by Kevin O'Brien on 04/21/2012

I decided to give my Eastern Electric Minimax DAC Plus an anabolic shot in the keyster a couple days ago. One quick and easy tweak you can apply to this DAC is changing out the operational amplifiers (op amps) to get a different sound. This is an option because Alex Yeung used sockets for the op amps instead of soldering them in like most other designers do. THANKS Alex!

A VERY helpful company based out of Oklahoma, Cimarron Technology, helped make this possible. They offer very handy adapters that allow you to drop in replacement op amps without the need to solder them onto the adapters yourself! I am specifically referring to the "SO8 to 8-pin DIP Adapter" that they offer for $3. They give the user several options for pre-mounted op amps such as the LME49990, OPA627AU, OPA2604, OPA827AI, AD8397, and the OPA2134 to name a few.

Alex, the designer of the Minimax DAC and DAC Plus, has approved these for use with both the DAC and DAC Plus. This voids the warranty but I'm not too worried about that. I've played the unit for over 8 months with absolutely no issues so I figured I'd just go for it and I'm glad I did.

According to Bill O'Connell of Morningstar Audio, the op amp rolling can make a nice improvement. He offers the combination that I have tried pre-installed for an extra $100 over the retail price of the DAC Plus. This way you can retain the warranty if that is important to you. You can save $20 by doing it yourself. I obviously opted to do it myself. The op amps are plug and play so there's really not much you can do wrong as long as you're careful.

I ended up going with the OPA2604 in the U1 and U2 positions. If the user is only interested in the tube output, he can choose to replace only the U1 and U2 op amps as the U6 and U7 op amps are used for the solid state output. I also ordered the OPA827 for positions U6 and U7. One quick note here: If you plan on ordering the above mentioned combination you have to order (2) of each op amp pre-soldered onto the "SO8 to 8-pin Adapter". Do NOT order any other adapter board combination. There are a couple more options such as the Burson Audio HD Op Amps as well as the NewclassD Dexa Dual 73728 and Dexa Single 73729. Both sets of op amps can be had from Parts Connexion. Folks have reported that a combination of Dexa's and Burson's can really take the DAC Plus to a new level but the price tag is a little steep. The Dexa combo (4 op amps) will run you $280 and the Burson combo (4 op amps) comes to $295!!! OUCH! Most users agree that the 2604/ 827 combo is the way to go for $80. If you're on a budget like I am, it's DEFINITELY the way to go. One caveat here: If you are using the latter op amp combo (Dexas or Bursons), the cover of the DAC Plus will not fit on top of the unit. You most likely will have to space the cover from the chassis with spacers and longer screws or something to that effect.

I figured it would be nice to try the solid state output of the DAC Plus with the tube removed just for fun. I'm glad I tried this. There seemed to be a bit more detail in the SS mode so I chose to keep the DAC Plus in that mode. I can alter the presentation of the music by switching my preamp tubes to GE 12AX7's from my current Siemens 12AX7's if things get a little too bright so I wasn't worried.

The op amp rolling results were pretty interesting. I noticed more detail/ separation and more punch in the low end. This was just what Bill had reported during his op amp rolling sessions. VERY COOL!  I could definitely hear more detail and the instruments seemed that much easier to identify as they felt like they were in their own space.

I ran the op amps in for 100 hours just to make sure before I did any critical listening. There seems to be some debate on whether "burn-in" is real or just a phenomenon. I am definitely a believer in burn-in. That is an entirely different discussion for another time!

I hope I've shed some light on what your options are for rolling op amps in the Minimax DAC and DAC Plus. It's as easy as popping off the cover, removing the original equipment, and then placing the new op amps in their place. Make sure you place them in the sockets facing the correct way and you're good to go.  That's about the only thing you need to pay close attention to as well as not discharging any static electricity into your DAC's internal components. Again, if you're not comfortable with this process, Bill will pre-install the 2604's and 827's for a $20 charge over the cost of the parts. THANKS Bill!

Until next time...


Associated Equipment For This Review:

  • HD Reference-2 Computer Music Server
  • Quicksilver 12AX7 Tube Preamp
  • McIntosh MC275 Tube Power Amp
  • Von Schweikert VR5 HSE Speakers
  • YFS Custom Litz Speaker Cables
  • YFS USB Reference V1 Custom USB 2.0 Cable Prototype
  • YFS Custom Room Treatment
  • YFS Custom Interconnects
  • YFS Custom Power Cables

Add a comment (2)

by Kevin O'Brien on March 19, 2012

We wanted to let YFS readers know about our recent investigation into our M2Tech USB to SPDIF converter. Should you hook your digital source to your DAC via direct USB or should you use a USB to SPDIF converter in the chain and go digital COAX or digital XLR out to your DAC's input? Basically, we were wondering if we should be hooking our YFS HD-Ref-1 music server straight into our Minimax DAC Plus' USB input? Or should we continue to use our M2Tech EVO/ TeddyEVO Power Supply USB to SPDIF converter's BNC digital output and then hook that into the Minimax DAC Plus? Which scenario works and sounds better?

We figured enough folks would have an interest so we checked it out. We used the same set-up within the "IBM T43 vs. Theta Carmen II" review so you can check that out here. We ended up using a DELL Latitude D510 as our other computer source. It has essentially the same specs as the IBM T43 so we could keep things fair (we added a 150 GB HDD, 512 MB of RAM {1 GB total}, and it has a 1.87 GHz processor). Foobar 2000 was the digital player on both computers. We used the Silnote Audio Poseidon USB cable plugged into the M2Tech EVO from the IBM T43. We then used the Veloce 75 Ohm Black Cat Digital BNC cable to go from the M2Tech EVO to the Minimax DAC Plus. We used an ACR Reference Silver USB cable out of the DELL plugged directly into the same Minimax DAC Plus' USB input. Another important point to note is that the M2Tech EVO USB converter is essentially buried within the Minimax DAC Plus chassis, external PS aside. It's really more like the HiFace is inside the DAC chassis but you get our basic point. We definitely thought it would be an interesting shoot-out. We would be toggling between the two set-ups via the input switch on the Minimax DAC Plus.

Just a small note to the reader here first. We have compared the ACR Silver Reference USB to the Silnote Audio Poseidon USB and they are practically identical in sound quality! (neither cable is available today unfortunately) I wanted to let the readers know we are keeping the comparison as fair as possible. We feel here at YFS that the USB interface is the most preferable way to hook up your digital source to a DAC. Why do we say that? Look at the trouble we've had trying to get digital 24.192 signals through a COAX digital BNC cable to a DAC! None of our USB cables have had ANY trouble sending that signal to a DAC. You decide for yourself. (We think it's even better than firewire) Sorry to get sidetracked.

Now that you are familiar with the equipment and what we are trying to achieve, let's describe the results. We did an A-B comparison with both set-ups and we could not hear a difference! I know that different USB cables are involved in the test but we tested those out independently of this test and we feel they're both extremely similar. Both computers are essentially the same although the IBM has more RAM. We are using a legit digital COAX cable as well so we feel those are not the main factors in the test.

Adding the SPDIF converter and the BNC cable had no effect on sound quality. It neither added, nor subtracted from what was going on. The only difference by going DIRECTLY into the USB input was that we could now enjoy 24.192 and 24.176 digital files without any upsampling or downsampling. VERY SWEET!

What's the lesson here you say?

If you need to use a USB to SPDIF converter, don't be afraid of degrading your system's sound quality. Although there is a plus to using a straight USB digital signal into your DAC, it's not a deal breaker if you're happy with the resolution (24.96) you're getting out of your digital COAX cable!

Thanks for reading and enjoy!



Associated Equipment for this Review:

  • Eastern Electric Minimax DAC PLUS
  • YFS/ SCH Custom Speakers
  • YFS Custom Room Treatment
  • YFS Custom CA-60a Preamp and Custom 6L6 Tube Power Amp
  • YFS Custom Interconnects and Cables

Add a comment (1)

by Brad Easton and Kevin O'Brien on 03/08/2012

We recently decided to upgrade from our Musical Fidelity V-DAC to the newer V-DAC MkII. We'd like to let our readers know about the main differences between the two in case anybody is in the market for the new version. We paired the older V-DAC with our CD transport and various computer transports to show our readers there is an affordable way to get into USB based computer audio without breaking the bank.

The original V-DAC is no slouch. I have to say it definitely sounds better than the older MF DAC's such as the A3.24 from circa 2002. According to MF, it even outperforms any of the slightly older DAC's such as the X-DACv3 and even the Tri Vista 21 Tube DAC. Although I'd probably take a Tri Vista 21 over any of the other older MF DAC's based on its tubed output. If it were up to me, I'd go with V-DAC over the older designs based on its USB input and updated processing which the older designs lack. There's probably one exception: Let's say you have a tubed DAC that you love and want to add USB capabilities. That's where the V-LINK comes in but we'll save that discussion for another time. Right now, we're focused on the two MF DAC's, not their USB to SPDIF converter!

Let's touch on the main differences between the two DAC's before we go any further. After checking the Musical Fidelity website, we learned the basic differences. The finish/ overall look of the V-DAC has been upgraded to a nice silver case vs. the old plain black case. The USB input has received a kick in the pants by adding an Asynchronous USB input instead of the original Adaptive USB input. The older version was stuck at a 16/44 input ceiling for digital files where the newer version has been bumped up to accept 24/96 digital files. NICE! The older version had a distortion value of 0.005% where the new version has dropped down to 0.002%! Stereo separation has also increased on the new model to -105dB.

We have to say the biggest selling point to us was the inclusion of an Async USB input and the upgraded 24/96 native resolution. We were downsampling our digital files with the original V-DAC. Remember, even though our Hi-Res files were downsampled, we still unanimously agreed they sounded better than the Red Book 16/44 files played through the same DAC and digital player. We don't have to do that with the new version and we can actually upsample ALL our digital files to 24/96 if we like. We choose to send the files through to the DAC at their original sample rate. We don't like to upsample/ downsample our files if at all possible.

It's important to note that we went with the Pangea P-100 external power supply mated to the V-DAC II instead of the Pyramid PS-3KX external power supply we used with the original V-DAC. Any external power supply will better the included wall wart. The P-100 is the better unit if you're deciding between the Pyramid and the Pangea. Let's keep in mind both power supply units are of the switching variety and NOT linear power supplies. If you'd like one of those, we could make you one or you could purchase one from Teddy Pardo or Wayne at Bolder Cables.





Well, let's talk about the sound of each unit. The original version sounds great with an external power supply. You don't have to spend a lot to upgrade the wall wart that's included. We spent about $25 on the Pyramid. As we stated before, the original V-DAC bests the older MF DAC's, even the Tri Vista 21 Tube DAC. (Though that's still up for debate) Now on to the new version, the V-DAC II. I have to say it definitely sounds better than the original. We are comparing both units with a CD transport as a source first. There is definitely a noticable difference between the two. I feel an audiophile would be able to tell the difference right away. A non-audiophile may not be able to tell right away but I think he or she would eventually hear the value in the upgraded unit.

If you'd like us to describe what we're hearing, we would say the MkII puts out an overall better soundstage, deeper bass, better mids/ highs, and more detail. Again, it's hard to quantify but the difference is there although it is a slight difference. Obviously your mileage may vary depending on your system.

Now onto the USB input. This is where the MkII shines. We can now run our digital files in their native resolution, whether it's 16/44, 16/48, 24/88, or 24/96. We still have to downsample our 24/176 and 24/192 files to 24/96 within JRiver but how many albums are out in that format right now anyway? Not many! (See our JRiver Review which shows the user how to handle various file formats) We can now implement multiple bit-perfect playback modes since the MkII has an updated Asynchronous USB input. We are referring to the multiple bit-perfect output options within JRiver which are ASIO, WASAPI, WASAPI - Event Style, and Kernel Streaming. Each output mode should allow the user to fine tune the sound to his system and liking. Show me a CD transport that can do that! The above descriptions on sound and performance hold true for the USB input as well. The main difference is that the V-DAC II can now handle the various current bit-perfect playback modes. YES! 

It's great to step into the current USB technology playing field. The original V-DAC was a great little DAC but the V-DAC II has raised the performance bar even higher. Musical Fidelity really has a winner on their hands here. We've heard around the campfire that the MF M1-A DAC is the same as the V-DAC II but with a built-in power supply in one box. You can try the MF M1-A DAC if you really want to but I'd go for the above-mentioned set-up and save yourself $300! (OR, find a used EE Minimax DAC for ~$700). You don't get the AES/EBU digital input, XLR analog outputs, or the choke regulated power supply but do we really need those in this price range anyway? You can get a custom, non-switching power supply from Teddy Pardo for ~$350 which brings the V-DAC II up to/ surpassing the M1-A DAC's performance level for ~$50 less. Personally, I like when the power supply is away from the main processing components since this method keeps both sections isolated from one another. You make the call!

THANKS for reading and keep on listening!



Associated Equipment for this Review:

  • YFS HD-Ref-1 (comp music server - more info here)
  • McCormack SST-1 CD Transport
  • YFS Custom Direct "Passive" Preamp and Custom 6L6 Tube Power Amp
  • YFS/SCH K08T21 Custom Speakers
  • YFS Custom Interconnects, Cables, and USB Cables
  • YFS Custom Room Treatment

Add a comment (0)

by Kevin O'Brien on 01/23/2012
UPDATED 2/23/2012

I have been using the modified Eastern Electric Minimax DAC Level 1 from Wayne at Bolder Cables for about 6 months. I can say it sounds great. So I know you're wondering how does it compare to the new Minimax DAC Plus? Let's just say it's worth your time to read more if you are considering either DAC.

First of all let me describe the stock Minimax DAC which is now discontinued but can be bought on the used market for around $700. It's a great DAC especially for the money. Unfortunately, the main constraint on the earlier version is its ability to only accept up to 24/96 digital files. However, this DAC sounds great and is a killer value.

Let's take the stock DAC one step further and send it to Wayne at Bolder Cables for the Level 1 modification. I was able to get a hold of one of these upgraded units and had the pleasure of using it for several months. Wayne recommends over 500 hours of break-in which I performed before critical listening. Let me tell you that the upgrade was worth the money at the time compared to the original unmodified version. This unit just plain smoked the older DAC's such as my Musical Fidelity Tri-Vista Tube DAC. There was no comparison. I believe this is due to the ESS Sabre DAC chips used in today's higher end DAC's which the Eastern Electric and Wyred4Sound DAC's employ.

Here comes the real meat and potatoes of the article, how does the DAC Plus stack up to the modified original DAC? Let's just say I noticed better resolution and the overall sound was more realistic to me than the original modded Level 1 DAC. Everything just seemed better to me. By how much I'm not sure I can quantify but I think it's safe to say most audiophiles would be able to hear the difference.

I like the fact that Alex lost the volume control as most folks use a preamp for attenuation and do not need it anyway. Wayne obviously bypasses the volume control on the original modded DAC so why incorporate it into the new version? Well, Alex chose to get rid of it which I believe helps let even more of the music through and keep the signal path even cleaner. I ended up using the same Psvane 12AU7 that Wayne sent with his modded Minimax DAC's and it worked quite well in my system with the DAC Plus. I was wondering if I was the only one hearing these differences or was this universal throughout the audiophile world?

I did not want to compare specs of both products and waste your time with the description of various inputs as you can do that by going to the manufacturer's websites (Eastern Electric and Bolder Cables) and see for yourself. Check out these sites if you are interested in comparing features, specs, etc. between the two DAC's. It's that simple. The one thing to note right away is the newer version of the Minimax DAC is slightly larger than the original due to separate power supplies for both the digital and analog sections unlike the original with only one power supply for both.

This DAC Plus stacks up VERY well to the Level 1 modded DAC and actually can stack up to the Level II mod from Wayne as well. I spoke with Bill O'Connell of Morningstar Audio and he agrees the DAC Plus is better than his fully modified Level II Minimax DAC from Wayne. It's that good. The one thing I do love about the new DAC Plus is its ability to accept 24/192 files from its USB input unlike the previous version. This is accomplished through the M2Tech USB interface within the DAC Plus. The DAC Plus uses VERY similar drivers to the M2Tech EVO which is to be expected as the same hardware is used inside the DAC Plus as I just stated. If you can get the M2Tech EVO working on your system, you will certainly be able to get the DAC Plus up and running in no time as well. One small caveat here in regard to drivers. If you are using a Mac you must uninstall any M2Tech USB drivers on your system before you proceed with the Minimax USB drivers. This is fairly straight forward. If you are using a PC, you will have to get rid of your M2Tech USB drivers by reinstalling Windows or contacting M2Tech for a script to do the job as well. As you can imagine, it's a little harder for PC users but this only applies if you already have M2Tech drivers installed on your computer audio source. Otherwise, get rid of any USB drivers from previous DAC's and devices BEFORE you install the Minimax USB drivers.

I love the fact that the user can switch between the tube output and the solid state output with a push of the button on the front panel. The solid state output does have slightly more detail but I prefer the smoothness of the tube output and will sacrifice a little detail for better overall sound. The phase button on the front panel will interest some folks as well although I did not find myself toggling back and forth between the two after playing with it for a couple minutes.

If you're wondering how the Minimax DAC Plus holds up against other DAC's I can give you a little insight. I am familiar with the Wyred 4 Sound DAC2 which I had in my system for several months. I switched from the DAC2 to the Level 1 Modded Minimax and I noticed it sounded more realistic and a bit smoother than the DAC2. The DAC2 just seemed a little too dry and it lacked the liveliness of the Minimax Level 1 DAC. I like the Minimax DAC PLUS slightly better than the Level 1 Minimax so this should give you and idea on how all 3 DAC's stack up. The W4S DAC2 was able to accept a 24/192 digital signal via it's digital coaxial input UNLIKE both Minimax DAC's which were stuck at 24/96! Don't believe every spec sheet you come across. In this instance I assumed it worked until I gave it a try. I have to be honest, this still bothers me a little. Which means, my quest for my final DAC has not yet ended. (Just trying to help potential buyers here - I am not affiliated with ANY audio manufacturers!)

With the new features added to the already great Minimax DAC why torture yourself wondering if the few extra hundred bucks is worth it or not for the MKII version? For $1100 you cannot go wrong here and as far as I'm concerned. Don't walk but RUN to the Eastern Electric website and get yourself one of these before you lose your mind. Stop thinking about it and just do it! It's that good. The one question you may still ask yourself is, will Wayne modify the DAC Plus as well and take it to the next level?

Stay tuned for more details!

UPDATED 2/23/2012:

Apparently Bill from Morningstar Audio does not want Wayne of Bolder Cables to modify the New Minimax DAC PLUS so there will be no Level 1 Modification to the DAC PLUS or any modification from Wayne for that matter. There is however a Level 3 Modification for the Minimax MkI DAC. Check Wayne's forum outlet,  Audiocircle for more details. I'm a little disappointed to say the least...


 Associated equipment for this review:

  • Von Schweikert VR5-HSE (Hovland Special Edition) Speakers
  • Quicksilver tubed Preamp and Monoblocks
  • IBM Laptop for source with Foobar 2K Digital Audio Player
  • Theta Digital Carmen II CD Transport
  • EE Minimax Phono Stage
  • VPI Scoutmaster Turntable with VPI Zephyr Cartridge
  • Equitech/ PS Audio Balanced Power Conditioners
  • YFS Custom Cables and Interconnects
  • YFS Custom Room Treatment
  • Herbies Audio Lab Dampening Devices and Tube Dampers

Add a comment (0)