Got me a new posh bass amp..

Bridgehouse

Weighs the same as my car.

Built out of (probably) iron and concrete

Apparently it's "150w" (lol). It's legendarily louder than the Bart Simpson "Testing" megaphone scene.

It's been serviced. Presumably by Harland & Wolff.

Uh, and it was 95 quid. 

(Pic not mine as it was dark and late when I got back - previous owners pic)

Bridgehouse

(I'm sure @ICBM will tell me I overpaid by about £90 )

Funkfingers

Probably the only TE model that HarrySeven never hoarded.

Sporky

Blimey - it's heavy and/or loud enough to distort the light nearby!

darthed1981

Looks suitably armour plated, nice Simpsons reference there as well.

Rocker

Removing the speaker grill will reduce the weight by at least 10 Kilograms......

ICBM

Bridgehouse said:

(I'm sure @ICBM will tell me I overpaid by about £90 )

Nah . Decent price - they usually go for around £150, and that one looks to be in better than average condition.

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 .

Funkfingers

ICBM said:

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 .

Shh!

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

Bridgehouse

Funkfingers said:

ICBM said:

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 .

Shh!

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

I’m not sure a frizzy perm beard would look very 80s...

Bridgehouse

@ICBM - I have played through an AH150 - yes it was very loud. Very loud. It was also in a different class of heaviness to this one as well (!)

Bridgehouse

Gave it a little go this afternoon. 

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

digitalscream

Aye, my dad had one of those - sold it to Mr Savage, as I recall, after the final Swinjam of the MR era. It did a perfectly good job there...easily loud enough to be heard over every guitarist who was twiddling around.

JezWynd

What makes it so heavy?  Does it have ballast or huge transformers?

Bridgehouse

JezWynd said:

What makes it so heavy?  Does it have ballast or huge transformers?

I reckon it’s the cabinet wood. And the transformers. 

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”

JezWynd

Bridgehouse said:

JezWynd said:

What makes it so heavy?  Does it have ballast or huge transformers?

To be fair, it’s light for a Trace - it’s only 32kg

That's approaching nailed to the floor status for me.

ICBM

Bridgehouse said:

JezWynd said:

What makes it so heavy?  Does it have ballast or huge transformers?

I reckon it’s the cabinet wood. And the transformers. 

And the speaker.

It's the cabinet - it's made from thick MDF. The transformer isn't that large, and the speaker is not particularly heavy. And as Rocker said, that bombproof metal grille isn't light either.

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 .

Bridgehouse said:

I’m shocked at how much trouser flap it has for “150w”

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.

Bridgehouse

ICBM said:

Bridgehouse said:

JezWynd said:

What makes it so heavy?  Does it have ballast or huge transformers?

I reckon it’s the cabinet wood. And the transformers. 

And the speaker.

It's the cabinet - it's made from thick MDF. The transformer isn't that large, and the speaker is not particularly heavy. And as Rocker said, that bombproof metal grille isn't light either.

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 .

Bridgehouse said:

I’m shocked at how much trouser flap it has for “150w”

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.

I suspected it was mostly cabinet. It feels very solid. Ridiculously overbuilt in some ways. 

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.

ICBM

Bridgehouse said:

The BLX130 is pretty tempting I must admit - I've seen a few of them on eBay.

It depends what you're trying to do with it - as well as the omni-directional, space-filling quality they have a rather undefined sound, with next to no punch out front - so good for filling a room from the stage in a jazz/folk/wedding type band, but no good for rock/punk/anything more aggressive - they just sound too polite.

And they are staggeringly heavy for such a small box, almost in the Mesa Mark series 'I can't quite believe it' category.

Sporky

ICBM said:

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.

I went to a thing by one of the AV kit manufacturers we use, and they had a presentation by the chap in charge of their power supply and amp design which was brilliant. 

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. 

ICBM

Sporky said:

So, TLDR: many class D amps are lazily designed. 

That doesn't surprise me, since actually quite a lot of Class AB amps are lazily designed too... and valve ones for that matter.

UnclePsychosis

Lots of these in the practice rooms round Edinburgh. Always enjoyed playing through them.