Dicky Twin Reverb.

[Sea Chief]

If it's for your consolation, you're not the only one.
The dialogue on the portals, takes place on the principle of a two-way street, everything else is a monologue ...

Again here. The 1st line is nothing else than a snipe at me, & a personal one. Just keep it in your head instead.

The second line I have no idea whatsoever as it is incomprehensible. Its certainly nothing to do with the thread that much I know, so again, just why post it-?? (I can only think its another sort of snipe at me but if so cannot understand it thankfully).

Don't post personal stuff people. Just leave it out. Be helpful only, & if you can't (like here ^) just don't post it.. please.

[Sea Chief]

https://www.sweetwater.com/sweetcare/articles/great-standby-switch-myth/
_{The Great Standby Switch Myth}

https://www.fender.com/articles/tech-talk/tube-prelude-warm-up-to-the-standby-switch
_{Tube Prelude: Warm Up to the Standby Switch}

http://www.valvewizard.co.uk/standby.html
_{Power and Standby Switches}

I sort of can't cope with the history of stby switches, but thanks its sort of relevant info I guess.

I did know that quote "Many guitar amps (too many) include a standby switch. This is meant to let the heaters warm up before the high voltage is switched on. Old books called it 'preheating'."

Which is the main point of all 3 articles afaict. So I sort of knew this, but isn't really relevant to my issue or my onward Q about what "in stby mode" means though.

[Sea Chief]

As far as the 'standby' terminology, the word itself is not the problem. You have it right, and most people get it, it's common sense.
The problem is when we add the words 'on' or 'off'. That's where people get confused. I prefer to use terms like 'standby mode' or 'play mode' to avoid confusion. Putting the words 'on' and 'off' on a standby switch does not make sense to me. Is the standby function 'on'? Or is standby function 'on' when switch is in 'off' postion?

I'm jumpy like you are. The biggest hazard for me working on amps is me jerking my arm when there is a loud noise or someone unexpected gets behind me and says something. In this situation I'd suggest you put in some earplugs or use hearing protectors. The noise is obviously loud enough that you'll still hear it, it just won't bother you as much.

Tubes haven't been used much? They still can go bad at any time, but I'm inclined toward what Chuch H suggested initially, an oxidized connection between socket and tube pin. Have you pulled all the tubes in and out of their sockets to see if that cleans it up?

Spot on re. the terminology specifically when On and Off are added.. I feel vindicated for being confused.

(But even so I am still confused about what "in standby mode" means: this hasn't been answered yet, unless I'm mistaken).

Ok I'll address the tube in sockets 1st & do your test now I know what to do. Ears defenders are a good idea.

Thanks, SC

[Helmholtz]

"in standby mode" means amp silenced, mostly done by disconnecting the high voltage (plates') supply while leaving the heaters on.

[Sea Chief]

"in standby mode" means amp silenced, mostly done by disconnecting the high voltage (plates') supply while leaving the heaters on.

Great ok thanks- so in the DOWN position then. Ok now I'm sorted/ gotta pluck up some cahones to do the test.. will do this week. I hate popping/ noisy tube amps I get the jitters poking & pulling.

[vintagekiki]

Which is the main point of all 3 articles afaict.

The story is about the purpose of the standby switch and is intended for everyone who is eager for knowledge.

[Sea Chief]

The story is about the purpose of the standby switch and is intended for everyone who is eager for knowledge.

Ok VKK.. I'm sure there's a huge list already of people fighting each other to find out all about their switch.

[g1]

You had it right early on. Like Helmholtz said, 'standby mode' is for all intents and purposes a 'mute' mode.

they come onstage go behind & flip a switch so the amp is on properly: I know only that the amp now is in fully-on bc I hear it being played. So, what was it whilst I waited? I can only surmise it was in "standby" mode, the word perfectly matching what me, the band, & the amp (afaict) was actually doing at this time.

[Sea Chief]

You had it right early on. Like Helmholtz said, 'standby mode' is for all intents and purposes a 'mute' mode.

Aha that's useful way of thinking of it: mute/ standby mode, flip the bird & its on.

One more symptom which might be of use: had another 1 hr on it, papery crackle to start but settled down ok this time.. but on turn OFF, I noticed the lingering chord I struck tailing off to nothing (coinciding with caps discharging-?) but was weirdly pretty distorted (only once turned off, for the quiet 2 seconds with no power diminishing away to 0).

[Chuck H]

One more symptom which might be of use: had another 1 hr on it, papery crackle to start but settled down ok this time.. but on turn OFF, I noticed the lingering chord I struck tailing off to nothing (coinciding with caps discharging-?) but was weirdly pretty distorted (only once turned off, for the quiet 2 seconds with no power diminishing away to 0).

I don't think this is a symptom of anything, but it's vigilant to include it for informative purposes if you're not sure. So thank you for being thorough.

It's common for amps conducted signal to be distorted as the voltage on the tubes fades. The operating parameters for the tubes changes to non ideal conditions and the performance suffers. The fade is indeed the voltage on the caps diminishing because the tubes continue to draw current before the cathodes cool enough to halt conduction.

I'm still thinking it's an intermittent contact. Oxide on tube pin contact/s or a cold solder joint. Cold solder joints don't always look bad or misbehave consistently on initial soldering and can absolutely take years to develop symptoms. It happens all the time. Before I was aware of this I had a similar problem to yours when an amp I built started to suffer unusual distortions intermittently about four years after being built. The problem was eventually traced to a cold solder joint. While my soldering skills are admittedly mediocre there was nothing wrong with the way the joint looked. And many amps have been "repaired" by re soldering contacts for the circuit a problem is isolated to decades after the amp was built. It just happens sometimes. So...

Having had the amp gone through and serviced, even by a skilled tech, does not "rule out" the possibility of a cold solder joint at all. Taking the possibility off the table on that premise is likely to have you spinning your wheels looking for problems where they don't exist. Imagine dropping a tiny doo dad in a dimly lit room and you didn't see where it landed. The process of finding it is daunting, yes. But you wouldn't go look for it in another room just because the light is better.

[Sea Chief]

Chuck H Ok understood (apart from the doo dad analogy!).

As there are about 400 solders, & 8 tubes, for me its sort of not even feasable I could start figuring out where a cold solder might be. So, this line of attack -must- be put aside for now & the tests wherby I could actually perhaps find something, done 1st.

Is pulling the tubes & spraying, for eg, servisol into the sockets/ inserting its tube in/ out say 10x.. not a good basic 1st step? (unplugged of course!).

If I can do anything prior to any test with the beast turned on.. I'm gonna try this 1st. I'm still hesitant to do any tube pull whilst on (& stby put to down position etc).
At the mo it seems loud papery crackle on turn on.. then settles down, more or less, but of course I'm still on constant edge playing tho waiting for it.

Another symptom: twisting the vol knob coincides with added papery crackle. And crackle increaces with volume turning/ in sync with this. No MV with mine.

thanks- SC

[Chuck H]

Chuck H Another symptom: twisting the vol knob coincides with added papery crackle. And crackle increaces with volume turning/ in sync with this. No MV with mine.

Does the crackle occur when turning the knob wven when you're not playing. That is to say, just turning the knob causes a crackle?

[Sea Chief]

Does the crackle occur when turning the knob wven when you're not playing. That is to say, just turning the knob causes a crackle?

yes. Turning it doesn't neccessarily cause the crackle I don't think, but crackle is affected/ exaggerated by dicking with it.

[Chuck H]

The most popular Servisol product is "10". I don't know if that's what you have, but that's not what you should use. Servisol 10 is a cleaner/lubricant and would be exclusively for switches and potentiometers. You would want to use a contact cleaner that doesn't include a lubricant. Also, you shouldn't have to plug/unplug ten times. You would add the cleaner, plug in the tube and then gently rock it in a rotating motion. Obviously you can't "rotate" the tube with the pins inserted, but this is how it's generally described and I hope the motion intended is clear enough. If not, don't ask me to explain it to your satisfaction. I'm certain I won't be able to.

Just contact cleaner. No lubricant. Allow twenty minutes for all the solvents to evaporate before firing the amp up.

[Sea Chief]

The most popular Servisol product is "10". I don't know if that's what you have, but that's not what you should use. Servisol 10 is a cleaner/lubricant and would be exclusively for switches and potentiometers. You would want to use a contact cleaner that doesn't include a lubricant. Also, you shouldn't have to plug/unplug ten times. You would add the cleaner, plug in the tube and then gently rock it in a rotating motion. Obviously you can't "rotate" the tube with the pins inserted, but this is how it's generally described and I hope the motion intended is clear enough. If not, don't ask me to explain it to your satisfaction. I'm certain I won't be able to.

Just contact cleaner. No lubricant. Allow twenty minutes for all the solvents to evaporate before firing the amp up.

what does the added lubricant do tho which is a no-no? I think ive used my servisol super 10 for all the sockets on all my amps! thought if its a cleaner for switches then gotta be good enough for sockets.. right will get some contact cleaner then/ ebay.

I do understand your rocking motion very clearly. thanks Chuck H