|
Audio Asylum Thread Printer Get a view of an entire thread on one page |
For Sale Ads |
99.149.238.6
Is there such a thing?
I imagine a LED,(The on LED?) that lights up only when the tubes are fully warmed-up.
Proudly serving content-free posts since 1984.
Follow Ups:
The amps. I build use a neon high voltage indicator, run on DC with a resistor in series. But it's only good for tube rectifiers that warm up slowly. A SS power supply will come up to voltage instantly, which in turn lights the neon instantly.
If you ran some cathode current through an opto-isolator, it would bias on the LED once the tube started conducting. Then the opto resistor can be connected in series with an LED to slowly light it up. But that requires some engineering.
You can 'fake' it as well by using a timer circuit that corresponds with the warm up time, then light an LED once the timer has timed out.
I am aware of two amps that provide something that could serve as you have asked-
1: the RM-9 - MKI - this amp has an LED in the bias circuit to indicate 'proper' bias as adjusted via the bias pot-
the way it would work as you requested is as follows: the LED, once set, will return to that intensity/brightness once the bias current has come up and stablized - so you turn the amp on, and the LEDs are not lit, but after a few minutes, when the bias current stabilizes the LED will be lit indicating that the PS has come up and the amp is ready to be listened to-
#2: the RM-10 MK II - this amp has a cathode bias (not adjustable by user) with LEDs across the cathode resistor- and will function as an indicator that the bias current is up and the amp is ready for listening-
Otherwise, I am not aware of an indicator
I do know that the Audible Illusions M3 series of Pre-Amps has a long timer circuit before the amp will switch into 'operate' mode from turn on- another way to address the issue-
Happy Listening
....it's just not built-in. :)
The only LED indicators I have seen are those for initial mute until the tubes are stabilized and safe to play. Usually a minute or so. The initial mute indicators I am familiar with are based on a timer or heat, like a multi-colored LED, or thermistor based delay.Beyond that, manufacturer's recommend a warm up duration for optimum performance. 10, 20, 30 minutes, more?
I suppose a "timed" circuit could be used to control the LED for optimum warm up time, but that would really be independent of knowing what's actually going on with the tubes. And you don't want your "timed" circuit kicking in for 20 minutes in cases you've already been running your amp for a couple hours, turned it off for minute and then back on. I'm sure there's some sort of design workaround for that but it starts to complicate things, parts, cost etc.
Having a circuit linked to the actual tubes would be more complex. I know there are amplifiers with power tube bias settings that you adjust until the LED glows a certain color. I don't know if there is a manufacturer's recommended time to wait until there is a concern of whether the bias is correct or not. Or if in itself you just wait until the bias indicators reach the good to go point.
Sorry this really doesn't answer your question with a direct "yes, this amp does what you are asking for".
I'm mostly thinking of some reasons why (edit) equipment does not have warmed-up indicators.
Interesting question.
Hope you get more responses.
Cheers!
Jonesy
"I know just enough to get into trouble. But not enough to get out of it."
Edits: 04/22/17
I own A one tube wonder headphone amp by a company named Garage 1217. The model is "The Project Ember" where the amp has an indicator led which lights up upon turning it on and then disappears, supposedly when the amp is ready.
It is a tube rollers special able to run a variety of 6 and 12 volt 9 pin tubes. It will even accommodate octals like a 6SN7 with an adapter.
FAQ |
Post a Message! |
Forgot Password? |
|
||||||||||||||
|
This post is made possible by the generous support of people like you and our sponsors: