Bottlehead Forum

General Category => General Discussion => Topic started by: Entropyman on December 22, 2018, 08:42:21 AM

Title: Tube Flair on start up
Post by: Entropyman on December 22, 2018, 08:42:21 AM

I managed to replace a bad capacitor in a tube integrated amp I have, but have noticed in the past that the 6SL7 on the left channel flairs (visually, there is an increase in the brightness of the tubed a bit on start up, then calms down after a second or so).  The left channel is also the one that seems to have the shorter tube life, and is a bit louder than the right channel.  Any possibility those issues are connected? The bad cap was also left channel......

Any insights would be appreciated.

Phill

Title: Re: Tube Flair on start up
Post by: Paul Birkeland on December 22, 2018, 08:59:09 AM

The glowy bits are the heaters in the tube, and they will tend to draw a bit of extra current on startup.  You can read up online about the "Mullard flash" that's associated with 9 pin Mullard tubes that flash when first turned on.  There's nothing wrong with any of this.

-PB