Hi prasen_b,
12AX7 tubes are used in the pre-amp section, and as such are regarded a very important stage. Hence these tubes should be chosen very carefully not only for the preferred tonality but also for low noise floor and less micro-phonics. Most of the new tubes are not very high quality ones, both sonically and longevity-wise. There are a few reputed new tubes - among the reissues there are the Genalex Gold Lions which are supposed to be good according to reports (I have not used them) and, among new tubes, the chinese premium tubes from Shuguang or Psvane Treasure series (I use their 12AX7 in the pre-amp section of my Leben CS 300 tube amp, and also their 12AU7 tube in my Line Magnetic LM215 CDP). These premium chinese 12AX7s are no worse than my NOS Telefunken ribbed plate 12AX7s, depending on taste some may consider them even better.
The Brent Jesse site gives an generally accurate overview of all NOS tubes. If I remember correctly, they do not discuss the new tubes. The reason I chose the TFK ribbed plates over the smooth plates was that the ribbed plates have more full-bodied sound than the smooth plates. As such the TFK tubes are supposed to be deadly accurate and that's why they sound a bit thin and perhaps a bit bright to some. Hence I chose the safer option of getting the ribbed plates which are also somewhat cheaper compared to the smooth plates. In addition, the whole sonics have to be balanced out with the power tubes too. If the power tubes have a bit too much of flesh, one needs to balance that out in the pre section with deadly accurate tubes. You mention that you use a hybrid amp, does that mean you do not have tubes in the power section?
One problem with NOS tubes is their genuineness. There are fake tubes available in the market which claim to be NOS. I am not really an expert in tubes, and hence I refrain from buying from ebay sites. But if you are an expert, you can get NOS at cheaper price from ebay.
I have bought from the following sites:
Brent Jesse's online store:
BRENT JESSEE RECORDING HOMEPAGE
Cryoset online store:
Cryoset.com - Cryoset Certified Vaccum Tubes
Psvane and Shuguang site:
Psvane & Shuguang Treasure Audio Tubes, Caps and Amps | Manufacturer Authorized Worldwide 5A Standard Re-seller
In addition, Jim Mcshane's site (
Jim McShane Home Page) is also heavily recommended by many tube users abroad. He is definitely very well respected by many. But I found his site a very complicated one to look at and to find the available tubes is a pain. Any way, I did not find what I was looking for at that time, and hence I ended up buying from somewhere else.
SND Tubes (
Vacuum Tubes, Electron Tubes, Tubes, Tube Testers and Electronic Parts) is another site which keeps many NOS tubes. In fact, I once ordered from them, but the credit card payment failed citing that his site was untrusted. I wrote to Michael Marx (owner), but he responded: "I cannot run the credit card in any other way. I no longer accept bank wire transfers due to security issues". I hope they have improved by now so that credit cards would trust his site, because he had a nice collection of NOS tubes.
Everybody will charge you some money for matched pairs. Respectable tube-sellers have the proper equipment to do that and the necessary stocks to pick from, good vendors also do a careful job of it, at least they advertise to be doing so.
Regards.
hyeah:
