Solid State Amp - Turn it down before you turn it on?

Discussion in 'Amps/Cabs Tech Corner: Amplifier, Cab & Speakers' started by ChrisN, Jul 28, 2019.

  1. ChrisN

    ChrisN Supporting Member

    Messages:
    110
    Joined:
    Nov 14, 2018
    I have a nice s/s amp that I'd like to keep healthy. I've typically flipped it "on" while the gain and volume were in the last settings used, but it occurred to me I might be slamming juice into some delicate-yet-critical electrical part with starting watts that could lead to failure. Then I wondered, "maybe I should turn down the volume and gain before turning it on. I should ask the collective."

    Am I worried for no reason? Or is it the best practice to turn down the amp first? I suppose the same question applies to tube amps, which I also use. Thanks for any info.
     
  2. HotBluePlates

    HotBluePlates Member

    Messages:
    6,179
    Joined:
    Mar 27, 2017
    Yes.

    You can reasonably assume any electrical item was designed to be able to survive being turned on.
     
  3. ChrisN

    ChrisN Supporting Member

    Messages:
    110
    Joined:
    Nov 14, 2018
    Thanks. Not the first time, nor likely the last, that I've worried for no reason!
     
    HotBluePlates likes this.
  4. gunslinger

    gunslinger Member

    Messages:
    1,611
    Joined:
    Mar 28, 2010
    Location:
    Louis XVI ville, KY.
    I turn all of my amps down before turning them on/off. If anything it may protect the speakers.
     
  5. HotBluePlates

    HotBluePlates Member

    Messages:
    6,179
    Joined:
    Mar 27, 2017
    That's a fair concern. One may not like a thump when turning on some amps. However, after a whole lotta years, I've never damaged anything (or known anyone that's damaged something) by turning on an amp with the volume turned up.
     
  6. teemuk

    teemuk Member

    Messages:
    2,920
    Joined:
    Apr 21, 2009
    It's a good idea if the amp makes that loud 'pop' sound when turned on (many solid-state amps have a delayed muting circuit that basically does the volume down to zero -thing automatically). If for no other reason then for overall convenience to one's ears.
     
    HotBluePlates and ClinchFX like this.
  7. 5F6-A

    5F6-A Member

    Messages:
    1,487
    Joined:
    Nov 23, 2013
    Location:
    Yorkshire, UK
    I remember a Parisian session player who used to go nuts if anybody forgot to turn the volume down before switching SS amps off. He said that it introduced "littles noises" over time. I thought he was an incredible musician but this seemed hocus-pocus to me...
     
  8. pdf64

    pdf64 Member

    Messages:
    5,871
    Joined:
    Aug 9, 2008
    Location:
    Staffordshire, UK.
    Maybe he was referring to tinnitus?
    As our sense of hearing is a consumable, a professional musician is under especially high jeopardy.

    If an amp makes a horrid noise at start up (or shut down), and turning one or all controls down stops or reduces it, then yes, as above, do it; plus it may help prevent pots getting stuck :)

    But if the power amp doesn't have a relay to disconnect the speaker at start up / shut down (do any regular guitar amps have them?), I can't see that turning controls down would stop or reduce the 'thump'?
     
  9. 5F6-A

    5F6-A Member

    Messages:
    1,487
    Joined:
    Nov 23, 2013
    Location:
    Yorkshire, UK
    He meant the amp but yes, loud rock music is not the best for our hearing. I know this first hand.... :(
     
  10. Sleepyscholar

    Sleepyscholar Member

    Messages:
    245
    Joined:
    Apr 26, 2015
    Location:
    Nagoya, Japan
    Here in Japan, the majority of musicians I've met (as well as rehearsal studios) insist on turning all knobs to zero when turning off an amp.

    I'm not one of those annoying gaijin who likes to badmouth Japanese people, but this has always struck me as crazy to the nth.
     
    5F6-A likes this.
  11. Jeff Gehring

    Jeff Gehring Silver Supporting Member

    Messages:
    4,994
    Joined:
    Jan 17, 2008
    Location:
    Kansas City area
    Everyone knows, the only way to really be sure you are doing no harm when turning your amp off is to:
    • Turn all knobs on the amp to zero
    • Turn all knobs on the guitar to zero
    • Turn all knobs on any pedals to zero
    • Turn amp standby switch to OFF, wait 37 seconds
    • Turn amp power switch to OFF
    • Unplug amp line cord at wall, and if an IEC cord, unplug at amp end also
    • Lift amp end of AC cord in the air to allow electrons to drain
    • Pick up amp head and shake vigorously, IEC connector down, to allow electrons to drain.
    • Wrap amp in tinfoil, and slowly back away
     
  12. Baxtercat

    Baxtercat Member

    Messages:
    11,817
    Joined:
    May 11, 2009
    Location:
    just west of Monterey, CA
    Remember though, 'no matter how much you shake & dance, the last three electrons go down yr pants'.
     
    Jeff Gehring likes this.
  13. ChrisN

    ChrisN Supporting Member

    Messages:
    110
    Joined:
    Nov 14, 2018
    Hmmmm, the Japanese were the original offshore manufacturing pioneers who actually made these things - it's almost like they knew something. :D

    Seriously, I'm sure I read somewhere long ago that electrical components (not sure if it's transistors, resisters, diodes, capacitors, cathode ray beams, what have you) will work, but they don't like to regularly be blasted with the starting amperage following the "on" switch - it's apparently quite a bit higher than the regular running power and the concern was that it shortened longevity. I was hoping an electronics guy/gal would put the concern to rest, but now you've gone and cited the Japanese!
     
  14. Alchemist XP

    Alchemist XP Silver Supporting Member

    Messages:
    8,200
    Joined:
    Jun 11, 2016
    If you're worried, leave the gain where it was at and just turned the master volume down. Shouldn't be that hard to find the right spot fo the Master Volume when you power back up.

    :spit
     
  15. HotBluePlates

    HotBluePlates Member

    Messages:
    6,179
    Joined:
    Mar 27, 2017
    Here's the issue: There is a pop at the speaker because of a d.c. shift being relayed through the output transistors to the speaker. But any volume control in your solid-state amp is before the output transistors, not between the output transistors & the speaker.

    Yes, if you turn the controls to zero, you might have less opportunity for a small shift early in the amp to be amplified by the rest of the amp, and sent to the speaker. However, there's still nothing keeping the output devices from having a d.c. shift. So if it's gonna pop, there might still be a (smaller) pop when you shut off the amp, regardless of the volume control setting.

    Current surge during power-on is a known thing. Any competent electrical engineer designing a piece of gear knows to account for it. Further, it's the reason time delay ("Slo Blo") fuses are used for the mains fuse, where any additional fusing protecting the output transformer is a fast-blow fuse. The time delay fuse allows for a current surge beyond the rated value for a period of time to accommodate turn on surges.

    Most likely (and giving the benefit of the doubt), whoever wrote what you read needed to distill a complex topic ("... well, sometimes you have to ...") into something easily digested by less-tech folks. Such simplifications are often a source of frustration because well-meaning readers misapply the "rule" in other places.
     
    xtian likes this.
  16. Tron Pesto

    Tron Pesto Member

    Messages:
    745
    Joined:
    Feb 18, 2016
    Location:
    Mahwah, NJ
    I've been working on a couple of Ampeg VT-22/V-4s lately. They have an interesting fuse arrangement on the primary side of the PT. They have two fuses in series - one is a 6A slo-blo (pretty beefy...) plus a "fast blo" 10A fuse. I believe the thought is if there is a VERY high current draw at the start up (or otherwise I guess), one that might not trigger the "slow" 6A, it will blow the 10A fuse. Seems a bit of an overkill, but they were clearly intentional with the design.

    A quirky addendum to that is the 6A slo blo is in a fuse holder accessible from the back panel, but the 10A "fast blo" is hardwired inside the amp. I guess the expected that a condition to blow the 10A fuse would be a rare event. Nevertheless, on the two I've worked on, I've mounted an internal fuse holder block for the 10A fuse. At least if it blows it would be easier to address than having to remove and resolder the fuse.
     
    HotBluePlates likes this.
  17. HotBluePlates

    HotBluePlates Member

    Messages:
    6,179
    Joined:
    Mar 27, 2017
    One brand's 6.3A Slo Blo fuse will tolerate 10A for at least 10,000 seconds (2.78 hours?!?). It will also tolerate 100A for 2/100ths of a second, and 30A for 3/10ths of a second.

    I'm guessing there are some significant allowances one makes in selecting these fuses, and some burn-in torture testing to verify what rating is really needed (or the minimum one can get away with). Seems like Ampeg was looking for a hard upper limit, without needlessly blowing blowing a mains fuse.
     
    Tron Pesto likes this.
  18. ChrisN

    ChrisN Supporting Member

    Messages:
    110
    Joined:
    Nov 14, 2018
    That makes sense - and it's entirely possible the author was correct and the distillation error occurred on my end.
     
    HotBluePlates likes this.
  19. HotBluePlates

    HotBluePlates Member

    Messages:
    6,179
    Joined:
    Mar 27, 2017
    Perhaps; it is very nice of you to step back and consider you might have remembered in error. But there are also some "well known authors" that have written some very technically-wrong things that sound like they ought to be correct. I know one prominent author whose information I had to mostly un-learn when I started to study electronics seriously.

    Things like incandescent lightbulbs & tube filaments have low resistance when cold, and higher resistance when hot. There's a surge of current you you first apply power to them. After all, most old bulbs tend to blow when you flip the light switch.

    I'm just saying engineers know about this and much more, and typically design their products to survive normal use.
     
    Last edited: Jul 30, 2019
    ChrisN likes this.
  20. Tron Pesto

    Tron Pesto Member

    Messages:
    745
    Joined:
    Feb 18, 2016
    Location:
    Mahwah, NJ
    Very interesting - I'll admit, I've never looked up any Slo Blo specs to see what the "delay time" really works out to be. And a little nutty - how can close to three hours of running essentially 50% over max be usable/tolerable? Maybe they really need to re-label them as "No Blo".
     
    HotBluePlates likes this.

Share This Page

  1. This site uses cookies to help personalise content, tailor your experience and to keep you logged in if you register.
    By continuing to use this site, you are consenting to our use of cookies.
    Dismiss Notice