Don't do this at home .........

Bulk metal foil resistor is very expensive but gained a lot of good words in audio application.

I thought you might have heard that there is a new type called the "Naked" foil. A lot of people claim that it has a very noticeable improvement over the traditional style, encapsulated type.

In order to see what's inside under the epoxy coat, I have cracked one and let's take a peep. :-P





After taking off the "black" coat, there is another coat covering the metal foil. It's obvious that it is used to protect the delicate metal foil.
So, you might ask, what's under the brown coat then?
Here it is,





Yes, the expensive metal foil resistor is now completely vanished. We can see the foil which is bonded to the brown coating.

OK, here is the real "Naked" foil resistor,





Sexy? I don't think so. :-P

How does it sound when comparing to the usual type?

It does show some merits, a little bit more open and relaxed but the difference is subtle.

Emerson, Lake & Palmer

"Welcome back my friends to the show that never ends,
I'm so glad you could attend
come inside, come inside......"

I think this is from a live around 1974,



is this from the same concert? :-)

Successfully transplanted

It was a nightmare to do this, but it's done successfully. The new ES9018 (Sabre32) is now sitting on the Buffalo board. The original 9008 was removed using an hot air rework station. Before lifting the 9008, I have to remove 4 decoupling cap surrounding the ESS.




Since the Sabre32 is pin compatible to the 9008, no additional adjustment needed and just solder the 9018 back will be fine. Here is the removed 9008 and the 9018,





As the Buffalo board is stuffed with other components, soldering the new 9018 back is a bit tricky. I first align the chip and solder 4 corner pin to hold the chip in place. Then I started to "flood" the pins with solder along the 4 sides of the chip. Finally, I started to blow hot air to the sides with the rework station and suck off excessive solder using a small desoldering pump. My pump is made by Goot and the result is great.

And here is the board with new chip. Not bad, huh? :-P





I need a break after doing this and hook it up again to the discrete I/V later.

Impression about this new chip will follow.

rolling game

A shot by Tomas Leandersson, my favorite bowler. :-)

It's getting better.........

I have finally added a discrete I/V board to the ESS Sabre DAC, bypassing the original I/V that used opamp. This discrete I/V is one of my previous design using all BJT that is in a single common base configuration.

The sound does open up a bit, the most noticeable improvement is the bass. With the opamp based I/V, bass is kinda artificial and colored a lot.
On the contrary, the discrete version gives an accurate presentation and somewhat more neutral.

The only draw back of this old design is that it's not direct coupled, I need an output cap to block the DC. I have an idea of improving the design by adding an "folded cascode" to the common base stage and an extra DC servo to monitor the output. A true balanced config is possible too.

Well, before I move on to a new I/V design. I have a good news that the newer ES9018 (Sabre32) chip has arrived and I'm ready to do a "transplant", replacing the ES9008 with the 9018.

The 9018 has a reconfigurable digital filter, ie. one can change the filter coefficients with an external processor. This allow a customizable filter that may (or may not) change the sound on the fly.

Let's wait and see if I like this new chip. :-)

Keypad fixed

After some cleaning of the keypad assembly, the non working key is now back to service. :-)




This is the keypad PCB.