attenuator airbrake

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colossal
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Re: attenuator airbrake

Post by colossal »

JimbpGaff wrote:
Tue 05/12/20 2:58 am
Great info.

not sure if I missed it in the threads but is this for a 16 ohm load and how much attenuation will it give.
Jim
As Josh said, the attenuator will "work" for 4 and 8 ohm loads, but is best suited for 16. See the first page of this thread for a plot of impedance vs. attenuation.
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Re: attenuator airbrake

Post by JimbpGaff »

Can I use a different value Rheostat ?
The 150 ohm 50 watt is hard to come by at the moment in the UK as they all seem to be on back order until the end of the year.
Jim
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Re: attenuator airbrake

Post by colossal »

JimbpGaff wrote:
Wed 05/20/20 12:36 am
Can I use a different value Rheostat ?
The 150 ohm 50 watt is hard to come by at the moment in the UK as they all seem to be on back order until the end of the year.
Jim
You can. Lower values will limit attenuation. Higher values will increase it at the expense of increasing impedance.
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Re: attenuator airbrake

Post by JMPGuitars »

colossal wrote:
Wed 05/20/20 8:05 am
JimbpGaff wrote:
Wed 05/20/20 12:36 am
Can I use a different value Rheostat ?
The 150 ohm 50 watt is hard to come by at the moment in the UK as they all seem to be on back order until the end of the year.
Jim
You can. Lower values will limit attenuation. Higher values will increase it at the expense of increasing impedance.
Limiting attenuation isn't a bad thing, since there will be less tone sucking that way. BUT there's limited options in that price range. I looked at alternatives, and they get pretty expensive. The RJS125E for example is 125 ohms, and $80. Some other variations were hundreds of dollars.

Personally I got a couple of the RJS150Es on eBay for $40 a piece. There is a seller in the UK selling the 150 also, but not as cheap. The 125 is available on there too, but I dunno about in the UK.

Thanks,
Josh
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Re: attenuator airbrake

Post by JimbpGaff »

Thanks Josh

Just found the one on ebay for $77.00.

A lot of money in these difficult times .

I will have to do some thinking .

The pure resistor attenuator is a cheaper option, But.....
Jim
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Re: attenuator airbrake

Post by JMPGuitars »

JimbpGaff wrote:
Thu 05/21/20 1:52 am
Thanks Josh

Just found the one on ebay for $77.00.

A lot of money in these difficult times .

I will have to do some thinking .

The pure resistor attenuator is a cheaper option, But.....
Jim
Yeah, it's not cheap. But it's only $14 more than Mouser sells it for if you can't wait for people to have it in stock. On the other hand, you could build this attenuator without the rheostat, and use the switched section until a better deal on the rheostat becomes available. You can increase the resistance for the lugs and have the switched section attenuate at higher levels in the meantime.
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Re: attenuator airbrake

Post by JimbpGaff »

Thanks Josh.

I will do some thinking .
Jim
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