Rectifier tube keeps blowing

A rectifier arcing over makes it ready for the dustbin. It's heartbreaking, not too mention a pain in the pocket.

Have you already disposed of your 274Bs? If not, and you're willing, I would be more than appreciative if you could send them to me. I decorate my Christmas tree with tubes(seriously), and the 274B would really look great! Of course, I'd be willing to cover all the costs in getting them to me, plus a bit more.

Heyraz, yes, I absolutely decorate my Christmas tree with vacuum tubes. My wife thinks it's ridiculous, but I think it looks very cool. I used to know how to post a picture here, but have forgotten.

I did the same thing back then when I replaced the incandescent light bulbs in my house with CFLs. I was in a really cool store that was selling incandescent bulbs that were painted in things like snowflake motifs and stuff like that, and I stole the idea from them. I figured vacuum tubes would also serve the bill.

None of the tubes (or lightbulbs) are connected, electrically. They just serve as ornaments. I probably will one day when I have enough on the tree to make a meaningful statement. It would be just the heater filaments, so they light up. But, if they were biased, you can bet it would be Class A all the way.

Oh, one other thing to look at Devilboy is to make sure resistance in the bleeder circuit of the power supply circuit is high enough. If it's not, too much power will be present, and you'll be arcing over rectifiers with no trouble at all.

Speaking from personal experience and expanding upon what Ralph intimated, the Chinese are great at screwing up both the design and implementation of high-end audio products. I'm not sure how old your amplifier is, or how long you've used it without encountering this issue, but what I'm saying is don't assume they specified/figured out the right value of the resistor here or even if they did, that the right value was installed in your amp. Their piece to piece variability can often be breathtaking, sometimes making their own schematics look like downright works of fiction.

Continued luck in solving this problem!

You could use one of those 845s for the star at the top of the tree, Goldeneraguy! That thermionic beast would make one heck of a statement.

Though I've got a really cool true 5 bulb star from the 1950s or 1960s on my tree, this seems like a novel and fun idea. I have some 845s and 211s around, and might want to give it a try if the heat isn't too much to disqualify it.

Heyraz, the tubes I use have metal or polymeric bases, and as you would well know, there's a "pinch" in the glass where the base and glass couple together. From there, I use a sort of string/thread to tie around them on one end, with the rest of that material forming a loop to hang from one of the branches. It's simple/crude, but it what a lot of Christmas tree ornaments use, and it's worked well enough for me for probably 10 years now.

Yes, a good suggestion, Ralph.

Along that train of thought, you can also start the amp up without the rectifier tube plugged in. That lets you see where the bias is without (hopefully) the amp going down, and get it right if it's way out of whack, or at least turn it way down. I would actually do this before firing up the amp with the rectifier in and the output tubes out.

Of course, this presumes the amp is fixed bias, and though we've not been told this (if I didn't miss it), have kind of been working under that presumption. A cathode bias circuit would open something else for him to think about.

There's a way to post photos here, Heyraz, but I've long since forgotten how. It used to be semi-common here back in the day. If no one comes to the rescue with that, I'll send something offline.

Detredwings gives the best advice, "Power supplies can be dangerous and if you don't know what your doing I would suggest you take it to someone who does. I'm only suggesting this because the high voltage stuff can hurt you."

As upset as you are, consider it a blessing that the rectifier and fuse are blowing before something more serious occurs.

If the filter caps do check out OK, look around for a heavy duty short somewhere in the power supply. After that, I'd be suspicious of the power transformer.