Mark IV power section load out?

[Grandor]

I keep reading in the Mark IV manual that you cannot use the amp at all (not even on standby, silent recording even!) with no cab hooked to the head.
Is this correct? or just some sort of precaution.

I assume this is because load must be on the power section otherwise tubes start breakin from the power going nowhere.

 

[ned]

G-

This isn't just the Mark IV but all tube amps. They need to speaker load or you will blow the transformer.

Ned

 

[Grandor]

Ohhh right.
Thanks mate

 

[mervgriffen]

Technically, you could just take a speaker plug and solder an 8 ohm power resistor to the two terminals (AKA Load resistor)......this may have an effect on how the power section reacts however. I wouldnt suggest doing this unless you're a bit of a tinkerer.

 

[Grandor]

Technically, you could just take a speaker plug and solder an 8 ohm power resistor to the two terminals (AKA Load resistor)......this may have an effect on how the power section reacts however. I wouldnt suggest doing this unless you're a bit of a tinkerer.

Where would all that load go?
Wouldnt that power resistor get heaps overheated also???

 

[mervgriffen]

The energy gets dissapated as heat through the resistor.....i just did a quick search and it might be difficult to find a resistor that can handle the wattage, but if you're going through a slave or recording output I don't think much is going out through the speaker jack..

webersvt sells alot of attenuation products....i'd check them out

www.webervst.com

 

[chedgeco]

The energy gets dissapated as heat through the resistor.....i just did a quick search and it might be difficult to find a resistor that can handle the wattage, but if you're going through a slave or recording output I don't think much is going out through the speaker jack..

webersvt sells alot of attenuation products....i'd check them out

www.webervst.com

The THD hot plate would be worth looking into as well. Never used it, but
I've heard a lot of good things about it.
http://www.thdelectronics.com/products/hotplate.htm

chedgeco... 8)

 

[CudBucket]

Technically, you could just take a speaker plug and solder an 8 ohm power resistor to the two terminals (AKA Load resistor)......this may have an effect on how the power section reacts however. I wouldnt suggest doing this unless you're a bit of a tinkerer.

Where would all that load go?
Wouldnt that power resistor get heaps overheated also???

Yup! Much hotness would ensue. I just picked up a Hotplate today on the bay for about $200. Can't wait to throw it between my MkIV and recto cab.

 

[rholap]

Technically, you could just take a speaker plug and solder an 8 ohm power resistor to the two terminals (AKA Load resistor)......this may have an effect on how the power section reacts however. I wouldnt suggest doing this unless you're a bit of a tinkerer.

Where would all that load go?
Wouldnt that power resistor get heaps overheated also???

Yup! Much hotness would ensue. I just picked up a Hotplate today on the bay for about $200. Can't wait to throw it between my MkIV and recto cab.

Cool... tell me how it works out. I have the same cab, oversized with V30s, I assume.

Robert

 

[surfingalien]

Okay I just accidentally pulled out the speaker cable from my Mark IV head thinking it was the cable going to my multitrack recorder. It was out for about 10 seconds before I plugged it back in. There was no indication of anything gone wrong when I played right after, and I turned it off soon after that. Does this mean it's okay, or just because it plays now doesn't mean it won't mess up the transformer in the future (from this incident)?

 

[908ssp]

Surfing was it unplugged while you were playing or between playing? In any case it is probably fine if it plays at all.

You can get 50 watt resistors from Webber for $2 I would use at least 6 to dissipate the heat from a full 100 watt amp. You can get and I have one 8 ohm resistor that can handle 300 watts it is about the size of a stick of dynamite. I add load resistors to a number of my amps to protect speakers that are under powered or flatten the tone a bit bit so I can run the amp harder. You treat them just like speakers only silent ones.

 

[surfingalien]

Thanks for the reply, it was while I was playing plugged in and turned on.