• These commercial threads are for private transactions. diyAudio.com provides these forums for the convenience of our members, but makes no warranty nor assumes any responsibility. We do not vet any members, use of this facility is at your own risk. Customers can post any issues in those threads as long as it is done in a civil manner. All diyAudio rules about conduct apply and will be enforced.

First One - mosFET amplifier module

Jump to Latest
F

fluid

Member
Joined 2009
Voysto said:
Is there any reason for choosing 47 or 55 V instead of the recomended 63V ?
Click to expand...

The Hypex power supplies only come in 63V or 45V as they are designed to work with Hypex's own amp which use these rail voltages.

There are a few reasons why you might want to run at a lower voltage. If you don't need the full power that the FO can produce then by running at a lower rail voltage you will need less of heatsink as there is much less heat produced at idle. If you are building amps for an active system this makes sense as the tweeters and mids will often not need as much power as the woofers or subs.
From experience I know there is quite a reduction in heat going from 60V to 45.

Another thing to be aware of is that the Mlytic capacitors on the First One M are rated for 63V so it gives more headroom to run at 55V or 60V. Almost all power supplies will sag under load so even though the supply is rated at 63V when unloaded it will probably be somewhere around 58 to 60 depending on the load and how the supply has been designed.

Also Cresnet was only able to supply 55V supplies in the recent past, this may have changed now but explains why that voltage was chosen for many;)
 
J

J.M.K

Member
Joined 2009
Is there any reason for choosing 47 or 55 V instead of the recomended 63V ?[/QUOTE said:
Hi !

I made some measurements and calculations : I don't need that much power on my system, I'm much above the max power I need with 47V !
Plus the unwanted overheating, and the fact that FO 1.4M works as well with less voltage .......... and the fact that higher the temperature, shorter lifespan for electronic components ....... this is a law of physics !

JMK
Click to expand...
 
Cresnet

Cresnet

Banned
Joined 2012
micro-audio.com
fluid said:
The Hypex power supplies only come in 63V or 45V as they are designed to work with Hypex's own amp which use these rail voltages.


Also Cresnet was only able to supply 55V supplies in the recent past, this may have changed now but explains why that voltage was chosen for many;)
Click to expand...

+-60V & +-63V +-65V +-81V will be available soon.

Already providing +-61V & +-65V but out of stock!


other voltages

+-39V +-55V +-65V +-47V +-75V +-90V


Thanks
 
Last edited:
J

J.M.K

Member
Joined 2009
Picture

J.M.K said:
Hi,

I just finished installing my 2 brand new Cresnet SMPS 600 psus (47.5Volts)
with my FO 1.4M modules (dual mono setup).

The sound I get is extremely good.
The previous PSUs I had were traditional R-Core 360VA transformers and about 10 volts less on the DC rails.

I'd say that the difference in the sound I get from my speakers is a better dynamic making small details more audible in all the spectrum.

Beside this sound improvement, there is an important difference I've noticed with the Cresnet smps: the current I now get allows me to fine tune the bias and offset of the amplifiers modules in a very stable way - when it was more or less floating (up to + or - 40mV sometimes, sometimes less) before with my r-core transformers and MUR rectifiers ............

Pictures will follow, hopefully tomorrow.

Cheers

JMK
Click to expand...

Here is a picture of my new amplifier (in my previous LM3886 recycled case).
Extremely good sound.
 

Attachments

  • _20161024_180804.jpg
    _20161024_180804.jpg
    889.3 KB · Views: 775
Lazy Cat

Lazy Cat

Member
Joined 2007
TNT said:
An overview of the different version modules with needed supply voltages and prices in the first post would be good.

//
Click to expand...

Hi, good idea, will do it. :)

Quite few requests for lower supply voltages came from guys replacing LM 3886 chip amps with FO M, which I think is a good thing, SQ wise. FO M module can be modified to supply voltage as low as +/-25 V with just few resistors change.
Serial FO M modules operates from +/-40 to +/-63 V as per User manual recommendation. ;)
 
Lazy Cat

Lazy Cat

Member
Joined 2007
Mark Verhoeven said:
Hi Andrej, are there still FO M modules left? Will there be made another badge afterwards? I would like to replace my V2 modules, but I am not in a hurry.
Click to expand...

Still few FO M v1.4 modules left here, waiting to be ordered. As it looks there will be a gap between next FO M batch since FO L is coming and I will need some more time to prepare new FO M series, just because few hundreds have to be ordered to avoid red numbers.
 
maxlorenz

maxlorenz

Member
Joined 2003
youtube.com/channel/UCIRNCQpvrl-EfalifsmR4KA
Lazy Cat said:
Still few FO M v1.4 modules left here, waiting to be ordered. As it looks there will be a gap between next FO M batch since FO L is coming and I will need some more time to prepare new FO M series, just because few hundreds have to be ordered to avoid red numbers.
Click to expand...

This is the spirit of DIY audio fora!
But maybe you are exaggerating your altruism... for which we thank you anyway. :D

Best wishes,
M.
 
Lazy Cat

Lazy Cat

Member
Joined 2007
Francois G said:
I would like to be on your list for FO L PC boards, 2 please.
Click to expand...
Please send request to an email in post #1 ;)

Erlend Sæterdal said:
???
Click to expand...
I complicated a little, they (production company) complicated a little, so as finally agreed production starts on wednesday next week. :Present:

maxlorenz said:
This is the spirit of DIY audio fora!
But maybe you are exaggerating your altruism... for which we thank you anyway. :D

Best wishes,
M.
Click to expand...
It's altruism all the way, anyway no exaggerating here, had to order at least 200 modules to be profitable. First batch of FO M almost sold out, so anyone interested please hurry up. :)

P.S. Small notice to all having SMPS1200A400 in FO M amp, add two 10mF/63 V per channel and enjoy the bass. Cap Bank from FO L clearly showed the benefit. :yes:
 
M

maxidcx

Member
Joined 2012
hi guys, I m just listening the new Gustard A20H (ak4497) on the dual-stereo (aka biamp or quad) FO M. well, obviously the FO is able to amplify amaizing details and subtile information that the DAC is providing. in other words investing in FO will give you full R.O.I for your future fancy DAC. thanks again LC. Next step Anagram with quad FO L ? lol
 
Lazy Cat

Lazy Cat

Member
Joined 2007
maxidcx said:
hi guys, I m just listening the new Gustard A20H (ak4497) on the dual-stereo (aka biamp or quad) FO M. well, obviously the FO is able to amplify amaizing details and subtile information that the DAC is providing. in other words investing in FO will give you full R.O.I for your future fancy DAC. thanks again LC. Next step Anagram with quad FO L ? lol
Click to expand...

As we found out here FO M or L are the amps with no limits, no details lost, music presented natural as natural could be. :nod:

So Gustard A20H is so good, tempted to order one just because is so cheap. :)
 
M

maxidcx

Member
Joined 2012
a20h juste arrived yesterday. after 24h burn-in, i m listening it since one hour and cant stop if you see what I mean... for the time being that's just an amaizing good investment and amaizing value for money. also it has xlr so I ll try in coming weeks a FO balanced/bridge config (as I have 4 module with 2smps) as you suggested in later post in may. stay tuned
 
You must log in or register to reply here.
Top Bottom