Tube rolling is a slippery slope. There is NOT a direct relationship between price and sound quality/results. As a result, it's a good idea to play around at the cheap end of the spectrum first if you are truly experimenting.
OTOH, if you find someone else who has the same unit, and has done some of the "work" for you, you can save a lot of trial and error.
For 6dj8's there are a lot of alternative tube types that might work in your unit, some of which might not be obvious. A good tube seller should be able to suggest some alternatives to match your desired sound profile. For instance, a Siemens 6922 or a Telefunken will be WAAAY different than a Mullard or an Amperex. But you might be perfectly happy with a $15 Reflektor, or a Valvo 7dj8. In other words, LOTS of options.
I'm a big fan of Jim McShane because he doesn't add huge markups and tests/guarantees his tubes. When a pair is "matched" you can be sure that it will be gain-matched correctly, both section to section (these are dual-section tubes) and tube to tube. Unfortunately, Jim doesn't often have many of the more rare and prized vintage tubes. But he would be a good place to start for some inexpensive more recent alternatives that you might be perfectly happy with.
At the other end of the price spectrum is Andy at Vintage Tube Services, or Brent Jessee. These guys sell primo vintage tubes at nose-bleed prices. To some extent, you are paying for knowledge and experience when you buy from them. But if you really want a pinch-waist Amperex 6922, then the one you get from Andy will be exactly that, not a knockoff or rebadged other brand tube. I strongly recommend them if you can pay the freight, but if you have the time/inclination and are somewhat lucky, you may well be able to find the same tubes for pennies on the dollar.
There are some reputable tube-sellers on ePay, but lots of horror stories as well. I've had good experiences with "TubeHunter" who is in the far East and has delivered some pretty rare tubes at nice prices, but they are often untested, or used "pulls" from vintage test equipment. Easy to get burned if you don't know the difference between a D getter or a frame-grid tube. Sometimes its worth paying the premium for experience.
It it were my money, I'd start with someone like Jim McShane first, and start to get a sense of what different tubes sound like in your DAC, before you go spend a lot and are disappointed in the results.
Hope this helps!
The sites below are reputable tube dealers that I have used in the past. I have never heard any Japanese tubes of which Matsushita is one, but the more sought after 6DJ8's are from Amperex (Holland), Telefunken or Siemens(Germany), and Mullard (England). There are others as well. The 6DJ8 is fairly inexpensive and plentiful when compared to the premium version which is the 6922 and the 7308. I think with $100, you will be able to purchase some very good 6DJ8's. BTW, Phillips is a pretty good tube.
Try Brandon or Rob @ 480-820-5411 @ Antique Electronic Supplies. I bought tubes in Nov. for my Cary V12R amp 3 matched quads and the rest for 232.00 and just ordered a new set of tubes for my Cary SLP98P preamp 6sn7 military type andthe rest stock for 135.00 inc. shipping. Good luck to all.
As you begin to hear about and meet these vendors it helps to know that some of these folks focus on selling current production tubes, while others specialize exclusively in what are called NOS tubes.
NOS is a much misused term - it stands for New Old Stock. But depending on the user it might mean an old tube that may or may not be brand new. Tubes that have been in equipment and used for an indeterminate amount of time are called "pulls" - because they were pulled out...
I suppose the grail is NOS NIB - meaning new old stock, new in the original mfgrs box. Of course how it can be new and tested is one of those zen problems I will leave to wiser heads
Four really broad strokes to divide the field (this goes beyond 6DJ8s). US made which includes GE, RCA, TungSol, National, KenRad and some Amperex. British made which includes Mullard, Valvo and Genelex. German made which includes Siemens and Telefunken. And of course Russia with the Svetlana and Sovtek - but also licensed reissues of old NOS designs from Mullard, TungSol and so forth. There were also a lot of tubes made in Holland. And yes there are tubes made in France and Japan. And modern tubes made in China.
Further complicating this is that a tube might have been labelled by one company but made under contract by another.
This is where the higher priced NOS specialist dealers really earn their keep. Based on personal experience I can highly recommend
Both these guys maintain very large inventories, are happy to make suggestions either to the max or bang for buck and maintain pretty amazing sites. They are very responsive. And they stand behind their products.
I also recommend
Dennis is a lot lower key but knows his stuff and is not opposed to saving you some money LOL
In the new tube space doing business with all three of the recommendations you have received is a good experience.
There is an enormous amount to be learned online. Just Google up any number of topics and go to town. Here's a couple:
Let me give you the benefit of my experience. You will end up with more tubes then you can possibly use. Do not be afraid to purchase a used tube or a pull if it is sufficiently discounted.
Many of these tubes were designed for 10,000 hours plus of service. Many were made to go in rockets, radars and other military gear and are not easy to damage. Others were made to go in televisions and radios. They are designed to burn and burn and burn.
If you get a tube from ebay or used, you love it, and it blows so what. Get another one.
Enjoy the hunt - it's a lot of fun
I also recommend Kevin Deal at Upscale Audio. If you e-mail him and tell about your system and listening preferences, he will make recommendations. I have bought many, many tubes from him through the years and he has never steered me wrong.
Really helpful advice from everyone - I am going to send some emails per your recommendations and see what happens.
One thing I am realizing about this hobby, I can't leave well enough alone. It is not just about trying to reach nirvana, rather it is fun to experience different things.
And . . I can't say enough about how much I enjoy Audiogon - no other forum I have tried has had such helpful and gracious participants! Thanks to all.
In addition to to the recommendations above, another source to consider is http://www.tubemonger.com
I've personally only dealt with them once for a very nice pair of NOS Telefunken ECC801s tubes that were priced well below some of the more well known dealers.
As you may or may not already know, many tube manufacturers, in addition to manufacturing their own tubes, sourced them from from other manufacturers and re-labeled them. Tubemonger really knows the tubes they sell and will disclose their provenance. For example, if an orange globe Amperex 12AU7 was made by Mullard in their Blackburn factory, it will be noted in the listing.
Tube rolling is an endeavor of trial and error, only limited by your funds. Recommendations can be useful but what matters is what sounds best in your equipment to your ears. In my experience sometimes a Goliath of the tube world is slain by a David. Good luck and have fun with it.
You can get 6922 matsushita's for $30 a piece at the Tubemonger. They're a very good tube for the money, right under the amperex, telefunken, mullards.
I wholeheartedly second all of the above suggestions. Not meaning to trash other tube sellers on the 'Gon or on e-bay, there are tubesellers on the net that are quite disreputable, selling fakes, relabeled tubes, used to death tubes, and the like, posing them as NOS or "matched". I recommend that you have access to or own for yourself a good tube tester before buying tubes in this fashion. Tubes with shorts can damage your equipment (don't use your amp as a tube tester!). Some individuals on the net will buy good tubes from one of the reputable venders, use them for 6-12 months or so, then put them back in their orignal boxes and advertise them with the test numbers from when they bought them. In short, beware.
Tubemonger has served me well. I've used them multiple times and have no complaints.
an update -
So I ordered 2 Matsushitas from Tubemonger and received them in 1 1/2 days! Here is some feedback on the swap.
Just so you know, I am a skeptic and don't rely on my musical memory. The nice thing about the Monarchy is that I can connect the SS and Tube outputs to different inputs on the Ayre and switch on the fly. This makes it easy to do a lot of focused comparisons.
I have to say, switching tubes pretty much accomplished exactly what I wanted. The tube section always sounded too euphonic and cluttered. It lost the separation and clarity in the upper mid and high frequencies. With the Matsushita's, all the upper frequency clarity is maintained but slightly more detailed. The big improvement was in bass and mids. Bass has more impact and mids are improved and more musical. The description I use is that the sound is "rounder" now in the tube section and "flatter" in the SS section. Since I listen to a lot of guitar, violin and acoustic instrument, this really makes a difference in my listening.
This has been the best $64 bucks I have spent in a long time - and to think I was going to go audition a Berkeley Audio DAC ($5000). All the advice was terrific and useful.
Great group of people here, thanks!
Drewh1, Its always good to hear that someone has benefitted from info received here on the Gon. I truly believe that's what this site was meant to do. Unfortunately, a lot times you get infomation here that you really don't need and can't use.
When those tubes break-in they'll sound even better.
Eee3 is right, give those tubes say 100 hours and they will be singing even better. Congrats on a excellent improvement and not a bank breaker at that.
I have had good luck with the Tubemonger ( he had some great sounding Mullard CV2492/6922) and with Tubeworld.