My advice would be to take your amp to an amp ‘doctor’ and get them to replace the tubes. I did it recently to my AC15 and it only cost me $180. But the sound difference is amazing.. seriously, you won’t regret it!

My blackstar series one 100 watt head I think has a faulty valve, and am in the process of getting it sorted. Just wondering would this effect the tone of the amp? I’m working on getting a good real heavy, metal tone with bite to it. Though in the tone there seems to be something missing, I think it may be due to the valve though, any advice?

I am of he mindset that almost any new tube produced today is garbage, with the exception of the original Svetlana, now Winged C i think and to a lesser extent JJ EL84s just because they are capable of withstanding the brutality of an 18 watt Marshall.

Than being said. I am a big proponent of old production glass. I have never had a n original, Mullard, Heerlen Holland Delta 12ax7 or vintage tube fail. WIth about 35 years of tube experience I am confident in this statement.

Or a step up transformer, if you happen to be using old AC30s, like I
am. The one I have gives the option of stepping up or down. Works great.

I am a guitarist and longtime tube tech. One thing to keep in mind If you are using a vintage amp, say from the 1960′s, you are working with a device that was designed during a time when the mains voltage in the United States was lower than it is today. Back then, 110-117 volts, today it is more on the order of 120-125 volts in most places. Mine here in Eastern Mass. is usually 123 volts. Running an amp such as this at higher voltages than it was designed for can cause the tubes to age faster. I recommend to users of vintage tube equipment that they invest in a stepdown transformer that will enable the amp to operate at the voltage it was intended for. A good one to look for is called an RCA Isotap. They show up now and then on ebay. You can adjust the input voltage and select an output that matches the AC voltage that your old amp was designed for.

A good tube tester is always helpful if you do a lot of work with tube amps. US Navy TV7′s are still the preferred workhorse. However, these tube testers do not always give accurate readings for common preamp tunes such as 12AX7′s. Make sure yours has been calibrated.

You can buy matched sets of tubes for your amp from reputable vendors and install them yourself, saving yourself a good deal of money. If bias needs to be reset, then you go to a reputable tech.
Best,
HP

If you have older valves it is a good idea to take the amp to a technician who
knows what he is talking about (this excludes most music shops,) and get
him to actually test the valves.

Will
Tubes are like strings? They wear out gradually and sound better if ‘fresh’?

Does this sound right to you guys?

My Futurama (by Selmer,) 15w Bass Major is 52 years old with the
original valves and works fine. I used it at a rehearsal last
week and it was more powerful and had better tone than
modern SS amps at twice the rating.

Back in the day Chinese valves were considered a joke and
a standard Mullard or Osram were what we fitted if we didn`t want
a call back. Now, of course, there is not the choice – what we once
took for granted is now a valuable rarity.

Will

It is my understanding that preamp tubes can last for years and power tubes wear out much faster.

Also IME, how much tubes are used are how much is asked of them also greatly affect life.