Hi there,
Something horrible happened... after two years of work, I managed to finish my sse. Everything checked, apparently everything ok.. when I turn on, check light turns on and valves start to glow. After, let's say 15 seconds, R2 burns with fire. I will post some pics later (but there is actually not more to see than what's described). R2 was 150ohm 3w 5% axial (23J150E-ND). My questions:
1- what can cause r2 to burn?
2- I have desoldered r2, will just replacing r2 work?
3- what should I check?
4- should I start a brand new pic?
Thanks and best regards!!
Something horrible happened... after two years of work, I managed to finish my sse. Everything checked, apparently everything ok.. when I turn on, check light turns on and valves start to glow. After, let's say 15 seconds, R2 burns with fire. I will post some pics later (but there is actually not more to see than what's described). R2 was 150ohm 3w 5% axial (23J150E-ND). My questions:
1- what can cause r2 to burn?
2- I have desoldered r2, will just replacing r2 work?
3- what should I check?
4- should I start a brand new pic?
Thanks and best regards!!
Hi, thanks for quick reply. Find attached photos. What do you mean exactly with schematics, what should I post? I have configured like that: [http://www.tubelab.com/images/AssemblyManualSimpleSE/Wiring/SSE_hookup_choke_triode_noCFB.jpg]
Thanks and sorry if my questions are to obvious!
Thanks and sorry if my questions are to obvious!
Sure! Thanks! How could you check them? And if they're not good? Desolder and solder again?
Thx!
Thanks 
I was actually expecting this being posted here:
instead of having to navigate an external page, but hey, better than nothing
And yes, *seeing* the schematic it´s easy to imagine what happened.
Hope the rectifier is fine .
Maybe the SS/Tube switch was ON and the SS diodes took the surge.
As a side comment, is that amp finished?
I see lots of too long cable all over the place, some of it with free ends.
As of soldering, it´s really hard to solder well with mandatory lead free type, can´t you get a little old style one somewhere?
A tiny bit of it added to each already soldered junction will make it way more reliable.
In any case, congratulations on your build and welcome to a fascinating Hobby
I was actually expecting this being posted here:
instead of having to navigate an external page, but hey, better than nothing
And yes, *seeing* the schematic it´s easy to imagine what happened.
Hope the rectifier is fine .
Maybe the SS/Tube switch was ON and the SS diodes took the surge.
As a side comment, is that amp finished?
I see lots of too long cable all over the place, some of it with free ends.
As of soldering, it´s really hard to solder well with mandatory lead free type, can´t you get a little old style one somewhere?
A tiny bit of it added to each already soldered junction will make it way more reliable.
In any case, congratulations on your build and welcome to a fascinating Hobby
+1
R2 is a bleeder resistor for the 1st filter cap, it has the full raw B+ across. It needs to be 150k.
Regards,
Rundmaus
There are no "members." Its available to everyone as all of my material.
Yes, R2 is the wrong value and would fry in a flash. It needs to be a 150 K ohm 3 watt part. R4 must also be 150 K ohm or there will be more bad parts.
It is possible that the rectifier tube got damaged by attempting to pass 3 amps or so of current.
I doubt it. R2 would have instantly vaporized, or the fuse should have blown. If you are on US power the fuse should be 2 amps, 1 amp on 240 volt power.
Surprises me that the tube took that near-short without a flash and a bang. I have a tube rectification supply that slightly pushes the spec boundaries - took a while to select a few tubes that work without flashing over...
Regards,
Rundmaus
Thanks.
I clicked http://www.tubelab.com/images/AssemblyManualSimpleSE/Wiring/SSE_hookup_choke_triode_noCFB.jpg] and page answers:
Hence my comment
Hi! thanks for the explanation. I don't know how could I make a 10^3 ohm mistake..... I checked values 10 times, looks like it was not enough. Anyway, happy to know where the problem is.
Regarding to the fuse, it has blown.. I was trying with 1A first and it blew, then put a 2A and there I got some second of work before R2 blew. I'm using 230V power (europe) so I should go for 1A? can I try higher values (maybe 1,5 or 2A) in case it blows?
thx!
With newly built hardware, there could be several independent problems, plus problems caused by
other problems (cascading failures) after turning it on for the first time. It's best to measure
the resistors with a meter, both before soldering, and after a failure. Until you know more about
circuits, just check everything you can, all the parts and all their connections. A dark filament will
usually be due to a bad or wrong filament connection. After checking everything, if possible test
the rectifier tube in a tube tester, or substitute a known good one. It could have been damaged.
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As to the power tube not lighting up - check that the tube socket is Installed ( oriented ) correctly. If it is oriented correctly, then the tube is bad.
As to no sound - lots of potential causes.
It looks to me like the rectifier tube you are using is the Sovtek "5Y3GT". These are neat looking tubes, but I have to tell you that I have found them to be quite fragile in my experience. First off, they are not a 5Y3 type - they output voltage about like a 5V4, but can only supply current about like a 5W4, in my experience. Second, if that was the tube that was in place when you smoked the bleeder, it is almost certainly fried as well. Third, if by some miracle it didn't fry when the bleeder fried, the current drain of two 6550 / KT88's will fry it in short order.
Just my $0.02.
Win W5JAG
As to no sound - lots of potential causes.
It looks to me like the rectifier tube you are using is the Sovtek "5Y3GT". These are neat looking tubes, but I have to tell you that I have found them to be quite fragile in my experience. First off, they are not a 5Y3 type - they output voltage about like a 5V4, but can only supply current about like a 5W4, in my experience. Second, if that was the tube that was in place when you smoked the bleeder, it is almost certainly fried as well. Third, if by some miracle it didn't fry when the bleeder fried, the current drain of two 6550 / KT88's will fry it in short order.
Just my $0.02.
Win W5JAG
- Rectifier tube has been checked (pin 2 and 7 are connected) plus it glows when turned on. --> Can this guarantee that tube is operational?
- What rectifier should I use, I have checked on several configurations other people have chosen and this is why I chose kt88 + 5Y3GT.
- KT88 is fully operational, I have changed position of KT88 and the one that was not glowing now glows. So there is someting about the socket..
- Plus, if I get really close to the speaker, I can hear a really really low hum in one speaker but not in the other..
What else? Should I take the valves out, turn the amp on and do some measurements?
THX!!!
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