A pair of nice matched Tesla E34L's in the power section, two matched Tung-Sol's in V1 and V2, and a JJ in the PI.
For some reason a couple of months ago, my SV20H just didn't seem to sound right. I think one tube was bad. But at the time I didn't have a lot of time, and I did have a fair amount of inventory. So I just swapped them all. The amp came back to life and still sounds fantastic. I use it every day and still with those tubes. It has a fantastic 70's classic rock plexi crunch when plugged straight in, and shapes well with a pedal or two.
I bought the tubes from both Antique Electronic Supply (TubesAndMore.com), and Tubes Unlimited.
I have two sets of the original power tubes/valves from Marshall. I believe they are Shuguang (not sure on spelling) but are likely Chinese, which have great tone, but are short lived if you play hard or for hours at a time.
All four have separation issues where the intense heat and vibration (combo VM) made the glass separate from the base. I even tried to super glue them back together but the heat is just too much. The leads from the base (pins) to the actual electrode eventually fail. They might light up, but no one his home or so I've learned the hard way.
The factory claw holder only hold the base and not the glass so I suggest the older style spring retainers for the combo. Actually, the full size spring retainers are even recommended in any head version too. Vibration is a different topic and not easy to solve but there are different kinds of rings you can buy that go over the glass bottle. A simple "high temp" silicone o-ring will do in a pinch.
Sorry, I got off on a side tangent, but it's all realated. Either way, the VM is worth finding solutions for and keeping in the amp stable.
Rock On !
Your SV20 gets that hot?
Red Marshall tube is JJ.I've experimented this morning with the V-1 in my SV20C, looking for less shrill/piercing tube. The stock one sounded dreadful. So, I took some of my spare vintage tubes to try to find most pleasant and quieter (hum/noise/microphonics) sounding tube. All of these were really nice and much better choice than stock V1But I've settled on this old RFT. Dead quiet on full volume and the sound was bit darker which I prefer in the Plexi style amps. The good thing is that you still can find 'em relatively cheap.I know that's nothing new to some of you, RFT's are known good tubes for V1 in Marshall in general. And btw, this one was stock in my amp:Not sure who makes those..