if you used a higher voltage battery, say 3v to 5v and cut the RF down to 50mw or even lower to 30mw like Audio LTD's MiniTX?

Might be a consideration for the UK Block 606 market as I'm sure your know since our requirements are slightly different than the US/World due to the way we work, our RF spectrum and the law.

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Hi John,

I'm going to put this in a logical decision order. First, we could make the unit smaller if we used a permanent rechargeable battery. We could also use a custom replaceable Li-Ion battery in a rectangular shape, like a cell phone or small camera. We've opted to go with replaceable batteries because common replaceables are available almost everywhere and anytime. Further, you don't need to be near a power source for recharging. Secondly, given the replaceable requirement, there are only two really common batteries that have reasonable costs, good power density and are available at your local Quikie Mart (Thank you. Come again.). These are the rectangular 9 Volt and the AA battery. I have been told that Europeans hate the 9 Volt and also that the AA is more available than the 9 Volt outside the U.S. Another small battery is the AAA but the power density is one third that of a AA. For instance, the AA alkaline works well in moderate power drain applications, the NiMh works well in high drain applications as does the lithium AA. Further the alkaline is one of the cheapest batteries on the market, the NiMh is rechargeable and the lithium is moderately priced with good power capabilities. There are also NiZn AA batteries that are low leakage (long shelf life) and there are very good low leakage NiMh's. The AA battery is almost the same power capacity as a 9 Volt but has smaller volume. Finally, AA batteries are constantly, albeit slowly, being improved. Look at the capacities now and ten years ago. This why new Lectro products will be AA based. Finally, there are no batteries at other voltages, i.e., 3 or 5 Volts, that are commonly available and low cost.

Replaceable batteries do add to the unit's size. The batteries take up room themselves but you also have the battery door and contacts. The various power supplies I alluded to in previous posts, take up some room, but a higher voltage battery would only eliminate one or two sections of the supplies. The batteries themselves take up the most room. Designing for the lower European power, would help a little on battery life, but the DSP and other digital circuits are the actual power hogs. However, with interference sources growing like Topsy in the U.S., higher power does seem to be the way to go, with variable power being a good compromise between punching a signal through the crap and battery life. Further, interference is only going to get worse in the U.S. Going to lower power helps some on battery life Below 100 mW, with current DSP designs, lower RF power does not buy any real advantages. If we went back to all analog circuity, reduced RF would then make a difference.

Finally, the dual battery SMQv out sells the smaller SMv by almost 3 to 1. Battery life and increased power seems to be of more importance than size. This is not what I guessed a few years ago. Interestingly, the retro UM400a (9 Volt unit), also outsells the smaller SMv. I guess this just shows that users prefer the UM400a black wrinkle finish over the smaller SMv size.

Best Regards,

Larry Fisher

Lectrosonics

So just how much physically smaller could you make an SM transmitter if you used a higher voltage battery, say 3v to 5v and cut the RF down to 50mw or even lower to 30mw like Audio LTD's MiniTX?

Might be a consideration for the UK Block 606 market as I'm sure your know since our requirements are slightly different than the US/World due to the way we work, our RF spectrum and the law.

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I guess this just shows that users prefer the UM400a black wrinkle finish over the smaller SMv size.

Best Regards,

Larry Fisher

Lectrosonics

Larry,

I know you're making a joke, but I actually thought this would be a good place to make a "feature" request since this thread has your attention.  I LOVE my SMV and SMQV transmitters, but I must say, I do sort of miss the black finish on the UM-series.  I'm sure they're both similarly durable, but it seems like the black finish wears a little nicer then the aluminum (or whatever alloy you use for the SM-series transmitters. 

The other (more important) issue is that when hiding the SM transmitters on the talent's belt, that blue clip really stands out, and is easier to see on camera versus the black clips from the UM tx'es.  It would be much better for me if there was a black clip option.  Any chance you could make these eventually?

That and a backlight on the SM-series lcd screen?  Please?

e.

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Hi Ethan,

The final finish on the SM's aluminum case is a cracked nickle plating with Teflon forced into the microcracks. We used it to improve assembly tolerances and because it is conductive. With the nickle plating, the negative contact battery door can make electrical contact with the case, completing the circuit. The nickle is pretty tough but will polish when rubbed against other metal.  On the belt clip, we kind of like the blue but can change our minds if many others feel the same way.

We have requested a possible lit LCD from our vendor but don't know if they can fit it in the available space. Several people have hammered on us about that LCD for years (Scott Farr, you know who you are).

Best Regards,

Larry Fisher

Lectrosonics

Larry,

Snip< I do sort of miss the black finish on the UM-series.  I'm sure they're both similarly durable, but it seems like the black finish wears a little nicer then the aluminum (or whatever alloy you use for the SM-series transmitters. 

The other (more important) issue is that when hiding the SM transmitters on the talent's belt, that blue clip really stands out, and is easier to see on camera versus the black clips from the UM tx'es.  It would be much better for me if there was a black clip option.  Any chance you could make these eventually?

That and a backlight on the SM-series lcd screen?  Please?

e.

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The other (more important) issue is that when hiding the SM transmitters on the talent's belt, that blue clip really stands out, and is easier to see on camera versus the black clips from the UM tx'es.  It would be much better for me if there was a black clip option.  Any chance you could make these eventually?

Have you tried the optional wire clip accessory? I usually use that on my SMQV, especially for film use. It's physically, and visually, low profile. http://www.lectrosonics.com/europe/en/58-SMDBC/View-details.html

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