Jolida JD9 phono preamp Upgrade Guide:

Intro: The JD9 is a very good phono preamp but with some easy upgrades it can perform well with the over $1,000 preamps out there. This guide will go through upgrading the JD9's tubes, opamps, caps, and installing dampening material into the case.

Tools needed:
Basic tools like screwdrivers, scissors, markers, soldering iron, solder (recommend WBT).

Upgrades used:
Lightweight Vinyl Sound Damping Sheet 10" x 13" (x2) from parts express
2x NEW JJ Tesla 12AX7 ECC83 ECC83S Vacuum Tube, Matched Pair
OPA637AP opamps (x6)
2x Obbligato Premium Film 1.0uF 630V caps

Case opened and the way it appears prior to any mods (note that the metal tube covers have been removed, and I recommend leaving them off).

Measure out the areas that you want to put sound dampening and mark up the back of the sheets so that they can be cut off. The white backing comes off to reveal the adhesive service so you can mark it up. Makes it easier to cut straight lines as well.

Cut out the individual peices.

This is for the top cover of the unit. I marked the widths (in inches) for the three pieces.

Cut and placed over cover to make sure it fits well.

Now peel the white backing and stick them into their place. For the smaller peices I just cut it free hand, but you can measure it to be more exact.

Same for the cover.

Overhead shot of the 6 opamps that we are going to replace.

The six opamps (as packaged) and a nifty little tool I bought off of ebay to extract chips. Even though I only paid 1 dollar (including shipping), it was a waste as the opamps are so close to other components that the tool won't fit in. I recommend using a pair of needle nose pliers and GENTLY grabbing the chips and pulling them out.

All 6 original opamps removed showing the empty slots.

This blurry picture is showing the new opamp in the socket and I'm putting very light pressure on it with my pliers to push it into the socket.

After that's all done, put the metal cover back on. This is another good shot of the dampening material on the inside of the case. Also, you can see that I removed the original tubes. You can do this earlier as it makes putting the dampening material in that area easier.

Ok, next we're going to remove the two original caps and put the new ones on the other side of the board.

And here it is removed. The best way to take this of is to gently grab it with your fingers or pliers if you have large fingers. Then with your soldering iron just touch the contact points on the other side of the circuit board. By only contacting it for 1 second at a time it will loosen each contact point and by doing this back and forth you can remove the capacitors without having to cut their leads or burning the board.

Here are the contact points of the original caps. So you can touch your soldering iron to these while simultaneously pulling them gently on the other side.

The old caps removed.

Ok, so here are the contact points that we're going to solder the new caps onto. Why not the original contact points of the old caps? Because, this will be a more direct connection and ideally the less length and connections in the circuit, the better the quality.

Here are the obbligato's. Whatever caps you decide to use make sure they have ample contact wire on them as you will have to bend it into a shape that will reach the solder points on the board.

First just bend the contact wires so that they match up to the soldering points. This means that there will not be much pressure on the contacts when soldering, and it will also give you an idea of what they will look like. Make sure the wire do not come in contact with any other metal areas like the cover or circuit board.

The first one soldered on to the board. I added a little solder to the end of the contacts prior to attaching and this made it really easy to attach it without the worry of solder dripping down and making connections with nearby circuits.

And the second.

And last, just put in the new tubes. Once again, I recommend keeping the metal tube covers off (and it seems that most people prefer this with their JD9 units as well).

And the job is done. New caps, tubes, opamps, and dampening!

Comments and suggestions welcome!

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