Fet Valve 200R, Why not, Frank?

Tom Alverson · « **Reply #20 on:** 6 May 2014, 03:10 pm »

Quote from: maty on 6 May 2014, 06:43 am

@Tom Alverson

To be perfect, they would have to be double monophonic but then the price would skyrocket.

But I do need the perfection because I do not have a perfect room.

They are nearly double monophonic since every amplifier stage has it's own separate regulator. The only thing needed to make them truly double monophonic would be separate power transformers, but that would probably not provide any benefit since everything is already regulated.

Tom

maty · « **Reply #21 on:** 8 May 2014, 11:25 am »

One improvement I can think for the future is the use of voltage regulators without feedback like...

Minn Mark · « **Reply #22 on:** 8 May 2014, 05:14 pm »

maty,
Sorry I am not an engineer. Can you explain to us uninitiated why volatge regulation without feedback is an improvement?

Mark

maty · « **Reply #23 on:** 8 May 2014, 06:27 pm »

First, I suppose that voltage regulators of AVA have a few feedback.

Typically, manufacturers use linear regulators with feedback to reduce the ripple of the power signal

These linear regulators add an additional noise.

Frank, like others, says very few words about its design, I can only suspect.

The added noise should be very little, hence the praise they are receiving AVA Fet Valve.

If I lived in the U.S., and with thirty day trial, I would have already bought!!!

maty · « **Reply #24 on:** 8 May 2014, 06:32 pm »

Maybe then they would lose the tube sound everyone says have. At the end we have to trust the designers, and Frank have many years of career

maty · « **Reply #25 on:** 8 May 2014, 06:39 pm »

-> http://en.wikipedia.org/wiki/Linear_regulator

Quote

In electronics, a linear regulator is a system used to maintain a steady voltage. The resistance of the regulator varies in accordance with the load resulting in a constant output voltage. The regulating device is made to act like a variable resistor, continuously adjusting a voltage divider network to maintain a constant output voltage, and continually dissipating the difference between the input and regulated voltages as waste heat.

By contrast, a switching regulator uses an active device that switches on and off to maintain an average value of output. Because the regulated voltage of a linear regulator must always be lower than input voltage, efficiency is limited and the input voltage must be high enough to always allow the active device to drop some voltage.

Linear regulators may place the regulating device between the source and the regulated load (a series regulator), or may place the regulating device in parallel with the load (shunt regulator). Simple linear regulators may only contain a Zener diode and a series resistor; more complicated regulators include separate stages of voltage reference, error amplifier and power pass element. Because a linear voltage regulator is a common element of many devices, integrated circuit regulators are very common; linear regulators may also be made up of assemblies of discrete solid-state or vacuum tube components...

Quote

The transistor (or other device) is used as one half of a potential divider to establish the regulated output voltage. The output voltage is compared to a reference voltage to produce a control signal to the transistor which will drive its gate or base. With negative feedback and good choice of compensation, the output voltage is kept reasonably constant. Linear regulators are often inefficient: since the transistor is acting like a resistor, it will waste electrical energy by converting it to heat. In fact, the power loss due to heating in the transistor is the current times the voltage dropped across the transistor. The same function can often be performed much more efficiently by a switched-mode power supply, but a linear regulator may be preferred for light loads or where the desired output voltage approaches the source voltage. In these cases, the linear regulator may dissipate less power than a switcher. The linear regulator also has the advantage of not requiring magnetic devices (inductors or transformers) which can be relatively expensive or bulky, being often of simpler design, and being quieter. Some designs of linear regulators use only transistors, diodes and resistors, which are easier to fab into an integrated circuit, further reducing their weight, footprint on a PCB, and price...

avahifi · « **Reply #26 on:** 8 May 2014, 06:43 pm »

Hi Maty,

Note that we are NOT using normal three pin regulators in our Fet Valve amps and preamps except for the low voltage, high current tube heaters. And even the tube heaters are very highly filtered and decoupled.

All audio signal regulators use very high quality adjustable voltage sources driving appropriate power mosfets as controlled high current and very quiet regulated current/voltage amplifiers, without feedback. And of course all the supply rails are also highly filtered and decoupled. Everything runs to a star ground and all circuit boards are full ground plane designs too.

Have no worries about power supply noise from any source in Audio by Van Alstine.

Frank Van Alstine

maty · « **Reply #27 on:** 8 May 2014, 06:53 pm »

Then the only problem is that they are manufactured in the USA while I live in Europe.

I understand that shipping has to be more expensive, but pay both customs and taxes makes me cranky. And lucky for now that now 1 $ = 0.73 € (at summer the ECB -something like USA Federal Reserve- will weak the euro => more cost to me!).

David has not yet decided the selling price and if I am the lucky? buyer

Frank: I want your baby!

avahifi · « **Reply #28 on:** 9 May 2014, 01:44 am »

Note that the Fet Valve 400R that Janszen will be using at the Munich audio show later this month is the pretty silver faceplate version. The price is $2999.

After a whole lot of people hear how well it drives the zA2.1 electrostats there, the price David can get for it there will be pretty much retail I suspect. It probably will only become available because he has another 120V Fet Valve 400R back home in the USA.

Do note that our three year parts and labor warranty will transfer to a second owner (you) if you are lucky enough to get it.

Note too that the shipping weight of a 400R is just 33 pounds so getting a new one directly from us will not be as painful as you think.

Regards,

Frank Van Alstine

PS: Yeah, that's right, just 33 pounds for a 225W/ch hybrid amp in a solid steel chassis, extruded heat sinks all the way across the back, a big shielded toroid power transformer, ten regulated power supplies, twelve double die Exicon TO3 case power mosfet output transistors, and the best sound you have ever heard. Nothing skimped, just really good mechanical and electrical engineering design.

By the way the power bandwidth is 3 dB down at 4 Hz and 350,000 Hz.

maty · « **Reply #29 on:** 9 May 2014, 09:17 am »

Quote

By the way the power bandwidth is 3 dB down at 4 Hz and 350,000 Hz.

Are you sure? Perhaps your audio analyzer would be better or the tubes are the bottleneck.

Without tubes like Synergy, I estime to the Exicon lateral MOSFET ECF20N20 & ECF20P20

-> http://exicon.info/products.php

-> -> http://exicon.info/PDFs/EC-10N16-20andEC-10P16-20.pdf

3 dB down at 4 Hz and 560,000 Hz (or something more)

Exicon Lateral MOSFETs

-> http://exicon.info/why-use.php

maty · « **Reply #30 on:** 9 May 2014, 09:29 am »

-> http://www.diyaudio.com/forums/solid-state/102273-10-watt-single-end-jfet-input-lateral-n-mosfet-output-6.html#post1607582

Quote

This is first result.

Idle power 100 Watt (2 x 20 Volt 2.5 Ampere Class A)

2SK389 JFET input

N-Channel Class A Push-Pull .. a la Quasi
using Exicon ECF20N20 250 Watt lateral MOSFET devices

Gain x14.6 (+23 dB)

Bandwidth, -3dB: 700 kHz

avahifi · « **Reply #31 on:** 9 May 2014, 02:20 pm »

The bandwidth of the Fet Valve amplifier is limited by design. We do not let the devices run to their absolute limits as that would induce slew limiting distortion at the frequency extremes. As you sweep the frequency up higher and higher the output never generates a triangle wave or has any dips or bumps at all, just a slowly decreasing amplitude perfect sine wave.

This is one reason the Fet Valve valve amplifiers are absolutely stable into any kind of weird speaker load and there has never been a catastrophic failure of one in all the years we have been building and refining this design.

Frank

maty · « **Reply #32 on:** 9 May 2014, 08:03 pm »

The designer has two options:

1st. Narrow bandwidth operation and thus ensure that the MOSFET can afford low impedances. Chosen by Frank / AVA.

2nd. Making the most bandwidth but limit the power for lower impedance, ie, delivering the same power at 8 ohms to 4 ohms. It is chosen by others, who boast high bandwidth.

If the speakers are 8 ohms nominal, both options work properly.

The problems come with the second option, when the speakers have lows below 2 ohms impedance, which often happens with electrostatic speakers.

Therefore, the choice made by Frank / AVA is best for Janszen. Or the most common Magnepan.

Am I right?

avahifi · « **Reply #33 on:** 9 May 2014, 08:26 pm »

You are making bad assumptions. You are assuming that our bandwidth design (which in no way is narrow) has anything at all to do with power available into different loads. The Fet Valve amplifiers are spectacular performers on electrostatics (just ask David Janszen) and on Magnapans, and on high resolution dynamic speakers too, such as the Salk Soundscapes and Exoticas and Dennis Murphy's full transmission line Philharmonic Threes. It even makes my own 25 year old B&W 801s sound like new speakers. The Fet Valve amps are great on the King electrostats too.

Frank

maty · « **Reply #34 on:** 9 May 2014, 08:31 pm »

JANSZEN zA2.1 SPECIFICATIONS

-> http://www.janszenloudspeaker.com/home%20frame%20specs%20-%20zA2.1.htm

Quote

Sensitivity -- 87 dB/1W/1m (pink noise)
Power handling -- 25W - 150W RMS/ch/8 Ohm recommended; up to 250W tolerated (500W/4 Ohm)
Impedance -- 6 Ohm nominal, 4 Ohm min., 10 Ohm max.

Magneplanar 20.7

-> http://www.magnepan.com/model_MG_207

Quote

Sensitivity 86dB/500Hz /2.83v
Impedance 4 Ohm

If I right, JANSZEN zA2.1 will work well with the two options. Magnepan will work much better with the first option (AVA / Frank).

maty · « **Reply #35 on:** 9 May 2014, 08:34 pm »

The problem, Frank, is my poor english.

I want to say that Fet Valve and Synergy amps will work very well with ALL electrostatic speakers => AVA amps will work very very very well with ALL speakers.

And, with two die and the tubes, Fet Valve amps are the best election I know. They will work very well with all speakers, active preamps, attenuator/passive preamps and DACs with pot.

They are amplifiers to bequeath grandchildren.

maty · « **Reply #36 on:** 10 May 2014, 07:43 am »

2014-05-04 0:13 GMT+02:00 David Janszen

Quote

The 400R is perfect for our speakers. I'll have to think about how to handle the sale, but sure, one way or another. I'll just have to figure out what the price should be...

Today is May 10 and silence...

********** **********

From USA, with 200$ shipping? and 1$ = 0.73€, the right price:

Fet Valve 400R (plated)

[ (2,999$ + 200$) + ( ) x 4.3% duones] + [ ] x 21% VAT/IVA + 27,4$ = 4,065 $ = 2,967€

Fet Valve 400R (black)

[ (2,699$ + 200$) + ( ) x 4.3% duones] + [ ] x 21% VAT/IVA + 27,4$ = 3,686$ = 2,691€

Synergy 300 with double die (only black, why?)

[(1,499€ + 55$ 230V/50Hz + 99$ + 200$) + ( ) x 4.3% duones] + [ ] x 21% VAT/IVA + 27,4$ = 2,366$ = 1,727€

WAF problem: she does not like Black faceplate! And 2,967€ is much money to her (and to me).

maty · « **Reply #37 on:** 10 May 2014, 07:51 am »

I just sent a reminder email to David Jantszen. I have included the link to my previous comment, with my calculations.

I want a new amplifier!

maty · « **Reply #38 on:** 10 May 2014, 05:49 pm »

After answering David Janszen, rule out the purchase of your amplifier Fet Valve 400R.

After which I have to choose between Exicon lateral MOSFET ECF20N20 & ECF20P20 and ECX10N20R & ECX10P20R and USA versus Europe (without customs, more cheaper and silver faceplate).

I'm really sorry Frank, because I think the Fet Valve 400R is the most logical purchase ... for an american but not to an european.

Rocket · « **Reply #39 on:** 11 May 2014, 12:37 am »

Hi Maty,

It sounds like your budget doesn't stretch far enough to enable you to purchase the 400r amplifier. All of these expenses would apply to other hifi products from dealers who import their products into your country. I have never heard of the products that you are going to purchase.

Regards Rod