Sorry about this seeming bad luck Mike. If I remember correctly, Decware guarantees the tubes for 90 days. I recommend reaching back to them.

In the meantime, you could check the fuse, but I'm not sure the other tubes would still light up if that were it. Most likely need to replace the rectifier. If you buy one, I would recommend NOS. At one point in the forum, Steve said the Chinese rectifiers the amps come with are meant to let you play the amp until you can get an NOS rectifier, then keep as a backup.

Maybe someone else will be more help... Take care,

There may be fuses mounted to the underside of the rectifier socket. You will have to remove the amp plate from the wooden base to see them.

The three other tubes light up and the transformer gets warm. The rectifier is cold. Would a burnt fuse cause this?  A new amp, so not wanting to mess with it if it is most likely just a rectifier tube. Does the rectifier have it's own fuse?  Kind of bummed...the Schleprock syndrome at play (cop talk) A Friday evening and three day weekend. This little amp sure does (did) sound amazing! I'll call Monday or Tuesday Morning~ As usual, you folks are just awesome  [smiley=icqlite20.png] Have a great weekend ~  Mike

Hi Mike.

Sorry for your trouble. I’ve had this happen several times in the past. I’m sure that what happened is, the rectifier failed, causing a fuse/fuses to blow. This is a relatively easy fix - take the bottom off, and replace the bad fuse/fuses under the rectifier. You may as well go ahead and take a look under the hood, and find the problem.

Like James said, you need back up tubes, but you also need several of each type of fuse for backups. Although a bit of a hassle, at least in about 30 minutes, you would be back in business.

Best,

Geno

Quote:


Great point Geno.

Here is a thread with a lot of good info on buying your first NOS rectifier:

https://www.decware.com/cgi-bin/yabb22/YaBB.pl?num=1605822949

It is a couple years old, but still points in the right direction.

Quote:

Good to know! I will get back on how this works when it arrives. Hoping for a replacement stock Decware rectifier one as well. I'm sure no problem. I'd use that one as a backup.....and get more replacements for the other 3 tubes as well. We love the sound so will stick with those 3 that Decware used on this amp. I hope I didn't screw up the other tubes etc.. by not immediately turning it off. I was pretty quick to though..lol

Hello Mike,
bought eight of those 20 years ago ( circa late 50s early 60s versions, black plate ), and have had only one failure so far, and that was after probably 15 yrs of use. Better than anything else I compared to except An EML mesh plate 5u4g, and it was very, very close.
Great rectifier. The old black plates are getting harder to find.

Cheers,                   Crazy Bill

If a rectifier tube does not light up but the other tubes do, it means the rectifier tube is either bad or the rectifier fuse(s) inside the amp blew.  Fuses never blow for no reason.  What blows the fuses are small electrical arcs inside the rectifier tube that act like shorts.  These are caused by the following things:  

1) Shipping causing the distance between the elements inside the tube to change making it more likely to arc.

2) Voltage spikes - either from bad weather, bad wiring, having the power cord not fully inserted into the IEC connector, using power strips.

3) Factory defects in the tube.

4) Using poor quality socket savers.

5) Using the wrong rectifier tube.

6) Using the tube past its recommended lifetime.


If a rectifier tube arcs, it is usually when the amp is first turned on, but can also occur at any time.  Sometime the tube continues to work fine after the arc, sometimes it works for awhile and then arcs again later, sometimes the tube is toast.

The reason for using rectifiers in tube amps is not for convenience it is for sound quality.  Having a spare rectifier tube on hand at all times is no different than having a spare light bulb when your lamp goes dark.

Steve

Mike, I don't think you would mess up the screwheads--I have an amp I have taken the top off of perhaps a dozen times and the screws are not even worn a bit.

And, from experience I've learned a good way to handle the fuse replacement. First, take all the cabling and tubes off the amplifier. Then unscrew all the screws. Then take hold of the big ass transformer and lift up. . . you can then turn over the chassis and the transformer will sit down inside the case and settle there--and then you can access the fuse panel on the underside. You may have to gently move aside a few wires to remove fuses but that's easily done and not risky to the circuitry.

If the rectifier is not lighting up it's possible if it is not the main fuse in the IEC power inlet, then it's the 5 amp fuse in the fuse board, which is the one closest to the left side of the chassis when it is upside down. If the rectifier and all tubes light up but there is no sound, then one or both of the 200 milli-amp fuses also on that board has failed, I always replace both of them.

Russian 5u4g´s are surprisingly good after some burn-in, stronger than the Mazda gz32´s they replaced and just as good after about 50 hours of burn, a bargain.

If I was worried about stripping the screw out of the wooden chassis I would,when everything is apart, put some Super Glue into the screw holes.
Let it set up, and Bob's your Uncle, Fanny's your Aunt, Your screw holes are like new.

Okay, seems odd to me. One thing: the other two tubes underneath are actually 200 milliamp, not 250, but that shouldn't make a really big difference. And those two fuses don't stop the rectifier from powering up, just stop "sound" coming out of the amp.

One final query: did you change the 3 amp fuse in the IEC connector? I have seen here on the forum I think that one was bad but still allowed some of the tubes to power up, but not the rectifier. If there is a new fuse in that receptacle, and the 5 amp fuse changed (and good) underneath. . . then it's time to talk to Steve I think.

Dang.

Another bad tube is unlikely but certainly not impossible. If the 5 A fuse is blowing it is almost certainly a rectifier specific problem, so unless something happened to one of the connections to the rectifier socket (even more unlikely than a second bad tube) I'm out of ideas. Well, one idea, but very much no warranty expressed or implied, is you could try a 6 A fuse and see if that buys you anything. But realistically that is a suggestion I'd wait for Steve to make.

Good luck.

Okay, I mention this because I made this error before: is the 5 amp fuse in the correct spot? When you are looking at the underside of the chassis and the top is the area with the transformer and the bottom is the area with the volume control, the 5 amp fuse goes in the left-most of the three fuse holders.

yeah, in the 3 fuse holder, it is labeled 6 A. the other two 1/4 A  I think..  Yup 6 A- left side. Thanks Lon ~~ Also, Kathy saw a tiny piece of solder slag sitting on the towel where I first removed the top and turned it over. She has awesome eyes. It's a very tiny/tiny piece, probably nothing, but I know about temps up and down can sometimes cause a cracked joint on a 'cold weld', but we looked around all over in this and it is so well done! Looks great.. Is it a full moon? Image from front deck.

Actually pretty bummed too because I was not going to order originally (Personal health reason) but kept looking over the amps and site, but not ordering. Then my wife asked why I didn't order yet, I just told a lame excuse. I went ahead and ordered it, or she said she would anyway..twisted my arm. hehe. The closer it got to being built, the more excited I got. Had it almost 3 whole weeks without a single problem..and poof. Here we go. Shit. Made no sense as it was already playing fine. We were so enjoying this. After reading a lot of responses and other takes on this type of issue, I think maybe a heat related cracked 'cold' solder joint, bad tube socket, or just very bad luck with two separate rectifier tubes. I burned 3, 5 A fuses trying to get it to work. So the last 5 amp tube I have is in it and fine...because I wont turn it on. ALL other fuses never popped. Will get to it soon. Mr Deckert has a note left so I am sure he'll call.  [smiley=icqlite20.png] The 5 a fuses I had were all NOT slow blow ones though, so not sure if that matters much. I cannot believe I am resorting to listening to Everyone Loves Raymond on a Friday night in the background.. he he. . All good anyway. Goodnight Gilf

Quote:


I'm no technician so take this with a degree of caution...

You should not be replacing a slow blow fuse with a fast blow fuse.  Slow blow fuses will take a spike when the amp is powered on but not a fast blow fuse.

It's my understanding that when an amp is powered on a spike can occur momentarily and then the amp settles to its steady state amp and voltage draw.  A slow blow fuse will not fail on a power up spike a fat blow will.  

I would confirm the above with a tech and then get slow blow fuses.

Quote:


This is correct. The power supply caps create a surge that will pull more amps then the fuse rating at the flip of the power switch. Slow blow fuses will withstand this surge.

Gilf said above:

I have a couple extra rectifier tubes laying around. If you PM your address, I’ll mail them out todayy

Gilf, nice touch. I find the generosity and support of this community remarkable. Sometimes it's a suggestion or a helping hand. It just makes a big difference when one runs out of ideas and a solution seems hidden.

And, Mike good luck with the tube.

Thank you Tony. And WE absolutely agree with you about folks here. I told her what Gilf said this morning and much of the rest of so much help offered here too. She's very thankful too. ...I'll bet the 'problem' is something that will be found to be something so simple. Have a great Saturday. ~Mike  ~~~~
also Geno: Right on, I will definitely do it that way next try for sure! I talked to Sarah at Decware last evening as everyone else was either gone or just about to leave for the weekend. Told her 'I was once a rocket scientist, but those days are all gone now'.  She was a sweetheart.

Quote:


Hate to say this to you but time delay and slow blow is just another way of saying the same thing.  Some slow blow fuse will have "TD" stamped on the metal collar.

Could be bad fuses???  If the new ones that you've ordered work then you'll know for sure.  If not the problem is elsewhere.  

Quote:


The only way you'll know for sure if it's in the amp is to send it back to be checked.  Yes that's a pain but it will be worth it.  Try sending components back from Canada to the States, what a... "TREAT!".  I've had greater inconvenience with some solid state components over the years.

One other consideration, before you send it back make sure that you know for a certainty that it's not in the house wiring to the receptacle.  Are the wires tight in the contacts???

Don't give up.

I did have the amp moved two different outlets to try, but only used a different, but brand new , never used plug from an Oppo 203 player. Nothing else hooked up to it. All of the amp fuses I have break immediately when switched on. Man, these fuses get expensive. I have one more 'time Delay' (retardo in spanish on the label, so of course perfect for me! Had to have it!) fuse left, so I am going to pop that Svetlana 504G in and give it a shot when it gets here. The image of the slow blow type fuse (like the original in the zen and one of those time-delay ones. They sure do look different. Slow blow ones resemble a tiny section of wound guitar string. https://www.amazon.com/gp/product/B07XYWZWV4/ref=ppx_yo_dt_b_asin_image_o00_s00?...
https://www.amazon.com/BUSSMANN-EATON-GMC-5-R-CARTRIDGE-5X20MM/dp/B011NAHQ0M/ref...  I really do not think a house wiring problem. House built in 2004. If I have to send it back in, sure will. I would have to pack it up just like it was at Decware. We've seen way too many packages look run over by the time they arrive here. Hired help is NOT what it used to be...not even close 'all day long~https://www.youtube.com/watch?v=dxuXDLHHRrY    Thank You JOMAN

Stoked to hear you are back up and running, that made my day.

Hopefully no long term PTSD from Judge Judy.  :)

Cheers,