Members WRGKMC Posted May 13, 2015 Members Share Posted May 13, 2015 I bought one of these Shure M267 mixers on EBay and thought it might work as a recording mixer. These are normally used as a mixer for remote broadcast and video work and had been a standard tool up till about 2000. This one has several advantages over some of the older M67 type Shure mixers. Its got a built in test tone for setting up levels through the output, Phantom power and an optical limiter. Both the inputs and output have impedance matching transformers. If they are as good as Shure's in line transformers I should be in good shape. I paid $20 for the unit and I figured its worth that in parts alone. The cool part is these can be modded very easily. The individual channels come into a single mixing buss. Between the channels and the buss is a high pass filter switch. That switch can be easily modded and have the low pass cap removed and instead of putting a high pass cap in series, you simply install a 1/4" jack on each channel and you then have a mixer with 4 outputs to record 4 different mics. If you want to use the buss then just switch back to normal. I'll just need to find a spot for the 1/4" jacks. The lid is a possibility, maybe one side or there may be room between the XLR jacks to drill holes. The preamp is a single op amp which plugs into a socket and those can be replaced with much faster high quality chips very easily. The power supply can have higher value caps installed too. If this comes out being anywhere close to sounding decent I can use it for recording or sell it for a decent profit. Its all going to come down to how noisy the resistors are. The circuit is super simple up to the buss so even replacing the resistors with metal film is no big deal. The unit is built well and it will even run on battery power which can be handy doing live video recordings. Don't know how well it will work out but I'll find out soon enough. When you consider they recorded Woodstock using nothing but these M67's I think I'll do pretty good with the newer version. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 14, 2015 Author Members Share Posted May 14, 2015 We'll see. I've read mixed reviews on just how musical their stuff is. The Shure Vocal Master PA was hugely popular when it first came out, mainly because there wasn't any competition in the portable PA field at the time. I'll just have to evaluate it against other preamps I have and see how well it does. If not I can simply resell it. Link to comment Share on other sites More sharing options...
Members WRGKMC Posted May 18, 2015 Author Members Share Posted May 18, 2015 I got the unit in very quickly and had time to test it out quickly. The 30 volt Phantom did power my EV condenser mic but its signal was much too hot for the preamp. I then tried an SM57 which was much better. The channels were still pretty hot for close micing so I may need to pad the input levels down. It does have a limiter threshold level I need to try messing around with. The unit uses pro level impedances which are very hot. I may be able to try using a 600 ohm resistor over the terminal output or some other tricks. The frequency response wasn't bad considering what it is. Maybe with the channels split from the buss it will make for a better vocal preamp. As is it may be good on instruments. I'm sure I could juice up the gains for some trash drum distortion. Its actually easier to get that using daw plugins today. Might do a good job on room mics too. I'll just have to experiment with it more. Link to comment Share on other sites More sharing options...
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