bg4533
Headphoneus Supremus
- Joined
- Jun 21, 2004
- Posts
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I am about to order some parts to mod my EMU 0404. Below is a link to a picture of what I want to do. I only care about improving the analog output of this card.
Picture
Color Codes:
Yellow: 10uF/16V caps, replace w/ Panasonic FC 10uF/25V (16V unavailable)
Red: 100uF/25V caps, replace w/ Panasonic FC 100uF/25V
Pink: 47uF/16V caps, replace w/ Panasonic FC 47uF/16V
Green: Output caps and buffers, remove and jumper
Orange: Opamp, replace with LT1364, bypass cap, Bias to class A with ~1.5mA CRD
Removing buffers:
The datasheet lists the pinout of these opamps as:
1. A Output
2. A- Input
3. A+ Input
4. V-
5. B+ Input
6. B- Input
7. B Output
8. V+
I obviously have to bridge A output to one (or both) A input, but which? The same goes for B.
Bypass caps:
I think I am just going to use a Panasonic ECQP Polypropylene here. I have not yet decided on a size. Should I bypass from rail-rail or rail-ground? Rail to rail will be easier. What are the benefits of each method (I want to know this for future projects mainly). If I go rail to ground can I use the silver box by the buffers as ground? Anywhere better for ground?
CRDs:
I have been unable to find these on Digikey. Anyone know any part numbers?
Capacitors:
I want to keep this a fairly cheap mod, so I am going to stick with Panasonic FCs for now. Are there any other caps on this board I should upgrade or are there any that I am upgrading that don't pertain to analog output? Provided the caps fit, could there be any problems with using a larger capacitance cap? Prices are about the same, so I might as well use larger ones if it won't hurt.
Thanks for the help. After I finish I can put together a modding guide with pictures if people want. The cost for all the mods should be ~$15.
Picture
Color Codes:
Yellow: 10uF/16V caps, replace w/ Panasonic FC 10uF/25V (16V unavailable)
Red: 100uF/25V caps, replace w/ Panasonic FC 100uF/25V
Pink: 47uF/16V caps, replace w/ Panasonic FC 47uF/16V
Green: Output caps and buffers, remove and jumper
Orange: Opamp, replace with LT1364, bypass cap, Bias to class A with ~1.5mA CRD
Removing buffers:
The datasheet lists the pinout of these opamps as:
1. A Output
2. A- Input
3. A+ Input
4. V-
5. B+ Input
6. B- Input
7. B Output
8. V+
I obviously have to bridge A output to one (or both) A input, but which? The same goes for B.
Bypass caps:
I think I am just going to use a Panasonic ECQP Polypropylene here. I have not yet decided on a size. Should I bypass from rail-rail or rail-ground? Rail to rail will be easier. What are the benefits of each method (I want to know this for future projects mainly). If I go rail to ground can I use the silver box by the buffers as ground? Anywhere better for ground?
CRDs:
I have been unable to find these on Digikey. Anyone know any part numbers?
Capacitors:
I want to keep this a fairly cheap mod, so I am going to stick with Panasonic FCs for now. Are there any other caps on this board I should upgrade or are there any that I am upgrading that don't pertain to analog output? Provided the caps fit, could there be any problems with using a larger capacitance cap? Prices are about the same, so I might as well use larger ones if it won't hurt.
Thanks for the help. After I finish I can put together a modding guide with pictures if people want. The cost for all the mods should be ~$15.