Jad Freer Sisma Mega Thread.

[gtirard]

It would be hard to resume 20 y in a forum for sure. But I don't understand why one brand say this amp is 900W and this is 700W but when I play through them there is not one that is louder than another. Is it because it is the exact same power amp module ?

There are many parameters:
- first the difference between 700 and 900 W is not as big as it seems - it take 10x the power for an amp to be twice louder. So the difference between 700 and 900 W is barely audible.
- some amps deliver 80% for their power when the volume knob is at noon, others 50%
- influence of the preamp, tone stack etc on the perceived output volume

 

[Franz975]

There are many parameters:
- first the difference between 700 and 900 W is not as big as it seems - it take 10x the power for an amp to be twice louder. So the difference between 700 and 900 W is barely audible.
- some amps deliver 80% for their power when the volume knob is at noon, others 50%
- influence of the preamp, tone stack etc on the perceived output volume

Yep I know that, it is why I "don't like" that marketing because if feel like (if you are not aware of) that 200W is way louder but it is not lol.
Mmh I feel like the bergantino have a volume change on all the knob from 0 to 100% and the darkglass is pretty much maxed at 50%

 

[agedhorse]

Yep I know that, it is why I "don't like" that marketing because if feel like (if you are not aware of) that 200W is way louder but it is not lol.
Mmh I feel like the bergantino have a volume change on all the knob from 0 to 100% and the darkglass is pretty much maxed at 50%

That is part of the perception, the taper of the controls plays very much into what the player may feel, and may result in an inaccurate perception.

None of the marketing that we do implies that 800 watts is way louder than 700 watts or whatever. Our lower powered model is 350 watts and a reasonable difference that most players can easily discern.

There are differences in how the different implementations of the same power amp can feel, and the perception of loudness by manipulating crest factor, overload characteristics and behavior when driven beyond its rated power.

 

[Franz975]

That is part of the perception, the taper of the controls plays very much into what the player may feel, and may result in an inaccurate perception.

None of the marketing that we do implies that 800 watts is way louder than 700 watts or whatever. Our lower powered model is 350 watts and a reasonable difference that most players can easily discern.

There are differences in how the different implementations of the same power amp can feel, and the perception of loudness by manipulating crest factor, overload characteristics and behavior when driven beyond its rated power.

No I don't say that marketing told us that 800 is way more than 700 but like, for someone who want an amp and don't know which one to get, 800 is more attractive than 700 even if the difference isn't incredible.

I talk to someone who explain to me why Tube amp and Class A/B amp (Carbine M3, M6, SVT3pro, etc) can move more air than a Class D amp even with less power.

Because a 300W class A/B like an M3 carbine is not more powerfull than an Ampeg SVT7 pro with 1000 watts but it can definitely push more air. They explained me some things about the power supply that are in those amp, technology etc, ...
There is way more voltage that goes in Tube, Mosfet amp than in a Class D and this is why it can push more air than a smaller amp.

 

[agedhorse]

No I don't say that marketing told us that 800 is way more than 700 but like, for someone who want an amp and don't know which one to get, 800 is more attractive than 700 even if the difference isn't incredible.

I talk to someone who explain to me why Tube amp and Class A/B amp (Carbine M3, M6, SVT3pro, etc) can move more air than a Class D amp even with less power.

Because a 300W class A/B like an M3 carbine is not more powerfull than an Ampeg SVT7 pro with 1000 watts but it can definitely push more air. They explained me some things about the power supply that are in those amp, technology etc, ...
There is way more voltage that goes in Tube, Mosfet amp than in a Class D and this is why it can push more air than a smaller amp.

The Carbine M3 absolutely cannot “push more air” than the SVT 7 PRO. There is NOT more voltage either, that’s an absurd statement. There is more voltage on the SVT 7 PRO than the Carbine M3.

This is where facts matter and why voicing often plays a greater role in perceived volume than power.

Power is important to know because this will play an important role in the selection of appropriate speakers, and when combined with the speaker’s sensitivity, give a good extrapolation of maximum volume and suitability for a particular application.

 

[Franz975]

The Carbine M3 absolutely cannot “push more air” than the SVT 7 PRO. There is NOT more voltage either, that’s an absurd statement. There is more voltage on the SVT 7 PRO than the Carbine M3.

This is where facts matter and why voicing often plays a greater role in perceived volume than power.

Power is important to know because this will play an important role in the selection of appropriate speakers, and when combined with the speaker’s sensitivity, give a good extrapolation of maximum volume and suitability for a particular application.

Power and speaker match is something to do correctly from what I understand. They build amp too, and they have compare an M3 or m6 carbine to an SVT7pro. To them there was a clear winner that destroy the other.

 

[agedhorse]

Power and speaker match is something to do correctly from what I understand. They build amp too, and they have compare an M3 or m6 carbine to an SVT7pro. To them there was a clear winner that destroy the other.

As always, you are entitled to your opinion, but why ask questions when you already know the answers and are unwilling to consider the information being provided?

 

[Franz975]

As always, you are entitled to your opinion, but why ask questions when you already know the answers and are unwilling to consider the information being provided?

I looked at the information and your experience but when even guys that are 20, 30, 40, 50 years older than me think that one is more impressive than the other what am I supposed to say considering your informations

If you have try amp (way more than me I am sure of that) you know that there are some amp that when you plug in you are impressed and other no, or not at all even if the spec are supposed to be impressive.

It is why when I have seen the JF Sisma for the first time I was like what is class G, are those 700W "real" and not another marketing stuff (like an amp I don't remember the name that say "Hey we make a 2000W class D amp that cost only 400$", and the 2000W is maybe there....at 25 kHz. Because a bass amp with 300W at 80Hz feel much more powerfull than an amp with 300W at 20kHz.
Now after looking at this thread, the comment, the reviews the though etc I know that the Sisma is no joke, sound great, perform great, outperform some other design.
I definitely want to learn more but maybe it would be better to talk about that in PM so ? :/ Because I want to understand all those things/infos that I see ahah

 

[agedhorse]

Spend some time learning about how amps actually work before making incorrect technical statements. I have provided lots of information but you still haven’t grasped the basics of how voicing and dynamics impact the perception of volume. This is “amplifier 101”.

 

[Franz975]

Spend some time learning about how amps actually work before making incorrect technical statements. I have provided lots of information but you still haven’t grasped the basics of how voicing and dynamics impact the perception of volume. This is “amplifier 101”.

Have you compare the Sisma to any other amp ?
I listen to your information but I feel like there is no amp louder than another it is just the "voicing".

I really want to hear a SUNN 300T 300watts side by side with a Mesa 350watts class D, if it is really push the same amount of air I would be impressed but I really doubt about that.

 

[agedhorse]

Have you compare the Sisma to any other amp ?
I listen to your information but I feel like there is no amp louder than another it is just the "voicing".

I really want to hear a SUNN 300T 300watts side by side with a Mesa 350watts class D, if it is really push the same amount of air I would be impressed but I really doubt about that.

I can not compare a competitor’s amp to any I designed, it’s against the commercial user policy.

I am providing accurate information regarding the technology and why you might have perceptions that appear to conflict with the numbers, even though they don’t when voicing and dynamics are addressed.

I have designed commercial power amplifiers of all technologies, I am plenty familiar with the realities and the mythologies behind them.

 

[DJ Bebop]

I really want to hear a SUNN 300T 300watts side by side with a Mesa 350watts class D, if it is really push the same amount of air I would be impressed but I really doubt about that.

Why do you doubt it?

 

[Franz975]

I can not compare a competitor’s amp to any I designed, it’s against the commercial user policy.

I am providing accurate information regarding the technology and why you might have perceptions that appear to conflict with the numbers, even though they don’t when voicing and dynamics are addressed.

I have designed commercial power amplifiers of all technologies, I am plenty familiar with the realities and the mythologies behind them.

I wasn't aware of that. The people I know that design good sounding amp try a lot of amp and compare them to know what sound the best.

I try to understand what you are explaining with your number, but I don't understand because when I feel something that is completely different than what is on the paper it doesn't make sense to me.

But what is your though on the Sisma amp/poweramp design and the general design behind it ? Making a preamp based on a B15 and an homemade poweramp is a good idea in your experience of amp maker ?
What do you think of Class G amp in general in comparison to other style of Power amp etc... ?

This would be much more interesting to know/learn from you than comparing thing like I did.

 

[Franz975]

Why do you doubt it?

Because one is like oh it is loud and the other is oh I am deaf now and I poop myself

 

[Jeff Scott]

I can not compare a competitor’s amp to any I designed, it’s against the commercial user policy.

I wasn't aware of that. The people I know that design good sounding amp try a lot of amp and compare them to know what sound the best.

I am pretty sure Andy is referring to the CU policy of TB, in that he can't discuss comparisons like us common fodder can. It is against the rules of this forum for a CU to do so.

 

[Franz975]

I am pretty sure Andy is referring to the CU policy of TB, in that he can't discuss comparisons like us common fodder can. It is against the rules of this forum for a CU to do so.

Yeah sure but it would be really nice to have his though on the Sisma, the overall design without comparing it to his own design

 

[DJ Bebop]

I try to understand what you are explaining with your number, but I don't understand because when I feel something that is completely different than what is on the paper it doesn't make sense to me.

I'm not answering for him, just giving my observations.

Besides the numbers, many people have tried to explain it without the numbers about how different amp companies voice their amps. How many amps set flat on their respective equalizers don't always reflect an actual clinically flat setting. One might boost the bass while another might hollow out the mids with the same setting of flat. They voice their preamps differently, hence the amps respond and sound differently.

One amp can sound louder at a quarter of the volume knob whereas another amp needs its volume knob at halfway to achieve the same volume. Yet the first amp at its quarter volume being louder may not have any more volume to give.

Cabinets also play a part in this as well. Not the same cabinets on the different amps can mask how they perform from one to the other. Some cabinets sound better with certain amps and visa verse. All of this and more, including the numbers will make the difference from one amp to another, understandable.

Those that understand this have no problem understanding the potential differences from one amp to another.

Still after it's all said and done, people like what they like. Regardless of what they know or understand.

 

[DJ Bebop]

Because one is like oh it is loud and the other is oh I am deaf now and I poop myself

So, you've heard them already?

 

[DJ Bebop]

Yeah sure but it would be really nice to have his though on the Sisma, the overall design without comparing it to his own design

Well one thing, we can't hear one, only on YouTube and sound samples because you can't import one into our country to try.

 

[faulknersj]

Yeah sure but it would be really nice to have his though on the Sisma, the overall design without comparing it to his own design

It would be awesome for you to get a Sisma and let us know how it is. We are all here because we are interested in it and I just bought an Aguilar DB 751 so it’s your turn!