The Last Bass Outpost

In regards to the Traynor, that is definitely an EL34. If there's a hole in its guide pin, it's a Mullard. Is there any marking for country of origin? BTW, that 6BQ5 is also known and as the EL84, and is a low-power, power tube. It acts as a driver for the reverb.  Its most famous application is as the output tube of the Vox AC30.

I always shoot for about a 20 -  25% higher power rating on the speakers than  what the amp delivers. Yes it is true that if you have a seriously underpowered amp you can screw up the signal coming from the amp and blow a speaker. I have never blown anything up like this, but it can happen . In the old days this was something that never happened..... it was always too much power that got got ya 
 
I'd like to hear Psycho Bass Guys take on this....he actually knows what he's talking about whereas I'm just a guy who learned a bit by blowing a lot of stuff up .
Rick

Don't feel too bad. I've smoked two sets of drivers in my life; the most recent was a pair of horns in some EV SX300's that had already taken a bad hit from lightning so anything would have killed them, but I spectacularly destroyed a pair of Cerwin Vega SL36 subs when an EQ feeding their power amp had a subsonic oscillation in its output and I had a real power amp pushing them, a bridged Crown MA3600. They got so hot, the magnets turned bright blue permanently and the voice coils had vaporized; not burned, not charred, vaporized.

For most instrument amps, ratings of thermal max power are pretty trustworthy, however, since we play bass which is:

a. hard to hear relative to most other instruments and
b.hard for speakers to reproduce relative to most instruments

... we get to deal with mechanical limitations of drivers as well as thermal. With porting, it is quite possible to destroy a 1000 watt rated speaker with less than 200 clean watts below its tuning frequency, which is why it's important to pay attention to the repsonse curves of a subwoofer and not try to get 30 Hz out of a speaker cabinet than has a 10 dB downpoint at 50.

 Now that I've added that little wrinkle, I've got some good news for the OP; your cab is sealed. That means that any added lows below its resonant frequency will simply result in less volume below that point, and unless you exceed the speaker's thermal limit (the wattage rating) with continuous power, you need not fear hurting the speakers. As far as the old saw of "underpowering,"  it was only true in the first decade or so of solid state power when poorly regulated amps would often dump all kinds of nasty stuff into their audio output when overdriven and many a speaker got toasted by having an amp with too little power ( and unrealistic expectations of volume).

As far as my personal philosophy on PA and "clean" ss bass rigs, I like to have a large margin of power in excess of the speaker's thermal rating so that I can attenuate on the front end of the amp. There are large transient signals that almost always exceed an amp's maximum input voltage, even if it's only for a few milliseconds, and if you can turn down the amp's input and prevent that, your overall sound will be better and punchier and your amps will last longer.

Sound Citys have sort of a bad rap "Sounds Sh-tty" is what we called 'em back in the day. I forget why but I think the preamp is a bit harsh (maybe a techie can really explain this)

Sound City used a really crappy sounding active EQ in most of their models' preamps. Get rid of that and you've basically got a Hiwatt.

The Shuttles are horses of a different feather entirely. Good amps.

Love the  Viggens & Drakens

You really need to check out the Griffen:




BTW, if you like the Draken, check out Firebirds from a few years back. It's a silly Nicolas Cage/Sean Young "war" movie that was a bad attempted promo for the AH-64 Apache to do for it what Top Gun did for the much (unfairly I might add) maligned F-14 Tomcat. The good parts are that the "bad" guys fly Drakens and Tommy Lee Jones gets to spend a whole movie being an ironically good actor in a crappy movie.

How good/bad are Celsetion G12 412 AVT 50w...?

...all but useless. Celestion made good bass speakers for Trace Elliot, but other than those, you don't want one for bass.

another idea - 2 G12K 100's similar in price to the above - split and seal the cab to house the 2 differing speakers... run 2 of the existing 30w speakers with the Marshall 50w "smallbox" and the 2x100w from the Hiwatt...?

If you can keep track of it, that's fine, but two different amps into one cab is a recipe for disaster if you're not around to hook them up or if someone screws with your cab onstage.

Unfortunately in Cincinnati the locally owned stores are pretty much just as bad.

You ever deal with Willis Music? They're headquartered across the river in Florence, KY. I used to work for them, too.

That low end rolloff is high on paper, however, since you're loading it in a sealed cab, you can boost the low end without the fear of overshoot or speaker crease that you get with ported bass cabs. that's how Bag End subs work.  Besides, that cab isn't going to have any real output below 60Hz or so anyway with ANY speaker. I don't think those specs are for the actual old EVM12L anyway, but the new "reissue" model targeted towards guitar players. The original was for PA use.