45 posts
So I'm jamming away, uber into hotplate... and I smell that smell you never want to smell.
no, not that... burning electrical components!
ugh, the hotplate was literally smoking - a lot.
powered down, email off to THD Electronics to see if there is a repair option or whatever.
never heard of this happening, kinda thought they were indestructible.
oh well.
dang... well at least it's not the Uber!
I'd say I never heard of it happening but I don't want to jinx myself.... :o Hopefully they can get it rightened for you.
Sorry about that Ironsheep.. :o
Fortunately you were using an analog device! If you were using a digital cab emulator the entire harddisk would be burned! :)
I've been considering one of these for several years now. (basically, forget about getting one used for a good price on ebay! WHich I guess says a lot for how good they must be... ) Anyway, never heard of this here or at TGP where they are discussed OFTEN.
Hope it's a simple fix. Are you're ears still up for the volume without it? :D
well, I have a 16 ohm spare if necessary ;)
yeah, I searched around and didn't see this anywhere. I read the manual (afterwards, of course) and it's probably just that I hit it with too much sustained power and blew it up - I was trying ch. 2 max volume with a little master cut... but apparently not enough master cut!
took it apart to see, should be fixable - a white rectangular something or other right after the amp input looks to be the blowup-ee.
verified that the uber is fine, so no biggie... just weird! I mean, literally, white smoke coming out!! freaked me out!
can you take a pic of this white mystery part? :)
in theory, yeah... but I put it back together already, so it's not too likely ;)
it had stuff that now smells like burnt solder flux and plastic in it... if that helps. white plastic rectangular box about 1/2-3/4 inch long... two legs to the board.
It's a wirewound cermet resistor... that's basically all these things are, networks of big resistors. A cermet resistor of the right wattage and value will be pricey (as far as resistors go at least--$1-2) but not as pricey as a new hotplate. Open it up, take a pic of all the numbers on it, there should be a wattage listed, something like 5 or 25, and some other numbers that tell you the actual resistance. Either take a pic or write everything down, then you can do the replacement yourself.
Honestly, I'm more concerned about "why" than the burnt part... are you making sure the hotplate has airflow around it? Maybe lift it off the surface it's on a few inches with some supports? maybe another heat sink--attach a big block of metal to the bottom, or point a small fan at it...
Another thing to remember, it's best to double the wattage if you are actually using the hotplate for an extended period, or running the amp full out... with a 100 watt amp, a 200 watt hotplate.
Also, if you smell burnt plastic, the board could be burnt too... that would suck. Resistors can withstand sustained heat much longer than the board I'd guess. Still, not a hard repair... even if a trace on the board is gone you can always run wire.
wirewound cermet resistor should be good to 155C, I'd guess 130C sustained... that's extremely hot for it to get in there, other parts might be burned... give us a gut shot...
I think this is the root of it: "Continuous power dissipation: 150W RMS"
running the power stage flat out and saturated was a pretty bad idea ;)
I'm not going to even think about fixing this myself - way too risky with an amp on the line if I don't get it right. $15 part could cost me a $2k amp... I'll pass! If THD will fix it for me, great - otherwise, I have another I can use. If they won't do the repair, maybe I'll ship it off to one of you who are interested and you can mess around with it - it'd just be a paperweight to me at that point.
hmm, maybe I'll just get my favorite mic from the redwirez set (AKG C414B-ULS), go back to mic'ing and call it a day. heh.
It's a $1 part... if THD won't fix it ship it to me!
The most I have run flat out into my THD (16 ohm) is 50 watts (marshall dsl 50)and even then the damn thing got really hot, which is why it's called a hot-plate I suppose :) but it does say in the leaflet that comes with it that top whack is 150w continuous ?
yeah:
III. Input: Impedance: Depends on model. - Continuous power dissipation: 150W RMS - Max. recommended amplifier power: 185W RMS.
but I suspect the rules for speakers apply - only really safe if you're twice the stated output of the tube amp. the uber is 120 watts but what it's capable of putting out is probably higher. to quote the promo material:
"UBERSCHALL" the German word for "Super Sonic", is really ARMAGEDDON IN A BOX!! Everything this amp touches is Chernobylized! Instant nuclear meltdown, VAPORIZED...
I thought Reinhold was just kidding. ;) ;D
I have read more than once that THD (and other people who make these too) recommends that you get a model that handles twice the power of the wattage rating of the biggest amp you want to use with it.
but they don't make them that way :(
THD doesn't, anyways - you can get different ohm handling models but not watts, afaik. might be available from another manufacturer though, no idea.
what I was thinking of doing is: get another 16 ohm model and running two (both 16 ohm) at the same time, each on it's own speaker output from the amp (amp set for 8 ohms, outputs are in parallel). that should split the load between the two, if I'm thinking correctly, and prevent this from being an issue even if I max the amp's output.
Other manufacturers DO rate theirs with wattage as well (my Weber Mass was a good example), however, looking at the tone curves you'll see that the Hotplate tends to be the best at preserving the tone.
The problem you will always face with any attenuator has to do with that 'ol Fletcher Munson curve and how we hear things at different sound levels. Anything that sounds good to us at lower levels will have too much bass and treble when turned up. Now if you're only using the Hotplate (et al.) to get down to about 80-85 dB then you should still be good and what sounds good will remain good!
Here's my usual FM crap I post about once every three months:
http://www.nwdreamer.com/misc/FletcherMunsonCurve.doc ;D
problem is that the uber is a 120W amp... so I'd be looking for a 240W MASS, that he doesn't make. ;)
200W would probably be fine though - 180W would be the bare minimum (150%) but, apparently, I can get it to peak over 185W -- and I don't know how much over that it went when it roasted.
there's a picture of a resistor that looks just like the one that blew up on the Weber page though, so that's confirmed - unknown is whether there was any collateral damage.
a few solutions I've thought of so far:
1) run two Hotplates
2) take out two of the output tubes and make it a 60W amp - it's unknown to me if this is wise with this amp... looking into it.
3) use a single Hotplate and be careful (what I'm doing now... but not a real solution)
as far as how the load box sounds... I don't really care that much. I'm not mic'ing the output - I'm recording the output from the amp's line-out. the speaker motor load thing on the weber page is interesting though... that might make a tonal difference at the line-out even if it's in load mode.
https://taweber.powweb.com/weber/mass200.htm
200 watts... The Weber MASS is a pretty cool little attenuator, we've got a much smaller one and it's got some nice features, the speaker motor used to provide the load is kind of brilliant, and the ability to switch 4/8/16, a 3 or 6 db treble boost compensation. This one's impedance neutral so you can go 4/8/16 with it without a switch.
From the web "With the resistors, more often it's the contact glue they use to hold them in place which often fails and emits a noxious odor and sometimes even begins smoking."
Weber, it turns out, is practically a neighbor - heh, never knew they were 40 miles away from here.
The MASS 200 looks like a winner to me - cool features and it's cheaper than another Hotplate.
+1 for the luck it wasn't the amp!
I've been tempted by the Weber Mass series as well, gets lots of great word of mouth on most of boards.
We've got a Scholz attenuator, a Weber Mini Mass, and a Hotplate. The Scholz pretty much sucks (but was cheap), the Hotplate is decent, and the Mass is our favorite. I'm thinking about building a DIY Mass.
Talk to Weber I'm pretty sure they could make you a 240w (or whatever) MASS pretty easily. They seem very willing to do things like that. As for taking out two power tubes, that should work to a degree, but there's some weird math that happens and you don't actually cut the power in half. You'd be better off for what you're doing just leaving the Uber alone and resolving things another way.
Taking out two tubes does cut the power in half... not the volume, though. I think a 200w attenuator would be fine--how often will you be diming the master anyway? Your tubes won't last all that long that way, and it puts a lot of stress on the components...
I'm diming the master all the time! I rarely use it on the uber - the channel volume control sets how much juice the output tubes get - I don't normally feed them that much to preserve headroom. the hotplate died when I decided to hear what the uber sounded like with a swamped output section (channel volume up around 3 or 4 o'clock - I normally run it at about 9 or 10 o'clock). I don't need to run it that way, so a repeat is probably not going to happen. a 200W attenuator would be great for piece of mind.
I do run the flexi dimed to 11 and beyond, though. it's a tank.
Sheep - while we're sorta on the subjet, you have one of the e609 mics...which is it, the older black version or the newer silver model? Thanks.
Cool. Been reading about the silver, seems like some like them, some hate it. Thinking about picking one up. Thanks.
it's fairly sm57-ish, just fyi.
Thanks. That's what I'm hearing...all three of those affordable dynamics (e609, sm57 and i5) are all in the same ballpark, nothing drastically different anyway. I love my e906, will never get rid of it, just want to add a second mic to slap right beside it on the same speaker. I was never a big fan of the 57 for some reason. Leaning towards the 609s. The Heil PR30 and Cascade Fathead cost a few more but I may give one of them a chance if I get the 609 home and it doesn't happen to play nicely with the 906.
if I go back to micing - I think this is the mic I'll try... or the 414... but that's pricier.
http://www.musiciansfriend.com/pro-audio/akg-c214-large-diaphragm-condenser-mic/271335000000000
^ Nice! That thing looks great.
still thinking a MASS is in my future... BUT! now I need to see what this sounds like...
You can remove the 2 outer tubes V7 & V10. Then set the ohm selector to 1/2 of your speaker load. If you have a 16 ohm cab, you would then set the amp to 8 ohms.
Thanks,
Charley Polacheck
Bogner Amplification
try one out and let me know. I am ready to stop playing around a buy one of these things. Just need to decide which one. I've been looking at the Dr Z Airbrake and Brake Lite.
(Charger, I have plans/specs for a DIY Airbrake if you and your buddy want them).
Everyone gushes over the Rivera Rock Crusher too but it aint cheap.
I removed the outer power tubes on my krankenstein years ago, never changed the ohmage though. However I did come across this idea today - use the HP as a parallel dummy load - HP on dummy on one speaker output, normal speaker on the other, cut the ohmage in half. That seems like a cool way to use it without having it affect the tone.
re: not changing the tone...
I did that for a while with the flexi so I could run it on the 4 ohm output (8 ohm cab and 8 ohm hotplate dummy load) - was supposed to sound better and it did... a little. so, if you do it, it might sound just a hair different from what you're getting now. it wasn't enough of a difference to really matter, though, and possibly amp specific.
also, update: THD sent me an RA number... so, it's off for a refurb. sorry charger! ;)
ironsheep — May 10, 2012still thinking a MASS is in my future... BUT! now I need to see what this sounds like...
You can remove the 2 outer tubes V7 & V10. Then set the ohm selector to 1/2 of your speaker load. If you have a 16 ohm cab, you would then set the amp to 8 ohms.
Thanks,
Charley Polacheck
Bogner Amplification
I wouldn't bother. As math tells us, 1/2 the power =-3db.
charger — May 13, 2012[quote author=ironsheep link=1336498641/25#33 date=1336681451]still thinking a MASS is in my future... BUT! now I need to see what this sounds like...
You can remove the 2 outer tubes V7 & V10. Then set the ohm selector to 1/2 of your speaker load. If you have a 16 ohm cab, you would then set the amp to 8 ohms.
Thanks,
Charley Polacheck
Bogner Amplification
I wouldn't bother. As math tells us, 1/2 the power =-3db.
but half the power into a hotplate would be good, db is volume isn't it? not the same as the number of watts going into the hotplate surely ?
yes, that was the point - 60w won't fry stuff the way 120w does.
volume is irrelevant to me - I'm either using a dummy load or a somewhat/partially isolated cab with a mic on it.
Just don't dime it. The last 3dB on the volume knob (probably the distance from around 8.5 to around 10) is the last 60 watts, given that the volume knob is audio taper and there's a farly obvious audible change between 8.5 and 10. The way volume works is logarithmic... 1 dB is defined roughly as the smallest unit of obvious audible change for humans... 3dB is 3 of these audible changes, and a doubling of power. So somewhere between 8 and 10 on your master is the last 60 watts of your power output.
that was going to be my suggestion. Just pull it back a bit. Isn't 8 loud enough? :o :o
;D
around my house, master volumes are for relieving swamped output tubes to reduce compression and attenuators are for relieving swamped speakers and/or reducing power output.
/shrug
this last weekend I was running at 60w. it sounds and feels so totally different from pulling back on the master at 120w... seriously, it's not the same thing - at all. I'm not saying better or worse either - just really different.
120w with master use but still fairly loud (though not compressing the output tubes), medium input gain = scooped (this can be adjusted with the presence control but the frequency range is a little lower than I'd like) with low end spikes and plenty of high end detail (most of the bogner clips I've ever posted are like this).
60w with no master and very loud (lots of output compression), low input gain = awesome mids with no scoop - no need for compensation - full of mids, smooth low end even to the point of it being (unpleasantly) loose and sparse high end detail (all the flexi clips are like this).
output tube compression. that's what I was trying to get with 4 EL34s and I'm pretty sure it killed a hotplate. we can talk about exponential functions and logarithms all day (something I used to actually do... ugh, lolbarrassment) but that's what happened and would likely happen again if I continue running at 120w simply because I like the sound of a fully engaged output section.
"sheep gets great tones mic'ed"... "sheep, set up your amp differently"... think about those two for a minute. heh.
I don't have a problem with you running 120 watts into a 200w-rated attenuator. There are some simple things you can do to make it safer. If it's not near your recording chain, run a fan through it. Or open it up and clip on some aluminum heatsinks. Either way it should work, it shouldn't blow up. If anything fails it should be a power tube... just get that stuff cooled down.