Yeah it's there. I accidentally hit it with my iron when rewiring it. It's superficial though...meaning it's not very deep, and I was too lazy to change it. Hey, it's just an airbrake.Structo wrote:What is the AB III?
I know this is a shot in the dark but I was looking at the photos and noticed what appeared to be some melted insulation on one of the wires to the switch.
Like the terminal below it got hot and melted it.
Could it be possibly shorting into the wire that is melted?
I circled it.
DIY Airbrake...
Moderators: pompeiisneaks, Colossal
Re: DIY Airbrake...
Re: DIY Airbrake...
OK, one last thought here....
Do you notice that you are counting the numbers BACKWARDS on the switch? The numbers count clockwise, 1-12, and you are counting 12-1.
If you take a look at the Lorlin data sheet, like this:
http://www.lorlinelectronics.com/pdf/CK.pdf
What do you think about this? If your friend's box works perfectly, I would still have to think that he might be one lug off - and here working backwards, the switch would still perform correctly.
OK, I hope this helps.
Do you notice that you are counting the numbers BACKWARDS on the switch? The numbers count clockwise, 1-12, and you are counting 12-1.
If you take a look at the Lorlin data sheet, like this:
http://www.lorlinelectronics.com/pdf/CK.pdf
What do you think about this? If your friend's box works perfectly, I would still have to think that he might be one lug off - and here working backwards, the switch would still perform correctly.
OK, I hope this helps.
Most people stall out when fixing a mistake that they've made. Why?
Re: DIY Airbrake...
Oh, wait a minute... I see that it says it is supposed to be backwards! And mine is, too, actually, although I don't have the Lorlin. Sorry about the confusion on my part.
So I guess I am still thinking that you are one lug off in the sequence perhaps. Maybe no help at all then if you are sure you are correct here...
So I guess I am still thinking that you are one lug off in the sequence perhaps. Maybe no help at all then if you are sure you are correct here...
Most people stall out when fixing a mistake that they've made. Why?
Re: DIY Airbrake...
You don't use the numbers you use the sectors of the switch as we have found that some switches are numbered completely different from others even though we all used the same part number on the BOM.
I had this issue and resolved the wiring problem on earlier posts.
I had this issue and resolved the wiring problem on earlier posts.
Re: DIY Airbrake...
Yeah, it does count backwards, which is a little weird to me. I don't like how the "clicks" work counter-clockwise too. Perhaps I should just wire it backwards so that the rotary works clock-wise, from 0 to max attenuation.rooster wrote:Oh, wait a minute... I see that it says it is supposed to be backwards! And mine is, too, actually, although I don't have the Lorlin. Sorry about the confusion on my part.
So I guess I am still thinking that you are one lug off in the sequence perhaps. Maybe no help at all then if you are sure you are correct here...
If I'm off a pin, as you suggest, Rooster, then it's beyond me how this could be. For I have pins 1 thru 3 bridged together. They're just all connected with a a piece of wire. You can see this in my pics. And this is just like AB III schematic below....and the Dr. Z AB layout below (albeit the Dr. Z has pins 1- 5 bridged together).
I'm ready to build another amp. These AB's are too hard.
You do not have the required permissions to view the files attached to this post.
Re: DIY Airbrake...
I have other layouts done by Barry (Bnwitt) besides the one you posted that Barry and I went over due to my problems with inconsistence numbering on the switches.
When a member asks me to mail them data I always provide about 3 different layouts so they know there can be that numbering problem and to avoid it by dividing the switch into the sectors and then use the numbers that are within that sector.
Mark
When a member asks me to mail them data I always provide about 3 different layouts so they know there can be that numbering problem and to avoid it by dividing the switch into the sectors and then use the numbers that are within that sector.
Mark
Re: DIY Airbrake...
Here is another version.
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Re: DIY Airbrake...
Ok, I completely re-wired my AB last night. I disconnected the rotary switch and turned it 180 degrees so that the hook up for pins 12 and 11, became 6 and 5, etc...
It works perfectly. First click registers about 13.7 ohms, and the remaining clicks bounce around 8 and 9 ohms. Yeah. Fixed and done.
It works perfectly. First click registers about 13.7 ohms, and the remaining clicks bounce around 8 and 9 ohms. Yeah. Fixed and done.
Re: DIY Airbrake...
Good job Ron and it tested well too.
Re: DIY Airbrake...
Cool, and thank you Mark for the switch info - that was good input.
Most people stall out when fixing a mistake that they've made. Why?
Re: DIY Airbrake...
Rooster you welcome finally I contributed something.
Re: DIY Airbrake...
I made the Airbrake, but as I understand, this schematic is more suited to an 8 ohms load.. My speaker is 16 ohms, so when I use the Airbrake it is not very effective... So I gues it means I have to change the two main resistors.. Anyone know what would be the ideal values for a 16 ohms load?..
Thanks
Thanks
Re: DIY Airbrake...
Here's a spreadsheet that can be used to see the results of tweaks on the Airbrake resistor values. Should keep you busy for hours!
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Re: DIY Airbrake...
I'm a bit late, but probably not too late
So, measurments shows as follows:
AB III - 8 Ohm (7,5 Ohms measured) speaker connected:
7 Ohm
8,9 Ohm
7,9 Ohm
8,6 Ohm
9,4 Ohm
AB III - 16 Ohm (13,4 Ohm measured) speaker connected:
8,8 Ohm
10,1 Ohm
8,4 Ohm
8,9 Ohm
9,6 Ohm
AB with rheostat (no 8 Ohm res.) - 16 Ohm speaker connected:
8,7 Ohm
11 Ohm
12,5 Ohm
13,7 Ohm
15,3 Ohm (rheostat full - 22,4 Ohm)
AB with rheostat (no 8 Ohm res.) - 8 Ohm speaker connected:
5,7 Ohm
8,5 Ohm
10,6 Ohm
12,1 Ohm
14,3 Ohm (rheostat full - 22,3 Ohm)
All parts from BOM, switch is now clock wise running (bypass-full) - thanks for this idea.
[img1704]http://www.moj-album.com/slike/5302071/ ... bgFd0t.jpg[/img]
[img1704]http://www.moj-album.com/slike/5302071/ ... BsEV5f.jpg[/img]
[img1704]http://www.moj-album.com/slike/5302071/ ... _2CHb2.jpg[/img]
So, measurments shows as follows:
AB III - 8 Ohm (7,5 Ohms measured) speaker connected:
7 Ohm
8,9 Ohm
7,9 Ohm
8,6 Ohm
9,4 Ohm
AB III - 16 Ohm (13,4 Ohm measured) speaker connected:
8,8 Ohm
10,1 Ohm
8,4 Ohm
8,9 Ohm
9,6 Ohm
AB with rheostat (no 8 Ohm res.) - 16 Ohm speaker connected:
8,7 Ohm
11 Ohm
12,5 Ohm
13,7 Ohm
15,3 Ohm (rheostat full - 22,4 Ohm)
AB with rheostat (no 8 Ohm res.) - 8 Ohm speaker connected:
5,7 Ohm
8,5 Ohm
10,6 Ohm
12,1 Ohm
14,3 Ohm (rheostat full - 22,3 Ohm)
All parts from BOM, switch is now clock wise running (bypass-full) - thanks for this idea.
[img1704]http://www.moj-album.com/slike/5302071/ ... bgFd0t.jpg[/img]
[img1704]http://www.moj-album.com/slike/5302071/ ... BsEV5f.jpg[/img]
[img1704]http://www.moj-album.com/slike/5302071/ ... _2CHb2.jpg[/img]
taking readings
Can you please clarify where the readings are taken. There is a jack cable that connects the output to to the AB then the jack cable that goes from the AB to the speaker.