Fender? MH-500? Amp all about the Metal ?

[Fragle]

Re: Fender? MH-500? Amp all about the Metal ?

little side note on the ohm issue:
the singer/guitar player of ancient frequently (but accidentally) ran his engl powerball with two 4ohm cabs plugged into the 8ohm/2*16ohm jacks, without any problem. he even powered it up (only standby, though) without any speakers attached, also no problem.
our lead guitar player used to plug two 4 ohm cabs into his marshall tsl100 head set to 4ohm (which essentially means that he put a 2ohm load on a 4 ohm output section) ...he did that for ages. no problem....and i'm sure that you all will agree that the tsl isn't exactly the best build amp around [img]/images/graemlins/smile.gif[/img]

my point is that it seems like one shouldn't take the whole ohm issue too seriously....but well, as far as i'm concerned i ALWAYS run the amp with the proper load attached (except for situations where it is impossible to match it correctly, then i'll go for a "safe" mismatch)

[charvelguy]

Re: Fender? MH-500? Amp all about the Metal ?

Tube and solid state have differing rules on mismatching ohmages.

In a SS amp you can run the amp with an output impedence at 4ohm into a 8ohm cab or a 16 ohm cab and it won't do any harm.

Meaning solid state amplifiers can drive higher impedances than their set output rating demands. So a transistor amp with a label saying "4-ohm" will drive 4, 8, and 16 ohms with no troubles. You can go up but not down. I wouldn't try 2 ohms. I fried an output chip on my GK250ML this way because I got it confused with the other rule for tube amps and mismatched cabs.

Older legends say that tube amplifiers can drive lower impedances than their rating demands. So a tube amp with a label saying "8-ohm" may drive 4 and 8 ohms. You can go down but not up. I wouldn't try a 16 ohm speaker cab with a 8ohm impedence out on your Marshall JMP and exp[ect it to survive for long. It is not a good idea run a tube amp without speakers attached. You can overload your output section..especially if you plug into it and start wanking away without any release for the signal.

Truthfully, you are far better off with a proper match. Just because your tube amp with 8-ohm output survives driving a 4-ohm speaker doesn't mean that it likes driving that load. You are probably reducing the life time of the amp, transformers or tubes. You wouldn't want to run improper bias or a overly high plate voltage on your 2000.00 amp would you?

[Fragle]

Re: Fender? MH-500? Amp all about the Metal ?

well, i think you got something wrong there. you can indeed plug for example an 8 or 16ohm cab into the 4 ohm input on your tube amp, no problem. even for example the mesa boogie manuals say this is a safe mismatch which results in a slightly different response.
but normally you canNOT plug a 4 ohm cab into the 8 ohm jack....or in ancients case, two 4 ohm cabs generating a total load of 2 ohm on an 8 ohm power section.

[zeegler]

Re: Fender? MH-500? Amp all about the Metal ?

Yes, with a tube amp, you can go up but not down. You need to have at least a 4 ohm load on a 4 ohm output. I frequently run my Randall tube amp with a 16 ohm cab on the 8 ohm output.

[metallicarocks]

Re: Fender? MH-500? Amp all about the Metal ?

Assuming an SS amp here:

I wouldn't over run the power amp at all. If I had a 4 ohm amp, I would be really nervous about attaching a 2 ohm speaker setup. An 8 ohm would be fine, you're just wasting alot of power. Hooking up a 2 ohm setup to a 4 ohm amp is making the amp work really hard. It probably wouldn't burst straight into flames, but I can imagine that it would decrease the life of it. If you left it on for a long time it would probably get really hot and could pose a fire hazard. I don't know how long, I don't have the budget to try and find out.

[metallicarocks]

Re: Fender? MH-500? Amp all about the Metal ?

*if I ever become a millionaire I would be happy to conduct a field experiment though. You know, see what amps blow up sooner due to mismatches. [img]/images/graemlins/grin.gif[/img]

[charvelguy]

Re: Fender? MH-500? Amp all about the Metal ?

yes, I realized after it timed out and I reread it again that I had one part of the paragraph incorrect.

[Drsracing]

Re: Fender? MH-500? Amp all about the Metal ?

I had a M-80 and it's probally been my favorite out of all my amps

[toejam]

Re: Fender? MH-500? Amp all about the Metal ?

[ QUOTE ]
he even powered it up (only standby, though) without any speakers attached, also no problem.


[/ QUOTE ]
As long as it's on standby, there won't be a problem anyway. [img]/images/graemlins/wink.gif[/img]

[savage]

Re: Fender? MH-500? Amp all about the Metal ?

[ QUOTE ]
Find a Fender M-80 they ROCK!

[/ QUOTE ]
I owned one [img]/images/graemlins/laugh.gif[/img] yeah these were great amps
as far as this new fender i would not take it over the peavey XXL i just got.
i was shocked that this thing is all SS [img]/images/graemlins/eek.gif[/img] does not sound like it at all!
my main amp is a 2203 and i love it but the XXL floored me, try one with a marshall 1960 straight front and a EMG 81 and see why:headbang:

[taxistationary]

Re: Fender? MH-500? Amp all about the Metal ?

One thing to realize is that if you take an amplifer off standby with a mismatched impedance, it's just not going to blow up; it takes more then that. Eventually the built up current in the output trannies will force the amp to either pop a fuse, or on a poorly designed amp, blow the transformer. It takes time for the current to build up. Esspecially the closer you are to the origianlly correct impedance.

[Dreamland_Rebel]

Re: Fender? MH-500? Amp all about the Metal ?

if the MH-500 is anything like the grey fuzzies (m-80) or the rock pro, then once again my hat goes off to fender for kicking ass and knowing what metal heads want out of an amp.