sunray

1 hour ago, Oscah said:

Hi, so I am working at a sixth form college, trying to make the most of an under equipped little theatre, I have a 1001 things to buy not least of which is a talk back system of some sort. Unfortunately we need lights more than we need talk back but considering we all have Chromebooks or laptops it would seem totally reasonable to have 1 in each wing with a headset with a long cable, 2 or maybe 3 more Chromebooks in the control room for sound lx and my trainee DSM!

 

What issues am I going to have that I haven't yet thought of?  I use discord a lot to talk to friends worldwide and have found it pretty stable and reliable really, at least more usable than no talk back system at all, so what do you think  good plan? bad plan?

 

 

thanks

If it's a 6th form college there are likely to be technical students with contruction abilities. Look on this forum for blueclone.

This sort of sleeving makes a good multicore https://www.ebay.co.uk/itm/175821632523?var=475224440614&itmmeta=01HVMD1FW5CW4TMA1EKRXBBY9V&hash=item28efc9340b:g:8XEAAOSwaxBktPWf&itmprp=enc%3AAQAJAAAA4O83tJaNvCmVhFZdXqXoVTLD5OAq6aCfYLqo1hbc2tgFXN%2FqVQVFdJvosaVxeYzcCeR8uwqiFGe8%2BF2oFUkwAJSjSGpzjqV8hAFzBOeI6z2EFntnMKxr43Lf5xEoInaS4PxXBY8IVA1H%2BLO3eqmfty9ZPtTzmDWJaLNJHLjDIcx19cX2j68Y1hq%2F0ITC5HZSodc3PO%2FVzvyu%2BeepxQZ4ppDgGZjqrKDPzU94ffRdx9BOpY1Vii1Tq8wZH7aHNSucMhy0nP1R09HFbZPpPFJRYKh8hMQ3BXQA5SjXZyZTXjCD|tkp%3ABFBMsv6Fjd1j

I often position radiomic receivers nearer to the source rather than run long aerial cables.

Bear in mind you will require a working space of at the very least the length of any loom you make, I've found it's easier to draw the sleeving onto the bunch of cables rather than pull them into the sleeve in which case you require twice the length. The longest I've done has been 50m, that requires at least 3 people but the end result is worth it.

3 hours ago, Tomo said:

Some demux units have individually isolated 0 to 10V outputs.

As individually-isolated outputs don't have any common reference, they'll drive either polarity when wired appropriately.

I have no problems with the operation if they are individual & isolated,  however to date I've only encountered them in groups of 4, 6 etc and so far only a common pin, I made up a cable just a couple of weeks back, DB25 (with only one common) to 4x 8 pin Din (with one common each) which is typical of what I've come across and until now assumed it's standard..

6 minutes ago, Bryson said:

FYI, at least with the Pathway DMX to 0 to 10V converters, you can just wire them "backwards" and they work just fine with old stuff thats expects 0 to -10v.  I have several installs out there with DMX control over old Strand JTM or STM dimmers that work that way.

How does that work?

I've had involvement with wireless DMX twice, one was the issue of sequencing the start-up routine to revent them going into transmit and we had to replug mains services to achieve that however after that we found the system, and the other had the same issue, developed delay issues when the venue filled up, at a scene change there were some, but not always, obvious delays between the cabled fittings and those on wireless links and also odd flickers. One of them had 3 significant glitches coinciding with the goals scored in a football match which was the clincher for us.

19 minutes ago, cedd said:

Hi all. Thanks for the responses. 

For clarity - I'm using these for data connectivity. I have looked at the xlr over cat boxes before and wondered how it got 12 pins over 8 cores. The ones I've seen have specified screened cable. 

I'm going to contact Canford and Lynx, as neither item I want is a stock item. Just need to suss out lead times for them both. I've had Lynx stuff before and liked it, and have also seen the Canford ones in the flesh too. Both look good. 
I did briefly toy with making my own using tape and individual cables, but when I factor in the cost of ethercons and cable, it's a cheaper option but not by enough versus the neatness of a proper multi. 

I find with many things like this it's not worth making your own...  But of course that's how I've always done it.

A little while ago I installed 16XLR audio tiepairs between stage and control desk in a school hall. It was just cheaper to buy a ready made snake from CPC than to buy just the 16 way cable.

5 minutes ago, cedd said:

Hi all. Thanks for the responses. 

For clarity - I'm using these for data connectivity. I have looked at the xlr over cat boxes before and wondered how it got 12 pins over 8 cores. The ones I've seen have specified screened cable. 

I'm going to contact Canford and Lynx, as neither item I want is a stock item. Just need to suss out lead times for them both. I've had Lynx stuff before and liked it, and have also seen the Canford ones in the flesh too. Both look good. 
I did briefly toy with making my own using tape and individual cables, but when I factor in the cost of ethercons and cable, it's a cheaper option but not by enough versus the neatness of a proper multi. 

it was common to use 4 cat 5's in an overall sheath to simplify structured cabled ethernet but sadly not flexible.

I used to use 7 pair stranded cat 5 a fair bit, we used to get it on 500m drums and behaved itself for portable work, even the overall braided screen version. It's possible I may have some offcuts lurking but doubt anything long. I don't see why larger sizes should not be available.

3 hours ago, timsabre said:

Some of these boxes don't connect the screen even if you use screened cable. It is often difficult to tell from the description.
I have seen a 3-way version of the box which uses the 4th pair as a common ground for the other 3 pairs.

You can run balanced mics fine with no pin 1, phantom power does not work though and it is somewhat more prone to noise pickup, though the controlled twist of the cat5 cable pairs makes it work fairly well without screen.

Absolutely. For years I've been using cat2 onwards for balanced audio and some very long runs, For OB's it's been common to use 2 pairs for stereo feed, 1 pair for return audio & 1 pair for talkback, sometimes as the actual link but more usually as the run between studio/radio and OB/radio and they may often be hundreds of metres.

Years ago I made up some boxes with 4 XLRs and RJ45 for 'stage snake' type use then added a switch to some to use pair 4 as the common ground for phantom use. Just recently I repurposed a male end which was simply 4 thin FSTs style terminated in a RJ45 plug and male XLRs.

1 hour ago, J Pearce said:

As above, the Bosch Dinion kit is good at this. You'll need to spend money on a camera with exposure and shutter settings, any of the cheap auto exposure CCTV cameras will struggle with the dynamic range of a stage lit production.

I started looking after I'd posted yesterday, I see a selection of models, are there any better/worse than others?

The usual camera I've been using for a long while was a pretty good CCTV camera 20 years ago, I think about 350TVL and TBH most of what its used for the momentary white/black out doesn't really matter that much unless there is significant flashing. As I'm claiming to have retired I'm not looking to invest much😉

Cleared a shelf today, these bits are going on ebay tomorrow (Monday) PM while I have 80% offer

Soundcraft power supply - CPS 150

Alice Matchpak  X2

Canford twin microphone pre-amp

Tannoy TX1   system controller

Kramer FC10  Composite/YC transcoder

Drake 1U IEC 10 way power distro -  10A max with 5m mains lead and 16A CEEform

SCV universal balanced/unbalanced interface - includes: 3* VCA/AGC (unbalanced),  5* in/out, 1* 4unbal in to 2balanced out, 1*PSU

Most unused since my last OB >10 years ago, just done very basic tests to confirm working and all have scratches from a working life.

Open to offers.

I have regularly put show relay in for village hall type shows, mostly to dressing rooms where latency is irrelevant, initially using 21" CRT TVs and composite, often running over cat5 with baluns. One venue had 19" flat monitors and VGA over cat5 receivers in place so sourced the same system from CPC and converted to VGA. despite being smaller the actors seemed to prefer the flat screens and found myself running VGA on 19" flat screens more than CV on bulky CRTs.

However a trip to the local tip at TV Digital switchover quite by chance I parked beside a vehicle from which a 15" and 19" analogue TV were being removed, the jobsworth staff member tried to argue I wasn't allowed to take them despite not even touching the ground, literally a direct vehicle to vehicle transfer and during that another person offered the 19" he was about to dump. Those 3 plus another 19" aquired since are my usual stock for such, occassionally 32"s/40"s from home when required but rare.

Do I regret disposing of CRT stock? Only once as relay to MD from SM feed. At one point both could be seen wiyh significant latency to MD.

I did try using a CCTV cat5 system... Yeah right, never again.

As far as I'm concerned it's analogue all the way, I just wish I could find a camera to cope with the dramatic light changes better.

I have had a couple where one output transistor has gone s/cct C to B (effectively a diode between C&E) which seems to 'work ok until the volume is cranked up', or so the docket says.

All sorted, luckily the double sided pcb (containing 2 pots each and linked with 3 pin jumper leads) are laid out in such a way that cutting 2 tracks by each pot and soldering a link across the pot pins was easy.

Input resistance is 6* 10K+10K in parallel = 3K33

I know it shouldn't but that arrangement seems to work more 'linearly'  than just one such control.

This came from AliExpress at a total cost including delivery under £7 with a white stripe to write on and took 20 minutes from the time it came through the door to modify and test. Yes it's cheap but at the moment it seems to be useful, even the XLR's feel OK. The only downside that I can see is it's only 58mm deep so can be very deeply buried when it comes to access for plugging.

14 hours ago, James said:

Just trying to sort some of my systems out and I can't seem to find any markings for frequency range (830-865MHz /  606-638MHz) on the Receiver Antennas 

Any hints of what I might be missing from other Trantec users? 

Thanks 

 

James. 

These are for S4 & S4000:

The shorter (top) aerials are for CH70/higher frequencies, the longer (bottom) aerials are for CH38/lower frequencies.

I assume other systems follow the same format.

10 hours ago, Stuart91 said:

X32 definitely makes sense for bands etc. but maybe factor in a smaller/simpler analogue mixer for events with basic requirements. 

Thank heavens I'm not the only one to have this thought.

11 hours ago, cedd said:

Thank you everybody. One of my trusty old crown amps worked a treat and we were able to locate all of the zones. Can confirm that my impedance meter also drove the circuits a-ok. 

A good result! CPC amp still hasn't turned up!!

I was surprised the first time I used an impedance meter just how efective it is for the purpose, did you think the same?

PM sent

As has been said any amplifier will do. I did exaclty this exercise in a shopping centre fitted with 32 zones of voice EVAC. Initially we tried locating failed speakers using the main system (450W per zone) but lack of volume control capabilities made it difficult. we used a small amp of around 30W at 8ohms to provide a low level signal on a zone by zone basis.

The thing about such a system is if properly designed there are no apparent gaps in the sound but running at a much lower level allows the gaps to form.

As Philip has mentioned the tone set may be enough for the job, the same is true for a loudspeaker impedance meter.

As an aside to this I'll shortly be sorting out my 'store' and disposing of my PA hire stock including a number of 120W mixer amps, typically TOA A512 sort of thing if it helps.

EDIT: Another aside: I've been using Eagle horn loudspeaker for 50 years 100V tapped at 15W and regularly run a row of them on a 120W 4ohm amplifier without a step-up transformer.

8 hours ago, sandall said:

A friend of mine used to hump around a load of large CRT TVs for the local am-dram musicals, which all used an off-stage MD & band. 

Me, Me🤫

Initially I had 2* 21" tv's to do show relay to dressing rooms, then used 19" VGA monitors, with CV to VGA  and VGA to CAT5 adapters.

Taking one of the TV's to the tip I was really lucky someone was dumping 2* 19" flatscreen analogue TV's a few days after digital changeover and used those ever since. I tried using TV internal speakers but find it's much easier with Fostex powered speakers.

If your current TV's have analogue tuners then the modulator from a VHS machine and the supplier may be pleased you take it off their hands😁

1 hour ago, IRW said:

Thanks folks...DVb-T Modulator was the key term that I didn't know! @sandall, that won't be a problem in this situation- if we needed visual relay to the box it would come straight from the composite distribution amp, rather than via the TV system.

CPC used to do several but IIRC the called them something like encoders

EDIT: Wow I can't believe the price hike, these: https://cpc.farnell.com/antiference/dmsd02/digital-modulator-twin-sd-dvb/dp/AP02864?st=dvb modulator

were <£100, now £510+

another at £289+:  https://www.alltrade.co.uk/shop/conexer-single-sd-dvb-t-modulator

also available at Alltrade:  https://www.alltrade.co.uk/shop/conexer-single-sd-dvb-t-modulator  but one has to convince them you are a TV installer

I've mocked this up and thinking about sandall's balance comment I set it up using a 10K lin pot for unbalanced stereo and played a bit of Pink Floyd Sheep as it has a heavy stereo effect.

Rather than having a balancing effect it narrowed the width of the sound and only cancelled those sounds equal on both channels.

Wiring as balanced attenuater (as Lamplighter offered) works a treat except for the kit I was using (Spirit notepad and Canford powered diecast monitor speaker via isolating transformer to ensure it is balanced) there is a very non linear feel with lots happening at each end of the track and not much over the middle half, reducing the 10K down to 2K made much better sense.

I will demonstrate it to the owner of the unit to see if he wants to reconfigure it.

As built the current arrangement is very difficult to alter on the hoof.

1 hour ago, J Pearce said:

Any reason not to use stage weights? If the french braces are made from 3x1 (or 18mm ply) then the notch in a stage weight secures them in place well on a french brace.

They're easier to handle so improves manual handling, they won't leak sand, won't get damp and go mouldy, they stack securely when not in use - lots of advantages. They'll cost a little more though.

Not something I'm particularly suggesting to do: At school we had lengths of railway lengths about 15-18inches long, very historic even back in late 60's stamped with '40lbs' and some half the size. I assume made in the metalwork shop with a couple of links and a 'T' handle which laid in the groove on the top (the rail laid on it's side) when not being lifted.

EDIT: no,got that wrong, thinking of something else. they had several holes through the web and a separate handle arrangement to hook through a hole and lift them:My proportions are wrong but the basics show and of course the profile of railway track is now very different.

They were stackable as the head and web were fairly similar sizes

5 hours ago, Simon Lewis said:

Audio Technica certainly made quite a thing about their microphones being re-engineered to reduce RF interference. I'm guessing that the rise of mobile communications meant that such a move was inevitable...

Now you mention that I remember the change of tech sheet that came with AT8033's.

On 2/27/2024 at 3:05 PM, Junior8 said:

No I'd just managed to forget them...

The only reason the pair are still here Is I wondered about converting to LED.

Rob

There are 2 of these, quite honestly they have been hanging up out of the way for a while. A bit fiddly to get them down at the moment (due to a foodbank invading the space) to take better pics. I planned to use them maybe 5-6 years ago (more for the prop value than lighting reasons) but the damaged cables & plugs/sockets didn't pass my PAT and it wasn't worth my time repairing them for the situation, in fact so wrong I'll strip them off before passing them over. I think a full set of bulbs but one unit is facing the wall, never seen them in use so no idea if all or how many are good.

The Strand 8 was eventually sent for scrap during a clearout.