I started to post earlier, realized I didn't have time, so I will finish now (can I finish? can I finish? can I finish?)
The following is a klutzs description of modding the Eastern Electric Minimax DAC via Dougs recommended op-amp rolling:
I had been enjoying this DAC so much in its stock form that I was more than a little reluctant to monkey with it in the name of what? Futzing around? Flirting with audiophilia? Refusing to leave well enough alone? I had to ask myself am I dissatisfied with the Minimax? Is there some aspect of its performance that I feel needs improving? The answer to both of these questions was no so I tried to just shove the thought of a mod out of my head altogether. But I couldnt do it. The seed had been planted: the mod was said to be cheap, simple to perform and effective so I picked up the phone and called Digi-Key.
Let me say that you will need more than the parts numbers given by Doug in his article. When I gave the phone person those numbers his computer came up with semiconductors costing over $100.00. I told him that couldnt possibly be. The ones I wanted were only a couple of dollars. He had to get a tech guy on the line who was able to figure out what I was looking for. The complete parts number they are looking for is LME49710NA/NOPB and LME49720NA/NOPB.
I started to skip the op-amp extraction tool figuring I could use a pair of tweezers or something, thereby saving a couple of dollars, but that would have been a big mistake. Youll need the extraction tool if you dont already have one, so dont cheap out here.
The parts came quickly but I didnt move to perform the mod quickly. I continued to enjoy the DAC in its stock configuration. The old adage, If it aint broke dont fix it kept coming to mind. But finally, last Tuesday night, I decided to go ahead and do what I knew I would inevitably do, but I definitely had qualms about what I was attempting.
I admit to being a klutz. Im not a hobbyist or a mod person at all. Im a dilettante, an aficionado who just wants to listen to and enjoy the music. Im gladly willing to pay someone else to do my killing for me. But Doug said that this was about a 1.5 on the difficulty scale so I decided, what the hey, lets open this sucker up.
I took the Minimax to the dining room table armed with a powerful magnifier and a Phillips head screw driver to remove the cover of the DAC. This was the first moment of consternation when I discovered that the cover isnt held in place by Phillips head screws. In fact, Id never seen the type screw used here, but I finally found a mini screw driver that would remove the screws. This was already taking longer than expected. Upon looking at the circuit board through the magnifying glass, I looked and looked but could not find U1 & 2 or U6 & 7. After 10 or 15 minutes of looking I had just about decided that the circuit board designations between Dougs and my unit were completely different. I thought the project would have to be postponed and I would post about this discrepancy.
Then, I finally saw the designated numbers. I admit that my workstation left a lot to be desired a dining room table with a chandelier overhead. I was using a bright penlight along with the powerful magnifying glass, but a proper, well lit work station would be a definite plus.
I used the extraction tool to pull the first op-amp out. This was fairly easy and straight forward. I then tried to put the first replacement op-amp in. This turned out to be much more difficult than I had expected. With four straight legs on each side it seemed as if it would be a simple proposition to push it down into its new home. But nooooo. Nothing is simple and easy for me. Shining the penlight and using the magnifying glass I lined up the legs on one side and got them started going in. I thought I had them lined up on the other side and pushed. Ahhhh, that great feeling of sinking in up to the hilt. But then I noticed that the legs on one side had not gone in but were splayed out over the side! I pulled the op-amp out and tried again with the same result. Now I noticed that one of the four legs on the left side was bent a little. This is when I started to despair. I knew that if I couldnt get the legs to go in while straight, I would never get them in with one bent. I imagined the leg breaking off if I tried to straighten it, and further imagined being without my DAC for awhile waiting for replacement parts to ship in. I thought that even if I tried to put the old op-amp back in, I probably wouldnt be able to get it back in without bending and breaking it too.
But the gods smiled on me at this point. I was able to straighten the bent leg on the new op-amp and finally managed to push all eight legs in successfully. Wiping my brow I followed suite on the next 3. All of them presented some difficulty to me. When I would line up and begin to push the 4 legs on one side in, the 4 legs on the other side would want to splay out over the side. But I finally was able to seat the other op-amps without bending. Finally it was done! Id have to say that if you are a klutz like me this will be more like a 5 on the 10 point scale of difficulty, but if youre the normal audio enthusiast, Dougs 1.5 is about right.
So, was it worth it? YES, YES and again YES!!! All I can say is WOW! This is indeed one cost effective and VERY worthwhile modification of the Minimax DAC. The openness and spaciousness of the soundstage is unreal: top to bottom, left to right, forward to back. There is now so much more depth to the soundstage. There is also more detail with a greater incisiveness than was there before.
On acoustic, small scale music, its like the ensemble is in the room with you. On large scale classical music, the broadened,deepened soundstage and heightened resolution are the best Ive ever heard a symphony orchestra sound on a home stereo system via Redbook CD. A soundstage has to be big to accomodate a full symphony orchestra! There wasn't the congestion that you so often get when listening to orchestral music on Redbook CD.
I was worried that a modification might somehow take something away from the Minimaxs presentation of rock music. Its rhythmic drive and bass do wonders with rock music and since this is my go to music and the area where I had been enjoying the Minimax most, I didnt want anything to change that aspect. I neednt have worried. None of these traits are lessened; you just get the bigger soundstage and greater resolution.
What a great upgrade! Many thanks to Doug for making owners of the EE Minimax DAC aware of this modification. For me theres no going back. I cant stop listening and am enjoying Redbook CDs like never before. I would say, if you own the Minimax and havent done the mod yet, go for it. But if youre a klutz like me, just be prepared for a little more time and effort into the equation. Definitely worth it. Thanks again Doug!
