Mixermend

Hopefully it will use a commonly available lamp, possibly a car or motor cycle type. Do you have any markings visible on the lamp? Perhaps it will be worth posting a photo - at least we can determine the fixing, or holder type of the festoon bulb?

Importers tend to import a batch, with few, or no spares - and often with no documentation either. After a year or two the spares (if any) - will be gone - and no more will be available.

A couple of quick checks to carry out:

1 - swop over a pair of multicore channels with one known to carry Phantom OK from the mixing desk. Does the fault stay on the suspect channel?

2 - if not, double check that Phantom is definitely coming from the suspect channel on the mixing desk?

As you have found that the channel works with a dynamic microphone - this usually means that the screen is disconnected at some point, or no Phantom is coming from the desk on that channel.

Please report back - as we are all keen to find out what the problem actually turns out to be?!!

Interesting that they are described by Fabory as being made of cast iron, surely a translation error?

I use Westfield Fasteners in the UK for machine screws and other fixings - and I see that they do have wing screws in A2 stainless.

Again - they are a bit spendy - and only listed in 60mm length, but not too expensive if you buy 30:

https://www.westfieldfasteners.co.uk/A2_ScrewBolt_WingAme_M10.html

They are a very good company - it might be worth speaking to them to see if they have any other suggestions?

I have always been of the opinion - that if it has been made, it can be mended, but companies often don't make this easy.

With each card having 8 microphone amplifiers on it - I can certainly imagine that complete new replacements are expensive.

What is the exact nature of the failures that you are experiencing? Often with stage box designs, with remote control of pads and Phantom, sensitive areas of the microphone amplifiers can be damaged, despite being protected. Are you just losing the odd microphone input?

Does anyone have a schematic diagram for this product?

Do you have a spare channel on which you can record a continuous tone?

It will be easy to make this operate a relay - and synchronise the on/off switching of the relay accurately at the appropriate place in the music.

It would be possible to make a music track level change operate the relay - but rather more complicated and not as reliable as using a tone.

I can let you have a tone detection circuit schematic - if required?

Can anyone let me know the connector size (possibly 2.1mm) and polarity for the power supply connector for the Behringer PS400 Phantom power adapter?

I don't have access to the actual unit - or this would be easy to work out!

The Orchid auto switching DI is about to make a return - by popular demand!

Enjoyed watching Carol King and James Taylor on BBC2 on Saturday night - they were using the AKG mic system for everything, including the piano. Carol has just celebrated her 80th birthday, so it was great to see her in 1971 - what a fabulous long career!

Lots of ways to do this of course - but you could use a 1:1 transformer at each end of the line, then use further transformers to tap off the signal at various points along the line.

A few things we need to know to be certain of this strategy - how far away is the most distant location?

How many taps are needed along the route?

As long as the source has a reasonably low source impedance - and the 'loads' have medium/high impedances, whether balanced or unbalanced, this should work well.  

Enjoyed the 2021 Richard Dimbleby lecture by Professor Dame  Sarah Gilbert - who detailed the development of the Oxford Covid vaccine. She spoke for about an hour without any visible prompting - and seemed to keep her eyes on the audience.  Was there a clever system in use - or is she simply a really good speaker?

Well worth watching - it is available on the BBC iPlayer - and doubtless other platforms.

I have been receiving e-mail messages from Maplin recently - so it seems as though the Company is back!

They seem to be selling the same sort of stuff (toys?) - as when they were last around, but on purely a web based set up.

There were occasions when you needed a Neutrik XLR urgently, for example - and could get one from the store, despite it being priced at double that of your usual supplier. So they won't now have that advantage as they are mail order, so I wonder what their new niche actually is?

The use of 10 ohm resistors on each PCB is common to many makes and models of mixing desk - they should be fusible types - and are designed to blow when excess current is drawn by the module.

So if you find open circuit 10 ohm (or near value) resistors in series with the +ve and -ve power supply rails - do check for short circuits on the circuit board, usually IC failure, or occasionally supply decoupling capacitors.

This is a typical type of fusible resistor:

Vishay fusible resistor

Rather poorly described in the Amazon advert - but I think the resistors are for L+R combining to give a mono signal from a laptop or similar 3.5mm TRS output.

Out of stock anyway - and not suitable for your requirement!

Have a search for L pad attenuators - it is possible to fit the 2 resistors needed into a standard 0.25 inch jack plug - you probably need about 10dB, this is an experiment, but that will be a good starting point.

This is really horrifying - and whilst we in the Industry allow ourselves a smile at the gross design incompetence, the reality is that these things will be used in homes and small halls for kids parties and similar events, due to the very low cost of buying it.

Trading Standards Officials must be made aware of this product and UK supplier - and I appreciate that there will be many other similar dodgy items for sale - but this seems so dangerous and lives could easily be lost.

The operation manual linked above - DOES have the schematics in it.

This EQ design does use KT's proprietary MELT thick film devices - so if one of these proves to be faulty, I wonder if spares can be obtained?

You need a 15 volt DC power supply, with around 550mA output - connected to a locking ring type DC connector, pin size 2.1mm and outer barrel size 5.5mm (very standard fortunately).

Positive to the centre pin and negative to the outer.

Yes - these are the same connectors, so order with confidence!

I always put a dab or thread locking compound on these screws - superglue could be used, if you never wish to take them apart again. This is not quite a daft as it sounds, as any future damage to the connector means that you just cut it off and replace it.

The Yamaha PA-10 power supply, intended for use with the MG series mixers, would also be fine with most other mixers needing 18 - 0 - 18 volt AC and is fitted with the same 3 pin circular connector.

A much cheaper connector, also available from CPC, could be used - and then you could use a PSU intended for a small Phonic or Behringer mixer, many of which use the matching connector and the same AC voltages.

Circular Multipole Connector

If you are wiring this yourself, connect 0 volt to the centre of the 3 pins (pin 2). The wiring colours inside the mixer should make the required connections obvious.

Cable mounting socket connector