Despite the fact that the stock tubes in PrimaLuna products are incredible, some "tube heads" simply LOVE to experiment with different tubes.
There is no need to change tubes in any PrimaLuna component. The stock tubes really are incredible and have won PrimaLuna many awards from all around the world. Ask any tube-head what tube is the most musically satisfying, and they will ALWAYS tell you it’s the magical EL34. Every brand out there would love to run EL34’s, but can’t because their designs run tubes too hard. PrimaLuna does not.
The above stated, some customers do enjoy fine tuning the sound to their exact personal tastes. It’s this “gentle nudge” that allows you hit that perfect spot that will send you to the moon. But with other brands of amplifiers, tube rolling can be risky. They run the tubes so hard you are forced to stay with the factory supplied tubes. Nothing is more disappointing than finding out you can't "play" with your amp.
We want you to have fun. And “tube rolling” in PrimaLuna products is easy because we run the tubes easy and Adaptive AutoBias means no manual bias adjustments. But before you explore, here’s what you need to know:
Don’t buy tubes from just anybody. Sadly tube manufacturers don't throw away anything if it can somehow be sold, so every tube will end up in someones system. Even the weak ones. A brand new Russian-made Gold Lion, Tung-sol, or Mullard re-issue could be brand new in the box, factory fresh, and have only 10% of its life left. Tubes are not like buying tires. Every single one measures different. If it’s lesser quality, it will go to sellers that deal in that type of product, and they sell it for a lower price to the unsuspecting public. You could save 10% on the price of the tube, and it will have a life that is 30-50% shorter. Or damage your amp. Not smart.
Tubes are the amplifying device in your system. It is critical that you get the best. They are more important than cables or virtually any tweak.
Buy from known sources. The importer and distributor for PrimaLuna in North America is Upscale Audio, and they are known for having the absolute finest quality tubes and the largest inventory in the world of vintage NOS (New Old Stock) tubes, with the best testing in the industry. Every pre-amp tube is measured for internal triode balance, then graded in a moving coil phono stage with headphones. Upscale Audio has re-tubed over 50,000 components, and has been involved deeply with PrimaLuna since day one.
We encourage you to have fun, but we also have a commitment to you to do the right thing. Changing a tube to a more expensive tube does not guarantee anything. You are adjusting the system as a whole, so think of it that way. Think about color. And when we say color, we are talking about things like brightness. Some people misunderstand what that means, so let’s get some clarity. If you have a forward midrange, that can sometimes be construed as brightness because people here a high shrill and assume they need it softer, when what they really need is a tube that has more extension at the tippy top so the voice peaks are not as apparent. But if you hear sibilance and bite at the very tippy top, you don’t want to make that worse.
A B&W owner may feel that the top end is too bity on the very top and want a warmer small-signal tube like a Vintage Mullard. A Martin-Logan owner may think his speakers are bright, when in fact they need even MORE extension at the very top and want to use a Cifte, Mazda or a few other brands.
Here are some tips you may find helpful:
- 12AX7 – There are current production tube available called re-issues from Mullard, Tung-sol, and Gold Lion. They aren’t re-issues in the purest sense, as they really can’t be. They don’t have the same plate structure and the same cathode materials. But they are really incredible sounding and last a very long time. In NOS tubes, an original Mullard CV4004 will relax the tippy top just a little bit, and because of that you will get just a little more body. They are expensive, but remember they will last from 5-10K hours. If you want to keep the top end response, look at early GE 12AX7’s. They have a nice sparkle to them, and that’s due to them having helical wound filaments. Also look at Tungsram for their juicy mids.
- 12AU7 – What’s cool about 12AU7 tubes is there are plenty of current production from Mullard, Gold Lion, and Tung-sol, but in addition there are a large number of vintage NOS tubes that are not expensive. The most popular are:
- Cifte 12AU7 – This is a tube made back in 1962 in France. They are fabulous if you are looking for a greater sense of space. The reason they have that sense is because they have a little more top end. In fact, they have a LOT more top end at first, but that settles a little after 100 hours or so.
- Mullard CV4003 or M8136 – This vintage British tube will have a little bit of a relaxed top end and a warmer presentation. For that reason, voices will have a little more body. But remember the very tippy top will soften a little bit.
- Brimar CV4003 – These are really popular. Also British. Brimar was one of the absolute premier tube manufacturers in the world. You may not have seen them as much in the U.S. because much of their business was supplying the military in Europe. So while they are very rare here, their quality and precision is incredible and they are worth seeking out. This tube does not exaggerate or soften the top end. It's very neutral and has a wonderful midband.
The 5AR4's used in our preamplifiers are considered to be fantastic. It is as close as you are going to get to a classic Mullard. We have found that the Mullard and Gold Lion Russian re-issues are not quite as dependable in PrimaLuna preamps, so it’s best to stay stock when it comes to current production 5AR4’s. There is a vintage tube that is quite popular called a Philips 5R4GYS. Very cool looking tube that lasts a long time. It has a slightly warmer presentation, if you need that. A lot of people like it, but if your speakers don't have enough top end, it may not be a good idea.
ProLogue Premium, and discontinued models ProLogue Three, DiaLogue Three: All four of the smaller tubes will have the same effect on the sound. To try a different "flavor" of tube, you don't have to change all of them. You can, if you choose to, do just one tube on each side, left and right. If you like what you get, go further. See photo below:
DiaLogue Premium: In addition to the the four smaller tubes referenced in the paragraph above, DiaLogue Premium has two extra smaller tubes outside and behind the front four. These two tubes are cathode followers and will not have as great an effect as the front four. Do the front tubes first. See photo below:
Integrated and Poweramps
ProLogue Premium, ProLogue Classic, and discontinued models ProLogue One and Two, DiaLogue One, Two, Four, Five, Six, Seven: The two small tubes in the very front/center are the gain tubes, and they are very much in charge of how the amplifier is going to sound. The tubes flanking the front two are the driver tubes, and they will also make a change but not nearly as great. So concentrate on the front two. See photo below:
DiaLogue Premium HP, DiaLogue Premium: The two small tubes in the very front/center are the gain tubes, and they are very much in charge of how the amplifier is going to sound. The tubes flanking the front two are the driver tubes, and they will also make a change but not nearly as great. So concentrate on the front two. See photo below:
The large tubes are called power tubes. They are the "engine" and what we strive to extend the life of at PrimaLuna. The stock tubes that we use today are EL34's, and they are known for having the most musical midrange but in many brands maybe not the best bass. That last comment about bass is an old-wives tale caused by manufacturers using off the shelf output transformers. PrimaLuna gets incredible bass from EL34's due to our proprietary output transformer designs. The stock EL34's are fantastic. Other EL34's to consider are the rare and expensive SED Winged C which is very good sounding. The Mullard re-issue which wears like iron but maybe not as warm. Tung-sol EL34B which we can't state an opinion on. There is a JJ large bottle 6CA7 that supposedly sounds incredible but in most amps may fail, but in our low-stress design should be fine.
If you want to go to a "larger" tube like a 6550, KT88, or KT120 the result may be a little more "pop" to the music, and while the bass may appear to go a little deeper, it will not be as "round" as an EL34. In KT88's the most common is the Electro Harmonix which is great, the Mullard re-issue and Gold Lion re-issue which in essence are the same tube and are superb. And then the Tung-sol KT120 which has even more "pop" and because we run them so easy, the tube may outlive you. If you use KT120's DO NOT ship the amp with the tubes installed. While they do fit under the cage, they get very close to the bars. The tubes will break in transit when (not if) the box takes a hit.
Then we have the KT150. It is a fabulous tube, but they're expensive. It has the immediacy of a 300B or 845 single ended amp sound but without all the drawbacks. It is important that you ONLY purchase KT150's from Upscale Audio. It is a large, expensive tube and they vary greatly from sample to sample. You could easily buy one that is brand new with only 10% of it's life left because the manufacturer does not simply throw out the weak ones. They get sold by dealers that are not concerned with you or your amp. A healthy one will last many many years based on our tests.