Can I damage 2x12 Alnico Blues with JTM45?

[omarxx]

Will I damage my Celestion Alnico Blue speakers in a 2x12 16 ohm cabinet by powering them with a JTM45 that has been upgraded with Mercury Magnetics transformers and KT66 tubes? Thanks.

- omar

 

[slider313]

Sure can. The blue is a 15 watt speaker. If you turn that amp up past "2" they won't last very long.

 

[Brewmaster]

Yep, sure will.

If you can swing the $$$ get Celestion Golds. I run a JTM45 into a 2x12 loaded with a Gold and a G12H. That is my current tonal Nirvana which may not be yours.

 

[omarxx]

Since it's called "JTM45", I always thought they were rated @ 45 watts, but I've read somewhere that they put out about 30 watts.

Here's one source:

http://www.kellyindustries.com/guitars/marshall_jtm45_amp.html

 

[silvertone]

I've used mine with blues for the past 5 years, and cranked at times. The speakers are fine. In fact, I think they've still not completely broken in.
It might depend on your playing style though....

 

[billstets]

I'm pretty sure a JTM45 is 30-35 watts, but that's clean. It will put out probably 45-55 watts cranked. Just like a JMP 50 watter, will put out 75 when cranked.

 

[utterhack]

I'm pretty sure a JTM45 is 30-35 watts, but that's clean. It will put out probably 45-55 watts cranked. Just like a JMP 50 watter, will put out 75 when cranked.

cf AC30, which maxes at 48 watts cranked

 

[Roe]

they will last a while. how long depends on b+, tubes, bias, playing style, amp settings, effects etc etc

 

[Roe]

also, running a 8ohm load for the 16ohms output on the amp (or a 4 ohm load from the 8 ohm outut) will increase the power and blow the speakers faster

 

[omarxx]

This might be a good excuse for buying a Marshall 4x12. Ah, it never ends, does it? :NUTS

 

[rockindog]

Why not go with a pair of Celestion Golds for about the same $$ as 2 Blues?

 

[ben_allison]

I've read somewhere that they put out about 30 watts.

That's RMS, not peak. RMS can be as little as half of peak output.

This is why you typically want DOUBLE your amps wattage in speaker handling.

50 watt head goes on top of a 4x12 of Greenbacks.
100 watt head goes on top of a 4x12 of V30's.

 

[dunara]

I have a JTM45 with KT66s, and a cabinet with 2 old ('70s) blues at 16ohms. I've dimed the amp once through that cabinet. It was starting to fart a bit on the low notes, so I turned it down and have never been back there - I have two other cabinets I can use, and now have a Weber mini-mass, so it's not really necessary.
One point - if the OT is tapped at 16 ohms, the rated output should be lower than 8 ohms, which is lower than 4 ohms etc. Anyone know the precise figures for each impedance setting?

 

[WesKuhnley]

Why spend the dough on golds? try some weber's for about $200 per, or WGS AlNiCo's for $230 ish...The new WGS Blackhawk 100 is fantastic

 

[amp boy]

Will you damage them....??
No, since yer in Texas.

Just bring them to Austin SpeakerWorks perhaps first.....might be cheaper than after the boom.

I say you want to play the amp.........so get some speakers for it.
can i get an ahmen....??
: )

 

[hathisisfunnyha]

do you have a lot of spare blues to put it when you blow the ones already in there?

 

[rockon1]

also, running a 8ohm load for the 16ohms output on the amp (or a 4 ohm load from the 8 ohm outut) will increase the power and blow the speakers faster

An impedance mismatch either way with a tube amp will cause a reduction in power output. Bob

 

[Roe]

An impedance mismatch either way with a tube amp will cause a reduction in power output. Bob

no, thats simply not correct in this case since the primary impedance is way high

 

[rockon1]

no, thats simply not correct in this case since the primary impedance is way high

Thats interesting. Ive been told many times that any mismatch will result in power loss with a tube amp. Bob

 

[willhutch]

There's a difference between "will damage" and "can damage". Clearly it's possible to hurt 15 watt speakers with a JTM45. How loud are you gonna play? You'll be fine as long as you don't push too hard. But of course, you never know where "too hard" is until you actually damage the speakers.