Simple B+ delay circuit for tube power amp?

rongon · 23rd August 2011, 04:56 PM

Can someone suggest a simple B+ delay circuit for tube power amp with full-wave diode-rectified B+ around 450VDC?

I found some circuits for solid-state amps, none for tube amps -- except many references to why tube rectifiers are superior, etc.

The idea would be... Turn power switch on, heater supply turns on immediately, ten seconds later the B+ gets switched on.

Thanks.

artosalo · 23rd August 2011, 06:15 PM

I prefer to have separate power and plate supply switches. This is simplest.
Then you can also put the amplifier to stand-by mode.

M Gregg · 23rd August 2011, 06:36 PM

Quote:

Originally Posted by rongon

Can someone suggest a simple B+ delay circuit for tube power amp with full-wave diode-rectified B+ around 450VDC?

I found some circuits for solid-state amps, none for tube amps -- except many references to why tube rectifiers are superior, etc.

The idea would be... Turn power switch on, heater supply turns on immediately, ten seconds later the B+ gets switched on.

Thanks.

Just for fun link:

B+ time delay circuit - your comments

Regards
M. Gregg

Merlinb · 23rd August 2011, 09:41 PM

Another related thread:
B+ time delay relay

razorrick1293 · 24th August 2011, 01:05 AM

what about making a 555 circuit that has a low output at turn on and a hi output after say 30 seconds. the output can be to a transistor that activates a relay. if theres enough current available you could rectify the heater supply.

bigpandahk · 24th August 2011, 09:14 AM

I use this soft-start B+ for my 300B SE and it works perfect. (right lower part of the diagram)

jsfinusa · 24th August 2011, 10:40 AM

I think what you're looking for can be found here: tubes4hifi amplifier KITs page I don't own one, but it looks like a simple 555 and relay based circuit that will meet your requirements.

VictoriaGuy · 24th August 2011, 05:38 PM

There' no harm in putting in delay or standby switch arrangements (except for more possible points of failure), but they're really not necessary with 'low voltage' tube circuits (B+ V<750v).
Kevin O'Connor at LondonPower has commented on this, others also.

But more switches and lights are always fun!

wfmali · 24th August 2011, 06:51 PM

Quote:

Originally Posted by VictoriaGuy

But more switches and lights are always fun!

Exactly right - and that's why I like to use 6D22S or EY500A as B+ delay

Marcus

Vinylsavor · 24th August 2011, 07:21 PM

Hi

That's right! Indirectly heated tube rectifiers, especially TV dampers as those mentioned are the easiest and most convenient way to get a delayed B+ and gentle rise of the voltage. And sounds better too

Thomas

23rd August 2011, 04:56 PM	#1
rongon diyAudio Member Join Date: Jul 2009 Location: Across the river from Rip's big old tree...	Simple B+ delay circuit for tube power amp? Can someone suggest a simple B+ delay circuit for tube power amp with full-wave diode-rectified B+ around 450VDC? I found some circuits for solid-state amps, none for tube amps -- except many references to why tube rectifiers are superior, etc. The idea would be... Turn power switch on, heater supply turns on immediately, ten seconds later the B+ gets switched on. Thanks.

24th August 2011, 07:21 PM	#10
Vinylsavor diyAudio Member Join Date: Feb 2002 Location: Lindau	Hi That's right! Indirectly heated tube rectifiers, especially TV dampers as those mentioned are the easiest and most convenient way to get a delayed B+ and gentle rise of the voltage. And sounds better too Thomas __________________ http://vinylsavor.blogspot.com/

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23rd August 2011, 06:15 PM	#2
artosalo diyAudio Member Join Date: Feb 2010	I prefer to have separate power and plate supply switches. This is simplest. Then you can also put the amplifier to stand-by mode.

23rd August 2011, 09:41 PM	#4
Merlinb diyAudio Member Join Date: May 2006 Location: York	Another related thread: B+ time delay relay

24th August 2011, 01:05 AM	#5
razorrick1293 diyAudio Member Join Date: Nov 2010 Location: England Hertfordshire	what about making a 555 circuit that has a low output at turn on and a hi output after say 30 seconds. the output can be to a transistor that activates a relay. if theres enough current available you could rectify the heater supply.

24th August 2011, 10:40 AM	#7
jsfinusa diyAudio Member Join Date: Jun 2011	I think what you're looking for can be found here: tubes4hifi amplifier KITs page I don't own one, but it looks like a simple 555 and relay based circuit that will meet your requirements.

24th August 2011, 05:38 PM	#8
VictoriaGuy diyAudio Member Join Date: Dec 2008 Location: Victoria, BC	There' no harm in putting in delay or standby switch arrangements (except for more possible points of failure), but they're really not necessary with 'low voltage' tube circuits (B+ V<750v). Kevin O'Connor at LondonPower has commented on this, others also. But more switches and lights are always fun!

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