attenuator airbrake
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- crgfrench
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Re: attenuator airbrake
Here is the same circuit that JMP built and that I drew from the Audiofanzine picture. I found this schematic on The Amp Garage, it was posted by bnwitt, Sat May 07, 2011 at 11:15 pm in the "Airbrake schematic or layout" thread. This is identical to my schematic of the JMP layout, just a slightly different visual.
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- crgfrench
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Re: attenuator airbrake
Honey Hush!
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- crgfrench
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- crgfrench
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Re: attenuator airbrake
Honey loves her knobs. Big knobs, small knobs, whatever.
But which are the BEST knobs for Honey?
A) Blue Chickenhead
B) Silver Aluminum
C) Black Aluminum
D) Skirted Oven Dial
But which are the BEST knobs for Honey?
A) Blue Chickenhead
B) Silver Aluminum
C) Black Aluminum
D) Skirted Oven Dial
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Re: attenuator airbrake
I think D fits the motif best.
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Re: attenuator airbrake
WOW, I just stumbled onto this thread. I just picked up the pieces for making two of these Airbrakes minus the rheostat only because they're not available. I'll likely build one up with the gold resistor in place of the stat for now. NICE examples. I was simply going to use the layout as posted in the very beginning of this thread, but would you recommend one of the others? Need to re-read this to find out.
The Honey Hush graphic is awesome, man!
The Honey Hush graphic is awesome, man!
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Re: attenuator airbrake
This is the project doc I made for it: files/JMPGuitars_Break_Wind_Attenuator.pdfViperDoc wrote: ↑Thu 10/01/20 5:59 pmWOW, I just stumbled onto this thread. I just picked up the pieces for making two of these Airbrakes minus the rheostat only because they're not available. I'll likely build one up with the gold resistor in place of the stat for now. NICE examples. I was simply going to use the layout as posted in the very beginning of this thread, but would you recommend one of the others? Need to re-read this to find out.
The Honey Hush graphic is awesome, man!
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Re: attenuator airbrake
The next ones I build are only going to have the rheostat, the switch doesn't really do much sonically -- 2dB cuts are kind of worthless IMHO; it's once you get to the -10dB to -30dB range that actually accomplishes meaningful volume attenuation.
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Re: attenuator airbrake
You're missing two things:
1. The 2db cuts can be set higher by where you position the tabs.
2. Those 100W resistors are what make the attenuator rated for 100W. Even if you skip the tabs, you still want the resistors to handle the power. The rheostat alone might be enough for an 18watter, but I wouldn't go higher than that without the fat resistors in there.
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Re: attenuator airbrake
Exactly. The 2 big ohmite hot dogs and the ohmite rheostat.
No lorlin switch.
Here's a schem and layout.
No lorlin switch.
Here's a schem and layout.
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Re: attenuator airbrake
Save some dough too!
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Re: attenuator airbrake
Note, this version has no bypass mode.
So it's going to be -10dB to -30dB output. No full strength.
You could stick a DPDT switch where the Lorlin normally goes and have a bypass mode.
So it's going to be -10dB to -30dB output. No full strength.
You could stick a DPDT switch where the Lorlin normally goes and have a bypass mode.
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Re: attenuator airbrake
So I built one of these and have It between my 100W head and 4x12 stack. Intrestingly, the Ohmite 100W resistor on the ground side is heating up like Satan's pocket watch. Is this normal? do I need to cut air holes in the side of this thing? Should I be considering thermal compound?
The other resistor isn't getting as hot and the Rheostat is staying cool also. Just that ground resistor is heating up.
It works great, cranked the amp and on bypass it brought my son and the dog both downstairs to investigate. Cranked up the resistance and we could almost carry on a conversation.
The other resistor isn't getting as hot and the Rheostat is staying cool also. Just that ground resistor is heating up.
It works great, cranked the amp and on bypass it brought my son and the dog both downstairs to investigate. Cranked up the resistance and we could almost carry on a conversation.
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Re: attenuator airbrake
Some people say to use an attenuator rated for double the wattage of your amp, especially if you're going to be attenuating a lot, or for extended periods.BlueBoozer wrote: ↑Sun 10/11/20 7:46 pmSo I built one of these and have It between my 100W head and 4x12 stack. Intrestingly, the Ohmite 100W resistor on the ground side is heating up like Satan's pocket watch. Is this normal? do I need to cut air holes in the side of this thing? Should I be considering thermal compound?
The other resistor isn't getting as hot and the Rheostat is staying cool also. Just that ground resistor is heating up.
It works great, cranked the amp and on bypass it brought my son and the dog both downstairs to investigate. Cranked up the resistance and we could almost carry on a conversation.
You could try leaving the cover plate open, and see if that has a meaningful effect on the heat issue before drilling any vent holes.
I'm using this with 18W to 40W amps. I don't think I would go above 50W.
Thanks,
Josh
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Re: attenuator airbrake
alrightythen. I'll just use it with my 18 and 50 watt heads. Thanks
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Re: attenuator airbrake
I've used it on 18W and 36W, never noticed much heating but I didn't test extensively at cranked volumes with the 36. Never used on any amp over 36 yet...
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Re: attenuator airbrake
With 25 Ohm R1 & R2, You won't get more than -8dB of total attenuation unless you switch on the Rheostat. The first 2dB comes from switching in R1, and the next 6 comes from switching in R2. No real audio value in shoving all the tabs together, for example, to increase one of those 3 cuts at the expense of the others. You won't get more than 6dB total out of R2. So if you increase the cut of first tab by sliding it to add resistance, you're just robbing the other 2 tabs of reduction ability.JMPGuitars wrote: ↑Fri 10/02/20 6:39 am... The 2db cuts can be set higher by where you position the tabs...
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Re: attenuator airbrake
There is an impedance mismatch for any given level of attenuation but 16ohm is the least mismatched.
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