How do i dummy load the 5150? (impulses)

F0RBIDDEN said:
I don't think this will work... As soon as you flick the amp off standby it's going to blow the output transformer if the speaker jacks aren't connected to something, end of story...

I don't know if there's a cheap way really... Just use a cab and turn the post gain down pretty quiet or buy a THD Hotplate or another attenuator.
Click to expand...

The speaker must be connected to the amp! (because of the load)!!! but you wont hear the cab anymore by this way. its just like muting the poweramp.

believe me - it works, im doing this all the time. and its undangerous as far you leave the cab connected to the amp!
 
Jesus...Listen carefully n00bs. :p

Every amp is setup a little differently, and because of that some people have to one of two different methods. Here are those two (proven) methods:

1) Turn the amp on, but leave the standby switch alone. You can then crank anything you want because the output (power) section of the amplifier is not on. Connect a cable from your FX Send or Line out (if you have one) to your interface and hit record. Use impulses later. You will be recording JUST the preamp output. Because the amp is still in standby you have nothing to worry about.

*OR - if your amp does not allow signal to pass through FX Send/Line output with the amp in standby*

2) Build your own (very easy) load "box". This basically consists of an input jack, a resistor (or several) that can handle the wattage and has the same OHM rating that is needed, some wire and a box to house everything in. Use this in the case that your amp A) does not have have an FX Send or Line output or B) when you leave the amp in standby no signal goes through the FX Send/Line output. Some amps do not allow any signal to pass, if it's in standby...it sucks but some amps are just simply designed this way. If this is the case then you need a load box so that you can flip that standby switch. You can use the load from Weber, or go to an electronics store and get several resistors. For a 120W amp (5150/JSX/etc.) you will need SIX 20W resistors...typically you should be using the 8ohm connection to your cabinet, resistors will come in 4, 8 or 16 ohm ratings. Whatever cabinet output you are using, the resistor's ohm rating needs to match that. I have built a load for my JSX and sold it to a friend for like $10...it cost me $12 to make it and I hardly used it. I made one using the six 20w 8ohm resistors. All you do is wire them parallel (positive to positive, negative to negative...think like patching a bunch of pedals together) and then put the positive wire to one of the contacts on the input jack, negative to the other...done. Then you can use a DI box in the chain between the amp and the load. DI->interface->impulses->silent recording of cranked amp->rock star.

~006
 
do you reckon if i buy the last 4 of these from amazon (20w each) it will cancel out the power of the 5150 completely?

[ame]http://www.amazon.co.uk/RadioShack-8-Ohm-Non-inductive-Resistor/dp/B00105UW5C/ref=sr_1_2?ie=UTF8&s=electronics&qid=1205615174&sr=8-2[/ame]

I hope so! think i'll pull the trigger now.
 
Im not sure whether i should wire it straight up in series, or go for parallel. I know that parallel offers less resistance?
I figure the higher the volume the higher the wattage? Completely oblivious to electronic circuits me lol
 
Parallel resistance adds differently. Parallel resistance is the inverse of the sums of the inverses, as opposed to series which is just the sum. In equation form, to make it easier,

1/(Req)=1/(R1)+1/(R2)+...+1/(Rn)

Also, the resistor wattage is the wattage at which the resistor will stop working properly, overheat, and eventually explode or become some bizarre circuit anomaly that will simply blow to deal with.

The links above show what you'll need, and how much of it you'll need, to do things like this... but be warned that the 'dummy load' will not sound as good as a slightly more complicated load that actually has its impedance across all frequencies calibrated to be very similar to a speaker cabinet.

Jeff
 
Sorry to bump an old thread but I finally have a potentially good deal on a 6505 and I just wanted to clarify one thing. You guys are talking about pre and post gain in relation to the FX Send but I can't figure out how this affects the sound. I'm not bothered about having totally silent recording and I'm perfectly happy to have a cab connected BUT do you need to have the Post Gain cranked when using impulses, or can you just leave it near to 0? Does it affect the sound when using Impulses? Thanks in advance guys.
 
Unfortunately yeah, the post gain affects both the output volume and the volume coming out of the FX send, so I don't know if you necessarily need to have it cranked, but it happens to control both :erk:
 
kev said:
Hi chaps,

Im after a cheap but safe way to dummy load the 5150 so i can record through impulses without actually having to hear the amp through the marshall cab at the same time. After a bit of searching ive not really got any closer but I saw someone make an awesome device on here somewhere once i swear!

Ultimate goal: record 5150 to PC with no cab.

Thanks in advance,

Kev

P.s

Is it better to use "SEND" or "PREAMP Out " When DIing? And also, what is the difference?
Click to expand...

My advice to you would be to get a presonus studio mobile (around 400 bucks I think) or something along the line. They are awesome. Take the PREAMP out from the 5150 and plug it into the back input of the mobile. when you install the software there will be a 3rd party mixer called presonus Universal Control, open that and disable everything except playback, that way when you click monitoring on you will hear only the impulse + 5150 tone and none of that scratchy ass crap tone.

Hope this helps
 
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