PSA regarding tubes

[Yatagan]

Rob

In general, are there a specific type of JJ's you typically would recommend for the modules? Are there types that will give a varmer tone than others?

Finally would the Preferred Series 7025 / 12AX7 tubes improve or alter the sound and/ or sensitivity significantly?

 

[KernelSanders]

Resurrecting an old thread but...

Rob, anything changed in the last 4-5 years regarding tube quality? I test with a digital tester and found the reissue Mullards to score consistently strong for transconductance and gain, but I haven't really checked them over time for reliability.

Also do you still order mostly from Euro tubes and if so what level of tube do you order? Looks like Euro tubes now has standard, high gain, and "definitive series" for different quality levels and the markup for the better levels is significant.

 

[notyet]

There is a fairly easy modification to the cathode follower circuit to deal with the voltage issue. Merlin Blencoe deals with it in his preamp book and probably on his valve wizard website.

Might be worth incorporating as a proactive measure- I think it would be mildly easy to do on the back of the tube riser board.

 

[Jaded Faith]

For the last two years I have nearly exclusively stocked and sold Ruby Tubes from Magic Parts with prescreening and burn-in. These services are for shops, so I don't know if the the consumer Ruby branded tubes have the bad tubes weeded out like mine do. It also allows me to offer a 3 month warranty period on tubes I sell and install.

That said, the following tubes have been what I recommend for the past 2 years in my repair shop:

Ruby 6L6GCMSTR
Ruby EL34BSTR
Ruby 6V6GT
Ruby JJ 6V6 (for amps with higher plate voltages)
Ruby JJ EL84
Ruby 12AX7AC5
Ruby ECC83S (JJ)
Ruby 12AX7WBC

Keep in mind the Shuguang factory in China closed a few months ago for one year due to a fire next door. They are moving the factory. As such, a lot of the Chinese offerings are starting to dry up or are already out of stock. I've moved over to the Sovtek 5881R/5881WXT and the JJ EL34 in the past two months due to stock drying up and so far, so good. I go through a ton of tubes, so the sample size is pretty good.