Almost nothing, except maybe saving some money. 5Z3 and 5U4G are the same tube, only difference is the base.

Are you saying they compare well with G.E.C 6080/6AS7G? I've been using A2293s for years (I have a lifetime supply, so go ahead and buy all the rest :L3000:) but the G.E.C 6080/6AS7G have been a little too rich for my blood. So I've wondered how they compare.

IMO at this level it isn’t about “better” it is about which one you like, and then the specific tube you receive. If I were to pick I’d take the hanging filament, but that doesn’t make it best for you. YMMV and all that.

That's good to hear. I was going to post that if a socket feels extra tight I'll work it with a socket saver rather than risk breaking a tube.

Sorry for your loss. FWIW I've been using those adapters for years without issues, it is possible the issue was with the tube. Also, I always use a pin straightener with 9 pin tubes before putting them into anything (including the box). Agree the sound is awesome, esp. for the money.

I don't claim any special authority in "tube noise taxonomy" but what you describe is what I'd call microphonics. To me, microphonics means turning any kind of vibration into audible sound, whether that is produced externally (e.g. by tapping) or just from playing music thru the amp. Or put...

I use mine as a preamp, probably more than for headphones. The volume knob works the same in pre mode as it does for ‘phones.

Guilty as charged :L3000:. I grew up LAish but moved up here 30+ years ago (after a brief stop in Santa Barbara). I have a bunch of family and friends in SLO/Cayucos/Cambria. It is a slice of heaven for sure.

IMO yes, the fat-base smooth-plate (no-notch) are the best. Also the most expensive.

Fuses are a controversial topic. I'm using Synergistic Research Orange fuses and think they made a noticeable improvement but FWIW/YMMV and all that. If you are #fusecurious my suggestion is to try a cheap ceramic fuse and see if you can hear any difference. If you can't then you are done. But...

Yes, I've got GEC CV1135s that are some of my favorite tubes. A lot like the GEC straight glass L63, but trades a little bit of transparency and high end sparkle for a little more warm tube yumminess. I like the Ken-Rad 7931s well enough, but I think the CV1135s are a lot nicer. JMO/YMMV and all...

My picks would be GEC A2293s with adapters for the 6080s and a Brimar 5Z4GY rectifier. But JMO/FWIW/YMMV and all that.

I actually just bought a quad of Soviet 6N5S/6N13S/6AS7G from the seller. They accepted my offer of $100 and the tubes sound great. I know of other people on this site who have had issues with the sellers from India but I've made 4 or 5 purchases from them without any problems. They are often...

The thing is there is a difference between gain: how fast the voltage aka volume increases and power: how much current the amp can source into the load at particular voltage. So, just because the amp plays louder for a given volume setting doesn't necessarily mean it has a higher power output in...

The 76 tubes I’ve used have not behaved like that. But, now that I think about it, very early on I might have had a couple of Tung-Sols that behaved very strangely. They were part of a grab bag and I quickly moved on, and don’t remember the details. So there might be something with TS 76s that...

Yeah, you're going to have to email them regardless, and my experience is Martin is happy to answer questions about what exactly they have in stock. Like leftside says, it takes patience, but I've also bought a lot of tubes from them and they've been great (both the tubes and dealing with Martin).

Yes, and they work fine for me. FWIW I get my ebay adapters xulingmrs whenever possible. I've had very good luck with them, I can't say that about other ebay adapters. It might be a problem with the tubes, although it is unlikely that 2 tubes are bad in the same way.

Cool. FWIW no mention of 2C22 an any of several RCA tube manuals. Those look like NU made to me.

Has anyone seen an actual 2C22? I have not. I have a lot of old tube manuals and the only reference I see to them is from Sylvania, which I didn't think ever made this type tube. Also no on the 6S8S. I've got a couple quads of GEC and one of Ken-Rad and that is plenty for me.

For me the big difference is they cost a lot less. :L3000: The Ken-Rads and GECs sound a lot like the 6J5GT/L63 versions. I have National Union 7193s that sounded soft and veiled, so very different from my NU 6J5GTs.

I'm not sure what tube your DAC uses natively. If you want to use 7193 in place of a 6J5 than you need a 7193 -> 6J5 adapter. You can get them from ebay or @Deyan on this site. FWIW I've been enjoying 7193 types a lot over the the last year or so, my favs are the Ken-Rad and GEC CV1135.

Certainly no tube tester will tell you how a tube sounds. For me, the big thing is if you are paying for "new" and the tube tests weak you aren't getting your moneys worth. And while there are certainly no guarantees that any tube will last any amount of time a strong tube is more likely to live...

All true but testers like your Amplitrex are the exception, and I think by a wide margin. I would say most testers are in fact designed to test if tubes are bad, not good or matched. And that assumes they are even calibrated.

There are a lot of theories, but too many of us, me included, experienced the sound changing (improving) after the new firmware had played for 50-100+ hours for it not to be a thing. But YMMV as always.

I would think any cable made with an RJ45 connecter would be wired according to the EIA-TIA standard, but I can't say that for sure. But there is a DSD Channel Swap option for exactly this situation, if your issue is with DSD.