March 21, 2011 at 4:14 pm #1050605
I need a replacement crossfader for my Gemini Executioner 10 mixer (yes I know it’s awful), I’m 99% sure it’s an RG-45 I need, but I can’t find the box for the last one and I don’t want to waste £15 if it’s not going to work. Can anyone confirm that it’s the right one or tell me which one is?
Cheers 🙂March 21, 2011 at 5:20 pm #1236724
rg-45 is for all the KL seris of gemini mixers 😉March 21, 2011 at 5:34 pm #1236731
Cheers matey 🙂March 21, 2011 at 6:02 pm #1236722cheeseweaselParticipant
Might be worth giving the old fader a clean before you throw it away (it’s only slightly more hassle than replacing it). Open the fader up and give the conductive plastic tracks a wipe with a little bit of water – if it’s just dirt on the tracks it will probably sort it out (some people use isopropyl alcohol but this can dissolve the lubricant and you’ll end up with a stiff fader – though if water doesn’t help then try it as it’s a much better cleaner).
If the fader is actually worn out though you’ll have to get a new one.March 21, 2011 at 6:23 pm #1236732
I’m pretty sure it’s fucked but I’ll give it a go, cheers mateMarch 26, 2011 at 10:52 am #1236725
butane gas can help get a bit more life out of dying faders (alltho it leaves a residue) …. mby a tiny bit of wd40 depending if it’s a contact fader or not (alltho i’ve never tried this so be aware it might fuck it up totaly lol). Or just a plane air spray like what you use to clean out keyboards … alltho all that will do is get rid of dust rather then help the contacts connect properly if there’s rust etc. in there.March 26, 2011 at 10:59 am #1236718
WD40 is nasty stuff. it gums up things. I won’t even let it near my bikes. there are better contact cleaners to use, you can buy a can from cpc.farnell.com and other similar places.March 26, 2011 at 11:01 am #1236726
yeah i was thinking that, hence the warning. That shit’s more used for hevey duty stuff like stiff padlocks etc. rather then electrical contacts.March 26, 2011 at 11:09 am #1236719
its been a long time since I did any mixing, but what I find more annoying is that often the actual fader itself costs 2 quid, and if you can get the component it could be soldered on to the PCB but it is near impossible (in England at least) to find them in electronics places at the right dimensions and resistance level :rant:
I used to repair sound mixers and other kit for the BBC, Anglia TV and other such places and they always used components you could buy from Farnell or Canford…March 26, 2011 at 11:11 am #1236727
I bought a vestax pcv (?) 275 and within one mounth the crossfader went so i took it back to get replaced … then 2 of the three up faders and the cross fader had fucking gone AGAIN! Expensive piece of junk. (faders are like £30< for that perticuler mixer – vextax are tight fuckers – it cost's an extra £50 per deck if you want plastic dust covers what tecnics come with as standard!!!)March 26, 2011 at 11:20 am #1236720
its a complete ripoff TBH. this is the actual bit inside your average mixer.
about 15(!!) years ago mixers didn’t have replaceable crossfaders, but as most pots were the same dimensions it was easy enough to mount another one in there..
I can’t remember though whether a crossfader uses a linear or log pattern. I think its linear or the centre point would be in the wrong place… cheesweasel would probably know for sure.,,March 26, 2011 at 11:21 am #1236728
what do you mean by linier or log patten, if you don’t mind explaining.March 26, 2011 at 11:23 am #1236721
Linear taper potentiometer
A linear taper potentiometer has a resistive element of constant cross-section, resulting in a device where the resistance between the contact (wiper) and one end terminal is proportional to the distance between them. Linear taper describes the electrical characteristic of the device, not the geometry of the resistive element. Linear taper potentiometers are used when an approximately proportional relation is desired between shaft rotation and the division ratio of the potentiometer; for example, controls used for adjusting the centering of (an analog) cathode-ray oscilloscope.
A logarithmic taper potentiometer has a resistive element that either ‘tapers’ in from one end to the other, or is made from a material whose resistivity varies from one end to the other. This results in a device where output voltage is a logarithmic function of the mechanical angle of the potentiometer.
Most (cheaper) “log” potentiometers are actually not logarithmic, but use two regions of different resistance (but constant resistivity) to approximate a logarithmic law. A logarithmic potentiometer can also be simulated (not very accurately) with a linear one and an external resistor. True logarithmic potentiometers are significantly more expensive.
Logarithmic taper potentiometers are often used in connection with audio amplifiers as human perception of audio volume is logarithmic
so its probably a linear used in the crossfader but log ones everywhere else in the mixer (its been a very long time since I replaced one..)March 26, 2011 at 7:04 pm #1236723cheeseweaselParticipant
I’m not sure really. Most DJ mixers nowadays use VCAs in any case so they probably use linear faders for everything as they’re cheaper (and since no audio ever passes through them they probably get away with using the shittest ones they can find).
Thinking about crossfaders, it’s almost the opposite of a pan pot (pan pot takes a single signal and sends to two buses, crossfader takes two separate and different signals and combines them to a single bus). With a linear panning law, you’d get a 3dB dip in the middle (which is why they aren’t used in desks). Not sure whether the same logic could be applied to a crossfader though – the fact that the two signals are different probably means it can’t. Maybe someone with more sound engineering knowledge could put me right?
Actually, looking at the datasheet for a Penny & Giles crossfader, they use a linear law.March 29, 2011 at 3:31 am #1236730
Some crossfaders dip in the middle (I dunno the tech behind it tho) so as to not get a audio boost from haveing two signles … some have a variable curve knob (called a hampster or squirel switch? – my mate allways takes the piss cos I allways get the wrong animal and that name might just be for the reverse input feature for scratching.) but most decent moden crosfaders (unless tech’s moved on even more since i last checked) are led/laser ones. Alltho they are not useualy standard in mid-range priced mixers afaik (you have to upgrade yourself). Only top spec ones have them as standard as they can be pretty expensive on there own.
You’ve got led’s one side and sensors the other like this:-
with something blocking them where the cross fader is :-
It’s basicaly a digital version. 1/0
The very top range are magnetic floating zero contact ones so not even the rail that holds the fader inplace can get stiff because of rust (aparently they tested how good one actualy was by pooring coke over it and it still worked perfectly even after it dried!) They are pretty much invinsible.
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