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Posted
4 minutes ago, Chienmortbb said:

45 Years as a Electronics Engineer involved lots of research but I am always willing to learn. Point me to your sources and I will gladly study it.

Check out the Acoustic (brand) forum's, where experts, including engineers who actually made them can answer questions you may have.

I've owned a couple of old Acoustic amp heads and they are far, far, far louder than equivalent modern watts.

Posted
2 hours ago, Chienmortbb said:

45 Years as a Electronics Engineer involved lots of research but I am always willing to learn. Point me to your sources and I will gladly study it.

I that case you should know this , but for younger forum members let me give my perspective and perhaps explain why not all watts are created equal.

The short answer is marketing.

Keen to flog more product, Amstrad came up with the ideal of 'music power' which rated their stereos according to their capacity to handle transients, like cymbal crashes and rimshots. This made them appear at least twice as powerful as amps rated by their 'RMS' capacity.

From then on, it a simple 'wattage rating' has never been enough to accurately judge how loud an amp is in a real setting, because manufacturers use all sorts of formulas an ways of assessing power...

 

The longer answer is a mixture of practicality, psychology and marketing.

Some truth in Amstrad's approach - music (at least in the old days before the 'Loudness Wars' has its peaks and troughs. The volume of an amp isn't just its ability to deal with brief transients, it relates to the bits in between as well.

Imagine a valve amp and a transistor amp, both being fed a pure sine wave such that they are almost starting to clip. Lets assume this is at the same power level for both amps, so on paper they both have the same continuous RMS power.

Now play bass through both amps and turn up. Push the valve amp into clipping on the loudest bits and it will sound rich, push the transistor amp into clipping and it will sound harsh.

This means that you can't have the transistor amp turned up as loud for the quieter bits as the valve amp, as the transitor amp sounds overloaded when you dig in.

So  the amps have identical wattage ratings, but the valve amp can be played in a way that is louder. Effectively it is compressing the signal upwards at the cost of distortion, but a type of distortion people generally like.

 

Also, some amps have power supplies with undersized transformers or smoothing capacitors, so when played hard the voltage 'droops' and overall power drops.

 

Other things affect volume; it's easy for a well designed speaker cab to double the volume.

There's a famous test on line where a Fender HRD (40W), Vox AC30 (30W) and marshall stack (100W)  are compared and they come out in that order - yes folks, the AC30 is louder than the Marshall stack. 124.6 db, 124.1 db and 119.5 db.

https://www.harmonycentral.com/forums/topic/931152-marshall-100-watt-stack-vox-ac30-fender-hrd-how-do-they-compare-in-volume/

It's not just speaker design. I have a Vox Valvetronix which is marketed as a 20W amp, but it has a 'power control' (it's a modelling amp) and you can actually turn it up to 30 watts... so not all headline wattage ratings are exaggerated!

The biggest pitfall is that, at usual volumes (i.e. not dead quiet or super loud) a doubling of perceived volume requires a ten-times increase in power. I've played a 1-watt battery powered amp through a JCM800 1x12" cab and it was way to loud to play in the living room. Anyone with a Blackstar Fly (3W) can test this!

Most bass amps fall between 150W and 500W, with outliers  at 100W and 1000W and above. The difference between 150W and 500W RMS is pretty small and in practice the extra volume is largely down to the same thing as that valve/transistor comparison - the more powerful amps have more headroom, i.e. you can play them significantly louder without distortion.

 

As for Trace Elliot watts, I think the legend (or myth if your are a sceptic) is down to four things:

  • Good power supplies that can sustain the rated outputs and don't 'droop' excessively.
  • Mosef amplifiers that, perhaps, clip less harshly and sound closer to valve amps.
  • Well designed cabinets with quality drivers.

None of those three is exclusive to Trace Elliot, but then:

  • A penchant for making amps with the wrong power supply when components run short, meaning there are 'under-rated' amps out there that really do sound louder than their ratings.

 

Sporry if anyone thinks I'm teaching egg-sucking...

 

  • Like 2
Posted
10 hours ago, Stub Mandrel said:

I that case you should know this , but for younger forum members let me give my perspective and perhaps explain why not all watts are created equal.

The short answer is marketing.

Keen to flog more product, Amstrad came up with the ideal of 'music power' which rated their stereos according to their capacity to handle transients, like cymbal crashes and rimshots. This made them appear at least twice as powerful as amps rated by their 'RMS' capacity.

From then on, it a simple 'wattage rating' has never been enough to accurately judge how loud an amp is in a real setting, because manufacturers use all sorts of formulas an ways of assessing power...

 

The longer answer is a mixture of practicality, psychology and marketing.

Some truth in Amstrad's approach - music (at least in the old days before the 'Loudness Wars' has its peaks and troughs. The volume of an amp isn't just its ability to deal with brief transients, it relates to the bits in between as well.

Imagine a valve amp and a transistor amp, both being fed a pure sine wave such that they are almost starting to clip. Lets assume this is at the same power level for both amps, so on paper they both have the same continuous RMS power.

Now play bass through both amps and turn up. Push the valve amp into clipping on the loudest bits and it will sound rich, push the transistor amp into clipping and it will sound harsh.

This means that you can't have the transistor amp turned up as loud for the quieter bits as the valve amp, as the transitor amp sounds overloaded when you dig in.

So  the amps have identical wattage ratings, but the valve amp can be played in a way that is louder. Effectively it is compressing the signal upwards at the cost of distortion, but a type of distortion people generally like.

 

Also, some amps have power supplies with undersized transformers or smoothing capacitors, so when played hard the voltage 'droops' and overall power drops.

 

Other things affect volume; it's easy for a well designed speaker cab to double the volume.

There's a famous test on line where a Fender HRD (40W), Vox AC30 (30W) and marshall stack (100W)  are compared and they come out in that order - yes folks, the AC30 is louder than the Marshall stack. 124.6 db, 124.1 db and 119.5 db.

https://www.harmonycentral.com/forums/topic/931152-marshall-100-watt-stack-vox-ac30-fender-hrd-how-do-they-compare-in-volume/

It's not just speaker design. I have a Vox Valvetronix which is marketed as a 20W amp, but it has a 'power control' (it's a modelling amp) and you can actually turn it up to 30 watts... so not all headline wattage ratings are exaggerated!

The biggest pitfall is that, at usual volumes (i.e. not dead quiet or super loud) a doubling of perceived volume requires a ten-times increase in power. I've played a 1-watt battery powered amp through a JCM800 1x12" cab and it was way to loud to play in the living room. Anyone with a Blackstar Fly (3W) can test this!

Most bass amps fall between 150W and 500W, with outliers  at 100W and 1000W and above. The difference between 150W and 500W RMS is pretty small and in practice the extra volume is largely down to the same thing as that valve/transistor comparison - the more powerful amps have more headroom, i.e. you can play them significantly louder without distortion.

 

As for Trace Elliot watts, I think the legend (or myth if your are a sceptic) is down to four things:

  • Good power supplies that can sustain the rated outputs and don't 'droop' excessively.
  • Mosef amplifiers that, perhaps, clip less harshly and sound closer to valve amps.
  • Well designed cabinets with quality drivers.

None of those three is exclusive to Trace Elliot, but then:

  • A penchant for making amps with the wrong power supply when components run short, meaning there are 'under-rated' amps out there that really do sound louder than their ratings.

 

Sporry if anyone thinks I'm teaching egg-sucking...

 

That must have taken you ages to type!

But there's lots of extremely useful information there.  Thanks for your input. :)

Frank.

  • Haha 1
Posted

a well, if we're going to get all sciencey about it..... 

I've been playing the bass guitar ever since I started - which I think we can all agree qualifies me.

I've only ever been told I was too loud on two occasions  Once playing through a big old Trace Elliot stack and once through an Orange Terror. 

QED. 

👨‍🔬

  • Haha 2
Posted
9 hours ago, machinehead said:

That must have taken you ages to type!

But there's lots of extremely useful information there

I did think of sticking it on my website...

Posted

 

On 23/08/2019 at 11:25, hooky_lowdown said:

Check out the Acoustic (brand) forum's, where experts, including engineers who actually made them can answer questions you may have.

I've owned a couple of old Acoustic amp heads and they are far, far, far louder than equivalent modern watts.

The 361 head was rated at 200W, but no impedance was stated. It was sold as a system with the folded horn cabinet ( again no impedance stated). The secret ( in my opinion) is the folded horn cabinet. Compared to a modern ported/ bass reflex design it should be 3-10dB more sensitive. 3dB is the equivalent of doubling the amplifier power ( but not be significantly louder). 10dB would be twice as loud but equivalent to an amplifier power of ten times.

The 361 would be lower powered than the 250W Trace Heads and ( possibly) slightly higher powered than the 150/130W variants BUT the difference would be barely audible.

Posted
35 minutes ago, Chienmortbb said:

The 361 would be lower powered than the 250W Trace Heads and ( possibly) slightly higher powered than the 150/130W variants BUT the difference would be barely audible.

I had an Acoustic 450 bass head (which I think was 170 watts output), running through a 4x10 cab rated at 8 ohms, which was literally twice as loud (audibly) as an Ashdown Mag 300 Evo bass head (rated at 307 watts) using the same cab. I'd also suggest an 80's Trace head rated at 130/150 watts would also be significantly louder than the Ashdown.

Posted
3 hours ago, hooky_lowdown said:

I had an Acoustic 450 bass head (which I think was 170 watts output), running through a 4x10 cab rated at 8 ohms, which was literally twice as loud (audibly) as an Ashdown Mag 300 Evo bass head (rated at 307 watts) using the same cab. I'd also suggest an 80's Trace head rated at 130/150 watts would also be significantly louder than the Ashdown.

Having now got my combo working 100% again, I had a go this morning and wired it up with an extension cab for a theoretical 300W, noting that the 4x10 speakers are now in phase, which definitely made the bass sound more solid.

With the input gain on 7 (not near clipping the way I was playing), pre-shape and about 3dB of bottom end boost I cranked it up.

At an output gain of 7 there were so many things rattling around the living room I chickened out of going louder. No sign  of distortion.

My perception is that it's louder than an Ashdown 500 through a single 15, but I would have to a/b them to be sure.

But it is loud, very loud and I can't see myself needing louder.

Posted (edited)
18 hours ago, Stub Mandrel said:

Having now got my combo working 100% again, I had a go this morning and wired it up with an extension cab for a theoretical 300W, noting that the 4x10 speakers are now in phase, which definitely made the bass sound more solid.

With the input gain on 7 (not near clipping the way I was playing), pre-shape and about 3dB of bottom end boost I cranked it up.

At an output gain of 7 there were so many things rattling around the living room I chickened out of going louder. No sign  of distortion.

My perception is that it's louder than an Ashdown 500 through a single 15, but I would have to a/b them to be sure.

But it is loud, very loud and I can't see myself needing louder.

This is what matters: "I can't see myself needing anything louder"

pre shape and boosting the bass will make it louder, but you do it because it's the sound you want. 4x10's are louder, all other things being equal, than 1x15's. The input gain doesn't matter a fig, you can have a 1W amp with lots of gain or a 1,000,000W amp with low gain. Gain and power aren't linked.

I kind of love the blank incomprehension of these threads. A watt is a watt, there's nothing magic about TE watts or any old watts v's new watts but lot's of technical reasons why people might think one amp is louder than another. For people with a love of Trace amps nothing else will do, they are just sharing the love with others who share their passion. For techies a watt is a watt so long as it's measured properly. We worry about people making poor purchases based on mythology or advertising hype. We can run on for more than four pages about all this :)

In the end though this isn't about MMR vaccination or using homeopathic medicine to cure cancer, it's about people getting pleasure from a sound they love.

We should cherish those who love vintage as much as those who want to help by sharing expertise. It's all good fun over a coffee break spent on Basschat.

 

Oh, well done for getting your combo back on the road Stub

 

Edited by Phil Starr
  • Like 1
Posted
34 minutes ago, Phil Starr said:

pre shape and boosting the bass will make it louder, but you do it because it's the sound you want. 4x10's are louder, all other things being equal, than 1x15's. The input gain doesn't matter a fig, you can have a 1W amp with lots of gain or a 1,000,000W amp with low gain. Gain and power aren't linked.

A few thoughts -not meant as argument, just adding detail!

Seeing as my 4x10 has had the Celestions swapped out for Alpha 10A it probably hasn't got brilliant bottom end. An A/B  with the 15" confirms this and I like the tone I get with them both regardless of volume (plus it LOOKS the part 🙂

I was just mentioning that to give people an idea of settings 🙂 Really I should have it on 8 (clips if I really dig in) for that bass but of course it varies from instrument to instrument. two reasons for that (1) obviously it makes swapping instruments predictable (2) the input gain really is 'gain' not volume and appears to be wired to have a non-linear frequency response so where you have it affects the sound; in another thread people mentioned how having it too low gives a poor tone. I may be wrong, but to me it looks like it's wired to give a 'loudness' contour and roll the treble off faster than the deep bass - this possibly leads to lack of presence at low input gains? I'd be interested in a second opinion on this:

image.png.4e83f21ee20009bea2055ff30aa036dd.png

No doubt another element of the TE sound, but no, it doesn't affect total power...

Posted

I'm quite rusty on electronics and I don't know what value those capacitors are but C1 and C2 just look like DC decoupling to me, They may well be rolling of the bass, C2 at least which is nice as it means you can boost bass by 3db without over excursion of the speakers low down below the port frequency. I'd have to go back and look at the whole circuit but I'll guess Trace designed a decent roll off in to make the most of those watts. It's a nice feature of old single ended power supplies. It's possible the values chosen will affect response but yeah it is a 'proper' gain control rather than just allowing you to overload the next stage.

In the end you have to trust your ears.

The Alpha's have poor damping of the one movement, the old Celestions may not have been much better as they tended to be under damped too. Is the cab sealed?  in any case the underdamped cone will jump around at relatively high bass frequencies and roll off early so you'll have plenty of warmth but little deep bass, I quite like that sound playing live. 

Sorry I didn't offer to help on your other thread, which I followed with interest

 

Posted
5 hours ago, Phil Starr said:

For techies a watt is a watt so long as it's measured properly.

And that is at the root of the problem. 

There is no ‘proper’ way of measuring them. 

Posted
5 hours ago, Phil Starr said:

I kind of love the blank incomprehension of these threads. A watt is a watt, there's nothing magic about TE watts or any old watts v's new watts but lot's of technical reasons why people might think one amp is louder than another.

I think it’s the lots of technical reasons that people don’t know enough about (myself included). Eg Gain and volume 

Posted
31 minutes ago, TimR said:
6 hours ago, Phil Starr said:

For techies a watt is a watt so long as it's measured properly.

And that is at the root of the problem. 

There is no ‘proper’ way of measuring them. 

 

Posted
22 minutes ago, Stub Mandrel said:

 

80s Whotsits were more yellow and hence much more powerful. The new Wotsits are less yellow and hence less powerful which is why they now come in bigger packets containing more of them.

  • Haha 2
Posted
16 minutes ago, TimR said:

80s Whotsits were more yellow and hence much more powerful. The new Wotsits are less yellow and hence less powerful which is why they now come in bigger packets containing more of them.

Any food technichian will tell you Wotsits are Wotsits, they just change the packaging... 🤣

Posted

The best thing is that we can take or leave both the tongue in cheek Trace Elliot Watts and the ultra technical A Watt is A Watt. 

Certainly no reason for anyone to get grumpy. 

For me the exciting thing to come from these threads is when I learn something. By staying out of the brouhaha I can do that. 

  • Like 1
Posted
1 hour ago, stewblack said:

The best thing is that we can take or leave both the tongue in cheek Trace Elliot Watts and the ultra technical A Watt is A Watt. 

Certainly no reason for anyone to get grumpy.

It's no coincidence that 10% of the UK was left without power when I was testing my amp...

  • Like 2
Posted
8 hours ago, Stub Mandrel said:

It's no coincidence that 10% of the UK was left without power when I was testing my amp...

OK, maybe they had a reason to get grumpy 

  • Haha 1
Posted

James Watt leaned back in his chair, stretching the feeling back into his tired limbs. Three hours he'd pondered the strange missive he'd received that afternoon - no progress had been made on his new efficiency calculations.

"Trace fecking WHO ?"

  • Haha 1
Posted

Something which may have been overlooked is that the more speaker surface area, the louder also. A 410 vs 115 using the same amp and ohms, the 410 will be far louder.

I saw a band called Death From Above 1979 many years ago, by far the loudest gig I've ever been to (no PA support), Jesse was running an Acoustic and Peavey heads through two 810's with PA speakers. Bloody LOUD!

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