listening to nxV200

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Thanks Anthony. :) Will come to you for devices when I'm closer to finishing my design.

Unrelated question: do you offer all your amp modules as partly-built-up kits (through-hole components unsoldered)? Or only the one or two which are listed in your shopping cart? The semi-complete kit is a great way to get the module for a builder because I can then decide how to fit the OPS devices to the heatsink, manage the mechanical engg of the construction better.
 
Anthony,

how does the Execon devices compared to the Toshiba devices, interms of techical specification and sonically?

How does this effect your supplies on current stocks for the 500W and the 800W modules? Will you supply a modification to the current circuit pcb that cater for all the pcbs that are Toshiba oriented?
 
Anthony,

how does the Execon devices compared to the Toshiba devices, interms of techical specification and sonically?

How does this effect your supplies on current stocks for the 500W and the 800W modules? Will you supply a modification to the current circuit pcb that cater for all the pcbs that are Toshiba oriented?

Hi Music Lover

The Lateral devices require a bit extra compensation and the Source and Drain pins are opposite to the Toshiba devices.
This requires the PCB layout to be changed some what to accommodate the Lateral devices.
The power bandwidth is lower compared to the Toshiba devices but the
THD is more evenly distributed across the frequency bandwidth.

Sonically I have not sat down and had a real good listen as yet.
So I really cannot comment.

I will be changing over to these devices in the next 12 months as the Toshiba devices are no longer in production.
But for the time been I have more than enough of the Toshiba devices to see me out of my present stocks of PCBs.
What it will allow is a new generation of NX series of amplifiers to be produced
with much high power and fewer devices.

Cheers

Anthony
 
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Hi tcpip

Currently I am using Toshiba Vertical MOSFETs 2sk1530 and 2sj201
However as these devices are now no longer in production I will be moving
back into Dual Die Lateral MOSFETs from Exicon.
The Toshiba devices are still in good supply as surplus supplies are everywhere
So it will be a slow transition into these Exicon devices which are in plentiful supply.
This is the first of the Exicon based amplifiers I am producing.

An externally hosted image should be here but it was not working when we last tested it.


Cheers

Anthony

Anthony, these new modules look very neat.

So about twice the power potential, more linear distortion characteristics, and what looks to be VAS supply option, if i read it right. -what's not to like :)

Please report when you have any listening impressions on how they compare to previous models. It would also be greatly appreciated if you could share a bit more specs, data and other relevant insights on these new babies.

BTW, is there any particular reason for angling the two FET devices in that particular way? As I see it, it greatly limits the room for different placement possibilities on heat sinks because the FETs can't be bended upwards for a vertical mount. -Is it because they generate far more heat and thereby a way to ensure adequately sized heat sinks? Or maybe the opposite?

If you could need a beta tester, and or supply them unassembled for a neat price, I'd be happy to give them a try :)

Best,
 
Hi Juhleren

The reason the Laterals are at an angle is to provide a much improved
cooling of the output stage, by giving each device more heat sink area.
As you have mentioned the dual die devices get quite hot and do need
as much heat sink real estate per device as possible.
So this arrangement works very well with this module.
This module does have separate VAS supply option as well
Here is some initial measurements on the prototype board.

Frequency Bandwidth 324khz -3dB
THD+N 1khz 0.028% at 132 watts RMS into 8 ohms
THD+N 10khz 0.08%
THD+N 20khz 0.1%
SNR around -100dB unweighted with respect to 132 watts RMS

I have not had a listen to these modules as yet, but I suspect they will sound very good indeed.:D

Cheers

Anthony
 
Hi Juhleren

The reason the Laterals are at an angle is to provide a much improved
cooling of the output stage, by giving each device more heat sink area.
As you have mentioned the dual die devices get quite hot and do need
as much heat sink real estate per device as possible.
So this arrangement works very well with this module.
This module does have separate VAS supply option as well
Here is some initial measurements on the prototype board.

Frequency Bandwidth 324khz -3dB
THD+N 1khz 0.028% at 132 watts RMS into 8 ohms
THD+N 10khz 0.08%
THD+N 20khz 0.1%
SNR around -100dB unweighted with respect to 132 watts RMS

I have not had a listen to these modules as yet, but I suspect they will sound very good indeed.:D

Cheers

Anthony

Thanks a lot Anthony,

Not that THD+N is all that is interesting of course, but do you for the sake of a neck to neck comparison have some figures of the "old" Toshiba FET based modules that are "compatible" with those of the new beast?

Your online data sheets seems to offer THD+N figures for the modules -which in some cases are specified @ 1kHz, but only as "typical" and not related to O/P power.

Will the dual die devices run with significantly higher bias currents, or is the increased emphasis on heat sinking more related to a potential for higher supply rail voltage and thus heat dissipation related to increased voltage drop on the trannies?

Do you have an idea of the nfb implementation/gain/damping factor aspects yet?

Yes "good" sound is the goal, however ears and systems comes as different as they get, so my major interest lies in the qualification of good/better/different (i.e. is it softer, harder, gruntier, silkier, darker, brighter?) opposed to something else. If you have to make the transition anyway, this of course becomes a mood point, but for someone like me who only have an idea of what the toshiba based animal is like, its central :)

Best,
 
The new module uses identical input/driver topology as used with the Toshiba devices with exception to the changes needing in biasing and Cdom compensation to suit the laterals.
Oddly enough distortion does not change much at all with biasing.
The optimum level for these devices is around 110ma per dual die device per voltage rail.
This is consistent with the use of the Toshiba devices as well that only need around 40ma max per device to achieve excellent results.
I do not place a great deal of faith in distortion levels, so long as they are of
a reasonable level in my experience of building amps since the early 1980s.

The Toshiba devices unloaded have lower distortion levels typically 0.005%, but when loaded have very similar distortion profile.
I fully expect the laterals to sound very similar to the Toshiba devices.

I have not had a chance as yet to do anymore tests as far as damping factor, I have a board full of orders to complete and ship so this is my priority at the moment.:)

Cheers

Anthony
 
Thanks for your response Anthony,

I totally get your priority on completing orders, so please excuse my line of questions and please take your time on other more pressing issues :)
-I just want to make my next amp project the last I need by taking in all the lessons I can...

I look very much forward to your reporting on the new line of amps when you get to it :)

Looking at your current line up I noticed that the new signature module deploys an extra set of supply decoupling caps compared to the other R2 amps.
I guess these are for the VAS/driver section...

Are these to be understood as to offer increased isolation from the output by supplying the front end and the driver stage with dedicated decoupling?
- If so, should one expect this unique feature to become part of the new die-lateral line up?
- and, would it be beneficial to offer optional separated supply rails for front end and driver stage -making the amps able to utilize up to three sets of +/- VDC supplies? I'd imagine that especially costumers of the higher power-range modules would like that kind of performance increasing potential -at least the built-in upgrade potential :)

Another thing, if utilizing the optional VAS supply configuration, then one should generally think that the better, cleaner, faster and stiffer one could make the supply, the better the result. However when deploying regulated VAS supplies, other amp circuitry (have not tried this on yours) has shown that too stiff regulation can result in staccato-like sound that destroys the rhythm and flow of the music. Now to the Question :)

- Would you expect that the faster and more rigid the VAS regulation is made the better your amps should perform -musically speaking?

-OR, should one be careful about this, and make such a supply ever so slightly "forgiving" in order to ensure the musical flow rather than trying to create "technically optimal" conditions?

More specifically, concerning VAS supplies, I am considering either to go for
1) a simple four-pole type cap supply (simple,fast and good noise isolation), or
2) the four-pole fed through a choke configured supply for stiffer voltage regulation (I presume that the current draw is pretty much constant, no?), or
3) some kind of actively regulation circuitry that can deliver the required HV

Any comments from you Anthony, or anyone else for that matter, would greatly appreciated

Best,
 
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The new module uses identical input/driver topology as used with the Toshiba devices with exception to the changes needing in biasing and Cdom compensation to suit the laterals.
Oddly enough distortion does not change much at all with biasing.
The optimum level for these devices is around 110ma per dual die device per voltage rail.
This is consistent with the use of the Toshiba devices as well that only need around 40ma max per device to achieve excellent results.
I do not place a great deal of faith in distortion levels, so long as they are of
a reasonable level in my experience of building amps since the early 1980s.

The Toshiba devices unloaded have lower distortion levels typically 0.005%, but when loaded have very similar distortion profile.
I fully expect the laterals to sound very similar to the Toshiba devices.

I have not had a chance as yet to do anymore tests as far as damping factor, I have a board full of orders to complete and ship so this is my priority at the moment.:)

Cheers

Anthony
Hi Anthony,
About HPA nx-V200 please tell me what happens if I try to change(increase) 100 mA or more per Toshiba device? Amplifier works more in class A?
Is beneficial or harmful to sound quality? Risk to ruin something?
I ask before making a blunder.
Thank you!
regards,
 
Hi again Anthony,
I want some advice on my new power amplifier project.
I want to use full HPA modules in dual mono configuration: HPA nx-V200 R2 Signature Series, HPA nx-Volt-One dual rail voltage, HPA PSU-three, HPA LSP-One, HPA Limit-One. (last three modules I have already!)
My question is which is the optimum voltage for VAS? I intend to buy custom power transformers with the following voltages on the secondary: 50V - 40V - 0 - 40V - 50V AC/ 3A.
40V-O-40V AC for HPA PSU and 50V-0-50V AC for HPA dual rail voltage.
I expect your advice!
Thank you!
Best regards,
 
Hi Hotzman

If you are going to use the Volt One regulator then you will need a 50-80VA
power transformer with 2 x 45VAC secondary windings as a minimum.
This would allow a regulated supply between 50 and 55volts DC on the input-driver stages of the nxV200 R2.

Send me an email and I will send you the installation manuals for the modules
you are looking at buying.

Cheers

Anthony
Holton Precision Audio
 
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