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First One - mosFET amplifier module

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Xerxes75

Member
Joined 2012
Well I am more than interested in this amp from Lazy Cat, but my own (very Lazy) cat decided to have an accident (he was to lazy to look Left and Right). The Bill from the vet was gigantically enormous. The worst thing is that he is better...and acting like it never happend...tell that to my bank account...:)

So NO! new project for me.
But seeing the long list of people I'm looking forwards to the builds and experiences.

Good Luck!
 
A

AP2

Banned
Joined 2009
Hello Andrey , I am sending two of these in the photos.
Sorry if I insist with the DA version. is perfect for your amp. Considering that you have to use 2 (one for each amp), the power is oversized in the right way, this is something that I have tested long and well.
if you start with 61V (59-61 ADJ), you can see a drop of just 300mV-500mV on 4R.
2xDPS-500S is very expensive, considering two units also, the choice is not justified by the current demand of your First One.

I hope you show the FFT of your First One also by DPS-500/DA ;)

Regards
 

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Esperado

Esperado

Banned
Joined 2011
esperado.fr
Single SMPS

Lazy Cat, may i insist on the benefit to use a single SMPS (or PSU) for both channels in a stereo amplifier ?
I find-it better for stereo image (more stable position of instruments during transients).
It gives more dynamic margin during transients (or equal when instruments are in the middle of the scene).
It avoid, sometimes, beat frequencies when the two SMPS switching frequencies are different.
It is less expensive.

The only negative point i can see is it require care with ground paths, but i know you are good at this. ;-)
 
Last edited:
supernet

supernet

Member
Joined 2001
AP2 said:
Hello Andrey , I am sending two of these in the photos.
Sorry if I insist with the DA version. is perfect for your amp. Considering that you have to use 2 (one for each amp), the power is oversized in the right way, this is something that I have tested long and well.
if you start with 61V (59-61 ADJ), you can see a drop of just 300mV-500mV on 4R.
2xDPS-500S is very expensive, considering two units also, the choice is not justified by the current demand of your First One.

I hope you show the FFT of your First One also by DPS-500/DA ;)

Regards
Click to expand...


Wov, it looks nice :cool:


I am only not sure about Nichicon KGs and Muse at secondary capacitor circuit. These capacitors are charged at high speed with almost right angle voltage steps. That means these capacitors should be low ESR (I doubt this about KGs) and high realiability due constant stress...that mean I (personally) would rather see here Nichicon KX (smps audio), Mundorfs or Panasonic EE...FC...FR on this position. What do you think about this?


Also...how is softstart figurated here? NTK in series?
 
A

AP2

Banned
Joined 2009
supernet said:
Wov, it looks nice :cool:


I am only not sure about Nichicon KGs and Muse at secondary capacitor circuit. These capacitors are charged at high speed with almost right angle voltage steps. That means these capacitors should be low ESR (I doubt this about KGs) and high realiability due constant stress...that mean I (personally) would rather see here Nichicon KX (smps audio), Mundorfs or Panasonic EE...FC...FR on this position. What do you think about this?


Also...how is softstart figurated here? NTK in series?
Click to expand...
You are right in part, if we refer to a traditional smps unreg / reg.
The problem must be seen with the frequency of the load ( not the frequency of the switch ) . In this particular case, the ripple amplitude under load is very small thanks to the two feedback (one per side ) and the speed of response of the error amplifier . In fact , when I replaced it with 2200uF muses, I had to change the values ​​in the feedback loop ( sensing is connected directly to the output connector ) .
In simple words , if the energy is constant on the capacitor , ESR = 0. DPS -500 in this variation is very small, for this reason I do not need low ESR , as I do not need large capacity .
Yes , inrush current is accettable with simple epcos THR , this is due to the low capacity utilization of the main filter ( only 470uF total) .. yes .. it seems impossible
whereas others have 1000/2000uF . con very poor PF in this case also.
We can also see only the voltage and current if we want, but this smps , has other important features .

EMI / RFI AC Line induction/conduction & ambient.
Regulation from Ac Line
Regulation Vs. load
Power Factory near to 1

I think LC can write well, if find immediately listenable difference in sound :)
 
Last edited:
C

chunek

Member
Joined 2010
Lazy Cat said:
Hi, proforma invoices will be send out as soon as the First One modules will be prepared, tested and packed. As to current situation that can be very soon, probably next week. Just follow the thread, all info will be presented promptly. :)

Regards L.C. :cheers:
Click to expand...
This is good news.
My VSSA with 2sets Connex's SMPSs are singing well and looking forward for your audition on regulated and unregulated of SMPSs. :)


Regards,
James
 
supernet

supernet

Member
Joined 2001
AP2: Thanks for explanation ;)


Xerxes75 & brianco: First One amplifier was tested in my setup on a 87dB 2way loudspeakers, feeded directly from CDP (LME 49710 TO99 output) via 10K potentiometer. I do not find any need to add buffer or preamp. I would rather recommend DAC with variable output or quality potentiometer like TKD or DACT, if analogue stage has sufficent current drive availability :cool:
 
Lazy Cat

Lazy Cat

Member
Joined 2007
Hi all :wave2:

AP2 said:
Hello Andrey , I am sending two of these in the photos.
Sorry if I insist with the DA version. is perfect for your amp. Considering that you have to use 2 (one for each amp), the power is oversized in the right way, this is something that I have tested long and well.
if you start with 61V (59-61 ADJ), you can see a drop of just 300mV-500mV on 4R.
2xDPS-500S is very expensive, considering two units also, the choice is not justified by the current demand of your First One.

I hope you show the FFT of your First One also by DPS-500/DA ;)

Regards
Click to expand...

Very well, if you recommend DA version that's OK. I will test it and post comparison FFT. :up:

brianco said:
Do You have a chassis size as yet LC? [I am having to rebuild my "in cupboard rack" and this measurement is critical for me. Many thanks,

Brian
Click to expand...

Chassis dimensions are 450 x 310 x 70 mm (W x D X H), will post pics as soon as one will be delivered to me, as promised from my supplier - this week. :yes:

Esperado said:
Lazy Cat, may i insist on the benefit to use a single SMPS (or PSU) for both channels in a stereo amplifier?
Click to expand...
Will do test single Connex SMPS in stereo and report. ;)

Cristi said:
Where is another one ? I sent you two pieces. Hopefully was not lost on the way....
Click to expand...
Cristi said:
Actually they are not identical, one is equipped with heatsink, the other one with heatslug and the secondary side capacitors are 1000uF 80V on one board and 560uF 100V low ESR on the other board, so the optimum configuration can be tested.
Click to expand...
OK, so that's why they are different, I was wondering ... will compare both of them and report soon.

Lately I'm busy with finalizing measuring station and with all preparations for the first deliveries to be ready, hopefully this week.

Best regards, L.C. :cheers:
 
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