Bill Fitzmaurice

[quote name='Kong' timestamp='1315969397' post='1372737'] There's a big difference between Pre-Amp - distortion and power-amp - distortion aka clipping. If You drive Your power-amp into clipping You will destroy Your speaker. This is why it is dangerous using a small amp (let's say 100 watt) into a big cab (let's say 500 watt). If YAou have Your preamp maxed out, it will start clipping. If You don't hear this, the speaker will get killed by thermal issues. Pre-amp - distortion, carefully amplified with the power-amp, will add harmonics to Your sound, compress it a bit and makes it richer. [/quote]Clipping is clipping, no matter where in the signal chain it occurs. That includes in the drivers; one reason why guitar drivers have a very small xmax is so they'll clip at relatively low signal levels. And if clipping hurt drivers guitar players would swap them out after every set. Only tweeters are inherently at risk with clipped signals, due to the higher percentage of harmonics, and that's one reason why they aren't used in guitar amps. Required reading: [url="http://forum.qscaudio.com/forum/viewtopic.php?f=29&t=2736"]http://forum.qscaudi...php?f=29&t=2736[/url]

[quote name='Mr. Foxen' timestamp='1347915958' post='1806704'] The Kappa pro 15 is a whole bunch less suited to the purpose than the Kappalite, different driver. Handles loads less power. [/quote]+1, about 75% less. Output is limited by driver excursion, not the thermal power rating. With 1/2 the excursion of the 3015 the Kappa Pro can actually make use of 1/4 the power, giving 6dB less output. That translates to needing two Kappa Pro loaded cabs to equal one 3015.

[quote name='JTUK' timestamp='1347795296' post='1804990'] It wouldn't be my choice on te face of it but it depends how they are voiced as to whether they compliment each other or step over each others toes... but if you like the sound, then ok... [/quote]+1. Virtually any two cabs together will sound better than either alone, that's just the nature of how speakers work. Whether or not any particular combination of mixed cabs will work better than a matched pair is a different story, being totally unpredictable, and unless you have actually tried the various permutations side by side you'll never know how cabs A+B compare to a pair of cab A or pair of cab B.

[quote name='Mr. Foxen' timestamp='1347734083' post='1804497'] You'll likely need a crossover and a midrange for a not dull or weird sound from a 3015LF. The 3015 not LF works pretty well in a Mag 15 cab though. [/quote]+1. The LF is a subwoofer driver, with scant highs. It also has less sensitivity than the standard 3015, and requires a larger box for good results. OP, if you can cancel the LF for a standard 3015 you should do so.

[quote name='skidder652003' timestamp='1347718921' post='1804317'] Does anybody of have experience of these speakers and their opinion of them would be much apprciated [/quote]Opinions are subjective, and everyone's will be different. Where replacing drivers is concerned just as important are the driver specs, which must be compatable with the cabinet: http://www.eminence.com/support/understanding-loudspeaker-data/ For best results you, or someone willing to donate their time, need to use speaker modeling software to see how the two drivers will work in your cab, if at all, then compare the results objectively.

[quote name='skidder652003' timestamp='1347709860' post='1804198'] . Im sure this has been asked before but has anyone run this config - one x 8 ohm and one x 4 ohm cabs into an amp with a 4 ohm minimum impedance? [/quote]Minimum load means just that, the minimum load you may safely use. 8 ohms plus 4 ohms is 2.7 ohms.

[quote name='Bassman Steve' timestamp='1347171389' post='1797569'] Did I not read somewhere that Hendrix actually used Marshall bass 4x12's? Maybe you need to turn your idea on its head and look at bass 4x12 territory. [/quote]The original stack was intended for bassists so that they could keep up with 2x12 guitar amps. That notion lasted perhaps a week before guitar players started using them. There was no real bass 4x12 versus guitar version early on though, as the drivers were the same. True electric bass drivers were still a decade away.

[quote name='shibby2407' timestamp='1347137098' post='1797398'] I have my eye on a cornford 4x12 with celestion v30's. [/quote]Their lack of bass output is why one had to use two of them back in the day, or today for that matter. Why guitar'd players think they need two when an AC30 with two v30s can kill small animals at 50 meters one can one only wonder.

If you'd read this you'd have known last night: http://basschat.co.uk/topic/135-impedance-etc/

[quote name='Lozz196' timestamp='1345586589' post='1779269'] 2nd time it`s happened to me as well with the PFs. The amp has a selector on the back for both 110, and 230, same as my last one. Just can`t remember which lead I bought last time, doh! [/quote]The jack on the amp should be the same in either case, the same style as used on computers.

If it's 2 pin, which is odd in itself, chances are it's for 110v.

Bridging should almost never be employed into a low impedance load. There's nothing to be gained except damaging the head by driving too low an impedance load or blowing the drivers with too much voltage swing, or both. Bridging should only be used into a high impedance load, say 16 ohms, which the amp would otherwise not be capable of driving to full output. The mechanics of what bridging does isn't about watts, it's about voltage swing. An instructive paragraph in the owner's manual about when to bridge, and more important when not to, should be SOP, but IME it's a topic that's seldom, if ever, addressed.

[quote name='VTypeV4' timestamp='1344893326' post='1770874'] Thats what I thought although I have seen versions with the fan mounted vertically blowing/sucking(?) at the valves in a Trace Elliot V-Type kinda way.. [/quote]Where valves are concerned keeping them cool isn't of any benefit, keeping the heat they create out of the other components is.

[quote name='warwickhunt' timestamp='1344844620' post='1769851'] it didn't seem to be 'that' hot at the end of the gig, certainly not enough to worry me! [/quote]Not worrysome perhaps, but that's not the purpose of a fan. Passive sinking keeps component temperatures down to a given differential above ambient. Fans can keep that differential smaller. The cooler components run the longer they last. And if you can hear the fan over your playing you're not playing loud enough.

[quote name='LiamPodmore' timestamp='1344780561' post='1769016'] would it not be easier for companies to use silent/low noise fans in the first place? [/quote]They cost more.

[quote name='scalpy' timestamp='1344768846' post='1768849'] The sticky point on Friday was that the guitarist has let me rag his Les Paul through his all original 58 Tweed Bassman, something it wasn't originally designed for either! [/quote]But at least it works well with guitar, never really did with bass.

AFAIK the Big Cat was an autosound driver. Hard to say for sure, as there are no references to it on the Eminence site. It appears to have been an OEM made for Maplins.

[quote name='Big_Stu' timestamp='1344531622' post='1766123'] That used to be a hanging offence in "What Hi-fi" magazine. [/quote]I guess that would have made Paul Klipsch public enemy #1?

Unless you have a valve head that can't run at 8 ohms there's nothing to be gained by using a 4 ohm cab. That's not the case with the 400+.

[quote name='Jimelliottbassist' timestamp='1344526968' post='1766006'] Have you had any experience with eminence speakers beta or delta? [/quote]What matters is matching them to the cab and amp, using their T/S specs and a speaker modeling program to determine suitability.

[quote name='Jimelliottbassist' timestamp='1344380315' post='1763828'] Hi I'm thinking about changing the speakers in a mesa 4x10 cab from 8 to 4 ohm. [/quote]Don't bother. Unless your amp is seriously underpowered it won't go any louder, which I assume is the reason for wanting to change.

[quote name='jezzaboy' timestamp='1344164132' post='1760509'] Why don`t they just fit a speaker capable of running at 300w at 4 ohms? I guess there must be a sound reason for it? [/quote]If they used a 4 ohm driver you couldn't add an extension. As for the power issue, few fifteens are capable of making use of even 150w, irrespective of the thermal power rating, so you'd need at least two to make use of 300w anyway.

[quote name='xgsjx' timestamp='1344118987' post='1760188'] Anyone know if it works & if so, why don't more cab manufacturers do this? [/quote]It does work, on tweeters, and many manufacturers use bulb protection. It does not work with woofers, the current flow being far too high. The only sure protection for woofers is an active limiter.

[quote name='Lozz196' timestamp='1344107438' post='1759979'] No doubts about that. But it sounds ideal to me. The same sound coming from either side of the stage. [/quote]Above 100Hz or so that's perfectly OK, be it on stage or with the PA. Below 100Hz not so much, as explained here: http://www.prosoundweb.com/article/in_search_of_the_power_alley/