New Amp!

  • Thread starter Thread starter ibanezrocks
  • Start date Start date
I'll just leave it plugged in, its not that much of a problem, and I wouldnt want to risk forgetting to plug it back in.
 
thanks for the help poltergeist
does anyone know how much hotplates/attenuators/power brakes/powersoaks cost? where to get them or if I could just build one myself?
 
ibanezrocks said:
I'll just leave it plugged in, its not that much of a problem, and I wouldnt want to risk forgetting to plug it back in.
Click to expand...

Sweet, one problem solved.

I would imagine that rather than a true mute, it's a large pad between the preamp and power amp. Turn it up far enough, and enough signal gets past the pad to fire up the speaker.

You can build an attenuator pretty easily, but your tone might suffer. The simplest kind is a big fat power resistor wired in series with your speaker.

The problem: A speaker is an impedance. An impedance is a reactive load. The value of the load changes with frequency. A resistor is a non-reactive load. It is the same at all frequencies. This can change your tone, and not for the better. Better commercial attenuators use reactive loads and compensating EQ circuits. That being said, I put a simple one in a Peavey Delta Blues for a guy, and he is totally happy.

A simple power resistor load could solve your silent problem, though. You could wire one into a little box and use it instead of your speaker in mute mode. It will be silent, and you won't have to worry about accidentally frying your amp.

Commercial ones ain't cheap, $2-$300 new.
 
If you use a power resistor, make sure you wire it correctly and use the correct resistance. For example, if you wire a 8 ohm resistor in series with a 8 ohm speaker, you will get a 16 ohm load, which shouldn't be a problem.

However, if you wire the resistor in parallel with the speaker (across the terminals), you will get a 4 ohm load. If you add more resistors in parallel, you will get too small of a load and will fry your amp.
 
Lopp said:
If you use a power resistor, make sure you wire it correctly and use the correct resistance. For example, if you wire a 8 ohm resistor in series with a 8 ohm speaker, you will get a 16 ohm load, which shouldn't be a problem.

However, if you wire the resistor in parallel with the speaker (across the terminals), you will get a 4 ohm load. If you add more resistors in parallel, you will get too small of a load and will fry your amp.
Click to expand...
Now a little help with this gossipee chic?
 
So what kind of resistor would I use? Does it have to be one that can handle large currents or would just any 4 ohm resistor work? Could I use a pot? How could I make one of those that respond to different frequencies? would I need parts that are hard to find our does it just involve using normal parts in a certain way?
 
ibanezrocks said:
So what kind of resistor would I use?? Does it have to be one that can handle large currents or would just any 4 ohm resistor work? Could I use a pot? ?
Click to expand...

You need to use a power resistor that can handle the full power of your amp. Big supply houses like Digikey and Mouser will sell power resistors. Ones up to about 100W are pretty easy to find. You can use a pot that handles power. They are usually not more than 50W, and sound like shit, if you ask me.

The resistance will determine the attenuation. More resistance=more attenuation.


ibanezrocks said:
How could I make one of those that respond to different frequencies? would I need parts that are hard to find our does it just involve using normal parts in a certain way?
Click to expand...

That's beyond me. :) Here is a website I found, though. Looks like a good site, I'm going to do some reading myself.


http://www.amptone.com/g243.htm
 
poltergeist said:
A HOT chic with rad lips on this site
Me thinks me wants
Click to expand...

Ahhh....
Yes, well, thanks for clearing that up. All better now.
 
ibanezrocks said:
So what kind of resistor would I use? Does it have to be one that can handle large currents or would just any 4 ohm resistor work? Could I use a pot? How could I make one of those that respond to different frequencies? would I need parts that are hard to find our does it just involve using normal parts in a certain way?
Click to expand...

What you need is a voltage divider network of power resistors which presents a nominal load to the amplifier while placing a large resistance in series with the speaker. Do NOT just put a big resistor in series with the speaker.

Please don't take this the wrong way, but the nature of your questions tells me that you should not be dinking around with this yourself. Playing around with the output stage of a power amplifier when you don't have a good working knowledge of electronics can be hazardous to the health of both the tinkerer and the amplifier. There are lots of commercially available units that will do what you want. Buy one; you'll probably spend far less on it than you will on hiring a tech to repair your amp after you blow it up.
 
I know plenty about electronics, thats not the problem at all, in the last month or so I've built a digital voice changer (not for music, just for playing around with), a 0-12 volt variable dc power supply, and I'm in the process of building a fuzzface.
I don't know anything about powersoaks, but I will read up on that site boingoman pointed out and see what I could come up with.
 
Wow. You went from an Ibanez/Crate setup to a SG/Mesa setup.

See how bad your sound sucked before? :D

But really, congrats. Have fun!

H2H
 
ibanezrocks said:
I know plenty about electronics, thats not the problem at all, in the last month or so I've built a digital voice changer (not for music, just for playing around with), a 0-12 volt variable dc power supply, and I'm in the process of building a fuzzface.
I don't know anything about powersoaks, but I will read up on that site boingoman pointed out and see what I could come up with.
Click to expand...

Well, OK then. The bridge resistor that goes across the terminals of the output transformer needs to be an 8 ohm power resistor rated at at least twice as much wattage as your amp delivers. The series resistor can be any value power resistor (though its power rating should be high), and the voltage drop across it versus the voltage drop across the speaker terminals will be roughly the ratio of its resistance to the nominal 8 ohms of the speaker (I say roughly because we are mixing types of impedance - resistive and reactive); the higher its resistance, the quieter the speaker will be.
 
Hard2Hear said:
Wow. You went from an Ibanez/Crate setup to a SG/Mesa setup.

See how bad your sound sucked before? :D

But really, congrats. Have fun!

H2H
Click to expand...
You know what the sad thing is?
I spent more on the new Ibanez ($700 when that model first came out) and the new Crate ($350) back when I got them than I did on the used SG standard ($600) and the used Mesa ($400)... It's like fate kicked me in the nuts then handed me a nice apology gift :eek: :rolleyes:
 
Yeah, I bought my first Stratocaster at list price cause back then I didn't know that there were dirtbag dealers like that, and there weren't catalogs or the internet to inform me of it.

H2H
 
You must log in or register to reply here.
Back
Top