Need 5E3 Build Troubleshooting Help

paul-e-mann

Well-Known Member
Joined
Dec 7, 2009
Messages
19,475
Reaction score
21,180
That sounds dead to me.

You should have about 380v DC at pin 8. If you only have 1v DC, that’s the problem. I would assume that a new tube would fix that.

So is there any indication that the rectifier heater momentarily gets hot?
It may be that the heater fails (goes open circuit) as soon as heats.
Maybe resoldering pins 2 and 8 would help :shrug:
Popped in a Sylvania 5Y3GT rectifier tube and the amp is alive! Cheap Chinese 5Z2P tube that only lasted a couple weeks or is there more for me to worry about?
 

william vogel

Well-Known Member
Joined
Dec 18, 2016
Messages
1,075
Reaction score
1,305
Popped in a Sylvania 5Y3GT rectifier tube and the amp is alive! Cheap Chinese 5Z2P tube that only lasted a couple weeks or is there more for me to worry about?
Did you measure your voltage as the tubes transition from cold to warm.
 

paul-e-mann

Well-Known Member
Joined
Dec 7, 2009
Messages
19,475
Reaction score
21,180
I just wanted to make sure the 5y3 quickly warming up didn’t send the voltage way above the capacitor ratings. I use a 6087 with an indirectly heated cathode and my HT voltage slowly rises.
Once I flip the switch on its a good 30 seconds before I get any sound.
 

paul-e-mann

Well-Known Member
Joined
Dec 7, 2009
Messages
19,475
Reaction score
21,180
I've got more problems. I took the amp to a jam last night and the fuse blew 2 hours in. Got home today and put a new fuse in and it blew immediately. Next pulled all the tubes, put another fuse in and connected the amp to my light bulb limiter and the bulb glows bright indicating a short. I get power to the fuse and the power switch, no power to the rectifier or to the pilot light. Does this mean I have a short in my power transformer?
 
Last edited:

neikeel

Well-Known Member
Joined
Feb 12, 2014
Messages
7,336
Reaction score
7,020
More like the power transformer.
When you say no power to the rectifier do you mean no heater voltage or no ac HT to the socket? Or either?

I guess you could lift the centre tap wire to the OT to get it out of the equation but leaving the on//off switch open has same effect.
 
Last edited:

paul-e-mann

Well-Known Member
Joined
Dec 7, 2009
Messages
19,475
Reaction score
21,180
More like the power transformer.
When you say no power to the rectifier do you mean no heater voltage or no ac HT to the socket? Or either?

I guess you could lift the centre tap wire to the OT to get it out of the equation but leaving the on//off switch open has same effect.
Yeah I meant power transformer, no power to either. So what I'm seeing, does it indicate the PT is bad?
 
Last edited:

paul-e-mann

Well-Known Member
Joined
Dec 7, 2009
Messages
19,475
Reaction score
21,180
Sounds like it. Where did you get that PT and how much did you pay out of curiosity?
It came with a $225 Chinese amp kit. I suspect they will send me a free PT replacement, I just want to make sure this is the problem before I ask. Theyve been really good so far, the kit came with a bad power tube and they sent me a free replacement and then the rectifier tube went bad a couple weeks ago and they sent me a free replacement.
 
Last edited:

william vogel

Well-Known Member
Joined
Dec 18, 2016
Messages
1,075
Reaction score
1,305
It came with a $225 Chinese amp kit. I suspect they will send me a free PT replacement, I just want to make sure this is the problem before I ask. Theyve been really good so far, the kit came with a bad power tube and they sent me a free replacement and then rectifier tube went bad a couple weeks ago and they sent me a free replacement.
If you pull all the tubes you can measure all the secondary voltage. You may need to remove the heater feed to ensure nothing being shorted to ground. I’m afraid that the power transformer failed but without the amp in front of me I wouldn’t be able to assess anything. I understand that they may warrant the transformer but if the current transformer failed and there isn’t any fault in the wiring, the transformer quality might be the problem and it could occur again. I’d definitely give them the chance to get you a replacement but if this occurs again, I’d get a Heyboer.
 

paul-e-mann

Well-Known Member
Joined
Dec 7, 2009
Messages
19,475
Reaction score
21,180
If you pull all the tubes you can measure all the secondary voltage. You may need to remove the heater feed to ensure nothing being shorted to ground. I’m afraid that the power transformer failed but without the amp in front of me I wouldn’t be able to assess anything. I understand that they may warrant the transformer but if the current transformer failed and there isn’t any fault in the wiring, the transformer quality might be the problem and it could occur again. I’d definitely give them the chance to get you a replacement but if this occurs again, I’d get a Heyboer.
I pulled all the tubes and measured all the secondary voltages and got zero. Ive been playing this amp for weeks, I cant imagine a ground problem all of a sudden, unless thats possible, I'm learning so I dont know...
 
Last edited:

william vogel

Well-Known Member
Joined
Dec 18, 2016
Messages
1,075
Reaction score
1,305
Ive been playing this amp for weeks, I cant imagine a ground problem all of a sudden, unless thats possible, I'm learning so I dont know...
Right, I also think that the wiring is correct because of the interval of operation but didn’t you have a rectifier failure?
 

paul-e-mann

Well-Known Member
Joined
Dec 7, 2009
Messages
19,475
Reaction score
21,180
Right, I also think that the wiring is correct because of the interval of operation but didn’t you have a rectifier failure?
Yes the rectifier failed a couple weeks ago, all voltages measured good then, I just assumed a cheap untested Chinese rectifier tube that failed. I got a new USA made rectifier tube that fixed that problem.

So do you think its a safe bet my PT is bad and I should order a new one?
 
Last edited:

paul-e-mann

Well-Known Member
Joined
Dec 7, 2009
Messages
19,475
Reaction score
21,180
A separate question unrelated to my current problem, why are amps designed to convert AC power to DC power, why not just design amps to run off AC power?
 

william vogel

Well-Known Member
Joined
Dec 18, 2016
Messages
1,075
Reaction score
1,305
A separate question unrelated to my current problem, why are amps designed to convert AC power to DC power, why not just design amps to run off AC power?
The first problem would be that tubes and transistors for that matter operate only with DC. They are modulated with AC but they are in simplest form just diodes and cannot operate on AC. In reality there’s only a few items in your house or shop that operate on AC. Everything else has an AC to DC power supply and the device operates on DC. Anything with an ECU in it operates on DC. Your TV, computer etc. a plug in drill is AC, saws are AC. Incandescent and fluorescent lights are AC. We use AC because we can generate it and transmission of it long distance is capable because of transformers and the generator is much more efficient. Therefore we generate AC and then convert it to DC for use in the end. Tesla vs Edison, read about it and you’ll see the advantage.
 

Latest posts



Top