My experience of Tube Rolling on a Phonostage Circuit, has opened up quite a large opportunity to learn.
Today I encourage it but do strongly recommend that Valves selected are proven through ’impartial testing’ to be 95%+ of Factory Spec’, have almost perfect matching on each Half of Valve and the same between Valves.
While I do not disagree that you should get what you pay for and should strive to purchase and maintain healthy matched and balanced tubes, there is nothing wrong with using healthy, used tubes.
In fact, to your point about the cost of tube rolling, a fantastic way to determine what it is that you like (and your system likes) and not have to spend much to do it, is buying low test or threshold tubes from a seller. As a seller, I often give away my threshold tubes to my clients so they can experience and learn from as many different types of tubes as possible.
One thing to remember is that when you buy a new tube and hear it for the first time, that is not how that tube is going to sound when it gets fully burned in. Some tubes can take months – or a year even – to fully bloom. Hearing used tubes is a much better indicator to determine how something is going to sound than a few hours with brand new, possibly unstable, definitely not yet burned in tube which you then use to make like/don’t like determination about a certain tube type.
When Valves are added to a circuit that have such accuracy proven, there is something quite discernible to be discovered.
What is sure are Two Things:
1, Tube Rolling is no longer a cheap option, especially when Vintage Production Rea Stock is being bought.
Tube rolling doesn’t have to be expensive. I let my clients audition multiple sets of whatever type of tube they are after before any money ever changes hands. And for at least a couple of weeks. This lets you make a more informed choice by letting you hear multiple options in situ of your home, music, kit and life. Frankly, that’s the only way we should be choosing tubes.
2, Caveat Emptor is extremely important to exercise, how does one really know the quality of the Valves being received, unless able to be tested after receiving on behalf of the purchaser.
Build a relationship with a seller you can trust.
Few involved with Valves have a knowledge of the quality of the Valves being assessed for the influence on the produced End Sound. This as an outcome, makes it very difficult to be able to take reports on experiences had, as a valuable source of information.
This is untrue, at least among all the sellers I know — and it’s small world, let me tell you. We know our tubes very well. What we don’t know is how they are going to sound in your system with X Preamp, and Z Amp, and Y Speakers and in a room with a low ceiling and two barking dogs. There is no one other than you standing in your home in front of your rig that can tell you how it does or will sound. Period.
Prime Quality and Poor Quality Valves both enable sound to be produced. It is not for myself to suggest a Poor Quality Valve should be less impressive than the Valve it replaced? It might be a betterment, in the assessment of the individual having the experience of different Valves.
Some tubes are higher quality than others, that is true. But just because a tube is used does not make it poor quality. It makes it used. And nine times out of ten, that used tube will sound better than your brand new tube.
FTR, when having purchased 2 x New Stock Matched Input Valves. When tested prior to being used, one Valve measured so bad, the owner of the test machine advised it was not used. The guidance offered, being the Amp could be damaged!! Due to the unknown effect of such a Valve on the circuit.
Things can happen to tubes, I’ve had a number die in transit. It happens. But even the most mariginally reputable seller should have replaced that tube, no questions asked.
My Valve Amp Designer / Builder, who become a friend of more than 30 years, has always made it known. I would be wise to allow for free service, for their checking of any Valves I may acquire outside of the original design. The idea being a simple mistake at my end is very easily avoided if overseen by their understanding of the Designs needs. They are also contented by my being able to have Valves tested on a AVO tester.
Good advice. But, remember your manufacturer has to maintain a 0% risk policy and advise against anything that could establish liability for them if something goes wrong. Especially if asked on the record.
Good luck out there.