wahts the differecne betaween an 18 watt design amp cranked and ..

[jerryjg]

OKay, heres a question. I have a 50 watt  tube amp( Crate Stealth Lee jackson) amp and I can crank it to ten with a 25 watt very inefficient speaker and the amp is delivering all its juice(tube goodness) and the amp is still not that loud. Even the speaker barely breaks a sweat.
 Whats the difference between that and dialing up an 18 watt amp up to ten with an efficient , loud, amp speaker? Is it only that your better able to get a better sound by BOTH amplifier and  speaker working to its full capacity/driven hard?

[AZJimC]

I'm betting something wrong with that amp, or it's rating. I have a super reverb, and  assure you, "Not too loud" is not one of the thoughts you will have after you endure it's 45 or so watts. Also a bassman 50, same thing, LOUD!

Jim

[bluesbear]

If your 50 watt amp was putting out 50 watts, that 25 watt speaker would only be useful as a boat anchor after a few moments. Something ain't right!
Dave

[AZJimC]

About the 18 watt, it should rock that 25w speaker, but I still like a 4x12 or at least a single 15" for any 10+ watt amp, and most below that. Some guys swear by 4x10's, and I can't deny they rock. The 50w is not right, or, as BluesBear says, about 10-12 minutes at full bore, and it'll either toss the cone or smoke the voice coil, if running right.

Jim

[Dynaflow]

 I had a 50 watt stealth and it wasn't a particularly loud 50 watter at all. I ran it through a 4x12 and a 2x12 and while it was loud enough for a medium room, I'm not real confident it was rated right. Mine had 4-6v6's and even fixed bias would have been something like 44 watts, it felt like less to me. The 18 watter fully dimed with a efficient speaker was pretty loud, I'd say nearly as loud or as loud as the Stealth. The 18 watter I was using was a lite IIb and it doesn't have near the gain that Stealth had in the gain channel which I found to be pretty squeely if it was up all the way (preamp). Even at that it should be hurting your 25 watt speaker I think. Might want to check the bias and or power tubes to see if its putting out what it should. I personally like the 18 watters a lot, they have a pretty biting tone and tend to cut through real well.

Regards,

Dyna

[Frankenamp]

Speaker efficiency is everything. Paul W Klipsch once said "what the world needs is a good 5 watt amplifier". Meaning, that five watts with an efficient driver will run you out of the room. Is your driver a 'musical instrument driver' or not. MI drivers typically have a fairly tight magnetic gap, short voice coil, and a correspondingly small Xmax (cone excurson) and no deep bass to speak of. "Regular" drivers or woofers, are not designed for guitar an voice frequencies in particular, but for more wide band work. Designing for more bass requires more Xmax  and unless you have a monster magnet and a very deep gap, you will give up efficiency in favor of more bass. Guitar needs nothing under 100-120 Hz. Most Bass guitar speakers won't go below 80 Hz (sorry bass players- your bottom end is mostly second harmonic). That bottom octave just isn't there unless you are using a folded horn or a kilowatt amp with a direct radiator. Go to the Eminence website and look at their guitar speakers average spl is 98-100 dB and the other woofers are 89-90 dB spl for 2.83 volts in at one meter. There's yer fifty watts right there. Assuming your driver is 90 dB efficient at one watt, 32 watts is 105 dB (loud but not that loud). same 32 watts into a 100 dB driver will give you 115 dB (now thats loud). For that 90 dB driver to make the same noise (114 dB) you need 256+ watts. Another reason that Deluxe Tweed with a cheap Jensen will own most modern transister amps with the equivalent cheap speaker.

[Dynaflow]

 Yeah, to be fair, my 18watt IIB (and its current reincarnation as a TMB 18 watter) are using a 1x12 Eminence Red Coat Wizard (102 db sensitivity) and that is one LOUD speaker, as he said, if your speaker is like 95-96 db its going to have way less perceived volume.

Regards,

Dyna

[thermion]

case in point - i built marshall 20watter head for a guy here in town and developed it around a vintage C15K "grail" speaker i had around the shop. i had no idea what speaker he would plug this amp into. when the amp was almost done i asked if he acquired speakers yet - "oh yeah dude, scored a 4x12". perfect. i finish up and deliver product only to find his crate 4x12, you know the one you can pick up one-handed and throw across the room, has possibly the lowest sensitivity speakers ever made. i own one of these crate cabs as well and have to hook up 100W to it to match the volume of the 20W+jensen set. the 20W into the jensen was very thick, loud, and only needed to be turned halfway up for an unmiked gig.
we setup the amp into the crate cab and had to use humbuckers, run an overdrive pedal wide open, and run the amp cranked just to get to volumes that wouldn't embarass me. some badass rock amp... with dog crap speakers.
i think leo is attributed with saying that the tweed amps didn't take off until he found the right speaker compliment. how true, it happens to make all the difference.