How can this Happen :( - Nickel Core - Tube DIY Asylum

Tube DIY Asylum

Do It Yourself (DIY) paradise for tube and SET project builders.

How can this Happen :(

Nickel Core

Hi All,

Two days ago I switched off my phono stage while it was connected to my amp with the volume at 90%. Normally I turn the volume down, because switching off the pre-amp, always results in rather hefty cone movement and a low frequency 'plop' through my speakers.

This time the same, but now the 'plop' was followed by strange noises trough one channel and finally the destruction of the 83 rectifier of the PSU feeding one of my 300B power tubes. Also a fuse tripped.

It appeared both the 83 and the 300B died (filaments open). Of course a NOS RCA 83, and a EML 300BXLS :(. Luckily my WE 300B where not in the sockets...

Apparently a large current was induced to flow trough the 300B resulting in this disaster. Replacing both the 83 and 300B proved to be enough to get the amp running again with no damages to OPT or other components.

But what happened here? Why would a very low frequency (but large amplitude) signal on the input of the amp cause one channel to go KABOOM this way? And how to prevent this from happening again?

Thanks,
NC

This post is made possible by the generous support of people like you and our sponsors:

Topic - How can this Happen :( - Nickel Core 11:41:53 10/23/14 (17)

RE: How can this Happen :( - Joao 02:12:50 10/25/14 (0)

Your amp is not DC coupled, is it? (nt) - Chip647 12:19:49 10/24/14 (1)

No, (nt) - Nickel Core 00:51:00 10/25/14 (0)

RE: How can this Happen :( - Stephen R 05:03:51 10/24/14 (1)

The funny thing is that my pre is TX out... (nt) - Nickel Core 08:01:02 10/24/14 (0)

RE: How can this Happen :( - sony6060 03:09:20 10/24/14 (2)

EML 300BXLS - Nickel Core 03:15:33 10/24/14 (1)

RE: EML 300BXLS - amnesiac 06:25:19 10/25/14 (0)

RE: How can this Happen :( - Paul Joppa 16:32:51 10/23/14 (0)

RE: How can this Happen :( - 6bq5 16:11:30 10/23/14 (0)

RE: How can this Happen :( - Al Noakes 13:31:23 10/23/14 (0)

RE: How can this Happen :( - Lee of Omaha 13:28:16 10/23/14 (5)

RE: How can this Happen :( - Nickel Core 14:02:55 10/23/14 (4)

Also.... - Nickel Core 14:05:55 10/23/14 (3)

RE: Also.... - Triode_Kingdom 20:31:52 10/23/14 (2)

RE: Also.... - Nickel Core 00:39:04 10/24/14 (1)

RE: Also.... - Triode_Kingdom 08:42:54 10/24/14 (0)

FAQ

Post a Message!

Forgot Password?

Moniker (Username):
Password (Optional):
	Remember my Moniker & Password (What's this?) Eat Me
E-Mail (Optional):
Subject:

Message:	(Posts are subject to Content Rules)

Optional Link URL:
Optional Link Title:
Optional Image URL:
Upload Image:
E-mail Replies:	Automagically notify you when someone responds.

To view your new posting or follow-up, click on the RELOAD or REFRESH button on your browser.