Asking for the truth. 6v6gt amp run EL-34 , 6l6GC , 6V6GT

[mcgjohn]

Vivatubes tests all the Psvane tubes and gives a 1 year warranty. That moved me to finally buy a Chinese tube.

Same place I got them from. On the 3 failures, they did ship out replacements to replace the defective.

 

[Musictubes]

I have been all rah rah tube rolling amps but I’ll give a few things to look out for.

First, if you actually want tube rolling options the power supply in general and the secondary in particular needs to be overbuilt. There are plenty of amps that have pin compatible tubes available but you run a danger doing. A classic example is using a Mullard ecc32 instead if a 6sn7. It has a great reputation but its heater draws a lot more and so can kill your power transformer. If an amp maker says you can roll different types of tubes pay attention to what they say. Don’t stray away from those guidelines unless you can establish that the tubes you want to use are within the heater and design parameters. I don’t think I’d trust a Chinese amp maker to have enough overhead in the power supply to get too exotic with the tubes.

You’re going to give up on maximum power. Typically amps that advertise tube rolling will come with el34 or even kt88 tubes. Most of those amps will run those tubes at a lower voltage, especially if they say you can use lower power tubes like 6l6gb or 6v6. Ideally you’ll pick an amp that allows you to change the b+ in some way, usually by changing the rectifier tube.

There can be big differences between different versions of the same tube type so you may not need to buy a special amplifier to try all this. You’ll typically hear bigger differences on amps with lower amounts of feed back and/or single ended. The 807, 5b/254m, and 6bg6 are all supposed to be electrically equivalent. Between those types I have 8 different versions and they all sound different. I’ve lost track of all of the 6sn7 equivalents I have like 6f8g, 7n7, and pairs of 6j5 plus all the 12v versions of them. I’m probably up to 20 different options or so. Plenty of good sounding combos, could be happy long term with lots of them. But it is fun to keep trying things to hear what you get. I think there is more room for experimentation with driver tubes. Many of them will be well within safe parameters to run so there’s no harm in trying them. But double check before trying anything crazy! Between using adapters and having variable heater voltages I have been able to try 5755, 6c8g, 4kn8, 402a, and pairs of triode wired c3m, 5a/152m, and 6j7.

So have fun but be careful!

 

[Musictubes]

IF you go down that path just be careful. I have done so quite a few times. Got burned over 50% of the time with tube failures, greatly imbalanced triode sections, etc. For the prices these "premium" chinese tubes are selling at, a person would think their testing and quality criteria would be much tighter than the standard product, but that is not the case.

Since I can use 12v tubes I have no interest in paying for the Chinese tubes. High quality 12sn7 are still really cheap.

 

[Musictubes]

McIntosh still makes tube gear, ya? Tube equipment was kind of the bench mark. When transistors came along some like Marantz, and McIntosh waited a bit before switching to SS until transistor technology got better than the Germanium transistors that were first available. Transistor equipmant had to be able to sound as good as tube equipment. Properly designed tube equipment can sound every bit as good as SS equipment. One of the reasons I prefer tube gear is being able to taylor the overall sound of a preamp or amp somewhat to your personal liking just by using certain brands of a certain tube, or it's equivalent.

Yeah, they reintroduced tube amps several owners later. Started with anniversary versions of the 275 I think. Made sense since originals were selling for so much. The dealer I worked at sold a large number of old Macs over the decades to Asian students that took them back home. It took a while for Americans to appreciate what the Japanese saw in them. Eventually McIntosh made new amps. I suspect but don’t know that they are simpler circuits these days. I wonder if they still have the know how to design and wind the transformers needed for their more out there feedback schemes of years past. They’re all built well and spec out incredibly well of course but they aren’t my kind of amp.