It looks like you're new here. If you want to get involved, click one of these buttons!
Subscribe to our Patreon, and get image uploads with no ads on the site!
Base theme by DesignModo & ported to Powered by Vanilla by Chris Ireland, modified by the "theFB" team.
Comments
Nil Satis Nisi Optimum
They just show how loud a *real* - no bullshit, 'programme' power or other number-bending - 150W Class AB amp with a transformer power supply and decent filtering is. And if you think this one is impressive, try an old MkIV or MkV AH150...
They're an ideal practice room amp - loud enough to fill a fair-size space without straining themselves, heavy enough that no-one will try to steal it or probably even move it, and pretty reliable - and being a combo, no speaker cable to get nicked or replaced with a guitar lead - there are a lot of them in studios I know, and I don't see them for repair very often. The only things you really need to know for servicing:
Make sure the fan is working properly and kept clean, likewise the heatsinks - an old paint brush and a hoover does that.
It might be worth lifting the power amp PCB and checking for cracking on the power transistor and filter cap solder joints - the PCB vibrates with the weight of the heatsinks and can cause that. It's best to get a piece of dense foam the right thickness to fit under the board, which will stop it vibrating.
The only other common fault is a blown speaker - simply replace with whichever 300 or 400W Eminence or Celestion Lean Business are doing cheapest this week and it won't go again.
Be careful if you're taking the power amp board out - the heatsinks operate at the DC rail voltages and they can retain enough charge to give you a surprise, if the screwdriver touches the screw and the heatsink at the same time .
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
What with active bass guitars and this amplifier, the old 'un is going all Eighties on us. A quick electric shock might complete the picture by giving him a frizzy perm. :-p
Bloody hell it’s loud. Input gain was about 8 with no clipping, and master on 1 - 1.5
Loud.
My ACG has an East Preamp with a bass boost. It drops an extra 10db at about 60hz (that’s how I set it on the onboard controls) - most amps I try it with wash out and become a muddy mess. This one is like plugging a sub in. Still lots of high end but this thumpy low end that shakes your chest cavity. Crikey
And the speaker. And the... you get the picture. To be fair, it’s light for a Trace - it’s only 32kg
I’m shocked at how much trouser flap it has for “150w”
If you think it's heavy for its size, try a BLX80 or 130 - that's the odd-looking one with the vertical slot port in the front. It's a clever internal acoustic design with a double port which maximises the efficiency of the speaker and makes the sound almost completely omni-directional so they're brilliant for filling a space, but the penalty is that all that extra internal baffling is made from yet more MDF... about twice as much as it looks from the outside .
It really is only 150W - but measured properly... ie the continuous, forever, full sinewave power before clipping - not a weighted average or 'programme' power where they claim more but it can only do it for short bursts. The power supply also has pretty big filter caps so it can produce big transients - although they're nowhere near the size of the ones in the old Mk series.
The funny thing is that despite the greater *electrical* efficiency of Class D and switch-mode power supplies, it wouldn't surprise me if this sort of old-school tech is more efficient at turning electrical power into perceived volume - you're right about what you said in the other thread, it's easily as loud as a typical 500W Class D amp, which may well draw slightly more from the wall.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
The BLX130 is pretty tempting I must admit - I've seen a few of them on eBay.. but this one was a known quantity from someone on Basschat - I know it's been serviced and looked after so for 95 quid it wasn't a risk at all.
And they are staggeringly heavy for such a small box, almost in the Mesa Mark series 'I can't quite believe it' category.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein
He went into a lot of detail on why class D doesn't tend to meet its theoretical capabilities, and all the things they do to make it more like the dream.
Fundamentally it seems a lot of "manufacturers" are using third party modules and cludging them together, so the power supply doesn't 'match' the power amp. Theirs are a single integrated design. Much better efficiency, so less heat. Less heat means no fans, which means less 'administrative' power draw. It also means longer life for the electrolytic caps (and they have a fifth of the caps the others do). Their amp was drawing 75% of the input power of the modular ones for the same output power, and they're not a company that fakes tests.
So, TLDR: many class D amps are lazily designed.
"Take these three items, some WD-40, a vise grip, and a roll of duct tape. Any man worth his salt can fix almost any problem with this stuff alone." - Walt Kowalski
"Only two things are infinite - the universe, and human stupidity. And I'm not sure about the universe." - Albert Einstein