Newbie working on Yamaha MC1604 console

fucanay · 18th October 2005, 08:12 AM

Ok, here it goes. I've never done any kind of modification or recapping or anything of this nature before, but I do have a very mechanical way of thinking and none of this stuff is real intimidating to me. I can solder just fine and my first project is kind of low stress because it was free.

So what I have is a Yamaha MC1604 mixer. Most of the channels works, but not all. Of the ones that do work, they have periodic crackling in them. I'm assuming this thing needs to be recapped. And it's a good exercise in soldering on a PCB anyway.

So tonight I took it apart. Each module has 4 channels on it. It has a various different types of caps in it. Most of the caps have their values printed on the board beside them. It also has some ICs (information printed on chip: 4558RV JRC 4937). It appears each set of 2 channels share 4 ICs in various places throughout the board.

View Pictures Here: http://fucanay.fischerworks.com/pictures/mc1604/

My big questions are:

1. When replacing the caps, is there a recommended type to replace them with. I've heard that ceramic disk types are not referred for audio applications, but this has them in there. Is there another type that would be preferable? Is there a type I should definitely NOT use? Are they pretty much all interchangeable, as long as I get the correct values?

2. I don't know much about ICs, but I do know that some people prefer some to others. Is there something that I could use in place of the ones in there, that could/would make the channels sound better/different? I've searched the web quite a bit and can't find much info on these chips, so I'm looking for guidance.

3. These are 8 pin IC's (4 on each side). Can I solder in a socket and try various IC's? Any 8 pin IC's? or do they do such varying things that I would risk the circuit by doing so. The reason I ask is that I would like to try changing parts out to see if I can alter the sound.

Thanks in advance!

fucanay

dhaen · 18th October 2005, 09:23 PM

Hi Fucany,

I don't see any reason to change caps willy-nilly, and don't believe they are your problem.
I'd look at the switches and possibly the pots first for crackles.
The 8 pin chips are most likely dual opamps. Like the caps, changing these should be a luxury to be done after you've fixed the faults.

Not really a direct answer to any of your questions, but my take on the situation...

philipbarrett · 18th October 2005, 09:54 PM

If you are undertaking this as a learning experience then great. However, if you are expecting to improve the sound of a venerable 1604 then save your money and time. These consoles were built to be cheap & durable in low end sound reinforcement applications, an aim they certainly achieved.

If you're looking for a console to use I'd suggest a Mackie, Yamaha's MC series or even a Behringer.

My 2 cents.

PB

18th October 2005, 08:12 AM	#1
fucanay diyAudio Member Join Date: Oct 2005	Newbie working on Yamaha MC1604 console Ok, here it goes. I've never done any kind of modification or recapping or anything of this nature before, but I do have a very mechanical way of thinking and none of this stuff is real intimidating to me. I can solder just fine and my first project is kind of low stress because it was free. So what I have is a Yamaha MC1604 mixer. Most of the channels works, but not all. Of the ones that do work, they have periodic crackling in them. I'm assuming this thing needs to be recapped. And it's a good exercise in soldering on a PCB anyway. So tonight I took it apart. Each module has 4 channels on it. It has a various different types of caps in it. Most of the caps have their values printed on the board beside them. It also has some ICs (information printed on chip: 4558RV JRC 4937). It appears each set of 2 channels share 4 ICs in various places throughout the board. View Pictures Here: http://fucanay.fischerworks.com/pictures/mc1604/ My big questions are: 1. When replacing the caps, is there a recommended type to replace them with. I've heard that ceramic disk types are not referred for audio applications, but this has them in there. Is there another type that would be preferable? Is there a type I should definitely NOT use? Are they pretty much all interchangeable, as long as I get the correct values? 2. I don't know much about ICs, but I do know that some people prefer some to others. Is there something that I could use in place of the ones in there, that could/would make the channels sound better/different? I've searched the web quite a bit and can't find much info on these chips, so I'm looking for guidance. 3. These are 8 pin IC's (4 on each side). Can I solder in a socket and try various IC's? Any 8 pin IC's? or do they do such varying things that I would risk the circuit by doing so. The reason I ask is that I would like to try changing parts out to see if I can alter the sound. Thanks in advance! fucanay

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18th October 2005, 09:23 PM	#2
dhaen diyAudio Moderator Emeritus Join Date: Jun 2002 Location: U.K.	Hi Fucany, I don't see any reason to change caps willy-nilly, and don't believe they are your problem. I'd look at the switches and possibly the pots first for crackles. The 8 pin chips are most likely dual opamps. Like the caps, changing these should be a luxury to be done after you've fixed the faults. Not really a direct answer to any of your questions, but my take on the situation...

18th October 2005, 09:54 PM	#3
philipbarrett diyAudio Member Join Date: Feb 2005 Location: Dallas, Texas	If you are undertaking this as a learning experience then great. However, if you are expecting to improve the sound of a venerable 1604 then save your money and time. These consoles were built to be cheap & durable in low end sound reinforcement applications, an aim they certainly achieved. If you're looking for a console to use I'd suggest a Mackie, Yamaha's MC series or even a Behringer. My 2 cents. PB