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Post by uncleebeneezer on Nov 23, 2009 21:11:51 GMT -7
Hey guys, my buddy was told that he can't use an attenuator with his Matchless Independence because it's a Class A and that it mess up the circuitry because Class A 's run so hot? What do you guys know about that sort of thing? It's a 35 W amp so I would guess that the Brakelite (or the Airbrake) would work for him but I don't know if what he was told about Class A's is truth or just a legend. Let me know what y'all think.
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Post by awesome on Nov 24, 2009 0:45:11 GMT -7
a few of the Doc's amps are biased close to Class A and it is fine with them. i've never heard of this problem, ever. if no one comes up w/ a definitive answer on here i would suggest contacting Matchless themselves, that would solve the confusion quick
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Post by hdahs143 on Nov 24, 2009 6:48:31 GMT -7
I think your buddy should make a simple phone call to Matchless, and speak with Phil Jamison, the chief designer and builder, and ask him.
It would seem to me that his is the only opinion that would matter, in particular if warranty is a concern.
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Post by bustertheboy on Nov 24, 2009 23:43:42 GMT -7
According to many people, very few amps including AC30's, Matchless et al, run close to Class A, but are in fact Class AB cathode biased. I'd agree with calling Matchless- it may be the issue of heat but also how the output transformer runs Brett
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Post by uncleebeneezer on Nov 29, 2009 14:14:10 GMT -7
For future reference, my friend said:
"I called Matchless and they said it has something to do with the output transformer. They said I can use one but it might shorten the life of my tubes considerably."
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Post by awesome on Nov 29, 2009 15:50:42 GMT -7
For future reference, my friend said: "I called Matchless and they said it has something to do with the output transformer. They said I can use one but it might shorten the life of my tubes considerably." well yes, but do they mean more than normal. if you run an amp at higher volumes the tubes will burn out faster. which if you use an attentuator then you will most likely be cranking it. not sure how the transformer would affect it, the Doc does have overbuilt transformers in all his amps so maybe this is why Z's can handle it.
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Post by benttop (Steve) on Nov 29, 2009 16:25:09 GMT -7
Think about it - they pretty much have to say that because every attenuator design is different, and may affect the amp differently. Without specific information on the loading of any given attenuator design, he'd be crazy to say it will work fine. First one he says that about and then blows up his design, he'll have a po'd customer and an amp to repair. By the way, remember with a Class A power amp, the amp is running wide open even when there is no signal to amplify. In fact, there is less current when the signal is present than when it is absent. Whether an attenuator works well with an amp is more about the impedance the attenuator presents to the output transformer than the power being dissipated. In this regard, each attenuator design has to be evaluated on it's own merits. If I've misstated any of this, please let me know.
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Post by hollywood88 on Nov 29, 2009 16:35:03 GMT -7
Well used properly and set correctly I've never heard of one burning up and amplifier....but like I said I've never heard of it.
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Post by uncleebeneezer on Nov 29, 2009 18:46:07 GMT -7
At this point, all I know is that it works great with my Z's!!!
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Post by Brian on Feb 22, 2010 11:28:31 GMT -7
AMEN to that!!!!!
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Post by Mostrummer on Feb 23, 2010 9:21:05 GMT -7
May not have any meaning for the issue, but the MiniZ is Class A and has a built in attenuator.
Also, when I first started using the Brakelite with a MAZ38 the power tubes burned out pretty quick, but the next set has been going strong for months. If your buddy tries it and the tubes burn out, it could just be that the tubes were on their last leg already...
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Deleted
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Post by Deleted on Feb 23, 2010 13:02:05 GMT -7
I never had good luck with the airbreak yet. Tried 2 of them. My amp would go along all right for about 10 minutes then completely shut down, no power, no nothing. Scared me off attenuators for good.
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Post by benttop (Steve) on Feb 23, 2010 13:11:35 GMT -7
I never had good luck with the airbreak yet. Tried 2 of them. My amp would go along all right for about 10 minutes then completely shut down, no power, no nothing. Scared me off attenuators for good. There has to be more to that story. I've played all of my Z amps through Airbrakes since the day they arrived. Never had any such issues, ever. In fact, my Stingray has never been gigged without the Airbrake on at least one click. It has literally hundreds of hours without any failures at all. So your double identical experience really perplexes me. There has to be something about your setup or gear that isn't part of your awareness.
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Post by dock66 on Feb 23, 2010 13:23:02 GMT -7
I have three Air Brakes that I run on three set-ups with different amps,so far they have been performing fine.Like Steve said,there has to be something else.I am curious to know what could be the culprit.Please share with us your finding.
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Deleted
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Post by Deleted on Feb 23, 2010 13:52:39 GMT -7
I never had good luck with the airbreak yet. Tried 2 of them. My amp would go along all right for about 10 minutes then completely shut down, no power, no nothing. Scared me off attenuators for good. There has to be more to that story. I've played all of my Z amps through Airbrakes since the day they arrived. Never had any such issues, ever. In fact, my Stingray has never been gigged without the Airbrake on at least one click. It has literally hundreds of hours without any failures at all. So your double identical experience really perplexes me. There has to be something about your setup or gear that isn't part of your awareness. I only tried it at home. Airbreak+Stangray+Telecaster. Everything worked fine with out the airbreak and still does. Airbreak #1 didn't shut my amp down. But it didn't sound very good. I didn't play with it too much and returned it to the store. About a month later I got to thinking that maybe I didn't give the airbreak enough chance. So I bought another one. The second time I didn't put it on bedroom level as that is where I thought the sound was really bad with the first one. So just clicking it down one or 2 didn't sound so bad. About 10 minutes in my amp just quits. No power, wouldn't turn on. This really freaked me out. About 10 or 15 minutes later I was able to turn my amp on. I don't know what happened but I wasn't in to troubleshooting it. At least not with my amp. It already felt like I dodged a bullet. I wasn't going to push my luck. Although again I'm in mind set that I'd like to try again except with my Mazerati. I really don't need the airbreak for the Ray as I like to run it around 3 (which I can do in my bands) for a clean sound. But I sure would like to run the the Mazerati around 12 to 1 oclock. And that just aint happening with out an airbreak. I don't know if I'll try another though as that episode with the Ray was scarey.
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Post by nori22 on Feb 24, 2010 6:17:43 GMT -7
that's odd
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daz
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Post by daz on Feb 25, 2010 23:05:49 GMT -7
If, like me you run your amps to the point of classic rock overdrive then I'd agree with your 1st scenario , Air Brakes don't sound very good past the 1st click of attenuation. I even adjust the 2nd click toward less attenuation to maintain the tone. Past that point the tone takes a nose dive ,and at bedroom level is hardly even a novelty. Other attenuators fare better in that area. That being said there's probably far more clean-er toned country-esque players than Les Paul classic rockers on this forum who would disagree.
Are you possibly running the amp noticeably harder when the Air Brake is connected ? I wonder if you might have a power tube or bias issue that only shows itself under a heavier work load. On a ship gig I was given a Twin reissue that sounded 'fine' at low volume, and was used daily by a solo instrumentalist. I turn it up to play rock and roll and it all goes to heck.Only 1 power tube worked.At low volume / easy work load nothing sounded obviously wrong.
So far as the original post : My RXES sounded ok with 1 or '1 1/2' click of an Air Brake, but not very good at 1 click on a Hot Plate. It's the only amp out of many I experienced sounding bad with that same THD.
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Post by benttop (Steve) on Feb 26, 2010 8:19:34 GMT -7
If, like me you run your amps to the point of classic rock overdrive then I'd agree with your 1st scenario , Air Brakes don't sound very good past the 1st click of attenuation. I even adjust the 2nd click toward less attenuation to maintain the tone. Past that point the tone takes a nose dive ,and at bedroom level is hardly even a novelty. Other attenuators fare better in that area. That being said there's probably far more clean-er toned country-esque players than Les Paul classic rockers on this forum who would disagree. Are you possibly running the amp noticeably harder when the Air Brake is connected ? I wonder if you might have a power tube or bias issue that only shows itself under a heavier work load. On a ship gig I was given a Twin reissue that sounded 'fine' at low volume, and was used daily by a solo instrumentalist. I turn it up to play rock and roll and it all goes to heck.Only 1 power tube worked.At low volume / easy work load nothing sounded obviously wrong. So far as the original post : My RXES sounded ok with 1 or '1 1/2' click of an Air Brake, but not very good at 1 click on a Hot Plate. It's the only amp out of many I experienced sounding bad with that same THD. The trouble is, we're comparing apples and oranges. The Z amp in question is cathode biased. The power tubes are running wide open at idle, and only start to cool off when the guitar's signal arrives. Conversely, that Twin is a Class A/B push pull fixed bias amp. The tubes are idling with no signal, and start to work hard when the signal arrives. They are quite opposite in this respect.
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daz
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Post by daz on Feb 26, 2010 15:59:02 GMT -7
The trouble is, we're comparing apples and oranges. The Z amp in question is cathode biased. The power tubes are running wide open at idle, and only start to cool off when the guitar's signal arrives. Conversely, that Twin is a Class A/B push pull fixed bias amp. The tubes are idling with no signal, and start to work hard when the signal arrives. They are quite opposite in this respect.
Aaah yes, it's a Stangray,I overlooked that.Hmm.Why would it react negatively to being used with an Air Brake ? The plot thickens !!
Back to the OP point on Class A and attenuation; With a THD Hotplate my RXES and my mate's Matchless DC30 didn't sound so good. Even at the 1st 4db click they lost their air and chime. However both sounded fine with light (1 click) Air Brake attenuation. That same Hotplate worked great even at 8db and very infrequently 12 db cut with Marshalls, Traynors, Fenders and a Z28 for the past 12 years. It seems amp type and certainly how we personally run them respond differently to each attenuator type.
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Post by bustertheboy on Feb 27, 2010 13:33:33 GMT -7
Sorry to open a can of worms, but are Matchless truly Class A? Most amps which say this including Vox AC30's are just cathode bias, biased "towards Class A". This stands for a lot of the Doc's amps. He makes no such claims. I do know that Matchless amps tend to run hot. Brett
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