Hybrid amps - yes or no?

[Mikey R]

28 minutes ago, LukeFRC said:

In this test Are you measuring it to achieve the same level of distortion? 

You're touching on psychoacoustic effects there.

A real experiment would have to be very complicated. But as a starter for 10, you could connect a 4 ohm dummy load across the output, and connect a a 440hz square wave from a function generator to the input. That way, clipping will have minimal effect - the signal is already clipped. Increase the input until the voltage across the output doesn't increase any further.

The voltage across the dummy load squared divided by 4 would then tell you how much power the amp is putting out at 440hz. Ideally, you'd repeast at 220, 110 and 55hz to get a fuller picture.

This will give you continuous power output. To get peak power output, you would have to drive the input with pulses of waveform.

It's not perfect, but it would give you an idea of how the two amps fare objectively. I wouldn't be surprised if the class AB amp does better in continuous output, by quite a margin.

21 minutes ago, artisan said:

Gigged my CTM100 through my fender bassman neo 410 on a pretty big outdoor stage this afternoon.

Input gain at 10 o'clock & master at 3 o'clock & it was bloody loud on stage, awesome trouser flapping  sound too,you'll never get that from a class D.

Plus the valves react to how you play beautifully.

 

Thanks Artisan! Thats exactly the feedback I wanted to hear. I wanted to know that there are at least some people out there who "get" the value amp thing. OK, now I'm showing my bias, I'm also a valve guy.

[artisan]

Lol good man.

They are just so dynamic,play gently & you're rewarded with a delicious creamy tone,but dig in but & you get a really nice snarl for your effort.

Love it 👍

[taunton-hobbit]

Matamp hand-build some very good all valve kit (I know, I own a couple)

Their prices aren't silly either (no, they don't pay me)........😁

[xgsjx]

There’s some great tube emulators out there for pre amps that can sound identical to tube preamps, but there’s the visual side of tubes. 

As for power sections, tubes do sound different. 

I loved my all solid state MarkBass amp. I also love the sound & look of my Radiovox amp, but it weighs more than my car and has no DI. 

I could do with another light amp for most gigs. 

[Muzz]

This is an emotive and subjective a topic as 'Jazz or Precision?' or even 'Rock or Jazz?', and as pointless as either. It's entirely down to what each person wants from an amp,  what they can hear (or what they think they can hear) or not, and what they ultimately want to own. And let's not forget the cabs, too, which can colour the output of any amp...

[discreet]

Preference is one thing, practicalities are another. IME you just can't beat a 70s P Bass through an Ampeg SVT-CL and an 8X10. This is my preference. But for various (and very good) reasons I actually use a small Class D Combo. Life is full of compromise...

[Mikey R]

5 hours ago, Muzz said:

This is an emotive and subjective a topic as 'Jazz or Precision?' or even 'Rock or Jazz?', and as pointless as either. It's entirely down to what each person wants from an amp,  what they can hear (or what they think they can hear) or not, and what they ultimately want to own. And let's not forget the cabs, too, which can colour the output of any amp...

Hi Muzz, I agree it's subjective, which is why I'm asking for people's opinions. I want to know if there are people out there who do like valve and hybrid kit.

I'm sorry you're not finding this conversation it useful, I can assure you that I am.  Hopefully, I'll be able to explain why in a few weeks.

[Mikey R]

6 hours ago, xgsjx said:

There’s some great tube emulators out there for pre amps that can sound identical to tube preamps, but there’s the visual side of tubes. 

As for power sections, tubes do sound different. 

I loved my all solid state MarkBass amp. I also love the sound & look of my Radiovox amp, but it weighs more than my car and has no DI. 

I could do with another light amp for most gigs. 

Hi xgsjx, would you find any amp more useful with a DI? What is your opinion on effects loops, yes or no? If yes, what do you use them for?

Cheers!

 

5 hours ago, discreet said:

Preference is one thing, practicalities are another. IME you just can't beat a 70s P Bass through an Ampeg SVT-CL and an 8X10. This is my preference. But for various (and very good) reasons I actually use a small Class D Combo. Life is full of compromise...

You can own something nice, and only bring it out for special occasions. Many of us here have several basses, and play them all, even though we might only use the one for live work.

[xgsjx]

5 hours ago, Mikey R said:

Hi xgsjx, would you find any amp more useful with a DI? What is your opinion on effects loops, yes or no? If yes, what do you use them for?

Cheers!

I often DI through PA.  Most of the time I use no backline, just IEM.  It would be good to bring the valve amp & 4x10 along sometime.

As for fx loop, my amp doesn't have one.  The MarkBass had one, but I never used it either.  FX loop is more for rack fx rather than pedals.

[LukeFRC]

On 25/08/2018 at 22:27, Mikey R said:

You're touching on psychoacoustic effects there.

A real experiment would have to be very complicated. But as a starter for 10, you could connect a 4 ohm dummy load across the output, and connect a a 440hz square wave from a function generator to the input. That way, clipping will have minimal effect - the signal is already clipped. Increase the input until the voltage across the output doesn't increase any further.

The voltage across the dummy load squared divided by 4 would then tell you how much power the amp is putting out at 440hz. Ideally, you'd repeast at 220, 110 and 55hz to get a fuller picture.

This will give you continuous power output. To get peak power output, you would have to drive the input with pulses of waveform.

It's not perfect, but it would give you an idea of how the two amps fare objectively. I wouldn't be surprised if the class AB amp does better in continuous output, by quite a margin.

I think that the phycoacoustic effects are the crux of the issue. All amplifiers are amplifying a signal - if all worked perfectly then there would be no difference between them - so the bits we are hearing that form a preference are the deficiencies from perfection. 

I think comparing like for like distortion levels is one of the key things- someone earlier compared a 300w valve ashdown with a solid state of the same preamp and said there wasn’t much difference between them as they weren’t pushing the valve power stage enough... 

if I took a solid state amp and added some pleasing distortion and some gentle compression like you would get in an all valve amp would you tell the difference? (Which I guess is part of the point of hybrid amps) 

silmiarly class D get a bad press as when turned up beyond the clean limits a class AB adds distortion (which make it seem louder) where as a class D just runs out of power. Hence “class D has no heft” is as much about the phycoacoustic effects as the amplification system. 

[Mikey R]

2 hours ago, LukeFRC said:

I think that the phycoacoustic effects are the crux of the issue. All amplifiers are amplifying a signal - if all worked perfectly then there would be no difference between them - so the bits we are hearing that form a preference are the deficiencies from perfection. 

I think comparing like for like distortion levels is one of the key things- someone earlier compared a 300w valve ashdown with a solid state of the same preamp and said there wasn’t much difference between them as they weren’t pushing the valve power stage enough... 

if I took a solid state amp and added some pleasing distortion and some gentle compression like you would get in an all valve amp would you tell the difference? (Which I guess is part of the point of hybrid amps) 

silmiarly class D get a bad press as when turned up beyond the clean limits a class AB adds distortion (which make it seem louder) where as a class D just runs out of power. Hence “class D has no heft” is as much about the phycoacoustic effects as the amplification system. 

Hi Luke. I don't think anything you said was wrong, but I do believe that the power output of class D amps is calculated differently, and therefore is inflated relative to how valve amps are rated.

I do believe valve amps are rated at continous sine wave output, as that is how the output stages of radios were tested back in the 50s. The limit for any amp is how much juice the power supply can, erm, supply. In class AB, this sets the maximum voltage swing, but also how that voltage sags as current is drawn. If the voltage doesn't sag, then the power output can be maintained infedinitely.

The rating system changed sometime in the 70s or 80s, and things like peak power output were invented to make hi-fi amps seem louder on paper. Some of this would have leaked into instrument amp specs, as transistor output stages became popular. I'm going to have to google "peak programme" and remind myself of all of this.

Then class D came along, and they are complicated beasts. OEMs buy their output boards wholesale, meaning that they have very little control over what is in their amps. If they use a 300 watt board originally designed for a car stereo, then they'll rate their amp at 300 watts. It may be able to handle very short bursts of 300 watts during the loud sections of classical music, but it couldn't keep that up if the signal was all bass guitar.

So, I don't think we are comparing like for like, even if we remove the effects of how valves compress as they are driven into clipping.

I'd also point out that modern valves don't kick out as much juice as NOS valves do. A 6550 pair, with 600 volts on the anode and 300 volts on the screen, dring a 5k anode to anode load, used to output 100 watts. If you use modern valves, you'll get around 70 watts, you need to increase the screen voltage to 400 volts to get the full 100 watt output, and that would be very hard on the valves. Even so, modern amp builders still rate their amps as if they had NOS valves, even though they don't ship with them. Your 100 watt amp is actually kicking out 70 watts, and it's still louder than a 300 watt class D.

[discreet]

8 hours ago, Mikey R said:

You can own something nice, and only bring it out for special occasions. Many of us here have several basses, and play them all, even though we might only use the one for live work.

Multiple basses are fine, but keeping a large and expensive Ampeg fridge just for home use is not!

[Muzz]

9 hours ago, Mikey R said:

Hi Muzz, I agree it's subjective, which is why I'm asking for people's opinions. I want to know if there are people out there who do like valve and hybrid kit.

I'm sorry you're not finding this conversation it useful, I can assure you that I am.  Hopefully, I'll be able to explain why in a few weeks.

I don't mean to be dismissive, it's just it's been done an awful lot, on all sorts of threads whether they start off that way or not (and it's become quite snippy sometimes, too, as fanbois of all kidney clash antlers), and what it boils down to is every type of amp, whether it's all solid-state, or hybrid, or reverse-hybrid (by which I mean solid state tone stack and valve power) or full valve, will have its fans, and a lot of that will be dictated by personal GAS/brand loyalty (people who always wanted an Ampeg/Mesa/whatever), personal circumstances (size and weight for gigging, ageing backs, etc), folk who can really hear the difference and to whom it's very important, and of course good old implicit peer pressure, marketing and fashion.

If there weren't people who like valve and hybrid kit, it wouldn't sell, but if you're thinking in any sort of commercial terms, this place is a microcosm of cork-sniffers (and I don't mean that in a negative sense: the level of technical knowledge, experience and, for want of a better word, connoisseur accessible here is very high indeed) and is dwarfed by the number of bassists out there who, for example, buy Ashdown (or Fender or Peavey or Markbass, etc...) because it's out there in the shops and on stages, and they can get a sound/volume out of it they like, without analysing it anywhere near as much as folk on here (and I'm including myself here) do.

On the numbers font, I think in terms of a lot of the buying public, an 800w Class D amp LOOKS louder than a 200w valve amp, and that (along with the fact that the new 800w Class D output stages really deliver) is what sells. Similarly, with cabs, there's no NEED any more (see the FRFR-Killing-Rock-N-Roll-one-slipped-disc-at-a-time thread) for a big stack of 8x10s or 2x412s down the Fox and Gynecologist, and all the logistical hoohah that entails, but people still love the look and will do awhile yet.

Edited August 27, 2018 by Muzz

[discreet]

2 minutes ago, Muzz said:

kidney clash antlers

Best band name of the day. So far.

[Muzz]

2 minutes ago, discreet said:

Best band name of the day. So far.

I knowwwww...I just reread that sentence and couldn't quite believe I'd written it. It's a slow Bank Holiday, after all... 😑

[Mikey R]

1 hour ago, discreet said:

Multiple basses are fine, but keeping a large and expensive Ampeg fridge just for home use is not!

 I clearly didn't get the memo. I nearly have as many amps as I do guitars.

47 minutes ago, Muzz said:

I don't mean to be dismissive, it's just it's been done an awful lot, on all sorts of threads whether they start off that way or not (and it's become quite snippy sometimes, too, as fanbois of all kidney clash antlers), and what it boils down to is every type of amp, whether it's all solid-state, or hybrid, or reverse-hybrid (by which I mean solid state tone stack and valve power) or full valve, will have its fans, and a lot of that will be dictated by personal GAS/brand loyalty (people who always wanted an Ampeg/Mesa/whatever), personal circumstances (size and weight for gigging, ageing backs, etc), folk who can really hear the difference and to whom it's very important, and of course good old implicit peer pressure, marketing and fashion.

If there weren't people who like valve and hybrid kit, it wouldn't sell, but if you're thinking in any sort of commercial terms, this place is a microcosm of cork-sniffers (and I don't mean that in a negative sense: the level of technical knowledge, experience and, for want of a better word, connoisseur accessible here is very high indeed) and is dwarfed by the number of bassists out there who, for example, buy Ashdown (or Fender or Peavey or Markbass, etc...) because it's out there in the shops and on stages, and they can get a sound/volume out of it they like, without analysing it anywhere near as much as folk on here (and I'm including myself here) do.

On the numbers font, I think in terms of a lot of the buying public, an 800w Class D amp LOOKS louder than a 200w valve amp, and that (along with the fact that the new 800w Class D output stages really deliver) is what sells. Similarly, with cabs, there's no NEED any more (see the FRFR-Killing-Rock-N-Roll-one-slipped-disc-at-a-time thread) for a big stack of 8x10s or 2x412s down the Fox and Gynecologist, and all the logistical hoohah that entails, but people still love the look and will do awhile yet.

Thats fair enough. I've been away for a while, and have missed out on shifts in the BC culture during that time, and what has and hasn't been flogged to death. When I used to read the Luthiers Corner on Talk Bass, there were sigh inducing reruns of tonewood discussions almost weekly,  with as much misinformation circulating as there are on the merits of values vs transistors.

The very reason I came here to guage the general feeling of valve kit, is that the BC bunch do sniff the corks, they are the kind of players who enjoy experimenting with top of the range kit, and they are a good representation of the kinds of players a small boutique company would target. The premium kit is subject to fashion, and fashion changes over time. I just wanted to check that valves and hybrids haven't gone out of fashion, because that would be a real shame.

They're also a really nice bunch who are happy to share their experiences, of which we have amongst us a huge stockpile.

[discreet]

1 minute ago, Mikey R said:

 I clearly didn't get the memo. I nearly have as many amps as I do guitars.

Nothing wrong with that. I much prefer a large all-valve rig, but the bottom line is I can't afford to have one hanging around if it's not being used. In fact I can't afford to have one, period. Most gigs I do these days are on tight stages and my current band plays quietly. I'm happy enough with my Rumble V3 500 combo, which sounds pretty organic for a Class D amp. It's all I need.

[Mikey R]

"It's all I need" - never before have I heard these words on BC!

[Merton]

11 minutes ago, Mikey R said:

"It's all I need" - never before have I heard these words on BC!

It gets written a lot, followed the next week with a NAD or NBD thread.

Normally all written by me 🤓

[discreet]

9 minutes ago, Mikey R said:

"It's all I need" - never before have I heard these words on BC!

It's a lie, of course. I have GAS for an Ampeg PF-50T. 

[pete.young]

5 hours ago, LukeFRC said:

Isilmiarly class D get a bad press as when turned up beyond the clean limits a class AB adds distortion (which make it seem louder) where as a class D just runs out of power. Hence “class D has no heft” is as much about the phycoacoustic effects as the amplification system. 

An observation: my LMII is class AB and doesn't seem to add any audible distortion. Is this true for all class AB?

[Mikey R]

3 hours ago, pete.young said:

An observation: my LMII is class AB and doesn't seem to add any audible distortion. Is this true for all class AB?

Hi Luke, it depends on how linear the amp is, or how soon the overdrive kicks in. But eventually, every amp of every class will hit the upper limit set by the supply rails, even the most linear. When that happens, theres nothing to stop it from clipping.

I suppose, if your amp had a limiter, then that could prevent this from happening.

Edited August 27, 2018 by Mikey R

[LukeFRC]

4 hours ago, pete.young said:

An observation: my LMII is class AB and doesn't seem to add any audible distortion. Is this true for all class AB?

I think it’s true for all amps of all classes. It’s more a point that if you are comparing a 100w valve amp pushed to gentle distortion and with some nice musical compression it might very well sound louder than a 400w Markbass LM11 which will have comparative little distortion until it hits its limiter. 

I think I’m with Muzz - in an ideal world valve amps sound nice so we might all have them - then you want something solid state and you can get lighter and debatedly cheaper to run amps, and you know what people design in different electronic designs to get different sounds... some of them might have a valve in the preamp but that alone doesn’t mean much... some valve preamps are super clean, others designed to add some pleasing valve distortion... but I don’t think having a valve or not is the point - do you like the sound of your Mesa walkabout or do you like the sound of your thunderfunk? I don’t think hybrid or not is the determining factor. Actually - if I wanted a more portable version of a valve amp a Line6 Helix into a FRFR speaker would be another viable option.

[Mikey R]

40 minutes ago, LukeFRC said:

I think it’s true for all amps of all classes. It’s more a point that if you are comparing a 100w valve amp pushed to gentle distortion and with some nice musical compression it might very well sound louder than a 400w Markbass LM11 which will have comparative little distortion until it hits its limiter. 

I think I’m with Muzz - in an ideal world valve amps sound nice so we might all have them - then you want something solid state and you can get lighter and debatedly cheaper to run amps, and you know what people design in different electronic designs to get different sounds... some of them might have a valve in the preamp but that alone doesn’t mean much... some valve preamps are super clean, others designed to add some pleasing valve distortion... but I don’t think having a valve or not is the point - do you like the sound of your Mesa walkabout or do you like the sound of your thunderfunk? I don’t think hybrid or not is the determining factor. Actually - if I wanted a more portable version of a valve amp a Line6 Helix into a FRFR speaker would be another viable option.

In some cases, such as some of the less expensive iphone docks that were popular a couple years ago, the preamp valve was nothing more than a marketting gimic. We know a large part of the valve tone comes from the interaction between the power pentodes, the output transformer, and the speakers, a single preamp triode won't simulate that.

Yes, there is a psychoacoustic effect of all those nice harmonics. It doesn't necessarily matter how those harmonics are generated. But it's proven to be very difficult to get it dead on, in a way that not only gets the harmonic content right, but also the timing and phase of those harmonics. You don't only need to trick the ears of the listener, you need to trick the ears of the player, who is well within the feedback loop of ears to brain to bass to amp to speaker back to ears.

Interestingly, the best amps to play aren't necessarily the best amps for the mix.

[LukeFRC]

2 hours ago, Mikey R said:

In some cases, such as some of the less expensive iphone docks that were popular a couple years ago, the preamp valve was nothing more than a marketting gimic. We know a large part of the valve tone comes from the interaction between the power pentodes, the output transformer, and the speakers, a single preamp triode won't simulate that.

Yes, there is a psychoacoustic effect of all those nice harmonics. It doesn't necessarily matter how those harmonics are generated. But it's proven to be very difficult to get it dead on, in a way that not only gets the harmonic content right, but also the timing and phase of those harmonics. You don't only need to trick the ears of the listener, you need to trick the ears of the player, who is well within the feedback loop of ears to brain to bass to amp to speaker back to ears.

Interestingly, the best amps to play aren't necessarily the best amps for the mix.

.... and the FOH is coming from the DI box the tech uses...