JohnH89

I understand your comments and concerns but am very aware of how it all works . I really don't foresee a problem but will give it a hard run at rehersal on Thursday and let you all know how it works out . I have used the head a lot in the past and even when driven hard for a long period , it barely gets warm . At approx 95% efficiency , at full power constantly of 250W (which it is nowhere near with normal playing ) it would have to dissipate a lowly 12.5W . If it turns out that there is a problem , the amp will protect itself and cut out . If it does I will design a forced cooling duct system for it . 

I'll keep you posted .

We'll see . I am not expecting any problems but can always add forced ducting if necessary . I have driven the amp flat out for 4 hours without the fan coming on for more than a few minutes when it was sat on top of the cab . I like the idea of it on its side as a simple solution if there is a problem .

Amp is mounted to the back board via 4 bolts and a ply pressure plate . The sides of the case are free for air to move . On the BQ250 , the fan and vent are mounted on the side of the case . With the amount of air that moves with the 12in driver , I would be very surprised if I have an overheating problem . 

1 hour ago, chyc said:

This looks lovely. Congratulations.

 

I've always had half an eye on the BN12-300S. It is a crazy light woofer that doesn't go deep, which is fine by me as I aggresively use a HPF anyway.

It does deep very well in a well designed cabinet .

A quick backstory behind this project . I use a Markbass 801 for rehersals with small acoustic folk band . I love it for its sound and form factor , a lot easier than schlepping a head , cab , cables etc . For outside performances that need more volume , I have been using a homemade 112 cab and TC electronics BQ250 . I though I would combine both ideas and made myself a bigger , louder combo , like the Markbass on steroids .
The Celestion BN12 - 300S 4 ohm speaker was robbed from the cabinet , and a new cabinet made . 16in cube made from 9mm ply that was laying around , laminated in parts for strength but still remarkably lightweight . Rear ported and the TC BQ250 built in . Fitted with a DI XLR socket with a ground lift wired in .
The cab was designed to be resonant at 41Hz and plugged it in this afternoon and was blown away by the volume and tone .

17.2kg - 38lb .
Heavier than I thought but still lighter than the original cab that was all timber .

1 hour ago, Ralf1e said:

I have no idea who he is but I know what he does is play a sax like no other and its great staccato sax amazing

Dana Colley on the baritone sax

1 hour ago, MungoBass said:

Am I the only person thinking this thread appears to be going off at a tangent? 😀

No you aren't .

All over a few ounces ? Who really gives a **** ?

Just picked up a new BB734a from the chaps at bass direct . Of all the basses I tried out , the set up from the factory and quality of manufacture are beyond compare . Across all musical instruments , Yamaha have been doing it brilliantly for years . If you want a label on your bass to impress people , buy a fender . If you want a bass to play and last for years , buy a Yamaha . 

How about picking up the phone and speaking to them ? Always helpful . And its not beyond the wit of man to do the conversion yourself if you are that bothered . Just bought a bass from them and decided to go in person . Without going into details , there were problems with the bass that were nothing to do with the guys at BD . 12 hours from finding the problem to picking up new bass , strings , straploks etc . And they did a great deal for me . It's easy to criticise . They will have my business for a long while . The measure of any company is how they deal with it when things go wrong . Hats of to Mark and the chaps from a happy customer .

This is mine . Hotone nano amp as preamp . Send socket to input of DIY class D power amp . Speaker out to PJB C2 . If more volume needed , I change cab to high sensitivity 112 . Plenty loud enough . All runs from an 18v 2Ah drill battery for at least 2 hours . Probably nearer 4 but not run it out flat yet .

Had a small problem with my out of warranty briefcase a couple of months ago . Selectron were polite on the phone but not interested in anything out of warranty . They put me on to a local amp tech . All sorted but no spares used so can't tell you how easily they are available . Good luck