First One - mosFET amplifier module

[Finnogangela]

Hi, sorry for being a newbie, thus dependent on information from more knowledagble gurus

LC, You stated somewhere that using a smaller PSU would make the F.O. better suited for low-impedance loads. I´m aiming at 2 X Cresnet´s 600w +/-55V SMPS, speakers about 3 ohms (due to 2 woofers paralleled).

Think I will be ok with F.O. "M" version (provided I follow the heatsink recommendations)- or better to wait for "L" version?

Tia, Finn

 

[Lazy Cat]

Hi Finn

You're just about right with your estimation. As you can see in upper post #2832 from Robert, he uses the same Cresnet's SMPS with great success. 3 Ohm from two bass drivers in parallel is a piece of cake for FO v1.4 M. The only thing to consider is to have 0,5 °K/W (or less) heatsink for each module, otherwise no restrictions.

It is also wise to connect DC sense module (one per channel) to shutdown SMPS in a case of FO failure (DC on SPK OUT).

Browse this page and few pages back to see pictures of Robert's amp and Black Mamba inside details.

Best regards, L.C. 🙂

 

[Finnogangela]

Thanks very much, LC! (Just about ready to order🙂

It is also wise to connect DC sense module (one per channel) to shutdown SMPS in a case of FO failure (DC on SPK OUT).

Ah, that´s what those small PCB´s at speakerterminals are🙂

Can they be ordered with the F.O modules?

Regards, Finn

 

[Lazy Cat]

Yes, DC sense is sitting on speaker's terminals, sending signal to SMPS's shutdown pins. Simple but very effective way to protect speakers without unwanted relay-switch contact in series with amp's output. Yes, DC sense modules available.

 

[Erlend Sæterdal]

Got the modules and they look fantastic.

 

[Lazy Cat]

Erlend, now we are all waiting to see your review soon.

It's like expecting new puppy to arrive home hehe, L.C.

 

[Overkill Audio]

FO 1.4 modules

Hi LC

Thanks for these modules, they are exceptional value for money.
They are very well made, flexible and sound sublime, really outstanding!

Thanks and all the best
Derek.

 

[BYRTT]

Overkill Audio,
Thanks review and for reviews other members a thanks too, look forward listening latest version intend join when small version is released and maybe also try to bridge that version.

Lazy Cat,
Thanks these must have modules, is it time now that so many have got a super amp and reported back that you release measurements : ) look forward see this new version without feedback cap topology show super flat time component in square waves all down from DC and up sky high > zobel smoke 😀

 

[ROGeorge]

I hope i'm not late for the party and i would like to get a 1.4m version for my ears. I have a pair of Mackie MRmk3 studio monitors for which I would like to beef up the amp.

I read a lot of positive comments and I share the users enjoyment regarding this project and want to try one of your great amp. I'm sure I will be satisfied another module will be needed soon.

 

[colin86325]

Hi there, this project looks very well received! Unfortunately the info is spread over some 280+ pages.
Would it be possible to edit the first post to include info like:
What parts are included/suggested parts list
Recommended PSU
What case is recommended
etc

Thanks!

 

[smoothquark]

Hi
Smoothquark, the choice for enclosure is a nightmare as long as you try to make it smaller and nice. The decision to go with 2 monoblock, is great but will increase the cost. The very minimum for such a project would be this case which is a new version half size of the usual "dissipante" model, you can find it here for example:
Hifi 2000 Botier avec Dissipateur 2U 300mm Faade 10mm Noire - Audiophonics

it is 240mm large and then 150mm internal.
you can mount the SMPS on one heatsink, say right, and the FO on the other heatsink, say left .
with such a configuration and an SMPS1200A400 (62V) you ll get a temperature of around 52-55°C depending on the overall conduction between the 2 heatsink.

My choice was to put 2 FO in the box, and the SMPS located on the front panel. But the SMPS is 165mm large so you have to make your own custom encloseure which is not a problem : I bought the same front panel 240mm wide here:
hifi 2000 - facade aluminium 10mm noire pour gx283-287-288
and 2 standard heatsink 2Ux300m which you just have to drill properly so they can be mounted together on the front panel at 90°.

Then you ll have to find a later solution for the lower, upper and rear panel, but you can make you personal touch with some nice wood for example. good luck, But do not underestimate the size of the heatsink, or lower down the SMPS for a 1200A180...

Thank you. Sorry for the rather late reply.

 

[Lazy Cat]

First One L PCB design completed

Good news guys, next week First One L goes in pre-production, four prototype modules will be tested thoroughly. First One L acceptance of +/-85 Vdc max. power supply will give enough headroom even at low efficiency speakers to produce undistorted high SPL. High hopes on L version includes same sound signature as M at double output current & power capability and only 6 cm longer PCB. 😎

 

[Cresnet]

Good news guys, next week First One L goes in pre-production, four prototype modules will be tested thoroughly. First One L acceptance of +/-85 Vdc max. power supply will give enough headroom even at low efficiency speakers to produce undistorted high SPL. High hopes on L version includes same sound signature as M at double output current & power capability and only 6 cm longer PCB. 😎

Sounds great, what is the price & delivery time? Recommended PSU voltage?

 

[Lazy Cat]

Hi LC

Thanks for these modules, they are exceptional value for money.
They are very well made, flexible and sound sublime, really outstanding!

Thanks and all the best
Derek.

Hi Derek

I'm glad your DB listening tests fulfilled high expectations. Competitors are fearsome but .. 😎

L.C.

 

[Lazy Cat]

I hope i'm not late for the party and i would like to get a 1.4m version for my ears. I have a pair of Mackie MRmk3 studio monitors for which I would like to beef up the amp.

I read a lot of positive comments and I share the users enjoyment regarding this project and want to try one of your great amp. I'm sure I will be satisfied another module will be needed soon.

Hi there, this project looks very well received! Unfortunately the info is spread over some 280+ pages.
Would it be possible to edit the first post to include info like:
What parts are included/suggested parts list
Recommended PSU
What case is recommended
etc

Thanks!

Hi guys, just send me an email. 😉

 

[Lazy Cat]

Overkill Audio,
Thanks review and for reviews other members a thanks too, look forward listening latest version intend join when small version is released and maybe also try to bridge that version.

Lazy Cat,
Thanks these must have modules, is it time now that so many have got a super amp and reported back that you release measurements : ) look forward see this new version without feedback cap topology show super flat time component in square waves all down from DC and up sky high > zobel smoke 😀

L done, S is next. 😉

 

[Lazy Cat]

Sounds great, what is the price & delivery time? Recommended PSU voltage?

It's too early at this stage, first I have to listen to L to see on what level it will qualify.

 

[Lazy Cat]

Black Monolith is rising

As announced in below's post, some preliminary pics of Black Monolith rising, just a teaser for the moment. 😎

First One Black Monolith monoblock chassis is coming to assembly this week. It will be impressive in its simplicity, still fully functional as Black Mamba.

Black Mamba and Black Monolith will be available as ready made products as well.

L.C.

 

[maxlorenz]

Nice idea!

How is the thermal behavior of the Black Monolith?

I guess we could add more heath-sinks to the other panels, provided there are enough bolt holes...

Congratulations.
M.

 

[Kindhornman]

LC,
What are the dimensions of that heat sink and how much heat does the smps contribute to the total? That heatsink looks smaller than the 3u x 300mm heatsinks I've been seeing others recommending as a minimum for the First One?