problem with Heater fuse and test

[fingerpicking]

. There may in fact be nothing wrong with your POS, other than the fuse being underrated.

Right. So it's normal to get continuity in a fuse holder with no fuse in it, using an auto-ranging digital meter designed for HT circuits.

[fingerpicking]

The suggestion is that you are getting a continuity reading due to a parallel load, depending on your meter range. There may in fact be nothing wrong with your POS, other than the fuse being underrated.

I'll explain: I got this amp almost for FREE, as 'spares' and 'untested'. That basically means: 'this stuff has something wrong with it, but we aren't telling you anything else, or we don't care'. The Heater fuse was MISSING, so I ordered them, which I still haven't got. Meanwhile, I just tossed a fuse I had, in the amp. Underrated, of course. Two reasons: 1. if I had the correct fuse, I would have used that, or 2. I would never have been so stupid as putting an OVERRATED fuse.
So I have put a smaller value fuse. I had nothing to lose and just hoped I could try the sound of this amp, because its hi-tech tube power amp intrigued me. And what happened? I heard the best amp I heard for the last 15 years, this considering I have owned various Marshall JCM800s, reissue plexis, Fender Blackface vintage amps, and a host of other great amps, which I never kept because expensive, but currently have an original VOX AC 50, a glorious amp of course.

Had fun a few hours with the DT 50, then the fuse blew. What I am saying is that I would be very surprised if there WEREN'T anything wrong with the amp, since I acquired it as HAVING something wrong. Who would be the idiot to give away a good and expensive amp? Duh.

See, that's what happens when people jump to conclusions without knowing everything, and thinking they do

[fingerpicking]

anyways, this forum is disappointing and people aren't competent. I'll go. Enough waste of my time.

[Dave H]

Right. So it's normal to get continuity in a fuse holder with no fuse in it, using an auto-ranging digital meter designed for HT circuits.

It's not an HT circuit it's. the heater circuit. The continuity path is through the heater winding and cold resistance of the tube heaters both of which are very low.
On its continuity setting a DMM buzzes when the resistance is below a certain value. I've just checked at Fluke and they say < 40 ohms. The heater circuit resistance is much less than 40 ohms so the meter will buzz when testing across the heater fuseholder.

[Leo_Gnardo]

It's not an HT circuit it's. the heater circuit. The continuity path is through the heater winding and cold resistance of the tube heaters both of which are very low.
On its continuity setting a DMM buzzes when the resistance is below a certain value. I've just checked at Fluke and they say < 40 ohms. The heater circuit resistance is much less than 40 ohms so the meter will buzz when testing across the heater fuseholder.

Thanks Dave, I was about to give the same answer. We're too late though, our young, loud and snotty amp "expert" has already made his exit, permanent I hope.

[Jazz P Bass]

"I was already getting killed once, 15 years ago, messing with these amps. I fell unconscious and went blind for about 2 seconds, then recovered."

Maybe it caught up with him.

FYI: I don't use the diode test feature of a DVM to check for continuity.
Setting the DVM to read ohms will give a lot more information.

[drewl]

Guys, it's a DT50!
Better sounding than any vintage Plexi's or Fenders or Vox..... we MUST fix the amp!

[dmartn149]

Thanks Dave, I was about to give the same answer. We're too late though, our young, loud and snotty amp "expert" has already made his exit, permanent I hope.

Well his instant oatmeal is getting cold, and you still haven't fixed his amp (for free) and it's been more that 4 hrs. WTF!

[tboy]

anyways, this forum is disappointing and people aren't competent. I'll go. Enough waste of my time.

I believe the reason you are getting a continuity reading has been sufficiently and competently explained. Please don't let the door hit you in the ass on your way out of here.

[nosaj]

anyways, this forum is disappointing and people aren't competent. I'll go. Enough waste of my time.

Your loss not ours. But just remember that when you go asking for help again.

nosaj