BHK250 tubes glowing red

I wonder, I leave my BHK250 in sleeping mode when not playing music. I only use the front switch. I bought the amp in November 2019. The amp is ‘sleeping’ much longer than actual music playing time. Usually only a few hours in the week end. I think the SQ is still improving. However, should I shut it off completely off during the week to save tube life-or let it sleep to burn in properly?

I thought the whole point of putting it in standby was to keep the solid states in optimal condition and to save tube life. I wonder why the tube heaters are still on!


OK, sorry, confusing photo… made when amp is on - not standby I mean…

From the manual:
“When the logo standby button is not lit, the amplifier is in standby mode, and the vacuum tubes are turned off. Standby mode keeps the solid state circuitry of the amplifier in a reduced power mode, maintaining excellent performance benefits while consuming little power.”

The red you are seeing may be a LED that is on to warn people when there are hazardous voltages in the area.

In both the amp and preamp, the high voltage is always on when the back panel power switch is turned on. The tube filaments are off. The tube filaments are turned on when the unit is taken out of standby. One advantage of this is that the high voltage regulators are always on and warmed up.

Additionally, the high voltage and output stage regulators are all on and the entire solid stage circuit is active, but at reduced current in all of the active devices. This way, the circuit takes less time to get up to full sonic quality when set into operate mode as opposed to starting from a totally cold start.

During the 45 second delay, the tube heaters come up fully and the plate voltages to stabilize. The delay also provides the coupling capacitors that feed the solid state output stages an opportunity to fully charge as their outputs are shorted to ground during the delay. After the delay, the coupling capacitor outputs are unshorted and the unit will play.


Thanks, you are right ;-).

I had to RTFM…!!

Thank you for the extra info!

1 Like

I should have asked: Should I keep it on instead or in standby to burn in…

If I were you, I’d just do what you’re doing now. Preserve the life of them tubes, and continue to let the amp burn in while in operation.

That is good. Something would be up if they were on in standby.

1 Like

To all above; thanx again! Yesterday I had not my most brightest hour re-reading my post!

1 Like

“Let them glow, let them glow, let the current flow”
Sorry- just watched Frozen with my daughter- again.