Hoffman Amplifiers Tube Amplifier Forum
Amp Stuff => Tube Amp Building - Tweaks - Repairs => Topic started by: TIMBO on March 06, 2014, 02:25:08 am
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:w2: I'm sure this must have been a topic at sometime. I am guided by you guys to how an amp is put together and trust that your technical knowledge and hours of tweaking have made certain parts a must have in a build.
So do we need a standby switch????
I was directed to this http://www.ozvalveamps.org/standby.htm (http://www.ozvalveamps.org/standby.htm) and left me :think1: and scratching my head.
All of my builds have a STANDBY Sw. and they all work well, but there seems to be some side effects of doing this, and I will say that like everything, there is always two sides of the story, what are you to believe??
The most common type is as fender does with a SW. after the rectifier and at times there are some pops and thumps and at worst the SW. has a meltdown and welds the contacts together.
IS there a better way or has the big boys already got it right. Thanks
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The page you linked to was a bit long, so I did not read it... But, other than being a convenient way (out of habit most likely) to mute the volume, there is really no reason to install a stand-by switch. Merlin's book also has a bit more detail if you want to look them up.
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I don't think a standby switch is necessary. A 'soft-start' switch is kinda funky tho'.
(But neither is necessary.)
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:w2: I'm sure this must have been a topic at sometime. I am guided by you guys to how an amp is put together and trust that your technical knowledge and hours of tweaking have made certain parts a must have in a build.
So do we need a standby switch????
My answer ; it is usefull. So yes.
For most of the amps , it save tubes . For other amps with slow start its usefull for a break on a gigs .
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For most of the amps , it save tubes...
Convenient to have, perhaps, but the stand-by switch does not save tubes, at best, it saves the under-rated filter caps in some amps.
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For most of the amps , it save tubes...
Convenient to have, perhaps, but the stand-by switch does not save tubes, at best, it saves the under-rated filter caps in some amps.
I desagree.
Cold power output tubes receiving B+ voltage may have their plate damadged . Never this will happen with standby switch .
I desagree with under -rated filter caps ; Use of Stanby switch is worst with these caps .
Anyway this is a topic discussed a million times on the web
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Sigh... have to agree to disagree then...
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I put them on amps because people expect the to be there. I still flip both at the same time. My tubes seem to last a very long time and I have never noticed cothod stripping. I have a friend who is a well respected amp tech who says you should wait 5 minutes to allow your heaters to warm up, then he will flip both within a few seconds and say "I have plenty of tubes".
My 5C1 champ is missing the standby and the power and rectifier tube is so old they may be original. Does single ended change things?
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Does single ended change things?
No but some rectifier tubes have a controlled warm up time (GZ34/5AR4) so they don't send B+ to the other tubes right away.
Brad :icon_biggrin:
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Does single ended change things?
No but some rectifier tubes have a controlled warm up time (GZ34/5AR4) so they don't send B+ to the other tubes right away.
Brad :icon_biggrin:
I knew this, but never considered it really. In this instance you think letting the rectifier warm up before unloading the DC is beneficial?
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The dcv B+ does not get sent to the other tubes right away. The rectifier tube has to warm up 1st then it starts to send the B+dcv to the other tubes. The controlled warm up time makes the rectifier tube it's own standby.
Brad :icon_biggrin:
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I don't think it's necessary for your amp to function correctly but I like them and include them on every amp I build. I do most of my playing in Church services and it requires starting and stopping the music up to three or more times in a service or one to two hour period, so being able to mute it and having it warmed up and ready to work at a flip of a switch is important to me. Also during a song service I may switch back between acoustic and electric a couple of times during a service. So in my case it's necessary for my operation. Platefire
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The dcv B+ does not get sent to the other tubes right away. The rectifier tube has to warm up 1st then it starts to send the B+dcv to the other tubes. The controlled warm up time makes the rectifier tube it's own standby.
Brad :icon_biggrin:
This is definitely the case for indirectly-heated rectifiers like the 5Y3GT and the 5AR4
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For most of the amps , it save tubes...
Convenient to have, perhaps, but the stand-by switch does not save tubes, at best, it saves the under-rated filter caps in some amps.
I never put one in an amp yet but my latest one might get one. It has SS rectifiers and when the output tubes are conducting the voltage is about 350V but with them cold it is 425V on 400V caps. As far as cathode stripping, if you put 400V between two pieces of metal in normal atmosphere would one strip the coating off the other? I would expect it not to, so why would it be able to do it in a vacuum? Especially when the coating is designed to stay on the metal when heated. I would expect the coating to be more likely to come off when hot.
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FWIW, I always used my standby switch playing in clubs, church or at practice. It was very convenient to have it. The big boss man didn't like it when he hit the stage and would have to wait for you, "got a dollar waitin on a dime." :laugh:
Brad :icon_biggrin:
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If all you want to do is to mute the output of the amp, it is easier and cheaper to install a mute switch at the input - you don't have to deal with the HV, the in-rush current that the stand-by switch requires. There is no science to back up any of the claims about cathode striping, improved life span of the tubes, etc. nor empirical evidences to suggest otherwise, since there are probably far more hi-fi amps in service than guitar amps, and most did not used a stand-by switch.
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It says right in the RCA tube manual that cathode stripping is not a concern with receiving tubes. The voltages just aren't high enough to damage the tubes in that way. Receiving tubes are what are used in guitar amps....I have a 1956 Fender 5E3 here with original RCA tubes in it. It was used at church gigs by the original owner for years and years. The amp does not have a standby switch and the original tubes are still going strong 58 years later....a lot of hifi amps don't use standby either....so the conclusion is that a standby switch is not necessary for guitar amps to save the tube life or anything of that nature. That said though, a standby switch or at least the mute function of it is useful in a performing application, and it is almost expected by most guitar players to be in an amp. It is useful for the repairman when working on the amp and the B+ can be shut off, at least if the standby is wired up like a Fender and interrupts the B+.
Greg
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Hi guys, I like a standby sw. as well, cause most of my builds start off as one and by the time I'm finish its something else, so that standby gets a real workout.
The conclusion is that the standby is a usable component. :icon_biggrin:
There is an argument to its use and strain on the PSU design,to which I don't think we'll never agree to how the best way to incorporate it. I think that you do what you feel comfortable with or what works for you.
Reflecting back to my Fi Sonic restore, the HT centre tap of the PT was used to disconnect the power transformer but still have the heaters winding active. The rotary switch could then be rotated to ON and the centre tap grounded to activate the HT supply.
After reading Merlins chapter on "standby Sw." the alarm bells started ringing to the demised of the original PT. The first mistake of the design was a under size rectifier (EZ81 suppling PP 6L6s) although it was cathode bias to 30w but having a standby on the centre tap was a big NO NO according to merlin. These two factors lead to a flashover in the rect tube and the rest was history............
Fender style standby is a common design and I use it a lot in my builds and although the switch itself is NOT designed for DC power, i must flick it a hundred times while tweaking, still works fine. :dontknow:
Marshall style (SPST or DPDT on HT leads) could this be a better way as it is less strain on the switch but brutal on the rect tube.
I've been told that there is NO proof that an amp suffers any damage or fatigue by subjecting the tubes with full B+ at the flick of a mains sw. so this is why a standby sw. is not necessary, but if a standby sw. is to be added it would be by grounding out the signal path at a volume wiper. Thanks
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Sigh... have to agree to disagree then...
If we take example of Fender amplifiers, how then explains that all are equipped with "stanby switch"?
Otherwise the philosophy of Leo Fender was to build the best amplifiers at the best price. It would not have installed a "stanby switch" if it would have been helpful.
All those who wanted to imitate later did the same thing.
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If we take example of Fender amplifiers, how then explains that all are equipped with "stanby switch"? Otherwise the philosophy of Leo Fender was to build the best amplifiers at the best price. It would not have installed a "stanby switch" if it would have been helpful.
Fender was trying to protect the power supply capacitors. In the 1950s, big, high-voltage capacitors were both expensive and unreliable. Fender used capacitors that could not withstand the peak (cold) voltage that exists if you don't use the standby switch. So he added the standby switch to allow the tubes to warm up, so when the switch it thrown, the supply voltage is pulled down to normal working levels, protecting the capacitors (and possibly the DC-coupled cathode follower too)
Cold power output tubes receiving B+ voltage may have their plate damadged .
The plate is a big piece of metal. How do you think it will be damaged?
Every shred of evidence shows that tubes do not live longer with a standby switch, especially if you leave them in standby for minutes or hours on end, because that leads to interface resistance (a sort of cathode poisoning). In other words, a soft start (milliseconds or seconds) may help, but the crude user-operated standby switch that most amps have is more likely to shorten the tubes' life.
One of the worst things you can do is to 'hot switch' rectifier tubes. In other words, letting the rectifier warm up before letting current flow into the reservoir cap. That's an excellent way to kill the rectifier tube, and rather a lot of amps make this mistake!
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This is an old recurring topic. Cathode stripping, a somewhat controversial notion, has not been mentioned in this thread. See: http://www.peavey.com/monitor/pvpapers/Chapter6.pdf (http://www.peavey.com/monitor/pvpapers/Chapter6.pdf) http://www.chiark.greenend.org.uk/scopes/weyer.txt (http://www.chiark.greenend.org.uk/scopes/weyer.txt) http://www.diyaudio.com/forums/tubes-valves/79405-doubts-cathode-stripping-tubes.html (http://www.diyaudio.com/forums/tubes-valves/79405-doubts-cathode-stripping-tubes.html)
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If we take example of Fender amplifiers, how then explains that all are equipped with "stanby switch"? Otherwise the philosophy of Leo Fender was to build the best amplifiers at the best price. It would not have installed a "stanby switch" if it would have been helpful.
Fender was trying to protect the power supply capacitors.
Capacitor could be more damaged with ( yes with ) stanby switch than no stanby switch ; standby to play position = surge
Cold power output tubes receiving B+ voltage may have their plate damadged .
The plate is a big piece of metal. How do you think it will be damaged?
It is well know chemical reaction . Sorry but just by reading that from you show your lack of information
One of the worst things you can do is to 'hot switch' rectifier tubes. In other words, letting the rectifier warm up before letting current flow into the reservoir cap. That's an excellent way to kill the rectifier tube, and rather a lot of amps make this mistake!
How often do you replace a rectifer tube on Fender like amp ? Almost never . Output tubes yes, preamp tubes some times.
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It is well know chemical reaction . Sorry but just by reading that from you show your lack of information
It would help if you can show some creditable references or explain such chemical reaction. Some of us lack the information - the wrong kind. :laugh:
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If we take example of Fender amplifiers, how then explains that all are equipped with "stanby switch"? Otherwise the philosophy of Leo Fender was to build the best amplifiers at the best price. It would not have installed a "stanby switch" if it would have been helpful.
Fender was trying to protect the power supply capacitors.
Capacitor could be more damaged with ( yes with ) stanby switch than no stanby switch ; standby to play position = surge
Cold power output tubes receiving B+ voltage may have their plate damadged .
The plate is a big piece of metal. How do you think it will be damaged?
It is well know chemical reaction . Sorry but just by reading that from you show your lack of information
One of the worst things you can do is to 'hot switch' rectifier tubes. In other words, letting the rectifier warm up before letting current flow into the reservoir cap. That's an excellent way to kill the rectifier tube, and rather a lot of amps make this mistake!
How often do you replace a rectifer tube on Fender like amp ? Almost never . Output tubes yes, preamp tubes some times.
Subscribed! :argue:
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I think that this is a good way to look at how a switch operates under AC and DC...............
AC versus DC load breaking comparison with a knife switch (http://www.youtube.com/watch?v=Zez2r1RPpWY#ws)
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I'm Fixing to give my opinion on Stanby Switches---Standby!
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Don't hold back PLATE the fuse is ready to blow................ :laugh:
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HI guys, I revised the build I am doing and have taken the standby out of the HT line and put it on the AC leads on the transformer, to me this is the best place (if you are going to have one)that will cause less problems.
With heaters warmed up and the standby turned on it takes a few seconds for the tubes to hit running speed, I can only think that this is good.
My amps will never really be put on standby (unless I forget to turn it off) for long periods of time.
There is always fore's and against to every thing, so do what works for you :icon_biggrin:
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Sorry to revisit an old thread. However, I did a search on this forum & on the internet about whether a standby switch is needed with solid state rectification. After reading Valve Wizard, Peavey, Dr. Z, etc .............. I found ongoing conflicted viewpoints. Some say not needed, some say needed, some say harmful.
It seems like the "most represented" position is no standby with tube rectification and that standby switch is needed with solid state rectification.
However, it appears that the Fender Pro Junior and Fender Blues Jr use solid state rectification without a standby switch? :
http://el34world.com/charts/Schematics/files/fender/Fender_Pro_JR.pdf
http://el34world.com/charts/Schematics/files/fender/Fender_BLUES_JUNIOR_REV_D.pdf
I'm slowly collecting parts to build a HoSo56 using 6BM8 tubes and a 5879 V1 preamp tube for a 7-9 watt push/pull amp. I'm going to build this in as small of a cab and chassis as I can and still use a 10 " speaker. (16" x 18" x 9.5") So, space is something of a factor.
I found Hoffman's on/off/standby switch so that is an option: http://el34world.com/charts/SwitchDPST.htm
My preference is a simple on/off switch with no standby IF that is not an issue with solid state rectification and 6BM8 tubes?
Thoughts? With respect, Tubenit
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Not needed on my opinion. Also i don't get how the on-off-standby switch would be any good, first you switch the amp on standby then off again and the on, what good does that too :dontknow:
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...also i have learned most of my stuff reading TUT books so that might have some affect on how i think:
http://www.londonpower.com/standby-switch (http://www.londonpower.com/standby-switch)
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Tubenit, I would not put a standby switch on that small amp, even if space was not a factor. But if you feel you just gotta have one, Hoffman's progressive switch is an elegant space saving solution.
...i don't get how the on-off-standby switch would be any good, first you switch the amp on standby then off again and the on, what good does that too
The switch doesn't work that way. Down is off, center is standby, and up is on.
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The switch doesn't work that way. Down is off, center is standby, and up is on.
Sorry my bad, didn't check the link. For mains switch i like to use double-pole switch so it switches off both live and neutral wire.
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Helpful responses, guys! Thanks! I'm gonna skip the standby and simply have on/off.
With respect, Tubenit
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Most guys who have been playing a while expect a standby switch. And again in this thread, a person stated Leo Fender would not have used one because he was cheap. What crap! Airline amps were cheap, Fender amps traveled the world and back and if you are lucky you may have one.
A cheapass buys his wife used tires! I can assure you as busy as Leo Fender was building a manufacturing company, he certainly did not have time to run around California changing his wife's flat tires. In addition, the switches were quite nice. I wish someone would provide some proof as to where Fender cut corners while under Leo Fenders Ownership.
Now be truthfull here. Say you won a contest and got to choose between a handwired Fender Deluxe Reverb or a Bugera V22 INFINIUM? The Bugera has more features and are said to have a good build quality. Today, supposed high quality Botique amps actually brag about using the SAME High Quality Components. Some even brag that cloth covered wire and Carbon Comp resistors are the only way to go. Just like a Swart Atomic Jr., which is a Champ with a tone control and no transformer reverb for $1300.
I own a 1964 Fender Super Reverb, now that is at least 53 years. I have not replaced a single component. Yes, it has a 2 prong cord and voltage to it is regulated to 117vac. It has never been anywhere except inside my house and my Fathers house. It gets about an hour workout every 2 weeks. The standby switch has never been down, only the AC switch is used.
My early 62 Bassman standby switch is about to go. They just do not like DC. Now I need to find an old USA Carling switch. I have one somewhere.
I do not ever switch to standby. All, every single amp I have, the DC switch is on all the time. I know some feel leaving an amp hot keeps tonal quality, but I have checked this. My slowest amp to reach full power is a Princeton Reverb Build when I have a GZ34 in it. This one takes almost 2 seconds longer for a total of 9 seconds.
I did this because of this topic all over the place. I even went as far as flipping the switch, pick up the guitar and put the strap over my head. Mind you, I still have not checked tuning, which all players should. The amp is ready even if the guitar is not. Amps also have volume controls which are mute, but if you are too drunk to remember the volume you were playing, you were already too loud.
So when the guy called to come to look/buy my Twin, I asked if he was wanting it to have a loop. Twins are great country amps and a slapback is really nice. He said no, he was looking for a regular Twin. I said come on over, I got what you want. Pulled the loop and put the switches back.
My point is I simply put one in and I do this because everyone who knows you do not need one, still doesn't mind one being there. You can bet if they do know they will inform you it is not necessary. Whatever! If they do not know and visited similar music stores as I have, usually to test an amp the Owner or Employee will get the amp out, and tell you about warming it up properly. I remember being told 30 seconds by the owner of the music store nearest my home.
Why should I believe some old electronics nutbag? Certainly, a music store owner knows and everyone seems to agree.
So after someone has been doing this, thinking it is the correct thing to do for the last 20 years, the last thing one person can con them of is the switch is not needed. That is one no vote to 20 years experience and the potential buyer will think you are crazy. After all, it has been working like this for 20 years and at least 1,000 other players disagree.
I just put in a switch because the Parker Fly didn't go over very well. Players still prefer wood guitars and standby switches, however, you could wire the on the lamp to the main switch and only the lamp and everything else on the standby. The only problem here is the amp would work without the light being on and you know good and well that little jewel lamp is where the mojo lives. :l2:
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...if you are too drunk to remember the volume you were playing, you were already too loud.
:l2:
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I love standby switches. I could not imagine life without them. IMHO the 3-position Carling Standby SW (which Doug sells) represents the pinnacle of human achievement & evolution -- for guitar amps. For hi-fi, or home theater (tube amps of course), my standby's are automated: octal plug-in time delay relays; or a clever SS circuit that flashes the power light during the warm-up period. A tube amp without a standby SW is like a day without sunshine.
Short version: I agree with Ed.
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I prefer mute switch
Franco
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:violent1: Mute SW's are only for yucky SS equipment! Someone should pass a law. :icon_biggrin:
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"IMHO the 3-position Carling Standby SW (which Doug sells) represents the pinnacle of human achievement & evolution"
A tube amp without a standby SW is like a day without sunshine.
I got a real grin out of your response! Thanks! Fun way to start the day.
:thumbsup: :thumbsup:
With respect, Tubenit
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Okay so I'm going to explain this as it's been explained to me, so that it hopefully makes sense.
Leo Fender first put standby switches on amps due to him seeing them on industrial tube equipment, and thinking it was necessary.
It IS necessary and cathode stripping is real ONLY IF you're using tubes at voltages OVER 1000V. And it may have even been over 2000V I can't recall.
In tube guitar amplifiers, the most robust tubes (6550 and the like) only go up to teh 600V range, never even exceeding 1000V.
So basically standby switches protect nothing, work fine as a mute option but only if setup rigth and CAN do damage to rectfiers and caps if the amp design is poor due to inrush current etc. So don't use them unless you absolutely think you'd prefer not to put a mute somewhere in the signal path dumping the signal to ground.
~Phil
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I've stopped bothering with them. The surge of current when you flip it on can damage tube rectifiers and often require a bigger than necessary high-voltage fuses.
Had a small 8W amp that kept popping the small 250mA fuse when going out of standby (47uF reservoir cap). That was already twice the current the amp would pull under normal usage. I removed the standby switch, problem solved
You want to mute the amp? Ground the grids (or lift the cathode if you really want to stop the power tubes from conducting).
There are many commercial amps on which the standby switch only mutes the power amp, this allows keeping the preamp on for recording.
I can only think of ONE use for a real standby switch: switching speakers (I just flip the amp off and back on, tubes don't get cold that fast)
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"IMHO the 3-position Carling Standby SW (which Doug sells) represents the pinnacle of human achievement & evolution"
A tube amp without a standby SW is like a day without sunshine.
I got a real grin out of your response! Thanks! Fun way to start the day.
:thumbsup: :thumbsup:
With respect, Tubenit
:occasion14:
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Okay so I'm going to explain this as it's been explained to me, so that it hopefully makes sense.
Leo Fender first put standby switches on amps due to him seeing them on industrial tube equipment, and thinking it was necessary.
~Phil
Please link a reliable source to this about Leo Fender. The only thing I know for sure is it was extremely common for him to talk to musicians to find out what they liked. There were many. Eldin Shamblin in the early days. The showman was a push to make Dick Dale the amp he wanted.
Leo Fender owned a radio repair shop and some of the giant radios had voltages very high and loads of current. Never seen a radio with a standby, doubt Leo Fender installed standby switches on repaired radios. Why, he knew they did not need them.
So, considering his first amp was actually lower current than radios he repaired daily, then unless he was stupid he had another reason. The statement about old caps of the time PRR mentioned is logical, but still doesn't explain why I have never seen a radio with a standby. I am sure there is one somewhere, I just have not seen one.
There is also the great debate on rectified tubes, you know they are not needed and sag can be replicated by resistors. They cost more and generate more heat and are not very efficient compared to the ultra fast switching diodes of today. Take up a lot more room.
Why are we still using tubes for rectified?
One day I read someone explain why fender amps used cloth covered wire and why he made the brown tone stack with the 350k 70k tap and this guy told it was because he could purchase them surplus. His story was his grandfather knew Leo and one night they were having dinner together and Leo Fender told him he sourced the wire and pots so cheap he had to redesign amps to use the parts. Every year that passes Leo stories grow.
The only reason I ask about these comments is until the early 1980s USA manufacturers were copied by everyone and the ones who copied them had to cheapen the product to sell it for less than fender. I remember very well guys buying Silverstone wanting a fender, but the price was a lot more. The American public supported US products, now you can get a 18 watt front China for 99 dollars.
And finally, the Champ does not have a standby, but I have put them in Champs. Some people like them and there is a simple way of installing one that Wil not damage the amp. The HT center tap is a good option.
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......... but still doesn't explain why I have never seen a radio with a standby. I am sure there is one somewhere, I just have not seen one.
Not on radios but BIG radio Frequency transmitters with Huge Power Tubes (at high voltage)
Try to ask to old Radio Amateurs, they will tell you about the ignition procedure on big transmitters
Franco
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......... but still doesn't explain why I have never seen a radio with a standby. I am sure there is one somewhere, I just have not seen one.
Not radios but BIG radio Frequency transmitters with Huge Power Tubes (at high voltage)
Try to ask to old Radio Amateurs, they will tell you about the ignition procedure on big transmitters
Franco
I have been in a transmission station, I know exactly what you mean. I go to hamfests often and see some of the guys with big stuff, but that is nothing compared the old WAGA station transmission here in Atlanta GA.
I toured the place when I was in grade school. These places were putting out wattage! They used to say it on the radio, WSB, 10,000 watts of power.
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Ed the Princeton (rev) doesn't have a standby either..
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Okay so I'm going to explain this as it's been explained to me, so that it hopefully makes sense.
Leo Fender first put standby switches on amps due to him seeing them on industrial tube equipment, and thinking it was necessary.
~Phil
Please link a reliable source to this about Leo Fender. The only thing I know for sure is it was extremely common for him to talk to musicians to find out what they liked. There were many. Eldin Shamblin in the early days. The showman was a push to make Dick Dale the amp he wanted.
I don't have one, and I read this a long time ago, maybe 2 years ago or so, and it may have been anecdotal like the point you and PRR made about protecting caps. Since there's no quote of leo saying that either, it has possibilities, but it isn't proof. The bigger point is the science that is proven, that cathode stripping is a thing and can only happen over 1000V so the high voltage amplifiers for RF output were the only ones that needed it. They had standby switches for that reason, so the tubes could heat up before the 1000 V was pumped into them. There is also known proof that poorly constructed amps with standby switches in the wrong place put overly excessive inrush current on things that aren't ready for it. Yes you can design around it 'if you must' but you can decide not to, and I never do, unless for some reason the amp I'm cloning already had one, and there's a hole in the chassis for it, if not I don't.
~Phil
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I have seen a communications receiver with standby. Tube radios drift. You like to keep them hot. But in some communications services the traffic happens on a schedule. So you keep it in standby until 7:59:30. Not a common feature.
BIG tubes need more than a standby, but a whole start-up sequence.
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BIG tubes need more than a standby, but a whole start-up sequence.
Yup, I've never used a stby in my builds, my career, ALL the tubes had standby :icon_biggrin:
most of the X-ray tubes, used a start-step, logic type switching, while in standby they also spun down the Anode. the RF transmitters took ~6 minutes to get up to operate, then kick down to standby electronically and start a timer, if it was in standby >10minutes, you waited another 6minutes for warm-up.
I'd guess I got paid ~ 2years wages waiting for systems to get up to temp :icon_biggrin:
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One of the ipotesis about the presence on Fender's amps of the standby advanced by Merlin Blencowe is
The other possibility is that the 5E6 was rhe first amp where Fender used a DC-coupled cathode follower. This stage will sometimes arc between grid and cathode at switch-on if the cathode has not yet warmed up. (These days you should put a diode or neon-lamp between grid and cathode to prevent this, not rely on the user).
Franco
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I'm not sure why there's a focus on Fender's use of Standby SW's. Other makers used them too: Magnatone, Ampeg, etc.
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May be it is a wrong news, but many say Fender was the first to apply that solution
Franco
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I'm not sure why there's a focus on Fender's use of Standby SW's. Other makers used them too: Magnatone, Ampeg, etc.
Because those amps came out after leo's first amps, as far as I recall the history. He was one of the, if not the very first tube guitar amplifier builders.
Wikipedia shows Leo's first amps were with K&F and were in 1946. Magnatone did start making some amps in the 30's but I can't see much documentation on them other than a few photo's that are really hard to see for sure, but I don't see any standby switches, the dickerson were the first generation: http://www.magnatoneamps.com/dickerson.html
Ampeg started in 1946 as well, but I can't find any data showing any of the earlier generation amps or their potential use of standby, all of the amps I find in pictures are the 60's to 70's style amps that do definitely have standby. I'd definitely love if you can find data supporting that one. As was shown earlier, I've read the blencowe books and part of my idea of this came from there, but I may be remembering a lot of it 'wrong' but the facts of the cathode stripping and the need for a stanby on those higher voltage amps is real, and does still indicate clearly that it's at least highly probable that people assumed (Leo included) that all tube amps needed one.
They don't. That's the bigger fact that is true and more pertinent to the thread imo.
~Phil
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Standby switches were introduced as a convenience feature for the player. It was also a good money maker for the manufacturer. Use a $1 part and charge the players $10 to $20 for that convenience. And the players wanted it. Any player whose amp did not have a standby switch wanted one. Soon they were on almost every quality amp that was powerful enough to play live venues.
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It's not clear that Magnatone, Ampeg etc. should be suspected of copying Fender's use of a Standby SW.
As to cathode stripping: my position is that it is a rude and reprehensible practice which has no place in our modern, enlightened society. All cathodes of every kind & description -- be they heated directly or indirectly; whatever their chemical composition; and whatever their voltage to the grid -- should be treated with the utmost respect that they deserve.
And what about the good, hard-working people who make & sell Standby SW's? What will happen to them if we abandon them to their fate just to look more technically prescient to the next guy?
Furthermore, we should consider the devoted beliefs of our fellow Forum members. For example, Ritchie200 declares himself to be a Cathode Follower. How would he feel if we went about stripping cathodes left & right?
'Nuff said! :angel
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Dave Friedman and John Suhr talk little about standby switches on 2 hour mark:
https://www.youtube.com/watch?v=9U5gX5J0pNQ (https://www.youtube.com/watch?v=9U5gX5J0pNQ)
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> those amps came out after leo's ... He was one of the, if not the very first tube guitar amplifier builders.
Gibson, Vega, Electro String, Rickenbacker, Dobro, National, Audio-Vox and others were in the racket before WWII; Leo may have fixed some of those, but as you say his building started after WWII.
OTOH, the pre-war amps were often more Hawaiian-style small-gain amps, and maybe (maybe!) less raucous when left on between hulas than the higher-gain jobs like in Bob Wills' band.
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D-Lab Terry did a fun video on standby switches showing the current spikes on a scope. Bottom line was that they always give tubes a current spike, whereas an amp with rectifier tube never does without the switch - concluding that if you want a mute switch, there are better ways to do it.
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Nowaday we can use this item to solve that kind of problem (spikes)
(https://i.imgur.com/Bw1oATu.jpg)
http://www.kemet.com/Lists/ProductCatalog/Attachments/146/F9000_GenInfo_RCUnits.pdf (http://www.kemet.com/Lists/ProductCatalog/Attachments/146/F9000_GenInfo_RCUnits.pdf)
https://www.terapeak.com/worth/rifa-film-capacitor-pmz-2035-rc-unit-0-1uf-330ohm-380vac-800vdc-x1-nos-m-paper/261437970833/ (https://www.terapeak.com/worth/rifa-film-capacitor-pmz-2035-rc-unit-0-1uf-330ohm-380vac-800vdc-x1-nos-m-paper/261437970833/)
https://www.rapidonline.com/kemet-pmr209mc6220m100r30-0-22-f-20-250vac-metallized-paper-rc-unit-capacitor-51-6823 (https://www.rapidonline.com/kemet-pmr209mc6220m100r30-0-22-f-20-250vac-metallized-paper-rc-unit-capacitor-51-6823)
http://www.xcomfort.co.uk/shop/accessories/113-cmmz-00-07-rc-unit.html (http://www.xcomfort.co.uk/shop/accessories/113-cmmz-00-07-rc-unit.html)
Franco
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Wow! This debate is still going on? Hey if a standby switch makes you feel good and happy about your amp's operation---like me!----use it, if it don't--forget it. I don't think it's going to makes a nat's hair worth of difference either way. A healthy amp will turn on and off no problem regardless. Platefire
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This debate is just getting "warmed up"! :icon_biggrin: Standing-by. . . for inrush of HT comments.
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Wow! This debate is still going on? Hey if a standby switch makes you feel good and happy about your amp's operation---like me!----use it, if it don't--forget it. I don't think it's going to makes a nat's hair worth of difference either way. A healthy amp will turn on and off no problem regardless. Platefire
The debate is more about 'what can damage the amp' not 'if it's setup right' Or at least that's what it seems to me.
They're never 'needed' on tube guitar amplifiers. The 'function' that people want them for is 'mute' not 'standby' so anyone building amps can and should make a 'mute' switch that grounds out some part of the signal path or lifts the cathode somewhere in the path so a tube can't conduct. That's the safest/most correct way to implement 'mute' If you MUST do standby (not sure why you ever would need to) you need to be careful of design considerations to ensure you're not damaging the amp with it. The section in Merlin's book covers this as well. He basically says don't do it unless you can't stop yourself, and if you must do some specific things to avoid making a standby that can cause damage to the amp.
That's all, nothing to see here, move along.
(I've also never gotten the need to 'mute' but then I've got a volume pedal on my board and just roll it off before swapping guitars (when I'm not using my A/B switch).
~Phil
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> ... or lifts the cathode somewhere in the path so a tube can't conduct. That's the safest/most correct way to implement 'mute'
That will POP bad.
The grounding of a zero-DC signal point is usually fine and quiet.
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Wow! This debate is still going on? Hey if a standby switch makes you feel good and happy about your amp's operation---like me!----use it, if it don't--forget it. I don't think it's going to makes a nat's hair worth of difference either way. A healthy amp will turn on and off no problem regardless. Platefire
The debate is more about 'what can damage the amp' not 'if it's setup right' Or at least that's what it seems to me.
They're never 'needed' on tube guitar amplifiers. The 'function' that people want them for is 'mute' not 'standby' so anyone building amps can and should make a 'mute' switch that grounds out some part of the signal path or lifts the cathode somewhere in the path so a tube can't conduct. That's the safest/most correct way to implement 'mute' If you MUST do standby (not sure why you ever would need to) you need to be careful of design considerations to ensure you're not damaging the amp with it. The section in Merlin's book covers this as well. He basically says don't do it unless you can't stop yourself, and if you must do some specific things to avoid making a standby that can cause damage to the amp.
That's all, nothing to see here, move along.
(I've also never gotten the need to 'mute' but then I've got a volume pedal on my board and just roll it off before swapping guitars (when I'm not using my A/B switch).
~Phil
I have a tuner pedal on my board, that'll mute the amp
If I must, I can just pull the input lead halfway and that will ground the input grid.
Turning 420VDC+ off with a switch rated for 240V just seems like a ridiculously complex and risky way of muting an amplifier
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Hey snick, looking forward to more on the video about the reactive load you're doing! ;)
~Phil
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OK, I see! Concerns about damage/Extra Wear-Tear on amplifier due to standby usage compared to just muting in however manner you chose to mute.
Regarding under rated standby switches. In my 55 years of guitar playing, I've never had one standby switch fail!?
So I won't argue my points for Yea! Standby Switches--any further because they are rather UN-technical and more about what I like and what I'm use to.
I keep thinking the new generation pickers and SS amps may gradually overtake us somewhere down the line but tube amps are still holding their own very good so far even with all the new technology. We'll see I reckon! Platefire
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Fun fact, look at Marshall's new Origin line:
(https://www.coda-music.com/media/catalog/product/cache/1/image/1800x/040ec09b1e35df139433887a97daa66f/o/r/origin50_h_detail3.jpg)
Notice something? No Standby switch, instead it's a power level switch.
I would bet money there is a time delay built-in instead.
Hey snick, looking forward to more on the video about the reactive load you're doing! ;)
~Phil
So do I hehehe
So many projects, so little time to work on them!
Hoping to do some tweaking to it this week. I got to try the "proof of concept" build at a gig last friday and ended up taking it out of the chain, it made things a bit too rubbery. I'm thinking the 1mF coil might be too much, so I have to source a smaller one to compare.
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So with only 6 builds under my belt you can discount my commentary accordingly - but for better or worse, I'm a cult follower of The Valve Wizard and he's not steered me wrong yet. He's proven to me time and again that much of what has ended up in modern amp designs has been perpetuated without question from 50+ year old designs. No standby switches for my amps. I just played my 50th gig with my first DIY amp and not failed me yet, still using original tubes. But now that I just jinxed myself with that amp, I'll be playing the next show with my most recent build - a modified 20W version of Sluckey's plexi/jcm800. Which also has no standby switch :|
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my 2 cents worth. Although I use a stand by in all my builds, I still have my dad's fischer stereo tube amp that came with SS rectifier and no stand by and it new seem to hurt the power tubes. In fact, they still test strong and he got it in the 60"s
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Yes, My son's Stromberg Carlson hi-fi amp of that period has no standby function (though I installed one when I rebuilt it).
But my Stromberg Carlson PA amps do have a standby function, operated off an octal plug-in relay, which can be remotely operated. It disconnects the power tube's cathodes from ground. There's no popping. It does this at the bottom of 10 Ohm bias sense resistors (which I think also serve as HT "fuses" ).
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I am not convinced it hurts anything at all to do it either way. That is unless Power Tubes and Caps should last more than 50 years.
I have seen too many old fender amps that I know the players used standby switches religiously that have tubes in them that are original. I have a 62 Bassman and a 64 Super Reverb with original tubes or at least the date code on the Bassman confirms the 5881 were older. The Super Reverb only began not using a standby about 7 years ago when My father gave it to me. He was always taught to turn on AC power for at least 30 seconds before turning on the DC.
Bassman is SS rectified and I did replace the Standby switch last night. The switch you could tell was used often as it had a loose feel to it. Partial from usage and part from switching DC. So from early 1962 until last night a fender bassman never needed a single part and even then the switch was still working, so it did not really need this. Would soon tho.
Before you consider the slow warmup for the Super Reverb, it does not use a GZ34, but a 5U4GB.
Also, after rereading this thread last night, I checked a few tubes which were original to amps I bought as collectable. This one is a 66 JTM45 and actually came with GEC KT66, which I replaced when I bought it. I have owned it for 12 years now so it only saw use by a dumb player who doesn't know standby switches kill tubes. He played the amp loud through the late 70's until I bought it 2005. I checked the tubes and they are still stunning.
What am I missing? If we were to slow the inrush and let the tubes take time to warm up and caps to not get hit, would they last forever? And even if they could last forever none of us could stand it anyway. All my friends who play use standby switches do the ritual startup and shut down. Most all of them play old fenders which according to standby is probably the worst design from what I read.
I have no doubt and am not arguing points of modern knowledge as it seem conclusive additional stress is caused by standby switches. It seems to me if you really like to turn off your DC and are willing to only use your tubes for 50 years, I say standy. If you have had problems with flipping a standby switch and blowing up tubes and caps, well by golly you just did not build them like they used to.
Anyone? Have you ever had a problem with an amp you know was caused by the standby switch, other than the switch itself? I am telling you, if the amp has one the vast majority of players are tearing up their amps daily. So next time you see someone playing a Blackface 65 Deluxe and they flip to standby for a break, simply remind them that their tubes, even though they may be original to the amp, would last longer if they understood the correct modern switching.
One more thing and I will stop. Is it best to let you car idle so the oil pressure is up when you first start it for a minute before putting it in gear, or is it 30 seconds? I cannot remember. I do know oil pressure almost immediately ramps up, but how much oil should be on the rocker arms before I start to drive.
This is a cool thread. :laugh:
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Anyone?
nothing to do with standby, but, I've found that electronics of ALL types, (under 600vdc)really likes either OFF or ON, doesn't really care which, and really HATES on/off/on/off, that's where I get paid :icon_biggrin:
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. . . and Peavey chimes in. See attachment.
Re car engine warm-up, :w2: I say let's keep the contrarian spirit alive & well, especially if a thread can be clandestinely :happy1: (well not anymore) hijacked at the same time: https://www.accuweather.com/en/weather-news/do-you-need-to-warm-up-your-car-in-cold-weather-experts-explain-engine-oil-life/55447779 (https://www.accuweather.com/en/weather-news/do-you-need-to-warm-up-your-car-in-cold-weather-experts-explain-engine-oil-life/55447779)
Hey, someone had to take the bait!
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. . . and Peavey chimes in
Except for the fact that the article is full of facts, and then says standby on guitar amps is to stop cathode stripping which it doesn't :D. (on sub 1k Voltages) Here the valve wizard explains it:
http://www.valvewizard.co.uk/standby.html
"You may have heard of 'cathode stripping', which is a specious argument wheeled out by standby-switch obsessives. In its purest form, cathode stripping occurs when particles of the oxide coating are physically torn from the surface of the cathode when it is exposed to a powerful electrostatic field from the anode. This would happen if the valve is operated at saturation, without a usual space-charge of electrons to protect it. Fortunately, this effect does not exist in receiving valves, even when operated at saturation, because it requires an electric field strength of at least 4MV/m (yes, 4 million volts per metre!). No guitar amp ever comes close to this. "
~Phil
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I've already clearly dissembled my beliefs on cathode stripping! See my Reply #55 hereinbefore.
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. . . and Peavey chimes in. See attachment.
Re car engine warm-up, :w2: I say let's keep the contrarian spirit alive & well, especially if a thread can be clandestinely :happy1: (well not anymore) hijacked at the same time: https://www.accuweather.com/en/weather-news/do-you-need-to-warm-up-your-car-in-cold-weather-experts-explain-engine-oil-life/55447779 (https://www.accuweather.com/en/weather-news/do-you-need-to-warm-up-your-car-in-cold-weather-experts-explain-engine-oil-life/55447779)
Hey, someone had to take the bait!
My oh my, Finally someone with s sense of humor.
I tried with the Rectifier, but the car got you.
BTW, when I lived in Germany I got a 150 mark fine ($50 at the time) for warming my car up before I drove it. Obivously, the polizei do not care to determine what is best for the car, it is what is best for thier country.
With that thought in mind, is it really wrong to have a standby switch. When flipped on not only do they cause inrush and a need to listen to Rush, the band, they will kill your amp or something in it evenually. I just have not found out what they kill. They are a major cause of pollution however.
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I've already clearly dissembled my beliefs on cathode stripping! See my Reply #55 hereinbefore.
I get that, I'm complaining about Peavey continuing to 'act smart, yet still be wrong and continuing the bs' :P
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> Is it best to let you car idle so the oil pressure is up when you first start it for a minute before putting it in gear, or is it 30 seconds? I cannot remember. I do know oil pressure almost immediately ramps up, but how much oil should be on the rocker arms before I start to drive.
What oil pressure?
The pressure at the pump may be rising just on the starter motor. It will typically be high at cold idle because the pump is constant-volume and the bearing leak is slow with thick oil. Old cars often nail 40PSI cold but can't hold 20PSI warm.
So the pump is fine; and the main leak is the crank so that's probably getting oiled within a few seconds.
You ask about rocker arms. (Revealing our age.) My Willys was a forced-oil F-head based on an older splash-oil flathead. The new-fangled rockers had an external oil line. Not very big. Not very clean. It took far over a minute to begin to see oil on the rockers. (But remember that many thousand external-rocker engines got oiled manually, including some reliable aircraft engines.)
The pushrod-oiled V-8s normally get oil fairly quick. They want some pressure in the lifter to keep quiet but not to stay lubrucated; thin no-pressure seepage will do. However the worst rocker wear I ever saw was on such an engine. Ball-stud nearly worn through the rocker. I assume pre-SE oil plugged the pushrod, and the splash from the 13 or so oily rockers was not enough to keep it slick.
And yes, I -still- have rockers. Five assorted yard-engines say "OHV!" on the rocker cover for no good reason. (OK, I have not peeked to see if truth or lie.) And my OHC sedan has a bushel of rockers, I guess 20 for the 16 valves. (Honda VTEC has added bumps and rockers to extend the exhaust opening above 3,600RPM.)
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I -still- have rockers
I believe my '08 3.9L Buick still uses old school PR/rocker
my '88 dodge definably does, and oil pressure at start IS 40psi, warm, optimistically 10psi :laugh:
and Peavey chimes in.
I had to use a fire extinguisher on a Peavey, I quit reading their attachments :icon_biggrin:
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> Is it best to let you car idle so the oil pressure is up when you first start it for a minute before putting it in gear, or is it 30 seconds? I cannot remember. I do know oil pressure almost immediately ramps up, but how much oil should be on the rocker arms before I start to drive.
What oil pressure?
The pressure at the pump may be rising just on the starter motor. It will typically be high at cold idle because the pump is constant-volume and the bearing leak is slow with thick oil. Old cars often nail 40PSI cold but can't hold 20PSI warm.
So the pump is fine; and the main leak is the crank so that's probably getting oiled within a few seconds.
You ask about rocker arms. (Revealing our age.) My Willys was a forced-oil F-head based on an older splash-oil flathead. The new-fangled rockers had an external oil line. Not very big. Not very clean. It took far over a minute to begin to see oil on the rockers. (But remember that many thousand external-rocker engines got oiled manually, including some reliable aircraft engines.)
The pushrod-oiled V-8s normally get oil fairly quick. They want some pressure in the lifter to keep quiet but not to stay lubrucated; thin no-pressure seepage will do. However the worst rocker wear I ever saw was on such an engine. Ball-stud nearly worn through the rocker. I assume pre-SE oil plugged the pushrod, and the splash from the 13 or so oily rockers was not enough to keep it slick.
And yes, I -still- have rockers. Five assorted yard-engines say "OHV!" on the rocker cover for no good reason. (OK, I have not peeked to see if truth or lie.) And my OHC sedan has a bushel of rockers, I guess 20 for the 16 valves. (Honda VTEC has added bumps and rockers to extend the exhaust opening above 3,600RPM.)
What do you call a rocker arm under a camshaft in a overhead cam engine?
I thought the rocker arm was kept and the push rod removed. Did they change it again.? I quit working on cars when I started fixing amps. Musicians may not have money, but most of them can maintain a old car and at least clean and wax one.
So, for a complete detail to my truck you can have your amp worked on. You still got to pay for parts.
Also, if you want a Standby switch installed on an amp you bought that doesn't have (Blues Jr.) you can get that too. I actually installed one on a Champ I built for someone by request. I figure, it is your amp, you tubes and your money. Spend it however you wish.
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I bet you can get a Fine for that in Germany!
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I bet you can get a Fine for that in Germany!
If I do, it will be my third.
Bogner amps have a Standby switch. Wonder how big his fine is or even if it is fine at all.
Finally, someone with the nerve to offer up the idea fo fining someone for improper movement and installation of a directional selector switch. Fine is $175.00 and is a moving violation, but we can change this to inproper use of equipment. No points on you license, but the fine is a tad more. Only $295.00.
They do this in North Carolina, so keep it in mind. Coming south on I-26 from Tennessee into North Carolina is a 7% grade and the speed limit changes from 65 to 55. Just as you see the sign, you will see a State Trooper. First he asks if you use Standby Switches. If you say yes, you get a ticket and leave. If you say you know better, he will instruct you to call the Solicitors office and they will reduce the fine to no points.
Don't ever say you know better, but will install them if requested. That is the same as telling a Georgia State Patrol officer when he pulls you over in a brand new red Lincoln Town Car while having a few beers and he asks "whats the hurry son, you heading to a fire"? You reply "does this look like a GD Firetruck to you"?
They will get pissed and take you to jail even if you have a stack of get out of jail free cards.
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Probably you can get a Fine in Germany for leaving your amp idling. No standby SW's on German tours! And, an idling car is the devils' workshop.