Brian

Is the noise of the fan really an issue? Most shows these days have so many movers in them, with their myriad of cooling fans, that there is a significant noise floor anyway. 

You might try the forum at speakerplans.com. Lots of posts there of amp internals.

10 hours ago, dbuckley said:

Different fogger.  I guess this one has some minor difference in hardware or firmware on the interface.

There are two main problems with cheap-arse manufacturers who are too tight to do things properly...

1) Break Timing - each DMX frame starts with a break. You're meant to test for the line being low for 88us to detect a valid break; that's 22 bit times. Cheapskate manufacturers only test for a data byte of 0 accompanied by a framing error. That's only a test lasting 36us, or 9 bits times.

2) Stop bits - each 8-bit data byte is followed by 2 Stop Bits. The cheapskates only check for the presence of 1 of those.

There are also issues around grounding topologies at both the transmit and receive end.

There would be a lot less oddities if people did things properly; it's not difficult.

On 6/24/2022 at 11:53 AM, Monk said:

I was wondering whether a bullseye level on the end of the bar might be a good way if you're on your own.

Assuming there's no flex in the bar.

Does the desk have a switch on the back to swap pins 2 & 3? Maybe it got knocked? 

28 minutes ago, timsabre said:

In my opinion, you would invoice an amount for doing the whole job and that would be fine..

And that's how I would do it. However, I'm interested in the other end of the process, ie the job ad.

I know none of us are tax lawyers but what are people's interpretation of job offers that specify a flat fee for a period of time?

Were that period a year then it'd clearly be the offer of a PAYE job. And I can't help feeling that it would, in HMRC's eyes, be the same for a shorter period of time.

One of the tests of true self-employment is that the person offering their services sets the rate they expect to be paid.

11 hours ago, sandall said:

I've been asked to connect an old Firewire soundcard...

17 years old to be exact.

6 hours ago, david.elsbury said:

I can’t find an impedance spec for it.

Interestingly the actual impedance doesn't really matter. Any two-core plus overall screen cable is going to be in the 90-130 Ohm range and any of them will work. Likewise, for a termination resistor, anything in the range 100-150 Ohms is way superior to having nothing. And, for DMX, it's not that important to match the resistor to the cable.

The reason for the latter is that there are so many discontinuities the overall impedance is rarely a single figure.

What is importance is, as David says above, the cable's capacitance.

On 6/23/2022 at 3:40 PM, kerry davies said:

Basically though if you join a production company on PAYE and they will supply what they consider necessary. Join as self-employed, you are the employer, you do the providing. 

Maybe, although the latest changes to the PPE Regs 1992 have brought 'limb (b)' workers under the regs. So unless you are genuinely self-employed, PPE should be provided.

And we all know what a rabbit hole self-employment status is.

Are you using chrome, or a chromium based browser? Try right clicking on the link and then clich save linked content (or whatever it's called) or click open in new tab. 

OK here.

Guitar cabs are normally open backed aren't they? The same driver in a sealed box will sound VERY different to what it does in an open-backed box. Very different.

What 'standard lightning controller' do you have available? 

It may well have been a custom effect controller but I can also see a way to do it by creating a fixture profile where the dimmer channel is LTP instead of HTP. 

Anyone using visualisers other than Capture and Wysiwyg?

Why exclude those? Wysiwyg is $3k, Capture starts at a more reasonable 395euro but you only get one universe for that.

Purely on price, I'm attracted to L8, starts at 88euro for two universes.

Is the BMD system compatible with Tecpro? There are a couple of incompatible systems out there. 

So U9 contains the program memory. 

There's something very wrong with your measurements. On the 7705 pin 4 should be connected to the 0V rail and not be some random voltage.

With the crystal across pins 18 and 19, like Tim, I'd imagine the processor is an 8051 family device. HOWEVER, if that is the case then pin 20 would be at 0V and pin 40 at 5V which is not as indicated above. @OP did you perhaps have the meter probes the wrong way around?

As for U9, a peel of the label to see the part number would be instructive. IIRC you used to be able to get a 'glue logic' chip to go alongside a '51 series chip that would demux the bus.

U9, the 'display driver' isn't the display driver. Those displays have on-board drivers (the black blobs on the back) and have a simple 8-bit parallel interface, and that appears to be driven from the parallel bus that runs the length of the display on the top side of the board.

The lack of voltage around the processor, as noted above, does seem to be a problem and would fit with the symptoms indicated by the display.

I bought a pile of these for a public planning enquiry, sold some when the enquiry finished but kept these as there was a chance of an appeal which didn't happen, and since then they've sat on the shelf. Time to spring clean.

4 x Mini Shotgun Condenser Microphones, CPC Part Number MP33866

4 x XLR Gooseneck Microphone Stand with Switched Base, CPC Part Number MP33248

Looking for £30 for the mics (current CPC price is £52.97) and £17 for the bases (current CPC price is £29.99). Discount for bulk.

Postage at cost.

Studiospares have been around a long while and have their own DIs.

38 minutes ago, J Pearce said:

I've not tried analogue comms down long runs of CAT5e, you'll need to resolve the shielding as comms is (usually) unbalanced, and I'd be wary of the current requirements - probably ok for a single pack but I wouldn't want to have a whole production desk world hanging off the end of a long run of CAT5e. 

Depending on the type of comms used it's fairly easy to solve with a PSU at each end of the Cat5 run and just bridge across the audio and signalling.

If you wait a month or so there's usually a detailed write-up in LS&I.

Or go to Facebook and look at various manufacturers pages and you'll find posts detailing their involvement. I see Madrix had a post listing just how much LED tape they used.