Another quasi-complementary design

[quasi]

All sevens;

--------------
Today I fired up one of the 2 power suplies. They will share a pair of identical 300va transformers running in series.

DC voltages are +90v +77v 0v -77v.

Cheers
Quasi

 

[TomWaits]

Re: All sevens;

Today I fired up one of the 2 power suplies.
DC voltages are +90v +77v 0v -77

Quasi, you have two amps in the DIY Audio? This power supply is for a different amp? Is it in another thread? I would like to see it as well.

Shawn.

P.S. I got a line on some 1/4 inch aluminum sheet. The case shouldn't be too far away.

 

[quasi]

Hi Shawn,

This power supply belongs in this thread. You are building the amp in the other thread called "Power amp under development". Use the power supply in that thread.

Cheers
Quasi

 

[TomWaits]

Hi Shawn,

This power supply belongs in this thread. You are building the amp in the other thread called "Power amp under development". Use the power supply in that thread.

Cheers
Quasi

That's funny! I'm lost in DIY audio🙂 I was once very good with a compass...hmmn.

Cheers.

 

[TomWaits]

I was jumping on the thread by looking it up by thread starter. That will teach me...not 😉

 

[quasi]

Doesn't matter Shawn, now you've seen this amp too. I haven't finished it yet....and people are waiting. Oh well.

Cheers

 

[kASD]

Hi Quasi,

Where is your latest schematic, which is currently upgraded.....?

regards,
K a n w a r

 

[mikeks]

..........many amp modules rely on the power supply collapse AndrewT refers to for survival.

Cheers

Bad idea!

What happens when you have an anomalous primary supply surge?

 

[quasi]

Umm...just been away for 4 days....fishing and eating and sleeping .....so no amp work done .... sorry.

 

[Flavio88]

Help

hi everybody
i've tryed to build this amp for 3 times but i've always the same problem:

the sound appears terrible... lookyng into an oscilloscope i've seen that only the positive wave comes to the speaker...
the two positive rail mosfets gets cold and the negative fets remains more cool.
i don't think that there is a connection error because all the 3 prototype has the same problem.
i used the attacched schematic
but i used for input pair the 2sc2240, and for drivers(MJE350) THE 2sa1156 and a power supply of 56+56v but i 've tryed also with +10v rail for drivers...
in the power on instant, the problem seems to disappear and the positive waves is present, but only for a moment


please help me!!!!!

 

[quasi]

The first thing I would check is the voltage across R16 & R19. When the amp is first setup there should be about 3.5 - 4 volts across these and the voltage should be the same.

Is anything blowing up? Are the FET's ok? Are the fuses ok?

Do you have a copy of the PCB layout you used?

 

[Flavio88]

hi quasi,
on the board there isn't nothing blowing up, symply the neg waves is not present(there appears only on the power on instant... ) i attached the layout board i've used.
Tomorrow i will measure r16 & r19's voltage.
the driver board:

 

[Flavio88]

and the power board:
thanks for your time...

 

[Flavio88]

sorry, this is a better quality driver board

 

[Flavio88]

and the power board

 

[quasi]

Hi Flavio88,

Can you please lable the value of every component on your layout.

Cheers
Q

 

[Flavio88]

driver

 

[Flavio88]

and power

 

[quasi]

Update

Well I finally mounted the board, ready to turn it on.

Here's how it looks

 

[quasi]

And a closeup

Here's a closeup showing the mounting detail. The 3 leads going into the heatsink (near the middle of the pic) belong to the heat sensing transistor of the second CCS.

Cheers
Q