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VSSA Lateral MosFet Amplifier

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P

PMI

Member
Joined 2013
tinitus said:
is there any specific reason to choose the SMPS400A180, and not the SMPS180 ?
Click to expand...
The answer is in the fine print. In the case of the SMPS180, see table on page 4 of the datasheet. Full power (180W) for 20 seconds, 50% power for 1 minute, and 30% continuous power, so only 50-60W, and much less actually, because hypex use a class D amplifier for testing. With class A-B some of that power just goes into the amplifier heatsinks.

These are very small power supplies, just because it is called a something-400, does not mean you are getting the load capability of a 400VA transformer, not even close. Bonsai saw that way back in March.

Read LC's post about the Hypex power output and ripple, with the SMPS180, I assume it would be much worse.

Hypex Power

Edit:

Another way to look at this - the 180 is a 50~60W supply which can provide 3x its continuous power during peaks. Not what LC had in mind for VSSA, I am sure, ;)
 
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P

PMI

Member
Joined 2013
Esperado said:
Thanks, PMI for a very interesting input, and AP2 for a good analyze.
PMI, if you have some time for that, can-you measure on the rails with a positive 1/30s pulse, and too with a negative one at full power of your amp ?
Click to expand...
I'll see if my signal generator can do that, yes. The supply will eventually drop out of regulation, I have no magic bullet for that, but it should be an interesting test. The output cap on my test board may be too large to show a loss in regulation, but when I get more boards, I have promised to build up a lower power version which may show this better.
 
D

dw1narso

Member
Joined 2004
tinitus said:
if only we could get good IE-core trafos
less aggressive than toroids
Click to expand...

Only 200W... but this could be better than IE core... for dual mono of 40-60Watter each channel...

220V 200W R Core Transformer Output 20V 20V 12V 12V | eBay

The choice for the 200W:
- 20V(4.75A)×2+12V(0.4A)×2，
- 24V(3.7A)×2+12V(0.8A)×2，
- 26V(3.4A)×2+15V(0.8A)×2，
- 28V×2+15V×2，
- 30V×2+15V×2，
- 32V×2+15V×2，
- 36V(2.45A)×2+15V(0.8A)×2，
- 40V(2.2A)×2+15V(0.8A)×2

PS. I do not in anything tie to this guy on ebay... nor even buy something from him... yet...
 
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analog_sa

analog_sa

Member
Joined 2002
ivanlukic said:
Why is Connex SMPS300R suitable for amps that have PSRR greater than 54dB (according description)?
Click to expand...


I guess it's just a question of the datasheet PS ripple appearing at the speaker output, or 100mV/500=0.2mV. Without information about the ripple frequency (50kHz?) this is not very useful. I wonder if a power amp with 54db psrr at 50-100kHz is common or even exists.
 
Lazy Cat

Lazy Cat

Member
Joined 2007
VSSA GB Info

evette said:
Ok Please put me down for 6 pcb,s Evette
Click to expand...
BYRTT 8 PCB set
CaféNoir 6 PCB set
ColinAlex 8 PCB set
DavorXXL 6 PCB set
DuffyDawg 4 PCB set + 4 SMPS400
electromf 4 PCB set
badrisuper 2 PCB set
volavola 2 PCB set
JethroTull 2 PCB set
kp93300 2 PCB set
momomo67890 4 pcb set
ua3grn 6pcb set
mj777 2pcb set
mkusan 2pcb set
Odysseas 4pcb (2 pairs)
hcbonfim 2pcb set
Albrerta 2pcb set
dw1narso 2 pcb set (1 stereo) + extra output device pairs & isolators (for stereo if possible)
supernet 2 pcb set
milandks 4pcb set
tjencks 2pcb set
quanghao: 2pcb set
audionootje: 4pcb set (2x stereo)
tritosine 4pcb (2 pairs)
Bobo le Chat 2 pcb set
AP2 2pcb set+2pcb empity (i need this also)
Meganinja 2 set ( stereo )
mikvous 2 pcb set
still4given 2 PCB set
Rick G 2 PCB set
kindhornman 2 boards
ravid 2 pcb set
evette 6 PCB set

At the moment we have reached to 108 VSSA PCB set. :up:

Only 2 VSSA PCB set still available. :wiz:

Who will be the lucky one? :cheers:
 
Lazy Cat

Lazy Cat

Member
Joined 2007
Esperado said:
PMI, i believe L.C. had followed the same road as me. First, suspicious with SMPS, then convinced with the sound improvement he could hear, comparing the two.
Click to expand...

Esperado said:
I believe L.C. did a much simpler and pragmatic study: tried both solutions, and chose the best.
Click to expand...

Exactly. Among the measurements at 5 A output DC current (output voltage drop, ripple voltage, HF noise, etc.) which were all in favour to SMPS, also the sound comparisons convinced me to use SMPS. What more to say? :cool:

The main difference I see lies in mains lower source impedance compared to transformer. In SMPS energy storage (smoothing) capacitors are charged directly by mains current from low impedance source. If you insert transformer between the two of them, as in classic PSU, you get much higher source impedance to charge main smoothing capacitors, so current on demand isn't that good as in SMPS. :2c:
 
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Siberia

Siberia

Member
Joined 2011
Paid Member
BYRTT 8 PCB set
CaféNoir 6 PCB set
ColinAlex 8 PCB set
DavorXXL 6 PCB set
DuffyDawg 4 PCB set + 4 SMPS400
electromf 4 PCB set
badrisuper 2 PCB set
volavola 2 PCB set
JethroTull 2 PCB set
kp93300 2 PCB set
momomo67890 4 pcb set
ua3grn 6pcb set
mj777 2pcb set
mkusan 2pcb set
Odysseas 4pcb (2 pairs)
hcbonfim 2pcb set
Albrerta 2pcb set
dw1narso 2 pcb set (1 stereo) + extra output device pairs & isolators (for stereo if possible)
supernet 2 pcb set
milandks 4pcb set
tjencks 2pcb set
quanghao: 2pcb set
audionootje: 4pcb set (2x stereo)
tritosine 4pcb (2 pairs)
Bobo le Chat 2 pcb set
AP2 2pcb set+2pcb empity (i need this also)
Meganinja 2 set ( stereo )
mikvous 2 pcb set
still4given 2 PCB set
Rick G 2 PCB set
kindhornman 2 boards
ravid 2 pcb set
evette 6 PCB set
siberia 2 pcb set
 
D

dw1narso

Member
Joined 2004
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Idefixes

Idefixes

Member
Joined 2003
audiyofield.wifeo.com/index.php
dw1narso said:
Lazy Cat,

do you mind to put on the first post of this thread (http://www.diyaudio.com/forums/vendors-bazaar/225747-vssa-lateral-mosfet-amplifier.html#post3285859).... all the parts that we need to source ourselves in addition to the parts+board provided with the GB?

I'm looking for them but lost after this thread is getting to 2000+ posts.

PS. could I use VSSA with simple passive volume pot? Cause I don't have any preamp ready at this moment...

Thanks,
David[/QUOTE

Here is L VSSA BBOM. What you need to source is 1000µF 50V, 2200µF 6v3, 10µF MKT RM15, and faston spad.

Marc
Click to expand...
 

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