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VSSA Lateral MosFet Amplifier

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T

Tyimo

Member
Joined 2002
Optimal output bias current is 160 mA. Other values according to personal taste of the user.

Procedure is simple, first solder 1 k multiturn trimmer potentiometer to R17 pads by the help of 2 cm wire for each trimmer's pin, start with zero ohm setting, trimm bias current to 160 mA, wait for the heatsink to warm up, readjust the trimmer to 160 mA, unsolder the trimmer, measure resistance of the trimmer with digital ohm-meter, use appropriate R17 SMD resistor size 1206 (3216) of the same value as measured, solder the resistor to VSSA PCB.
Click to expand...
Thanks!
 
Esperado

Esperado

Banned
Joined 2011
esperado.fr
Tyimo said:
Is it possible to use vertical fets instead of latherals in your circuit?
Click to expand...
Lateral FETS have a a negative temperature coefficient, Vertical, not. This means vertical FETs require a bias circuit with temperature compensation.
For the fuses, once your amp has been fully tested in real situation and 'burned' during enough time to ensure it works perfect, you can short-them... at your own risks.
 
C

CaféNoir

Member
Joined 2010
I am planning to use one more set as a headphone amplifier.
What modifications would you recommend for that purpose?

I am adding myself for one more set, (and also adding DavorXXL and sadki that were left behind).

So in total:

Joachim Gerhard 2 PCB set
AKN 2 PCB set
Idefixes 4 PCB set
kimon 2 PCB set
brianco 2 PCB set
Dane 2 PCB set
MKHunt 2 PCB set
Cambe 2 PCB set
Supernet 2 PCB set
boyet0173 2 PCB set
tom42107 2 PCB set
presbel 2 PCB set
meltman 2 PCB set
gannaji 2 PCB set
dodo 2 PCB set
coolet 2 PCB set
jj506 2 PCB set
vgeorge 2 PCB set
touchdown 2 PCB set
wponline 2 PCB set
Luke 2 PCB set
cvtaudio 10 PCB set
Renio 2 PCB set
maillard 2 PCB set
PauloPT 2 PCB set
hcbonfim 2 PCB set
gusto142 2 PCB set
PinkPink 2 PCB set
dine1967 2 PCB set
bressix 2 PCB set
nico2k3 2 PCB set
routhun 2 PCB set
CaféNoir 4 PCB set
ColinAlex 8 PCB set
Murdoc 2 PCB set
regal 2 PCB set
AUSTINP 2 PCB set
kroyin 2 PCB set
fredlock 2 PCB set
mikvous 2 PCB set
myfi 2 PCB set
FelixG 4 PCB set
ichiban 2 PCB set
padamiecki 2 PCB set
gogu 2 PCB set
joshvi 2 PCB set
philippeleite 2 PCB set
mefistofelez 4 PCB set
DavorXXL 6 PCB set
sakdi 2 PCB set
buzzforb 2 PCB set
acqu27 2 PCB set
 
Siberia

Siberia

Member
Joined 2011
Paid Member
Joachim Gerhard 2 PCB set
AKN 2 PCB set
Idefixes 4 PCB set
kimon 2 PCB set
brianco 2 PCB set
Dane 2 PCB set
MKHunt 2 PCB set
Cambe 2 PCB set
Supernet 2 PCB set
boyet0173 2 PCB set
tom42107 2 PCB set
presbel 2 PCB set
meltman 2 PCB set
gannaji 2 PCB set
dodo 2 PCB set
coolet 2 PCB set
jj506 2 PCB set
vgeorge 2 PCB set
touchdown 2 PCB set
wponline 2 PCB set
Luke 2 PCB set
cvtaudio 10 PCB set
Renio 2 PCB set
maillard 2 PCB set
PauloPT 2 PCB set
hcbonfim 2 PCB set
gusto142 2 PCB set
PinkPink 2 PCB set
dine1967 2 PCB set
bressix 2 PCB set
nico2k3 2 PCB set
routhun 2 PCB set
CaféNoir 4 PCB set
ColinAlex 8 PCB set
Murdoc 2 PCB set
regal 2 PCB set
AUSTINP 2 PCB set
kroyin 2 PCB set
fredlock 2 PCB set
mikvous 2 PCB set
myfi 2 PCB set
FelixG 4 PCB set
ichiban 2 PCB set
padamiecki 2 PCB set
gogu 2 PCB set
joshvi 2 PCB set
philippeleite 2 PCB set
mefistofelez 4 PCB set
DavorXXL 6 PCB set
sakdi 2 PCB set
buzzforb 2 PCB set
acqu27 2 PCB set
siberia 2 PCB set
 
mravlca

mravlca

Member
Joined 2009
Joachim Gerhard 2 PCB set
AKN 2 PCB set
Idefixes 4 PCB set
kimon 2 PCB set
brianco 2 PCB set
Dane 2 PCB set
MKHunt 2 PCB set
Cambe 2 PCB set
Supernet 2 PCB set
boyet0173 2 PCB set
tom42107 2 PCB set
presbel 2 PCB set
meltman 2 PCB set
gannaji 2 PCB set
dodo 2 PCB set
coolet 2 PCB set
jj506 2 PCB set
vgeorge 2 PCB set
touchdown 2 PCB set
wponline 2 PCB set
Luke 2 PCB set
cvtaudio 10 PCB set
Renio 2 PCB set
maillard 2 PCB set
PauloPT 2 PCB set
hcbonfim 2 PCB set
gusto142 2 PCB set
PinkPink 2 PCB set
dine1967 2 PCB set
bressix 2 PCB set
nico2k3 2 PCB set
routhun 2 PCB set
CaféNoir 4 PCB set
ColinAlex 8 PCB set
Murdoc 2 PCB set
regal 2 PCB set
AUSTINP 2 PCB set
kroyin 2 PCB set
fredlock 2 PCB set
mikvous 2 PCB set
myfi 2 PCB set
FelixG 4 PCB set
ichiban 2 PCB set
padamiecki 2 PCB set
gogu 2 PCB set
joshvi 2 PCB set
philippeleite 2 PCB set
mefistofelez 4 PCB set
DavorXXL 6 PCB set
sakdi 2 PCB set
buzzforb 2 PCB set
acqu27 2 PCB set
siberia 2 PCB set
mravlca 2PCB set
 
B

baswamin

Member
Joined 2011
LC,

Please add me for a pair of boards.

Joachim Gerhard 2 PCB set
AKN 2 PCB set
Idefixes 4 PCB set
kimon 2 PCB set
brianco 2 PCB set
Dane 2 PCB set
MKHunt 2 PCB set
Cambe 2 PCB set
Supernet 2 PCB set
boyet0173 2 PCB set
tom42107 2 PCB set
presbel 2 PCB set
meltman 2 PCB set
gannaji 2 PCB set
dodo 2 PCB set
coolet 2 PCB set
jj506 2 PCB set
vgeorge 2 PCB set
touchdown 2 PCB set
wponline 2 PCB set
Luke 2 PCB set
cvtaudio 10 PCB set
Renio 2 PCB set
maillard 2 PCB set
PauloPT 2 PCB set
hcbonfim 2 PCB set
gusto142 2 PCB set
PinkPink 2 PCB set
dine1967 2 PCB set
bressix 2 PCB set
nico2k3 2 PCB set
routhun 2 PCB set
CaféNoir 4 PCB set
ColinAlex 8 PCB set
Murdoc 2 PCB set
regal 2 PCB set
AUSTINP 2 PCB set
kroyin 2 PCB set
fredlock 2 PCB set
mikvous 2 PCB set
myfi 2 PCB set
FelixG 4 PCB set
ichiban 2 PCB set
padamiecki 2 PCB set
gogu 2 PCB set
joshvi 2 PCB set
philippeleite 2 PCB set
mefistofelez 4 PCB set
DavorXXL 6 PCB set
sakdi 2 PCB set
buzzforb 2 PCB set
acqu27 2 PCB set
siberia 2 PCB set
mravlca 2PCB set
baswamin 2PCB set

Thanks
 
Lazy Cat

Lazy Cat

Member
Joined 2007
Hi guys :wave:

At this point 146 PCS sets, all together with PMs, confirmed, thanks a lot, respect. :grouphug:

Few words about current situation. First batch of a 6 test PCBs will be ready this week. This six PCBs will be reviewed in detail regarding expected level of quality, two of VSSA PCBs will be assembled according to BOM and simultaneously parts markings to values will be checked too. This procedure is absolutely necessary prior to produce full package of PCBs, also I will be sure that all of you will get what promised here. ALFs will be assembled in a matter of few weeks, so I will have just enough time to prepare all semis and printout the addresses to envelope stickers.

As you all probably know I tested VSSA with linear power supply 350 VA toroid and 40 mF per channel. This solution of PSU is a commonly in use but it is a little bit expensive, big and heavy, maybe also obsolete too. As I had very good experience with Hypex's SMPS600 when tested NC400, today I decided and ordered two SMPS400A180 (400 W, 2 x 46 V) for VSSA, one per channel. If this PSU solution reveals to be on the same level or even better, than this will be a mega solution, since one SMPS400A180 costs only 61,20 EUR/net price. It also has DC error input to instantly shut down PSU output voltage if triggered, also soft start and over current protections included. So all we need is one SMPS400A180 plus VSSA for one channel.

This combo will be killer solution for a very low bucks regardless price target to compare and will shake Hi-End amps market to the bones. :up:
 

Attachments

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Last edited:
G

gazzagazza

Member
Joined 2004
Added my name at the bottom...

Joachim Gerhard 2 PCB set
AKN 2 PCB set
Idefixes 4 PCB set
kimon 2 PCB set
brianco 2 PCB set
Dane 2 PCB set
MKHunt 2 PCB set
Cambe 2 PCB set
Supernet 2 PCB set
boyet0173 2 PCB set
tom42107 2 PCB set
presbel 2 PCB set
meltman 2 PCB set
gannaji 2 PCB set
dodo 2 PCB set
coolet 2 PCB set
jj506 2 PCB set
vgeorge 2 PCB set
touchdown 2 PCB set
wponline 2 PCB set
Luke 2 PCB set
cvtaudio 10 PCB set
Renio 2 PCB set
maillard 2 PCB set
PauloPT 2 PCB set
hcbonfim 2 PCB set
gusto142 2 PCB set
PinkPink 2 PCB set
dine1967 2 PCB set
bressix 2 PCB set
nico2k3 2 PCB set
routhun 2 PCB set
CaféNoir 4 PCB set
ColinAlex 8 PCB set
Murdoc 2 PCB set
regal 2 PCB set
AUSTINP 2 PCB set
kroyin 2 PCB set
fredlock 2 PCB set
mikvous 2 PCB set
myfi 2 PCB set
FelixG 4 PCB set
ichiban 2 PCB set
padamiecki 2 PCB set
gogu 2 PCB set
joshvi 2 PCB set
philippeleite 2 PCB set
mefistofelez 4 PCB set
DavorXXL 6 PCB set
sakdi 2 PCB set
buzzforb 2 PCB set
acqu27 2 PCB set
siberia 2 PCB set
mravlca 2PCB set
baswamin 2PCB set
gazzagazza 2 PCB set
 
J

Jay

Banned
Joined 2003
Lazy Cat said:
I will test one to one just for max performance outcome in comparison with linear PSU. :cool:
Click to expand...

Invite also some audiophile friends, especially those who don't like class-D :) Imo, it is not easy to "hear" the issue with SMPS. Most of the time, it will be perceived as better because it is cleaner than conventional power supply.

An easy way to help catching some issues with audio systems is by listening from a distance. MP3 recording for example, sounds "normal" from nearby but when heard from a distance, clearly show what it is. This trick works with many other issues.
 
Esperado

Esperado

Banned
Joined 2011
esperado.fr
Lazy Cat said:
As you all probably know I tested VSSA with linear power supply 350 VA toroid and 40 mF per channel. This solution of PSU is a commonly in use but it is a little bit expensive, big and heavy, maybe also obsolete too. As I had very good experience with Hypex's SMPS600 when tested NC400, today I decided and ordered two SMPS400A180 (400 W, 2 x 46 V) for VSSA, one per channel.
Click to expand...
I believe the Hypex's SMPS600 is not regulated. On an other point of view, they have a very good common mode symmetry. I don't know if VSSA will get benifit from this feature.
May-be would it be worth to test less expensive, but very good too connexelectronic (Cristi) SMPS ? They are regulated.
 
Lazy Cat

Lazy Cat

Member
Joined 2007
Bonsai said:
I took a look at this thread - very cool looking little amp LC! I am looking forward to seeing some pictures of fully wired up and houses systems.
:)
Click to expand...

Hi Bonsai

VSSA up to now only as fully functional test setup with linear unregulated PSU, which will be compared to the one with SMPS. There will be a lot finished VSSA amps if we just look to the list of PCB sets confirmations, so a little while to wait. ;)

Yes, VSSA is a very cool looking small amp module and it works like a charm, on everyday basis. So far no flaws, no unpredictable behavior. Most of the day is on, playing music. :cool:
 
Lazy Cat

Lazy Cat

Member
Joined 2007
Junie said:
a silent and peaceful morning in the office, i made this one (in PAINT). Let me know your toughts :).

VSSA_zpsa1d9068d.jpg


BR,
Junie
Click to expand...


Hi Junie ;)

That's really fine in-case layout, outer hight dimension can be less than 6 cm if VSSA is fixed in landscape position to the heatsink. For protection you would need only DC sense on each channel's output terminals, both connected to SMPS400, like the one on pic attached. :up:
 

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