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Post by doveman on May 19, 2012 5:10:04 GMT -7
I have been doing some research on this attenuator. I ordered a Dr Z Brake Lite for my recent Route 66 head acquisition. I found an old thread at TGP that included info from Randall Aiken. The BL is advertised as 4-8-16 ohm ... all reasonably safe ... but there are differences. For example, the effective attenuation is apparently doubled for 4-ohm cabs and halved for 16-ohm cabs. So for the 1-2-3-4 settings respectively: 8-ohm cabs (as advertised) - 2db-5db-8db-11db 4-ohm cabs (attenuation doubled) - 4db-10db-16db-22db 16-ohm cabs (attenuation halved) - 1db-2.5db-4db-5.5db How does the Brake Lite actually perform with 4-ohm or 16-ohm cabs ... volume and tone? Are the 1-4 settings any more or less useful? Maybe these differences are actually an opportunity?
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Post by Mark (Basement Enthusiast) on May 19, 2012 7:14:42 GMT -7
BUMP... because I could swear that I just read a Z-Talk post about this yesterday. But then my computer later crashed, I lost where I was at, and for the life of me I cannot find it anymore. But I remember it distinctly because the Excel spreadsheet was awesome (I'm a spreadsheet guy). If anybody finds that one, could you maybe link this thread over to it..?
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Post by doveman on May 19, 2012 7:26:29 GMT -7
I deleted it and reposted it in a simpler form. I posted it in three forums yesterday and got no response. So I thought I'd simplify it to the basic question and see if I got a response. Here's the jpeg ... the spread sheet was from data I copied off the original TGP thread from Randall Aiken here: www.thegearpage.net/board/showthread.php?t=327189Sorry ... sometimes I get too complex but I still think this is kind of cool info. My Brake Lite should be here Monday per the UPS tracker. So maybe I can answer my own question soon. Thanks for the interest.
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Post by benttop (Steve) on May 19, 2012 8:09:31 GMT -7
I thought it was interesting too, but didn't have time for a response at that time. I'll be interested in your findings, if you intend to validate the information. It definitely appears if you have a couple of cabs you can get more or less effect just by the way you wire them - that would be fascinating and useful.
The problem I see is that in order to manipulate your speaker impedance, you have to use more than one speaker, which itself changes the SPL. Lots of variables to contend with here...
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Post by doveman on May 19, 2012 8:28:53 GMT -7
I have a 2x12 cabinet loaded with a Celestion G-1265 and a Scumback M75 that I'd like to use with the amp. I can run 4-ohm or 16-ohm with both speakers or 8 ohms with either speaker. Via this contraption ... pretty nice But if I find a real advantage to 4-ohm or 16-ohm, I might permanently wire the Brake Lite in at one or the other to make it easy. If I find that the 8-ohm is better, I might use my 1x12 EVM12L cabinet ... that thing is a real winner with my Brown Note but it's louder (see it in the back of picture). Both cabs actually match the look and dimensions of the Route 66 head. Anyway ... experimenting this week. I just figured someone had stumbled on this before and might have some Brake Lite experience with 4-ohm or 16-ohm cabs they might share.
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Post by Mark (Basement Enthusiast) on May 21, 2012 6:49:12 GMT -7
doveman, I'm getting some different values for "effective ohms" than you for the 4- and 16-ohm cabinets. We must be reading Mr. Aiken's chart differently... which isn't surprising because it's a little wonky, as benttop (Steve) pointed out in the original TGP forum thread. I'm working-up a spreadsheet like yours to compare—I'll double-check my numbers again and then post to see if we can figure this out a little better.
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Post by doveman on May 21, 2012 7:29:04 GMT -7
UPS just delivered the Brake Lite ... first thing I did was hook it up and just get the direct ohm readings from the meter. I know the readings on a meter are generally slightly lower but it indicates that the values change significantly and are "ball park" with the meter.
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Post by doveman on May 21, 2012 13:33:43 GMT -7
Well I spent about half a day playing with the RT66, Brake Lite, and the 2x12 speaker cab in all kinds of configurations. I also tried the 5U4 rectifier (although I could not rebias) and the 5A4. Here's what I learned: - Geez ... this thing is loud ... I can easily hit over 100db on just about anyway setting ... just leaving the meter in the center of the room. I'm about deaf. LOL
- The meter I have can't really capture averages ... just short and fast averages that continue to move all over the place. Not very useful. I did take a bunch of measurements 1 meter from the cab with the MAX ... but they were pretty close all the way through the test. Sort of useless because the cab was getting quieter ... but showing only 5-8 db difference from top to bottom on the max.
- An EVM12L with this thing is deadly ... even a 1x12 EVM is just too much ... the weaker speakers are better even two at a time. I think even a 1x12 with the weaker speakers would be better ... but I don't have an extra one.
- As most report, the first two clicks 1 & 2 are the better sounding ... doesn't really matter the ohm configuration ... so I don't think what I read about Db halving and doubling is real world. Although it makes sense ... doesn't match what I heard with my own ears.
- I do think the effective loads vary like I have them on the spreadsheet ... but even though they swing widely ... probably reasonably safe. The 4-ohm setting probably the most risk at high clicks 3 & 4.
- I think the 8-ohm 1x12 Scumback and the 2x12 4-ohm combination sound the best ... using only the first two clicks of the Brake Lite. The Brake Lite would be handy and necessary in most venues. Again the 1x12 is probably enough if I had one.
- I think I like the 5U4 a bit more than the 5A4 and it would probably be better if I could figure out how to bias it properly. But the 5A4 is tighter and that is good too.
Not sure how to set it up for my best use for me ... but will think about a few things ... then decide. I will have to work on it a bit to make it work for me but it's clearly the loudest amp I have now ... too loud I think. It may not be the amp for me but I have more to do before I'll know for sure.
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Post by benttop (Steve) on May 21, 2012 16:17:04 GMT -7
Nice! Thanks for all of the effort. Now try one more thing - just humor me. It is my contention that guys don't like positions 3 and 4 because of physiological affects. When you start full volume, on thru, and then move to position 4, your brain tells you something is missing. When you have not been playing, and your ears are fresh, set the Brake Lite to position 4, THEN turn on the amp, and set it for the best tone you can manage. You will be amazed - it will sound great. Try it. THEN, turn up to click 3, and it gets better. And it's even better on 2 and 1, etc. The point, of course, is that it DID sound great on position 4. Honest - you will be shocked. It is not fakery.
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Post by doveman on May 21, 2012 17:46:03 GMT -7
Thanks ... I will give it a try ... I did play a bit through 4 this evening. Sounding best with just one speaker but probably on about 8:00 ... so pretty low. I will have to try this tomorrow when I have the house to myself and can cut loose again. But worth a try. The one thing about setting 4 is the effective ohm load ... bothers me a bit if I set this thing up for 4-ohm across the board. What might be nice is to have the amp set up to easily do one 8-ohm speaker with the BL but if you need a fuller sound, add the other speaker in parallel 4-ohm mode and stay away from setting 4. But that should be no problem because you thought you needed a fuller sound anyway. This is where my thoughts are right now. Edit: The 4-ohm cab setting does seem to have at least a bit more attenuation at the high settings ... still relatively safe because the BL is a resistive load. The 4-ohm load cab just sounds better to me through the frequency range ... less constricted. So ... I think I'm going to simply set up the cab for 4-ohms with the BL mounted in the cab and tied betweed the speakers and jack plate. I like the idea of starting at the higher levels and finding the best sound then reducing attenuation ... worth trying.
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Post by Mark (Basement Enthusiast) on May 25, 2012 11:48:04 GMT -7
Nice! Thanks for all of the effort. Now try one more thing - just humor me. It is my contention that guys don't like positions 3 and 4 because of physiological affects. When you start full volume, on thru, and then move to position 4, your brain tells you something is missing. When you have not been playing, and your ears are fresh, set the Brake Lite to position 4, THEN turn on the amp, and set it for the best tone you can manage. You will be amazed - it will sound great. Try it. THEN, turn up to click 3, and it gets better. And it's even better on 2 and 1, etc. The point, of course, is that it DID sound great on position 4. Honest - you will be shocked. It is not fakery. Steve—I've seen you post this suggestion elsewhere about starting at a higher number THEN coming down. I think it's a very sensible approach (I'd try it myself, but I don't own an Air Brake or BL.. only a MiniMASS). In fact, the Doc himself pretty much endorses this method on his web page. Check it out: ...the beginning of the night (when the club isn't full) click the Air Brake to a level of attenuation to allow for smooth tone at a lower volume level. As the night progresses, reach back and remove degrees of attenuation until the desired level is reached. This will allow you to manage your amp's overall volume without varying from your amp's favorite settings.
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Post by benttop (Steve) on May 25, 2012 12:37:35 GMT -7
Interesting... I hadn't noticed that. Cool!
Sent from my SGH-T959V using ProBoards
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