I found this write up on how to use starved plate better than what I have seen. http://www.freewebs.com/valvewizard2/Triodes_at_low_voltages_Blencowe.pdf (http://www.freewebs.com/valvewizard2/Triodes_at_low_voltages_Blencowe.pdf)
So I was wondering if the smart minds on this board could come up with a better design than the valvecaster, but stayed @ 12volts. No voltage doublers. I am not afraid of throwing in a op-amp or something else, but this could be all tube. According to the document it looks like 2nd order harmonics are doable with just a tube design.
So I was thinking.. a pentode in front of a triode @ 12v. so the pentode does the boost into the dual triode. I have two 6au6's I got from a hammond organ I could use..
In any case. I am looking for others smarter than me, to review this and give their two cents.. When I get back Sunday I can start putting this together.
here is an example...
(http://dl.dropbox.com/u/14312589/example.png)
Looks simple.. This should be clean, so that the pentode should be able to overdrive it.. So a 12au7 or some other low or med Mu triode would give a better overdrive, but a 12ax7 should also work.
Thanks
ok I tested this.. I works.. but its clean, unlike a valve caster which gets dirty, this stays clean... But way overdrives my input on my amp. I turn it down and get a good clean boost.
so at 12volts the same tube is giving more output than the valve caster @ 30. I am using a 12ax7.. I am really impressed with the output.. its almost like the first stage of a normal high voltage preamp
I think if I drive the pentode with this I should get a good overdrive...
Working on it.. will let you know..
ok here is what I got so far.. I can not believe how good this distortion sounds.. The only problem its full on, a way to kill the gain would be good.. Need to play more.. But full on power tube distortion @ 12V
No need for to raise the voltage... Maybe.. but here it is so far
Tubes.. Pentode is a 6au6 and the Dual triode is a 12ax7
(http://dl.dropbox.com/u/14312589/SkyHunter.png)
Tips and ideals welcome..
Name so far.. Sky Hunter...
12ax7 has more gain ;D
you could try 12U7 instead of 12AU7, about same gain, but designed for 12V car audio.
triodes en pentodes distort different. Pentodes behave more like fet's. Triodes a bit cleaner / linear (ideal for clean/crunch).
Hey, that's interesting. Starved plate is usually regarded as "charicature" tube sound - very non-linear and squashed. If dynamics are okay, this might be interesting for other starved plate circuits - such as compressors, mic-pres. Starved plate comps and pres usually don't hold up to high voltage ones, I need to find my breadboard and a box of time....
Thanks, good find.
Quote from: Steben on May 23, 2011, 05:20:31 AM
12ax7 has more gain ;D
you could try 12U7 instead of 12AU7, about same gain, but designed for 12V car audio.
triodes en pentodes distort different. Pentodes behave more like fet's. Triodes a bit cleaner / linear (ideal for clean/crunch).
Thanks for the suggestions..
In this case the 12au7/12u7 distorts faster and is louder as it is more linear of a tube, but tube rolling is good, I you replace the 690K with what ever gives you about 6 volts for the other tube type or go by ear, I had a 220K and a 1M pot for this, but 640K is what I measured when It sounded best.. If you just have the fist part with the 12ax7 you get zero distortion in this build..
I have tried 12u7, 12au7, 12ae7 and this 12ax7. In truth I kind of want to get a 12AX7 to run well, as with other starved plate you have to get above 30v for this to work.. And it does work well, I just need to turn it down so it makes a useful pedal, right now for me, it would be on or off.. no need for pots
The pentode in starved plate is the one overdriving.. In this design just the pentode overdrives a little. with the 12ax7 it overdrives a lot.. I'll make sound clips tonight.. I have a volume between them, but all the way down the pentode is still overdriving.. I am thinking of putting a resistor in between the two so there is a min about of load. But a resistor on a grid creates distortion to some degree..
Quote from: Mike Burgundy on May 23, 2011, 07:26:06 AM
Hey, that's interesting. Starved plate is usually regarded as "charicature" tube sound - very non-linear and squashed. If dynamics are okay, this might be interesting for other starved plate circuits - such as compressors, mic-pres. Starved plate comps and pres usually don't hold up to high voltage ones, I need to find my breadboard and a box of time....
Thanks, good find.
I was very surprised that in this configuration I could not get the 12ax7 or 12u7 and a 12au7 and a 12ae7 to overdrive, they just got louder.. so it worked.... the paper was not BS....
then adding the pentaboost behind it gave full power tube distortion, not the grainy distortion a 12ax7 gives by it's self... and I put this on a clean channel of my amp... @12v (running off a computer ATX power supply I have as bench power.. makes it nice as I can use 5v for the heaters.)
Schematic front side side works as Linear Tube Booster on 9-volts stand alone.
Would make a great one knob Volume booster pedal.
EDIT: I used a .047 uf oputput cap, and swapped out the 690k for a 620k r.
Quote from: ThunderShowers on May 23, 2011, 05:01:01 PM
Schematic front side side works as Linear Tube Booster on 9-volts stand alone.
Would make a great one knob Volume booster pedal.
EDIT: I used a .047 uf oputput cap, and swapped out the 690k for a 620k r.
I was thinking of putting a bypass so you could switch in the pentode when you want overdrive.. and just have the clean boost..
Did the .047 do anything to tone for you?
and 620k is good, I had a 220k and a 1 meg pot and came away with the closest resistor, I have the 220k and 470K in series right now..
Dunno, it's what I had on hand: also stuck a .1 uf Cap at the front so tru-bypass don't pop as loud.
Works better with the 12ax7 then it does with the 5751 I love with the 'Castor.
Sounds warmer way up the neck then just the guitar into the amp (Valve SR.)
Makes a Stock 'Castor sound cooler then hell when you boost into it.
I dunno, I'm just loving it as a Standalone Front of Line Booster.
Quote from: ThunderShowers on May 23, 2011, 06:21:03 PM
Dunno, it's what I had on hand: also stuck a .1 uf Cap at the front so tru-bypass don't pop as loud.
Works better with the 12ax7 then it does with the 5751 I love with the 'Castor.
Sounds warmer way up the neck then just the guitar into the amp (Valve SR.)
Makes a Stock 'Castor sound cooler then hell when you boost into it.
I dunno, I'm just loving it as a Standalone Front of Line Booster.
+1 thanks for the feedback, will think on that, IF you have an 12AU7 or by chance a 12U7 I found it gives more or a boost, if you need it? So some reason the Lower Mu tube gave more output.. I did not try a 5751, which I have in my valvecaster @ 30volts.
I am thinking of doing this with a 6112 and a 5840 sub-mini, one button boost, second button over drive.. two volume pots.
I did not put a cap in front as I was thinking 10uf but had no non-polarized caps in that range.. Will go with a .1 good suggestion.. I can not wait for the kids to wake up so I can work on this some more..
I am getting lots of low end farting.. Need to trouble shoot.. IT may be the breadboad.. But need to check.
Quote from: iccaros on May 23, 2011, 08:06:54 PM
I am getting lots of low end farting.. Need to trouble shoot.. IT may be the breadboad.. But need to check.
Lower your output caps values. 10uf is p. high, so you're going to get tons of bass though.
EDIT: Running guitar, bass and Longhorn Bass (Mid-Range sound heavy), switching between the Booster shown here and a modified 'Castor, both on straight nine V.
With guitar, the Booster is louder. With the longhorn, the 'Castor begins to pickup slack and breaks about even (Fully up on gain and volume) and on the bass, the 'Castor roars out and the Booster stays about the same. Not Quite sure what the heck is going on there, I'm supposing it's a biasing reaction with the input signals strength...
Quote from: ThunderShowers on May 23, 2011, 08:54:30 PM
Quote from: iccaros on May 23, 2011, 08:06:54 PM
I am getting lots of low end farting.. Need to trouble shoot.. IT may be the breadboad.. But need to check.
Lower your output caps values. 10uf is p. high, so you're going to get tons of bass though.
EDIT: Running guitar, bass and Longhorn Bass (Mid-Range sound heavy), switching between the Booster shown here and a modified 'Castor, both on straight nine V.
With guitar, the Booster is louder. With the longhorn, the 'Castor begins to pickup slack and breaks about even (Fully up on gain and volume) and on the bass, the 'Castor roars out and the Booster stays about the same. Not Quite sure what the heck is going on there, I'm supposing it's a biasing reaction with the input signals strength...
lowed the caps, sounds much better. my supply is caps from .04 - 1.0 so I used what I had
I updated the schematic..
here is a really bad video but gives an ideal of the overdrive this gives..
Ignore the fat dude talking.. :)
Hmmmm, With a pinout change could I get a 6v6 running instead of that 6au6?
Sounds nice as it is though, Just have a spare 6v6 on hand here (My ARC takes them)
Quote from: ThunderShowers on May 23, 2011, 08:54:30 PM
EDIT: Running guitar, bass and Longhorn Bass (Mid-Range sound heavy), switching between the Booster shown here and a modified 'Castor, both on straight nine V.
With guitar, the Booster is louder. With the longhorn, the 'Castor begins to pickup slack and breaks about even (Fully up on gain and volume) and on the bass, the 'Castor roars out and the Booster stays about the same. Not Quite sure what the heck is going on there, I'm supposing it's a biasing reaction with the input signals strength...
I have not tried other things in-front of it.. Just the Les Paul
I added a 1m to ground on the input before the cap and seamed to help stabilize the input.. but it could be placebo effect
Quote from: ThunderShowers on May 23, 2011, 09:33:48 PM
Hmmmm, With a pinout change could I get a 6v6 running instead of that 6au6?
Sounds nice as it is though, Just have a spare 6v6 on hand here (My ARC takes them)
Let me know.. I don't have a 6v6 to test.. But I do not see why not...
I am looking at a 6112 and 5840 submini.. Fit into a small pedal.... :)
Quote from: iccaros on May 23, 2011, 09:36:01 PM
I have not tried other things in-front of it.. Just the Les Paul
I added a 1m to ground on the input before the cap and seamed to help stabilize the input.. but it could be placebo effect
pull down, cap, pull up... That... I, ah...
Now I've got to try it, d@mnit.
Mini can be cool. I'm just trying to stay towards readily available; I have enough trouble getting the 6av6's I need for my ARC. Shipping them in takes forever.
I just bought (4) 6112 and (5) 5480 off ebay, they have a lot more.... tempting? ..
Quote from: iccaros on May 23, 2011, 09:56:50 PM
I just bought (4) 6112 and (5) 5480 off ebay, they have a lot more.... tempting? ..
Nah.
Just tried again;
The Bass sucked all the power out of the Linear Boost, even with the pulldown resistor. And the 'Castor increased in gain compared to the guitar. With a guitar, the Booster definitely is a winner, but it's not liking my Bass at all (a Dano '63)
hmm , May need... Gasp.... an opamp, Don't throw rocks.. to give a better input impedance. Or someone way smarter than me.. But I have faith they are on this board.
Yeah, fiddling with volume knobs on the guitar, even a LITTLE, kills the Linear Booster...
Quote from: ThunderShowers on May 24, 2011, 01:37:13 AM
Yeah, fiddling with volume knobs on the guitar, even a LITTLE, kills the Linear Booster...
I don't have that issue with the les paul..
I turned up and down volume on the guitar in the video..
What are your voltage readings?
ok so far the 6112 is a no go for this.. I can not get anything out of them.. I may have bad tubes.. but I will readjust tomorrow.
pin 1 5.35
.9
0
0
9.45
9.45
5.34
5.17
I think the 1M r is too small of a input resistor for this circuit, because with it off, it gets worse.
I never found 6112 to work well at low voltage.
Quote from: ThunderShowers on May 24, 2011, 02:26:46 AM
pin 1 5.35
.9
0
0
9.45
9.45
5.34
5.17
I think the 1M r is too small of a input resistor for this circuit, because with it off, it gets worse.
Ok I noticed.. I have a 1K from the input to pin 2.. Updated schematic..
Also Pin 5 should be ground (or pin 4)
and pin 8 should not be that high.. It is a cathode ...
Edit, I have been testing 6112, so I have to reconnect the power to the other..
Quote from: frequencycentral on May 24, 2011, 02:31:12 AM
I never found 6112 to work well at low voltage.
I believe you.. Its specification is so close to a 12ax7 I just want it to work.. well really a 5751, but that also worked..
In this case the Grid seams to leak less giving me almost no negative voltage on with the pull up, unlike with the 12ax7 I get .6
I will have to build one of your 6112 designs to test the tube.. :)
Quote from: iccaros on May 24, 2011, 02:44:37 AM
Quote from: ThunderShowers on May 24, 2011, 02:26:46 AM
pin 1 5.35
.9
0
0
9.45
9.45
5.34
5.17
I think the 1M r is too small of a input resistor for this circuit, because with it off, it gets worse.
Ok I noticed.. I have a 1K from the input to pin 2.. Updated schematic..
Also Pin 5 should be ground (or pin 4)
and pin 8 should not be that high.. It is a cathode ...
Edit, I have been testing 6112, so I have to reconnect the power to the other..
Pine 4 is ground, pin five is 9v in.
Pin 8 is connected to ground (And output, as per your Schem.)
I'll look over this again sometime tomorrow.
I got
5.37
(bad) something not right
0
12
0
12
5.39
5.29
so 8 is cool with voltage..
I hate bread board.. one time everything is good.. 10 min later things are off. I would bet if you are using bread board, then your are getting capacitance that is causing issues.
I will have to leave this for tomorrow also.. Thanks for the help
Quote from: iccaros on May 24, 2011, 02:54:15 AM
Quote from: frequencycentral on May 24, 2011, 02:31:12 AM
I never found 6112 to work well at low voltage.
I believe you.. Its specification is so close to a 12ax7 I just want it to work.. well really a 5751, but that also worked..
In this case the Grid seams to leak less giving me almost no negative voltage on with the pull up, unlike with the 12ax7 I get .6
I will have to build one of your 6112 designs to test the tube.. :)
Ok for those following @ home, I calculate the 6112 would need a ~1.3 meg pull up resistor to get -.2 volts on the gird. The 6112 has only .9ua of leak current compared to 9 ua for a 12ax7. so 12.2 / .9*10^-6 = 1,355,556oms
6111 no go.. I get signal but no boost..
So this is only good for 12XX7 series.
:(
It would be interesting to figure out the input impedance of this amplifier. By pulling the grid positive, you have reduced the input impedance of the tube substantially as its grid is now conducting current. It may be necessary when using 12 volts on the plate to get any conduction - otherwise, the contact potential from electrons hitting the grid would bias it negative and cut off the current.
It could go the other way, we could bias it off the cathode, But would that change a lot, this is just like the valvecaster, low input impedance
I have a butt ton.. of 2n222A... If I put one of those infront of this would that fix some of the impedance issues?
Quote from: amptramp on May 24, 2011, 10:21:30 PM
It would be interesting to figure out the input impedance of this amplifier. By pulling the grid positive, you have reduced the input impedance of the tube substantially as its grid is now conducting current. It may be necessary when using 12 volts on the plate to get any conduction - otherwise, the contact potential from electrons hitting the grid would bias it negative and cut off the current.
according to the link I provided at says its 11K
Ok ..
so I got submini tubes to work
Had to kill the pull up part, put a 150ohm resistor on the cathode pin (4) to give me -.4 on the grid
then instead of a 1m from pin 2 (grid) to ground, used a 120 ohm.. Still got a good clean linear boost,
Used the 5840 design Rick had..
A nice overdrive.. But I got the same with the valvecaster. So I am not sure the point. I am going to try the 12ax7 to the 5840 and see what that does..
I can not get any audio from the 6112 @ all (any suggestions Rick on a way I can test these?) . I may have some bad tubes... Which would suck ... I expect to get something
Switching a 12u7 and 12AU7 farts out.. So that will take some adjustment..
Right now this sounds good to me with the 12AX7 and the 6AU6.. If I could find a modern replacement for the 6AU6 then this would be good to go.. I did pick up 3 for $5 off ebay..
I am thinking of doing a cathode follower for both stages.. This should give me better input impedance... ?? opinions?
Mini Version.. I hope I did not make any mistakes.. I think this sounds as good as my valvecaster @ 30 volts.. but more smooth.. The valvecaster seamed to be too harsh all the way up, to farty..
SkyHunter Mini... where the name comes from.... -> (http://isbn.abebooks.com/lbr/56/81/0815411456.jpg)
Now all Airborne units use this phrase..
Sound clips coming tomorrow.
(http://dl.dropbox.com/u/14312589/SkyHunter-%20Mini.png)
thanks to Frequency Central For allowing me to build on his work..
Also to the reading from the valve wizard and Merlin Blencowe
(http://dl.dropbox.com/u/14312589/2011-05-25%2023.46.55.jpg)
(http://dl.dropbox.com/u/14312589/2011-05-25%2023.48.38.jpg)
Interesting thing to report: Mesa tubes seem to be less then liking this design; One tube outright refused to work, returned that one, the second one works, is clean - But barely adds anything.
So far, I'm getting good results out of long-mid plate tubes only (Ruby's work nicely.)
are you still running 9 volts? I would not expect 12 to be diffrnet, I will try my other tubes.. I am using Sovtek i pulled from my Carvin.
I have some JJ's I can try.
Quote from: iccaros on May 26, 2011, 02:26:58 AM
(http://dl.dropbox.com/u/14312589/SkyHunter-%20Mini.png)
clearly there is a misstake in this schematic.. R5 surely must be intended to go to the Anode (pin 5 of the 5840) and not to the cap, otherwise there is no voltage to the tube.
J
Ok, 9-volts, different tubes run down:
Ruby 12ax7a; high output, lots of bass.
Some old Canadian Tube that I can just read 12ax7a on; Smoooooth, medium high output.
Sovtek 5751; low to Medium output in this circuit, adds it's own little bit of breakup.
GT 12ay7; Low output, barely adds any boost.
Mesa 12ax7a; lower output: barely breaks even.
Out of these, the only old tube is the Canadian one.
Plate lengths, from small to large are:
Mesa
GT
Ruby
Canadian
Sovtek
Gonna buy a Sovtek 12AX7LPS and maybe a Sungtol, see what happens.
Edit: It should be noted this is a pretty common thing, as plate lengths and Gain are indeed Related: it's just more pronounced then I expected.
Quote from: Johan on May 29, 2011, 03:06:28 AM
Quote from: iccaros on May 26, 2011, 02:26:58 AM
(http://dl.dropbox.com/u/14312589/SkyHunter-%20Mini.png)
clearly there is a misstake in this schematic.. R5 surely must be intended to go to the Anode (pin 5 of the 5840) and not to the cap, otherwise there is no voltage to the tube.
J
Thanks will fix.. The cap goes to the output...
Quote from: ThunderShowers on May 29, 2011, 07:54:43 PM
Ok, 9-volts, different tubes run down:
Ruby 12ax7a; high output, lots of bass.
Some old Canadian Tube that I can just read 12ax7a on; Smoooooth, medium high output.
Sovtek 5751; low to Medium output in this circuit, adds it's own little bit of breakup.
GT 12ay7; Low output, barely adds any boost.
Mesa 12ax7a; lower output: barely breaks even.
Out of these, the only old tube is the Canadian one.
Plate lengths, from small to large are:
Mesa
GT
Ruby
Canadian
Sovtek
Gonna buy a Sovtek 12AX7LPS and maybe a Sungtol, see what happens.
Edit: It should be noted this is a pretty common thing, as plate lengths and Gain are indeed Related: it's just more pronounced then I expected.
In other low starved plate designs, keeping linear is not the goal.. So I expect some things to be weird.. I am just happy the 12AX7 worked at all @ 9 volts for you. I could not get any of mine to work in a valve caster @ 9volts.. It took at least 20..
You're going to want a buffer at the output, pentodes have a much larger output impedance than triodes, you gotta pay for that extra gain somehow. A direct coupled MosFET source follower would do the job well. http://www.geofex.com/Article_Folders/mosfet_folly/mosfetfolly.htm - First image, just hook the 1uF cap to the source (along with a little series resistance, say 1k-4k7), and perhaps change the 1M pot to 10k, another advantage of using a buffered output. Another thought it to AC couple the buffer, keep the high value pot control, and instead of connecting the lug of the pot to ground, connect it to 9V or so. Here's another Geofex link with a little info on source followers and MosFET boosts. http://www.geofex.com/Article_Folders/mosboost/mosboost.htm
Just a thought, you could turn the buffer that's pre-pentode into a MosFET, and use a joint anode line paralleled triode arrangement. This would allow a high-low gain input or even allow two guitarists to play into it.
Quote from: panterafanatic on May 30, 2011, 07:39:32 PM
You're going to want a buffer at the output, pentodes have a much larger output impedance than triodes, you gotta pay for that extra gain somehow. A direct coupled MosFET source follower would do the job well. http://www.geofex.com/Article_Folders/mosfet_folly/mosfetfolly.htm - First image, just hook the 1uF cap to the source (along with a little series resistance, say 1k-4k7), and perhaps change the 1M pot to 10k, another advantage of using a buffered output. Another thought it to AC couple the buffer, keep the high value pot control, and instead of connecting the lug of the pot to ground, connect it to 9V or so. Here's another Geofex link with a little info on source followers and MosFET boosts. http://www.geofex.com/Article_Folders/mosboost/mosboost.htm
Just a thought, you could turn the buffer that's pre-pentode into a MosFET, and use a joint anode line paralleled triode arrangement. This would allow a high-low gain input or even allow two guitarists to play into it.
Thanks for links, if you read the first link I give, the author talks about using buffers, but I am attempting to do this all tube as I would have to buy silicon as a I have few opamps and a couple 2n222, I am stubborn like that :icon_biggrin: , but if someone wants to test adding silicon and report back, that would be cool add sound samples Please!!! , the first stage could be replaced with MosFet it would lose the fattening in "Clean mode" as I am putting a bypass switch to switch in and out the pentode. I could be wrong though.
So far this works great for me, but may not for others (I need to test with my delay and my Wah pedal) .. I am going into an all tube amp, so this just acts like another stage, with some nice "power tube" distortion. Which allow me to keep the amp clean, use the clean boost to give a little bit of 2nd order distortion (fatter tone) and then kick in a nice smooth distortion that is very pick sensitive.
I am guessing I just want this set for unity gain for the output..?
I have added a opamp to the input set for unity, biasing the input with two 2meg resistors on the input, one going to ground and one going to + voltage. This does a good job eliminating issues form other pedals or changing guitars.
my issue now is that I get 2.1 volts out. This is too hot I believe, I place a 120k resistor on the output and that have voltage swinging between 1.5 and 2 volts.
so the question, what is a good way to reduce the output, I thought of putting knee compressor at the output, but I do not know a good design for one.
I appreciated any help..
thanks
PS I tried a opamp on the output, but it just farts out.. and since the gain control is really adjusting plate voltage, turning it down just changes the sound, not real volume.
how about a master volume pot at the very end??? or will it suck tone or something ???
Quote from: vendettav on June 21, 2011, 06:09:00 AM
how about a master volume pot at the very end??? or will it suck tone or something ???
Not sure, I can try a small 1meg trimmer which I could set output voltage I guess? would that add noise?
Dead links... :(
Quote from: Renegadrian on January 27, 2019, 05:40:48 PM
Dead links... :(
Which links? The one in the first post is here:
http://valvewizard.co.uk/Triodes_at_low_voltages_Blencowe.pdf
Quote from: merlinb on January 28, 2019, 10:07:56 AM
Quote from: Renegadrian on January 27, 2019, 05:40:48 PM
Dead links... :(
Which links? The one in the first post is here:
http://valvewizard.co.uk/Triodes_at_low_voltages_Blencowe.pdf
yeah I meant dead images links, poster said he had a schem or something. I got valvewizard pdf safely stored in my hard disk and it's so useful, along with all the other info at the site!
Here is a site:
http://www.sophtamps.ca/www.sophtamps.ca/mambo/index862b.html?option=com_content&task=view&id=25&Itemid=37
you might want to try for information on low-voltage tube amps. These use 12 volt car radio tubes but the 12K5 space-charge grid tetrode is interesting. The first grid is pulled to the +12 volt supply and the second grid is used as the input. I wonder what would happen if you used this with a 12AU6 with the control grid at +12, the signal going into the screen grid and the suppressor could be +12 or connected to the screen. The space-charge grid is one way to accelerate electrons before the pass the second grid which is used as the control grid.
Ron I do know the sopht site well, thx anyway for posting! :)
> with a 12AU6 with the control grid at +12
Technically, this is tube abuse. G1 is not made to go positive. G.E. data (http://www.mif.pg.gda.pl/homepages/frank/sheets/093/6/6AU6A.pdf) specifically says Max Positive 0 Volts. Counting my thumbs, I'd guess it will flow 12mA, at 12V, is 144 milliWatts in a grid with NO dissipation rating.
Given the current value of 6AU6 ($8-$13, $6 for the 12AU6), I really can't care what you do to your poor _AU6es. Maybe the worst can happen is a red-hot grid comes loose and shorts-out your power supply, be ready.