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Author Topic: How bad is this for my amp?  (Read 2727 times)

Antag

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How bad is this for my amp?
« on: March 30, 2009, 10:55:43 AM »
I have a half stack: Engl Savage 120 head on an Engl 4x12".  I modified my cab to have 2 Classic Lead 80s & 2 G12K100s.

Normally, I run a speaker cable from the 8 ohm output to the cab's mono input (with the cab switched to mono).  But occasionally I want to play through just the 2 K100s, so I do the following:

Stop playing
Switch the standby switch to off
Lean over the amp & switch the cab to stereo
Unplug the speaker cable from the 8ohm output & plug it into the 16 ohm output
Switch the standby switch back on
Carry on playing

Am I damaging the amp by doing this?   I know that you shouldn't run a valve amp without a speaker plugged in, but by switching it to standby & momentarily changing the connection is it putting any strain on the power valves?

Or do I need to power the amp off fully, change the connections then power it back up?
BKPs: HD, MM, NB, PK, CS, Ab (b&n); Am (b only); VHII, Tril (n only); IT, Slow, Sult (m&n)

Twinfan

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Re: How bad is this for my amp?
« Reply #1 on: March 30, 2009, 11:01:19 AM »
Switching the output on standby is fine - that removes the load from the amp and just keeps the valve heaters on  :)

Dmoney

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Re: How bad is this for my amp?
« Reply #2 on: March 30, 2009, 11:11:33 AM »
Switching the output on standby is fine - that removes the load from the amp and just keeps the valve heaters on  :)

This can vary in other amps can't it?
im sure i read that in some cases all the stand by does is disconnect the input jack...basically.
maybe im thinking of a certain matamp????????

ive turned my dual rec on stand by before with no power tubes in. it still works...with the tubes in...i did that to fault find why my dual rec kept blowing fuses.



Twinfan

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Re: How bad is this for my amp?
« Reply #3 on: March 30, 2009, 11:44:50 AM »
Good question - MOST amps use the standby in the way I described bu there may be exceptions...

hamfist

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Re: How bad is this for my amp?
« Reply #4 on: March 30, 2009, 12:29:12 PM »
As Dave said, it should be just fine. I'm sure Engl make their standbys the same as most other mainstream manufacturers these days,by only leaving current to the valve heater elements.

Denim n Leather

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Re: How bad is this for my amp?
« Reply #5 on: March 30, 2009, 05:34:20 PM »
Not sure. I know that unless you have a Hot Plate set at the 'Load' setting, the Splawn manual is very clear in that you should never disconnect the amp from a speaker load while the main power is on.

I guess it varies from amp to amp.

The ENGL manual doesn't say anything?

You should email ENGL and ask them directly if it doesn't.

m0jo

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Re: How bad is this for my amp?
« Reply #6 on: April 01, 2009, 09:27:24 PM »
The standby switch is primarily for taking off the current from the output valves, it says so in the Engl manuals.
So you're golden on that point. :D

But you also switch the amp to the right ohmage I hope? Otherwise you'd damage your amp (I suspect the output transformer and tubes ..) that way.
Turning the amp all the way off would kill your tubes faster because of the voltage/current spike


edit:
By the way, when I saw the topicname I laughed  :lol: I was expecting some story like  "my amp fell off the cabinet and down the stage, is this bad for my amp?"  :lol:
« Last Edit: April 01, 2009, 09:30:16 PM by m0jo »
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Antag

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Re: How bad is this for my amp?
« Reply #7 on: April 02, 2009, 09:36:30 AM »
But you also switch the amp to the right ohmage I hope? Otherwise you'd damage your amp (I suspect the output transformer and tubes ..) that way.
Yes - my cab is 8 ohm mono, 16 ohm stereo.  When I switch the cab to stereo, I also move the speaker cable from teh 8ohm output to the 16 ohm one.
BKPs: HD, MM, NB, PK, CS, Ab (b&n); Am (b only); VHII, Tril (n only); IT, Slow, Sult (m&n)

Antag

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Re: How bad is this for my amp?
« Reply #8 on: April 02, 2009, 09:39:39 AM »
edit:
By the way, when I saw the topicname I laughed  :lol: I was expecting some story like  "my amp fell off the cabinet and down the stage, is this bad for my amp?"  :lol:
That did once happen to a little solid state combo I used to own - even I knew that wasn't the best way to look after an amp.... :)
BKPs: HD, MM, NB, PK, CS, Ab (b&n); Am (b only); VHII, Tril (n only); IT, Slow, Sult (m&n)

Dmoney

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Re: How bad is this for my amp?
« Reply #9 on: April 02, 2009, 09:42:41 AM »
ive kicked an old jcm900 head around the floor of a venue after i leant it to someone and they dropped a pint of water in it.

never looked at it... few months later, cleaned it up, opened it up, checked for rust or signs of water damage, put some new 5881's in it, and it worked fine! solid as a rock!

the jcm900, under rated. with a few tone stack tweaks it can be pretty nice.


anyway, please dont try to prove your amp is as tough by pouring a pint down through it.

JDC

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Re: How bad is this for my amp?
« Reply #10 on: April 02, 2009, 12:51:34 PM »
The standby switch is primarily for taking off the current from the output valves, it says so in the Engl manuals.
So you're golden on that point. :D

But you also switch the amp to the right ohmage I hope? Otherwise you'd damage your amp (I suspect the output transformer and tubes ..) that way.
Turning the amp all the way off would kill your tubes faster because of the voltage/current spike


edit:
By the way, when I saw the topicname I laughed  :lol: I was expecting some story like  "my amp fell off the cabinet and down the stage, is this bad for my amp?"  :lol:

lol I saw something similar happen to a professional band, they had a crane to get stuff out the back of the venue and a cab fell off about 3 or 4 metres to the ground and everyone was like "oooooooo" about 5 mins before a very drunken me went "don't drop it!"

m0jo

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Re: How bad is this for my amp?
« Reply #11 on: April 06, 2009, 08:08:23 AM »
Ouch, getting a cab on your head would be a definite lights-out!

Lucky that didn't happen though! :) And I'm surprized at how many people have dropped their amps haha I'm allways very careful with it, guitars is a different thing though :lol:
MXG custom '60s fiesta red strat
Ibanez S470DXQM
-->shiteload of pedals-->
Laney VC100