5150 evh preamp?

[azzxaa]

hey guys, I just bought a 5150 EVH "the first one" and I heard you can use the preamp to record strait to computer and add a cab in a simulator?

is it safe to do it without the cab plugged in? or any trick like using the standby button without burning it up.

and anyone have the manual in pdf and machine heads "studio" settings for it or in flames

tnx!

 

[Kazrog]

Don't use it without a cabinet! You will fry your amp!!

OK, now that we've gotten that out of the way, here's a product that will allow you to use it without a cabinet:

http://www.musiciansfriend.com/product/THD-Hot-Plate-Attenuator?sku=481283&src=3WFRWXX

I have one of these, it works great. It soaks up all the power load that a cabinet does, so you won't fry your amp, and it gives you a safe direct out to use for recording. I've gotten some great results running the direct tone out of the 5150 + Hot Plate into convolution reverb such as AltiVerb.

 

[azzxaa]

http://www.musiciansfriend.com/product/THD-Hot-Plate-Attenuator?sku=481283&src=3WFRWXX

I have one of these, it works great. It soaks up all the power load that a cabinet does, so you won't fry your amp, and it gives you a safe direct out to use for recording. I've gotten some great results running the direct tone out of the 5150 + Hot Plate into convolution reverb such as AltiVerb.

ahh nice! excatly what I was looking for..isnt that good even if you mic you amp? if you wanna record at low volym?

 

[Metaltastic]

Don't use it without a cabinet! You will fry your amp!!

Having never owned a head before (just a 5150 combo), but planning on getting a good one soon, I'd appreciate some clarification on this. At what point will it do damage? Can the amp not even be turned on without a cab plugged in? What about turned on, but with standby off? Or both on, but no guitar plugged in? I ask only because in my research for the perfect amp, I've been reading through a shitload of .pdf manuals online, and none of them have made any mention about this. It seems like the kind of thing that'd be in its own box with a big "WARNING!!" sign.

 

[colonel kurtz]

it's fine to turn an amp on, including the standby, without a cab plugged in.

the one thing you DON'T want to do is use the direct/preamp outs without having a cabinet plugged in - this is when the amp overloads and goes boom. i've also seen amp manuals stating that you should not plug in a cab after the amp is already on, even though i know of many instances in which i've seen this done with no apparent harm.

 

[cobhc]

An amp in standby mode is fine without a cab, as soon as you turn it on without one, you could be in trouble, things start to fry from here on.

Also plugging a cab in while it's on, is like turning it on and not plugging a cab in, you're still turning it on without a cab initially, definetely not good practice for a tube amp.

I think they don't have a warning in the manuals or anything because if you're buying a tube amp, you need to know these things. Like turning the amp onto standby to let the tubes warm up first, before turning it on to play, and putting the amp back in standby, when you're finished playing, to let the tubes cool down again, before you turn it off. If you didn't know these things about a tube amp, go read up before you buy one, or you could risk killing your expensive tube amp.

 

[Metaltastic]

Well apparently "these things" are not so universally understood among tube amp owners, seeing as how you and Colonel Kurtz have contradictory views on the subject, and I definitely don't think it's as obvious as the power/standby functions, which anyone could realize that there must be some reason for two separate switches rather than just an "on." So where would you suggest I read up on this?

 

[Loren Littlejohn]

You could always call voodoo or FJA, they didn't seem to mind when I did.


Here is there numbers:

Voodoo: 607-256-0465
FJA: 315-505-6604

 

[cobhc]

http://www.metaltronix.net/metaltronix-amp-basics.htm

That is a good place to look. And trust me you should never turn a tube amp off of standby without a cab plugged in, I think everyone else here will agree with me.

 

[VH100R]

never operate a tube amp without a load (a cab or something like THD hotplate).

If an amp is being used at a decent volume and suddenly you disconnect the cab (or load) you are in trouble.

The power amp produces a fairly powerful signal and that signal is dissipated on to the cab (or load), when you take the load that energy has to be dissipated on something and normally that damages the amp.

As a stupid analogy think this:

You are going to sneeze, a really big sneeze but you have your nostrils completely sealed. That has go to hurt

take care

 

[Soundlurker]

The person who built my amp said pretty much what cobhc did.
1. Connect a cab to the output with the correct impedance (8ohm cab -> 8 ohm out if the amp has seperate outs and not an impedance switch that is)
2. Set 'Power' switch to on and wait at least 30 seconds
3. Set 'Standbye' switch on and you are ready to play (I am not sure if it's the same with other amps but with my amp when the standbye switch i pointing upwards you are NOT in standbye mode)
4. After you've stopped playing switch to standby mode and wait again at least 30 seconds
5. Turn 'Power' off, unless you'll be playing again soon.

 

[demeyed]

You can't turn an amp on fully without any cab or power sink to take the load. I've heard you can have it on standby before but I don't want to try it.

 

[Metaltastic]

Alright, I guess I'll just make every effort to be sure a cab is always plugged in. Cobhc, thanks for the link, though I can't deny I got a chuckle out of this passage from it, which was contrary to what you said:

"To turn it off, simply flip the power switch to "off", don't use standby. This lets the still-conducting tubes bring down the high voltages in the power supply."

Just goes to show how much confusion seems to surround the specifics of this topic.

 

[Metaltastic]

And I would point out that I never contested the fact that a load is necessary; rather, I wanted to know at which point it became necessary (see my first post). But thanks for the help everyone, all the same.

 

[cobhc]

Glad you got your answer in the end dude

 

[Rob Logic]

I've owned a peavey ultra 120 plus, a 5150, 2 XXX's, a triple rec, and now I have a Rivera Knucklehead Tre and every one of them, the manual always said allow tube warm up and cool down with the standby switch. I spent $2000 on the rivera and I baby the fuck out of it because I love it and it just makes logical sense to use the standby. As far as the "...don't use standby. This lets the still-conducting tubes bring down the high voltages in the power supply.", that to me sounds like I'm running on the a treadmill at full blast and then the thing stops on a dime and me falling on my face. I would never wish my amp to fall on its face... its just too sexy! cobhc's got it right all the way.

 

[ochants76]

The reason for not using the standby to power down would be to help discharge the capacitors in the power section. You would do this if you plan on opening the amp up to work on it. Some guys will just unplug the amp from the wall while it is running..essentially the same thing. You would also want to use a bleeder resistor to keep the voltage down while you are in there. The article is a bit misleading. It is always a better idea to put the amp on standby prior to powering down during normal use.

The charge held in these capacitors = death

Most modern tube amps have built in tolerance for running without a load(in case the speaker cable is accidentally unplugged while playing). But this only lasts so long (I wouldn't trust it more than 30 seconds). Most likely what will happen is you will fry your output transformer. Which is a $150-200 part most often...but the cost of getting it replaced is pretty high.

If you don't believe me...turn your amp up to a decent volume unplug the speaker and just start strumming. Keep this up till you get a nice smoky flavor.