Building a Mixing Desk

cutlunch

Active Member
Joined
Jan 12, 2005
Location
Auckland, New Zealand
For this I would be happy using 1/2 watt metal film resistors. (1/4 watts would probably do as well) Get the ones that have 1% tolerance. They shoudn't be to expensive also now they come in the same size as the old 1/4 watt carbon that had a 20% tolerance.

Just for a better quality result I would use multimeter to match the resistors when there are things like voltage dividers etc where the two resistors have the same value. Eg Such as R# and R4 in Fig 4. This will help minimise any offset due to the resistors. EG the 6k8 that feed the phantom power to the microphones.

Just remember that he hasn't shown the power supplies to the IC's so you need to check the specifications. Also make sure you look at his page on the power supply http://sound.westhost.com/project30c.htm

Are you going to make this up using his PCB's ?

Before you get carried away with this project ensure that you can still get the parts or an an equvialent.

Cutlunch
 

Diarmuid

Active Member
Joined
Oct 24, 2005
Location
Cornwall, UK
Thanks, once again, for saving the day lol!

For this I would be happy using 1/2 watt metal film resistors. (1/4 watts would probably do as well) Get the ones that have 1% tolerance
I will indeed, (now) use the metal film resistors and test them with my DMM.
As regards to the PCBs, I am planning to use most of the ones available, but as I cant see any for a large part of the product, and dont have the know how or equipment to make any, I am planning to put the rest together on stripboard.

Hopefully, all of the chips and parts will still be available, but I will check as soon as I get out of the tech rehersal tommorow.

Thanks

Diarmuid
 

Diarmuid

Active Member
Joined
Oct 24, 2005
Location
Cornwall, UK
All the parts are available, at least from various suppliers around the world.

Does anyone, know how capacitors vary in audio circuits, basically does anyone know what frequency, type etc, are needed in audio circuits. Is there a single fixed frequency for all the circuits and are there simply two different types of capacitor needed one polarized, and one not (I realise that those two things do come in a wide range of different capacitors). If they do vary for each circuit, how do I work out what I would need? I am still using the circuits fromhere
Also, is there a difference between earth and ground, because in the UK, there is but I am not sure where the diagrams in the above link come from, and due to varying symbols, I thought I would check, also, does the earth/ground signal, just go to the earth pin on the plug or does it have to be removed in a different way?

Thanks and sorry for all the questions.

Diarmuid
 
Last edited:

cutlunch

Active Member
Joined
Jan 12, 2005
Location
Auckland, New Zealand
The earth /ground we talk about is the power supply ground not the mains ground. If you look at other projects on his web site also look at some of the articles he has written wou will be able to answer most of your own questions. Just use the index link at the bottom of the page.

Just a quick one, the capacitors marked with the + sign are electrolytics and must be put in the right way round. Most come with the negative leg being indicated on the side not the positive.

Cutlunch
 

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