JohnH89

Because , my learned friend , I am , maybe optimistically , confident that the original design , all things considered , has a far better than even chance of being absolutely fine . If you can wait until thursday late evening or more likely Friday morning GMT , then we will know for sure . I think you may have misunderstood #agedhorse and his very well informed opinions but I will leave that between the two of you . He has quite a background in design and development of bass amplification . Be assured that I will post the results of a test and will willingly admit if my assumptions/calculations prove inaccurate .

The BQ250 is a lot bigger than the BAM200/Warwick gnome/TE Elf with better heatsinking and considerably more venting and bigger fan .

As pointed out , the case and heatsinking on the BQ250 is a lot larger than the Warwick . I have also come across the following from TC electronics Which is a 750 combo using this head Also vented from the side and a lot less airflow than the BQ250 . My money is still on the little BQ having adequate cooling .

Thanks for your concern . We'll try it out first . Two small ports at the top of the rear panel , ducted to the fan / outlet will take care of that if necessary . I'll have a virtual bet with you to see if I can get it to overheat at rehersal this week . I'll try hard 🤪

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 .

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 .

Dana Colley on the baritone sax

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