Strange Behavior for New Tubes in Preamp

False alarm for me. I discovered that I had a bad CD. Speaker cables first, reversed them, problem solved. Next problem turned out to be a flaw in a new/used CD.  I have had bad tubes before but not this time. A relief really. 

The average Tube User is not able to access an Oscilloscope or a Tube Tester. The average Tube user really does not know the quality of the Valve they are using, the Trust is in the supplier and what they are reporting with the sale advert.   

Put either device used to measure a Valves condition in front of myself and will not know how to use it, unless given special guidance.

I don't have to, I have support from others who knows exactly what is required from their own devices when measuring a Valve to see where it compares to the Manufacture Spec'.

It is very very easy for myself to learn what has been delivered usually within a few days of receiving the Valves if a short notice request is made to test and if pre planned and I have the time, delivered Valves can be tested within hours of being delivered.

I do know exactly the condition of the Valves I am to use in a circuit and as my Tranxs on some devices are Hand Wound - Bespoke and not repeatable, it is very important I make sure the circuit is at its optimum.

Many Valves have been returned for a full refund due to the Testing showing Valves to be quite different to what was the shown in the advertisement.

Chinese Import Valves will not be given the same support, the Companies do not accept returned data sent about their Valves, they only accept their measurements done prior to packaging and the sale occurring.

If Amp's cost multiple thousands to buy, and a certain Valve is able to cause damage to the Amp' if not in a particular condition to support the circuit. The likelihood is that the cost of a repair might exceed much more than swapping out a Valve that might have been at the Top End of pricing and thought to be perfect for that reason.

Do all that can be done in ones capacity to ensure their Valve Purchases are exactly as they believe they have purchased. 

My friend who is the Valve EE whom designed / built my PP Power Amp's has informed me to be very careful with Valve usage. I am knowing from guidance given that a bad Valve (unknown meaning to me) can take out the Amps Output Tranx's. These are Unique / Bespoke and not repeatable, new Tranx's would be required and a whole new End Sound would be the result, which from my end is totally not wanted. 

Hence, I am very very careful about what is introduced to the Circuit.         

I've never had much luck with JJ tubes, and use NOS GEs in my preamp and amp (both use 6SN7GTBs) and they're dead quiet, sound great, and last a really long time. I won't tolerate hiss or any noise really as I know I don't have to.

I have a large selection of that value tube and have never experienced that, but I have a different amp. I would suggest that you contact Van Alstine and ask them. It would be interesting to see what they say. With the new tube getting louder and louder I’d guess it’s a compatibility issue with your pre. Most people including myself don’t care for the JJ’s. I have multiple sets in my extras box that are all pulled from new equipment with about 5-10 hours on them. If you don’t want to go nos try some new production Gold Lions or Tung Sol. Please post your findings this is interesting. Cheers, Mike B. 

@dekay   I used CAIG D5 to clean the tube pin sockets because the JJ tube seller (Eurotubes) recommends it in the FAQ on their website.

I thank you all for your comments. It's puzzling.  Is it just coincidence that both of the tube numbers that are a problem have gold pins ?   Also, all tubes were purchased from reputable names and not from ebay or anywhere else. 

I will contact AVA and report back.