close call with single rectifier: impedence mismatching (long read)

Re: close call with single rectifier: impedence mismatching (long read)

Zerberus said:
Totally irrelevant, why not play the black minority card while you´re at it, that way you can scream forum brutality and get off lightly... :evil:

i'm done arguing about this, but that was just a little ridiculous
 
Re: close call with single rectifier: impedence mismatching (long read)

muttonchopsrule said:
i'm done arguing about this, but that was just a little ridiculous

Yes, it was, and I apologize.. Off topic has been getting to me a bit lately, that was uncalled for. I totally forgot about that or I would have already deleted it, sorry.....

But the point was that you age plays no role, at least not for me, *late edit for full meaning* or rather it didn´t until you mentioned it ;)
 
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Re: close call with single rectifier: impedence mismatching (long read)

*off topic*

people argue too much
 
Re: close call with single rectifier: impedence mismatching (long read)

Colma said:
*off topic*

people argue too much
Some people say "I'm wrong, I was out of line, sorry, my bad."

Some people stick to their beliefs in spite of being told otherwise by owners' manuals, experienced amp techs, and drunk dorks who just got back from a kickass rockshow.
 
Re: close call with single rectifier: impedence mismatching (long read)

The Golden Boy said:
Some people say "I'm wrong, I was out of line, sorry, my bad."

Some people stick to their beliefs in spite of being told otherwise by owners' manuals, experienced amp techs, and drunk dorks who just got back from a kickass rockshow.


i just got done doing this with someone else, and i don't want to do it again....

stop trying to be subtle. if you have something to say, then say it.
 
Re: close call with single rectifier: impedence mismatching (long read)

muttonchopsrule said:
i just got done doing this with someone else, and i don't want to do it again....

stop trying to be subtle. if you have something to say, then say it.
OK. I was actually getting ready for bed and thought "I'm going to delete that post because this is over, and there's no reason to post what I did."

Then I see this.

Cool.

You tried to do a nice thing in letting people know you had an incident, and what you believed to cause that incident, and to not have people repeat the mistake that was made. That's cool. That's good. That's being a member of the community.

Being told over and over (and, in fact, disagreeing with the manual) that because "A" happens and "B" happens does not necessarily mean "A" caused "B," you still have yet to say "I may be wrong in my assumption."

Because I don't have the manual for the Single Rectifier handy, this is directly out of the Dual and Triple Rectifier manual:
"Both Dual and Triple rectifier solo heads are not very sensitive to speaker mismatches and will not be damaged by them, except that very low ohmage loads will cause the power tubes to wear faster."
Consult your manual to see if a similar passage is not in yours.

If you're running a 16 ohm load and your amp is set to 4, your amp is working less than running a 2 ohm load being set to 4 ohms.

Your assumption is wrong. You didn't take to being told you're wrong with any kind of humility, in fact you got snippy about it.

i've read the manual, thanks. and as you could see by reading the post, it was a careless mistake made my buddy who was playing through it at the time. granted i should have been more responsible and double checked that everything was connected properly. but regardless of what the manual says, a 16 ohm load connected to the 4 ohm tap obviously causes problems.
i'm not trying to gather sympathy or advice, because the amp is working fine now.
And then, rather than say: "my assumptions may be wrong" you come out with:

i don't know why everyone wants to argue this instead of just taking it for what it's worth. maybe my words just aren't credible because i'm an 18 year old kid that doesn't own a wall of tube amps... i guess nobody can take a kid seriously these days. maybe it's just me, but if gearjonser posted this same thread, i'm sure people wouldn't be arguing him (no offense to GJ at all, i'm just using someone who has a well-respected name on this forum).

Basically saying: "You're saying I'm wrong because I'm 18, not because I'm wrong."

If you wish to believe that having a Mesa amplifier set to 4 ohms plugged into a 16 ohm cabinet blew the tubes- cool. Keep thinking that. But keep those thoughts to yourself because if you tell someone who knows better, they will laugh at you.

If you wish to yell at me or whatever, PM me.

But I think you at least owe an apology to Zerberus and other people who attempted to help you.
 
Re: close call with single rectifier: impedence mismatching (long read)

this is all becoming very humurous to me.

for the record, i did apologize to zerb for lashing out at him. as far as i'm concerned, i have no problem with him whatsoever.

i'm not going to argue with anything you just wrote, because to be honest, i really don't care anymore. what happened to the amp happened. what happened with zerb happened. it's all behind me now.

fine, maybe a relatively fresh pair of tubes just blew out of sheer coinsidence when the impedence happened to be mismatched. maybe i am wrong. there's no way to really know for sure, but whatever. i don't care.


i appreciate everyone else's input, but yes, i did get snippy with you. and that i'm not sorry about at all. because it's one thing to be told you're wrong, but it's another thing to be mocked.

The Golden Boy said:
Some people say "I'm wrong, I was out of line, sorry, my bad."

Some people stick to their beliefs in spite of being told otherwise by owners' manuals, experienced amp techs, and drunk dorks who just got back from a kickass rockshow.

there it is for you one more time.

i can handle it when people tell me i'm wrong. but when i'm clearly being disrespected in such a way, i'm not going to put up with that. as i did with zerb, i'm all about getting along and settling whatever conflict may be happening. after cooling off and having a discussion as opposed to an argument, things got worked out. but until you can stop dropping subtle little hints and start having a respectful discussion, don't expect me to reply to you.

sweet dreams ;)
 
Re: close call with single rectifier: impedence mismatching (long read)

If I may put my two cents in here...

We've been told all our guitar-playing lives to be careful not to mismatch impedences because we'll blow up the amp. Whether there's truth in it or not is irrelevent - by the time we get our first halfstack (or fullstack), we've all heard it about 10,000 times. Then you go and mismatch impedences, and what you're told would happen happens.

Then somebody says, flat out, "no, you're wrong."

Regardless of who that person is, you're going to be sceptical. Then everyone else starts disagreeing with you and some not being so nice about it. What started out as a simple discussion thread turns into a full-fledged argument and you feel like you've gotta stand your ground. And why not? All you've ever been told is that you shouldn't mismatch impedences, and you did, and something blew. NOW all of a sudden people are going to disagree with you?

In the end, what happened happened, and it's just the internet so lets all be friends.

That concludes your message from hippy land.
 
Re: close call with single rectifier: impedence mismatching (long read)

muttonchopsrule said:
this is all becoming very humurous to me.

for the record, i did apologize to zerb for lashing out at him. as far as i'm concerned, i have no problem with him whatsoever.

i'm not going to argue with anything you just wrote, because to be honest, i really don't care anymore. what happened to the amp happened. what happened with zerb happened. it's all behind me now....

Yep, We cool :beerchug:

I also thing this is slowly getting blown out of proportion.... ;)
 
Re: close call with single rectifier: impedence mismatching (long read)

Robert S. said:
I am not a super fancy amp tech and I dont do my own fretwork but I have managed to keep my amps running and guitars playable for more than a couple of years now

Classic!
 
Re: close call with single rectifier: impedence mismatching (long read)

:offtopic: ide like to thank everyone for posting this topic and replying to this topic. wile the posts were not always in agreement, I did learn alot by reading this topic. I have always wondered- in some what a state of paranoia- what would happen if I missmatched the impediance from speaker to amp becouse I have and have had several cabinets over the years that I like to run to different amps for even more tone versitility. currently at this time I have a 4/10 cab and two 2/12 cabs that I like to toy with for different sounds by running them into different amps. thnx all for posting and thnx again for the topic. this cleared up some questions I had always wondered about.
:beerchug:
 
Re: close call with single rectifier: impedence mismatching (long read)

**THREAD HIJACK** Do these rules apply with solid state amps? I only ask 'cuz yesterday I was jammin with my friend and his brand new Peavey Supreme solid state halfstack and when he was plugging it in he said "Well...I haven't unplugged it in a while...so i don't remember where anything goes...so i'll just plug stuff in." which of course scared me and lead me to match the impedences and all that...

but assuming I hadn't and he had set it for 8 ohms into 4, what would've happened and how could we have fixed it? heh i'm probably only asking in case he just "plugs stuff in" next practice....

-X
 
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Re: close call with single rectifier: impedence mismatching (long read)

actualy heres an interesting piece of information. Ever wonder why older amps have a certain jack for speakers and a certain jack for extension cabs? Back in the day, Tubes were built much better and more plentiful (thus cheaper), thus tranformers were sometimes one of the parts that manufacturers skimped on, such as fender. The speaker jack is a shorting jack, it shorts the output of the tubes to ground. The transformer had a better shot at surviving that then if there was nothing connected. This is becuase with a higher load, the voltages build up in the transformer and cause it too fry. With a lower load, the tubes are under much more stress. Its much easier to replace tubes then a transformer, especialy if you dont have to rebias excelent and plentiful tubes. Anyway, Impeedance missmatching is never perfect, Matchless for example runs their El84's very hot, half the load. This is the equivilent to running 8 ohm into 4 ohm. But they dont cook very often, qualitiy of the parts is very important in this case. Tonealy, the intended tone of the amp comes from a match, so try to stay around there. Just a little bit of info for all of you.
 
Re: close call with single rectifier: impedence mismatching (long read)

muttonchopsrule said:
sweet dreams ;)
Funnily enough, I've been having dreams about kissing Glenn Danzig's sideburns...

Nothing I posted towards you was disrespectful or malicious. I'm happy you got things straightened out with other members, and I'm happy that your amp is working, and I'm also glad that you're at least willing to concede that the makers of the amp probably know a bit more about the amp than you do.
 
Re: close call with single rectifier: impedence mismatching (long read)

Empty Pockets said:
**THREAD HIJACK** Do these rules apply with solid state amps?
From what I'm aware of- and I'm not familiar with a lot of newer solid state heads (unfortunately)- is that tube heads will be more forgiving of an impedance mismatch than any solid state amps.
 
Re: close call with single rectifier: impedence mismatching (long read)

Ok, let's summarize.....easy simple to follow rules:

Running an amp/cab combo where the cab has a higher impedance than the amp is OK.
Running an amp/cab combo where the cab has an equal impedance to the amp is OK.
Running an amp/cab combo where the cab has a lower impedance than the amp is NOT OK.
 
Re: close call with single rectifier: impedence mismatching (long read)

Big thing: Check your manual for any special instructions. Some amps have more tolerance for impedance mismatches, some don't.
 
Re: close call with single rectifier: impedence mismatching (long read)

I'd like to toss in something here (kudos to Jeff, Zerb, Robert, and others on the info), ... Solid state and tube react differently to impedance mismatches:
With solid state upward is generally just fine and dandy, going below the recommended minimum Z is generally going to burn out the output mosfets (or whatever SS componenet the manufacturer is using), unless some form of protective current limiting is built into the design (and those are fail-safes only -- Read: Not to be abused). SS will generally run into very high mismatches ... Up to a point. A line level SS circuit can run into an open load all day long ... and even though many claim that an SS amp can also, I have seen SS power sections burn up doing just that. The old, *well, I need to record ... it's Solid state, so I'll just unplug the speakers to run a line out direct thru a red box (or what have you)*. There are probably a few contributing factors there specific to each amp design, however, I think it's mainly a matter of the power involved.
With tube, ... well, it gets complicated real quick. It depends on a lot of variables:
Does a particular amp have a tube or SS rectifier? A tube rectifier will sag, and current limit to some degree on it's own, while many SS rectifiers will happily provide more current than they should under a given mismatch ... this may not be a good thing, for the rectifier circuit, tubes, and other circuits, also for the input tranny.
If the amp has a tube rect it is more (most often) comfortable with a lower match , than an upward one ... most often the power supply will sag, not supply full voltage and/or current, and then an input fuse may blow ... no harm to tubes, OT, or speaker(s).
An upward match will produce extra return voltage, due to mmf ( although the amp's damping factor may control this well) of the speaker and the tranny's reflected impedance (also known as flyback voltage) to the secondary , and of course back to the primary, and of course the tubes, screen grids, etc. In severe cases, tube sockets can arc and short out the tubes, and take the tranny with it (sometimes not), or just annoy the OT until it finally builds up enough heat within the winds to short to the core (you better hope there are multiple fuse points in the amp design).
An amp is happiest of course running into the load is was designed for of course. Generally, a mismatch either way won't kill and amp (by one factor say 16 ohms, or 4 ohms, if the amp wants to see 8 ohms.
Sometimes you can get away with more.
So, why would Jeff and Zerb say that it would be okay? Well, there is more to the story ... Continued.
 
Re: close call with single rectifier: impedence mismatching (long read)

Hey Kent. LTNS. :)

Great info, as always. ;)

Artie
 
Re: close call with single rectifier: impedence mismatching (long read)

Part of the reason also has to do with the plate voltage the tubes are running at, the higher that voltage the higher the flyback voltage, mentioned in the previous post, from an upward mismatch (and the more severe the mismatch the greater the fv, and the more potential to do damage to the amp). This brings us to yet another part of the equation as well, the harmonic content of the tone ... roughly speaking ... how much treble/presence frequencies and how much clipping (distortion). A clipped waveform has much more power than an unclipped waveform, and since all OT's has an uneven frequency response due to there inductive nature (and since they have capacitance as well, the have a resonant peak all their own); they also have a much higher reactance to higher frequencies (read treble, and/or harmonics of distortion), and as such want to reproduce those frequencies to the secondary at a higher induced voltage (great, great ... even more current that won't get used, and more flyback and increased reflected impedance ... not to mention that a speaker's impedance rises with frequency also ... :saeek: )
Of course all this *assumes* that the *type* of tube (EL-34/6L6GC) is biased properly (different bias points, and different max dissapations, and output power). If that not the case, well then you can have some problems right there ... two 6L6's running at 60Watts output into a said load might be in the neighborhood of 37mV; two EL-34s running at 50Watts might be running about 31mVs on the bias (Jeff, please note I'm pulling the figures out of my memory as estimates only). Improperly set bias can eat tubes out quick, or kill them in short order.
I'm not familiar with the single rectifier, so I don't know what Randall Smith has going on with regard to his bias arrangement on those.
I tried to roughly gloss over everything, *parameter*-wise, as Zerb so accuarately pointed out, sorry if I missed anything ...
However, the answer is that, it really depends on the conditions of a lot of variables, and how overall well-built the amp is, and Mesas are some of the toughest built (read put up with abuse and say ... *that all you got? ... Hah!*) amps, both in design and component quality choice.
What will kill a so-so designed budget bedroom amp, wouldn't even bother something like a Mesa or older Marshall (although, some of those Marshall OT's are kinda quirky). Heck the extension speaker jacks on old Fenders (with tube rectifiers) intentionally dropped the load down to half, as they were wired in parallel (although you should never run the extension speaker jack without the main speaker plugged ... I forget exactly what the deal with that is ...schematic not handy).
When all else fails go with a specific manufacturer's recommendations (yeah, RTM); please note also that not all tubes are the same as pointed out, generally if you get replacement tubes from Mesa for a Mesa, you toss 'em in, and that's that. They are already matched for the specific amp. with any other brands ... err, it's crap shoot.

( Now, if I can learn how to type again. Oh, well, busytime, I'm off ... Peace)
 
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