6SN7GT VT231 TUBES

One of the best things about the 6sn7 tubes other than they sound great is there are still a ton available and many at reasonable prices. I use them in a Modwright LS 100 preamp. I didn't go all in on the Tung Sol round plates that go for such high prices but I have a nice selection of Sylvania, Raytheon, Tung Sol, and RCA that should take care of me for many years. I much prefer those to any newly made tubes I have from Russia or China. The somewhat standard Sylvania 6sn7 gtb sound very good in my system and they are plentiful. 

I love the Tung-sol 6NS7 I use them in my Triangle Arts I've owned the older version & his newer line. Pre Amp & Mono-Blocks. They're inexpensive balanced & sound great. When I compare the difference in prices I'll go with Tung-Sol's. More money for vinyl.....

I have a pair of Sylvania VT 231. 6SN7GT on my OPPO 105 Modwright and when I open the drawer on the player I can hear the noise of the opening on my speakers 

Are these normal??

I have a pair of Sylvania VT 231. 6SN7GT on my OPPO 105 Modwright and when I open the drawer on the player I can hear the noise of the opening on my speakers

Are these normal??

@zorro

That’s very normal for vintage 6SN7GT in "upstream" slots. That’s why I mentioned I hate these tubes in anything but power amps - where they’re far enough downstream from most of your system’s net gain (gain structure). The problem is:

1. 6SN7 has very LARGE plate structure compared to its moderately high mu / gain
2. Vintage 6SN7GT (and VT-231) are very old, and its large mica spacers are not holding the internal parts as tightly as they should, especially after all these years. Later GTA and GTB variants improve the plate & mica structures for this reason; you might try those though they don’t sound as "sweet" as GT.

And yes, any mechanical switches or motors in the SAME box as a 6SN7 is going to cause audible mechanical feedback. That’s not specific to 6SN7 - I have 6H30 preamps with the same issue (they are very sensitive to this). Tube dampers are worthless for this; don't even bother - the problem is how they are mounted to the sockets and PCB / chassis. 

Anyways, if your Oppo 103 has a digital volume control (I forget if it does or not), and you’re using this to directly drive your amps, your problem is gonna be SO MUCH WORSE. If you had an analog preamp with volume control, then that attenuator is at least able to filter some of the microphonic noise (a downstream attenuator reduces the "net gain" the 6SN7 sees downstream). By contrast, the Oppo’s digital volume occus before the 6SN7, so your tube noise effectively bypasses it.

Frankly, 6SN7 here is a rather sadistic choice on part of the modder.

@acresverde seems as though the Melz tubes have a reputation of having problems. Reading on other forums shows that many of the noise and different failures can be fixed by resoldering the connections inside the pins. I’ve been put off buying them because of the issues people have reported. It would be a shame to throw out expensive tubes if they could be repaired.