Airbrake Questions

[Littlewyan]

Hi Guys

I currently have an attenuator which I'm not too happy with. I find that it matches the impedance perfectly at all attenuation levels, however it kills the tone of the amp. I only found this out as I built a 1Watt Marshall and using the inbuilt attenuator on the amp the tone is great, through my attenuator the midrange disappears (weird). My attenuator basically cuts the wattage down to 1/4 Power (50Watts will be 12.5Watts) and then it goes into a rheostat that I can use to go from 12.5watts down to nothing. Tried bypassing the rheostat with a 3.3uF Capacitor but there was no difference, I'm guessing the cap isn't big enough or something.

So I was thinking about building an Airbrake to try but I have a few questions.

1. Will it actually enable me to play my Express at Bedroom levels?

2. I can switch between 4 and 16ohms on my 2x12 Cab, do I need to worry about impedance matching at high attenuation levels?

[vibratoking]

So I was thinking about building an Airbrake to try but I have a few questions.

1. Will it actually enable me to play my Express at Bedroom levels?

2. I can switch between 4 and 16ohms on my 2x12 Cab, do I need to worry about impedance matching at high attenuation levels?

1. You will get bedroom levels, but it will sound like shit. All guitar amps sound bad when they don't move enough air.

2. Not with an Airbrake. It's not matched to any impedance anyway.

You can search the forum on this. There are a lot of threads and you will get any and every answer you want. If you decide the answer is that it works, you build one, and then don't like it, remember I told you so.

[Colossal]

I built an Airbrake (specifically for use with an Express) and at what could be called 'bedroom' volume, let's call that low enough to be enjoyable but not loud enough to bother anyone, it just didn't cut it. I found it to be quite fizzy. It sucked the life out of the amp. Bummer.

[Littlewyan]

Well I understand that amps need to move air to sound good, but the tone just changes so much. With my 1Watt Marshall the built in attenuator uses the same design really, all except it uses carbon film resistors and they are completely different values to what my rheostat attenuator uses. Using the built in attenuator sounds good, however using my rheostat attenuator at the same level it sucks the tone to the extent that it sounds like I've lost distortion! All I can think of is its sucked the high mids out of the tone somehow so it just sounds empty.

With my 50W Marshall however I will say that it sounded good through the attenuator. The Express sounds ok, although I've never had a chance to crank the bugger without the attenuator yet so cannot compare. Soon I will be able to tho so will know for sure then if the attenuator kills the tone. I have heard about different attenuators sounding good/bad with different amps, I would love to know what makes this so.

[Gibsonman63]

JM2C, for the price of getting an attenuator to sound great at bedroom volume, you can build a nice sounding bedroom amp. I have an Express clone and an Airbrake that I built. It sound great down to about -12dB. You lose something with every click, though. I plan on building a couple more simple ones without the rheostat. The rheostat destroys the tone completely.

I installed a mercury magnetics mod kit on an Epiphone amp for a guy and it sounded great as lower volumes, but that was a fairly expensive way to go, but there are other ways to skin that one. I cheated and bought a 5W amp from PassFan at a very fair price.

[Hogy]

This works better than anything I know of:

http://www.thegearpage.net/board/showth ... ?t=1226066

[vibratoking]

That looks like a lot of work and equipment to get buzzing bees. I don't believe it matters how much equalization and processing you throw at that problem. If you're not moving air, then your screwed, IMO. Where's my Rockman?

[Hogy]

That looks like a lot of work and equipment to get buzzing bees. I don't believe it matters how much equalization and processing you throw at that problem. If you're not moving air, then your screwed, IMO. Where's my Rockman?

You could always try it and surprise yourself.

And like I said in the other thread, if playing around with music gear feels like "work", then maybe this isn't the right hobby for you.

It is no more complicated than the most basic pedalboard, and once it is set up it's plug and play.

[ubxf]

For 16 ohm output you recommend 25 ohm load
what about for 4 or 8 ohm output what would be the ideal load

[vibratoking]

That looks like a lot of work and equipment to get buzzing bees. I don't believe it matters how much equalization and processing you throw at that problem. If you're not moving air, then your screwed, IMO. Where's my Rockman?

You could always try it and surprise yourself.

And like I said in the other thread, if playing around with music gear feels like "work", then maybe this isn't the right hobby for you.

It is no more complicated than the most basic pedalboard, and once it is set up it's plug and play.

I know what happens when air doesn't move. I am sure you like your method

[Hogy]

I know what happens when air doesn't move.

This thread isn't about what you "know". The thread starter specifically asked for a way to play his Express copy at bedroom levels. The method I described works best for that purpose. Better than any attenuator I have tried. Better than any master volume.

Once you start "moving air", you're way past bedroom level, so that argument is utterly pointless.



Best way I can describe the result of my setup to those who don't already know everything and are still interesting in trying stuff is, it sounds like a recording of your amp. Some immediacy is (naturally) lost, but the tone is really great and very satisfying.

[vibratoking]

Once you start "moving air", you're way past bedroom level, so that argument is utterly pointless.

Thank you for making my point.

[ubxf]

Sorry to ask again but what would be the ideal load if the output is 4 or 8 ohm. Do i still go with 25 ohm or should i lower the value

[M Fowler]

Sorry to ask again but what would be the ideal load if the output is 4 or 8 ohm. Do i still go with 25 ohm or should i lower the value

I'm probably wrong but I would say increase the load resistor:

suggested 22R-16 ohm load=6

6 + 22R= 28R for 8 ohm load

6+ 28R= 34R for 4 ohm load


Mark

[Hogy]

Sorry to ask again but what would be the ideal load if the output is 4 or 8 ohm. Do i still go with 25 ohm or should i lower the value

You can safely use the same 25 Ohm load for an amp with an 8 Ohm output. Or you could go a bit lower and see how it sounds. For a 4 Ohm amp I'd definitely experiment with something like a 10 Ohm resistor. Honestly, I've never tried what sounds best with 4 Ohm, all my amps are 16 Ohm.