i used markIV rec out but.....

[willrock]

i didnt put the a speaker load on! i heard its bad for the transformer.. i have the head so i thought i dont need to bring my heavy recto cab with me since i wanna try plugging direct to the board,, and i used it like that for 3 hours! i wonder if i did a damage on my precious mark IV already? does anyone of you guys know? :?

 

[Schmoog]

certainly doing that can cause a great deal of undue stress on your output tranny, and over time it WILL kill it. the "time" in question varies based on the tranny. i.e. lesser trannies will fail easier. however as long as its not dead right now, and you don't do it again, I think your fine.

 

[willrock]

i really felt so bad bout it,. yah my mark is working, so i guess its fine. i hope it didn't affect my mark's tone though

 

[willrock]

anybody knows where to order/get load resistors from?

 

[Schmoog]

there are a lot of dummy loads out there. the THD hotplate is the most popular (and one of the most expensive) but not necessarily the best. the weber mass100 is probably the best, and is a little cheaper than the THD. theres also the Dr. Z airbrake, and the marshall powerbrake. any one of these will do the trick.

 

[4Eyes]

Doesn't have the mark IV "silent recording" switch which disconnect the power amp and then is safety to use recording out without cab? :roll:

 

[Pinweaver]

Doesn't have the mark IV "silent recording" switch which disconnect the power amp and then is safety to use recording out without cab? :roll:

You always need to maintain a load on the amp, even when you use this switch.
Whether it's a cab or a soak resistor doesn't matter. If there is no load you will damage your transformer.

 

[willrock]

Doesn't have the mark IV "silent recording" switch which disconnect the power amp and then is safety to use recording out without cab? :roll:

thats exactly what i thought too. i talked to 2 mesa rep yesterday, the first one i forgot his name said that most probably my amps transformer is fried already, some crap like that, then afterwards, i talked to m. taylor, then he said as long as my mark IV is still working which it is, it should be all fine, transformers doesnt give up that easily he said, and if something gives up, it should be the the power tubes first. Then it made me feel better =)

 

[willrock]

there are a lot of dummy loads out there. the THD hotplate is the most popular (and one of the most expensive) but not necessarily the best. the weber mass100 is probably the best, and is a little cheaper than the THD. theres also the Dr. Z airbrake, and the marshall powerbrake. any one of these will do the trick.

hey schmoog, thanks lots for the suggestions. whats the cheapest one though?

 

[4Eyes]

Doesn't have the mark IV "silent recording" switch which disconnect the power amp and then is safety to use recording out without cab? :roll:

You always need to maintain a load on the amp, even when you use this switch.
Whether it's a cab or a soak resistor doesn't matter. If there is no load you will damage your transformer.

I forgot..sorry for my stupid comment

 

[willrock]

**** just noticed 3 hrs that seems very long (a whole gig/set). shows how solid these amps are.

I think the exceptions to the "must have load when amp on" rule are the following:

1) SS amps

2) tube amp w/ no load in standby

I have a feeling that's why the Mr. Bungle guitarist uses the JMP-1 preamp only. no power amp, no cabs, straight to PA live. couple preamp tubes. easy as sh!t.

i tried my mark IV with my band practice last night, the tone is just as nice as usual, no sign of tranny stress at all! these amps are solid

 

[holdsworth]

How about using Silent Record Out with a MKIV combo? I record alot with the Silent Record pulled on the master, and I usually have it set to about 7. Do I need to stop doing this and wait until I get an attenuator?

 

[Restless Rocks]

When you pull the "silent record" switch on the Mark IV you are disconnecting the audio signal to the power amp section. You must maintain a load on the output tranny because the power section is active, but in "idle". You could essentially crank the master to ten and not send any more or less signal to the power section as it is electrically disconnected from the preamp. If it were set up with say a secondary standby switch which would disconnect the B+ voltage supply from the power amp section (the output tranny, screen grids, and phase inverter) it would not be necessary to have a load on the output tranny because it would not be "turned on" so to speak. Oh no! Have I thought of a MkIV Mod?

 

[holdsworth]

Oh no! Have I thought of a MkIV Mod?

lol, just go for it! :lol: