New Hybrid Single Ended Power and Stereo Amplifiers - Feedback/Poll needed

[Mike Lavigne]

Sorry Mike confused you with another Mike (maybe someone on TV)

Why would it have to be the best sounding when it could just be the best sounding to its relative price point SS or Tube?

because it's a non traditional category of amps so there is no built in marketplace. there are lots of 'good sounding' inexpensive amplifiers. it will take something exceptional for 25 watt 'intenders' to seriously consider it.

maybe someone doing tri-amping or such use might think about it as it would be low noise. but how many people are in that category? very few. not enough to support the cost of development. so unless it's very special sounding I don't see it.

 

[Believe High Fidelity]

because it's a non traditional category of amps so there is no built in marketplace. there are lots of 'good sounding' inexpensive amplifiers. it will take something exceptional for 25 watt 'intenders' to seriously consider it.

maybe someone doing tri-amping or such use might think about it as it would be low noise. but how many people are in that category? very few. not enough to support the cost of development. so unless it's very special sounding I don't see it.

A very good point.

 

[Audiophile Bill]

I meant that the SET amps can drive the speakers, but not very "well". Not if reference to SET designs having an impact on this.

As far as the rest goes it is not a matter of my taste vs my experience with clientele. My taste would eat up to much data on this server

Ok - so you are saying that your data confirms that ~80% of speakers can be driven on paper but *not* well.

The market research data you need is the % of speakers that can be driven *well* with standard and market leading SET amps - that figure will be a lot less than 80%. So it comes back to my original point - if you make this amp capable of driving ~90% of speakers *well* then your potential customer base has moved from those with super efficient horns / cones to most speakers.

There is no amp in production that sounds like a SET but can drive almost any load. That would be very cool. Anyway - if you went high power / current - what specs are we talking about and how stable will it be into low impedance speakers?

 

[Aries Cerat]

Hello there

I was not aware of the poll,but since Josh initiated it,as well as i go along

I want to give some info regarding our new hybrid technology,with some background.Our hybrid technology is based on our Triodefet breakthrough,please forgive my blabber

What is Triodefet technology

Fets, of Field Effect transistors, used in many audio amplifiers, present characteristic transfer curves typically like the following.



As seen in this graph, the Fet is not the most linear of active elements.All modern and vintage production Fets present non-linearities,as shown on the above graph that make the use of simple feedback-less topologies and designs unpractical, and when they do, often mediocre sounding.

Tubes on the other hand, is another story all together. Triodes are the most linear active element engineers came up to.

Below is characteristic transfer curves of a typical triode.





It’s linearity is unmatched by any silicon based active element . However, the triode is a high output impedance, high voltage/low current device, making the use of impedance matching transformers mandatory, when driving low impedance loads, such as our loudspeakers.

So…What if we had a low voltage /high current active device , that had the linearity of a triode?..
Here comes the Triodefet.
The Triodefet is a three terminal device, like any Fet or triode, that presents the low voltage/high current operating mode of a high power Fet, at the same time, it’s characteristic transfer curves are exactly like a high quality triode.

Below are the characteristic transfer curves of the Triodefet device.Notice that the curves triode -like and very linear.



The TriodeFet can be used to design incredibly simple ,good sounding circuits, that could not be possible be designed otherwise.
Using the Triodefet device,we come up with very simple and straight forward designs,that have very high linearity, sourcing from the inherit linearity of the Triodefet.The Triodefet can be used in very high bandwidth circuits, without the use of global of local feedback,use of degeneration etc.

 

[Aries Cerat]

The design is stable down to 1ohm at full power, for the 25W and 120W version

 

[Audiophile Bill]

The design is stable down to 1ohm at full power, for the 25W and 120W version

Thanks so much for that walk through - sounds very interesting indeed. If the design is stable to 1 ohm but with SET sound - 120W should cover most speakers. What is the purpose of the 25W version - is it quieter or does it sound identical to the 120W? Or put another way, could you use either amp into a 108db efficient horn and it sound the same?

What triode is used in the circuit?

 

[Aries Cerat]

Thank you
The triodefet is not another tube-driving-fet design. The tube used is not actually driving the fet,the fet "mimics" the triode characteristics,and both drive the load.Please allow me to not actually describe how this works

Input tube is the 814 DHT interstaged-coupled. It is also available in single stage(without input tube),but only available with our proprietary AClink inputs,this version (1 stage,no input tube)can only work with our preamplifiers coupled via AClink. Standard version is using the 814 as mentioned


The 25W and 120W are identical sounding...However,the 120W will be much more expensive.The 25W 's goal is to give top level SET sound at lower price,if you can live with this power. Top SETs need TOP quality output transformers,and unfortunately the majority does not.The Triodefet is implemented in a tube-like circuit ,as simple as it gets, exploiting it's inherit linearity.

 

[LL21]

Thanks so much for that walk through - sounds very interesting indeed. If the design is stable to 1 ohm but with SET sound - 120W should cover most speakers. What is the purpose of the 25W version - is it quieter or does it sound identical to the 120W? Or put another way, could you use either amp into a 108db efficient horn and it sound the same?

What triode is used in the circuit?

Also very interested in learning more. i am no techie but should be interesting reading!

 

[Audiophile Bill]

Thank you
The triodefet is not another tube-driving-fet design. The tube used is not actually driving the fet,the fet "mimics" the triode characteristics,and both drive the load.Please allow me to not actually describe how this works

Input tube is the 814 DHT interstaged-coupled. It is also available in single stage(without input tube),but only available with our proprietary AClink inputs,this version (1 stage,no input tube)can only work with our preamplifiers coupled via AClink. Standard version is using the 814 as mentioned


The 25W and 120W are identical sounding...However,the 120W will be much more expensive.The 25W 's goal is to give top level SET sound at lower price,if you can live with this power. Top SETs need TOP quality output transformers,and unfortunately the majority does not.The Triodefet is implemented in a tube-like circuit ,as simple as it gets, exploiting it's inherit linearity.

Very cool. Best of luck - it sounds like a great product. Can't wait to see a photo of the 120W monster

What are you thinking price wise?

 

[FrantzM]

Hi
Just a thought why not a very high power version. For some it could be heaven on earth: The sounds of Triode with their favorite power hungry speakers! Of course "heaven" is price dependent

 

[Audiophile Bill]

Hi
Just a thought why not a very high power version. For some it could be heaven on earth: The sounds of Triode with their favorite power hungry speakers! Of course "heaven" is price dependent

That was the point I was making Frantz but I am guessing that the output transformers are the limiting factor. I think (I might be wrong) that even the 120w will be a huge beast and very expensive.

 

[FrantzM]

That was the point I was making Frantz but I am guessing that the output transformers are the limiting factor. I think (I might be wrong) that even the 120w will be a huge beast and very expensive.

I might have missed something: I though the whole point of "hybrid" was to avoid an output Transformer? The Triodefet seems to be the output device low voltage/High Current IIRC?

 

[Audiophile Bill]

I might have missed something: I though the whole point of "hybrid" was to avoid an output Transformer? The Triodefet seems to be the output device low voltage/High Current IIRC?

Hopefully Mr Aries Cerat can answer your query....I am also interested as to what would stop a 500W one being produced for example.

 

[Aries Cerat]

Thank you for the interest and feedback

Yes,the output stage is an OTL single ended stage using the Triodefet,no OPT

The amplifier is scale-able from 25W upwards ,and having strict Class A operation for the entire power output(being SE), dictates big PSUs( very high idle currents) and adequate heatsinks.


An example for the Triodefet technology is our Ianus monoblock amplifiers( http://aries-cerat.eu/products/amplifiers/ianus),using the same Triodefet device,BUT while Class A for the entire power output,it is PP (floating circlotron variation) not a SE design.
Current idle for the Ianus is at 12A per channel.
For size reference,the heatsinks are 60cm tall .



Size and cost is the major limiting factors,not the technology per se

We be happy to give more info and pictures as the finilization of the design continues ,as well as pictures of the first batch build.Hey maybe we have the first demo at the US.

 

[Audiophile Bill]

Thank you for the interest and feedback

Yes,the output stage is an OTL single ended stage using the Triodefet,no OPT

The amplifier is scale-able from 25W upwards ,and having strict Class A operation for the entire power output(being SE), dictates big PSUs( very high idle currents) and adequate heatsinks.


An example for the Triodefet technology is our Ianus monoblock amplifiers( http://aries-cerat.eu/products/amplifiers/ianus),using the same Triodefet device,BUT while Class A for the entire power output,it is PP (floating circlotron variation) not a SE design.
Current idle for the Ianus is at 12A per channel.
For size reference,the heatsinks are 60cm tall .

View attachment 24561

Size and cost is the major limiting factors,not the technology per se

We be happy to give more info and pictures as the finilization of the design continues ,as well as pictures of the first batch build.Hey maybe we have the first demo at the US.

Holy crap. 85kg each. Assume this new version will be heavier still with 120w? With the Ianus, when you move from 4 ohms to 2 ohms and lower, how much class A mode is it still running in?

 

[spiritofmusic]

Hi
Just a thought why not a very high power version. For some it could be heaven on earth: The sounds of Triode with their favorite power hungry speakers! Of course "heaven" is price dependent

Frantz, check out the Nat Audio Magma SETetrode, all-Class A up to 170W, using the ABSOLUTELY most scary and threatening tube you have EVER seen.
Just what you would need to go beyond this, doesn't bear thinking about, unless y'r prepared to have yr mind melted!

 

[Aries Cerat]

The easiest way of figuring out what is the real power in Class A for any given design,is their current idle.

No matter what marketing dept of a company claims,one can easily spot true ratings behind smoke and mirrors.

Take for example a very successful Class A design,claiming 100W class A.Current idle is .. 2A
Theoretical absolute maximum power(before leaving Class A) for that design at 8ohms is =sqr(2*idle*0.7)*loadresistance= 32W for Class A power
At 4ohms will be 16W
At 2 ohms will be 8w and so forth

2A idle is pretty high,usually many "Class A" amplifiers will be half of this



Have this in mind whenever someone claims some extravagant power number of "pure Class A"

The Ianus has adjustable bias.With the Factory setting of 6A per bank(12A total per channel)

maximum Class A power is

140W @ 8ohm(voltage rail limits the power,no current limit)
260W @ 4ohm
140W @ 2ohm (450W AB)


The SE 120W will be heavier,being single ended. For a given power level, a single ended output stage must have current idle double that of a PP design

 

[amirm]

Thank you
The triodefet is not another tube-driving-fet design. The tube used is not actually driving the fet,the fet "mimics" the triode characteristics,and both drive the load.Please allow me to not actually describe how this works

Input tube is the 814 DHT interstaged-coupled. It is also available in single stage(without input tube),but only available with our proprietary AClink inputs,this version (1 stage,no input tube)can only work with our preamplifiers coupled via AClink. Standard version is using the 814 as mentioned


The 25W and 120W are identical sounding...However,the 120W will be much more expensive.The 25W 's goal is to give top level SET sound at lower price,if you can live with this power. Top SETs need TOP quality output transformers,and unfortunately the majority does not.The Triodefet is implemented in a tube-like circuit ,as simple as it gets, exploiting it's inherit linearity.

So reading between the lines , the tube is just for the input stage. The output stage is FET design operating at very low Vds but high input current to keep it in the linear and so called "triode region" of the FET that is most linear. I assume you are paralleling a number of FETs to accomplish this. In other words the tube plays no role in power amplification as I think you mentioned.

If so, I would market this as a transistor design that is very linear by design like tubes. Calling it a tube amplifier causes confusion and the purists would of that world would avoid it on principal.

 

[amirm]

Hi
Just a thought why not a very high power version. For some it could be heaven on earth: The sounds of Triode with their favorite power hungry speakers! Of course "heaven" is price dependent

If I understand the design right, the answer is right in this graph:

Check on the left where the response is linear (flat line). At low input currents you basically have a tiny region which will not allow much swings around 2 volts. Push the input current way high and you get to the top graph where you now can have a healthy swing around 2 volt. Just like a class A design, you are having to bias the transistor with tons of idle current which goes to waste and needs to go some place. You also have pretty small voltage swings. Careful selection of FETs may provide a better center voltage but still, between the high input current and low voltage swings, making high power version of this will be tall mountain to climb.

 

[Aries Cerat]

Hello Amir

Nope
Please see and compare the transfer curves of the triodefet and a typical FET.Note the scales







As i write above,
The triodefet is not another tube-driving-fet design. The tube used is not actually driving the fet,the fet "mimics" the triode characteristics,and both drive the load.Please allow me to not actually describe how this works


The transfer characteristics of the output device is what dictates the behavior of the output stage.It is a hybrid,but hybrid term is usually associated with tube-drive-fet stage.This is not the case.

Imagine a 3-terminal power device, containing an x number of parts( ..), and presenting the above transfer curves at it's terminals.What happens inside the "box" is another story