100W Ultimate Fidelity Amplifier

[apexaudio]

So I am done with this amp.. I used preamp and transformer from original.. for premap was used dual PSU with LM337 and 317 ... I need solve problem with very little hum.. any idea with grounding , because there is no ground wire.. (two wires only for 220V)

short movie:
APEX A14 - YouTube

There is no earth wire (earth and ground is different), you need star ground for preamp psu ground and amp psu ground... nice work anyway
Regards

 

[apexaudio]

tomorrow i hope to try it,i need to put L-profile to output transistors and connect it to a heatsink(s). this is what i did today:

Nice work,
Regards

 

[maxwell007]

There is no earth wire (earth and ground is different), you need star ground for preamp psu ground and amp psu ground... nice work anyway
Regards

yes i Know...I usualy using this schematic:

 

[olafk]

tomorrow i hope to try it,i need to put L-profile to output transistors and connect it to a heatsink(s). this is what i did today:

Wow. Looks really good.
I'm curious to see how it sounds.
My next project!

regards Olaf

 

[apexaudio]

yes i Know...I usualy using this schematic:

It's schematic ground to chassis conection, can you post your ground wireing (preamp psu gnd, amp psu gnd, preamp gnd, amp gnd, input gnd, speakers gnd conections)

 

[maxwell007]

this is how my actual grounding looks like..

 

[maxwell007]

I did mistake, output ground from preamp is connected to amp SGND

 

[maxwell007]

this is correct

 

[apexaudio]

this is correct

Star ground

 

[AndrewT]

post3649 takes the charging pulses of the lower PSU through the audio circuits' star ground !!!!

 

[maxwell007]

Andrew, any suggestion ?

 

[AndrewT]

Do not connect the PSU "charging circuit" through the main audio ground. NEVER !!!!

The AC twisted triplet from secondaries MUST go to the first smoothing capacitors.

The DC twisted triplet from the LAST smoothing capacitors MUST go to the amplifier.
This applies to BOTH PSUs.
3648 is correct. I note there is NO CONNECTION between Speaker Return and Signal Return

 

[olafk]

Your A9 with NJM2068 sound good, A17 must be upgrade.
Regards

Do I need changes for running A17 with +-50V DC (because I have some of nice +-36V AC-transformers in the shelf)?

regards Olaf

 

[apexaudio]

Do I need changes for running A17 with +-50V DC (because I have some of nice +-36V AC-transformers in the shelf)?

regards Olaf

No changes, but you can increase gain: use 47R instead 100R in feedback loop.
Regards

 

[apexaudio]

Ground

 

[AndrewT]

The lower PSU power twisted triplet should go to the preamp.

The Signal OUT of the Pre-amp is a two wire connection to the Signal IN of the amplifier. This is where the In/Out get it's relative levels of the signal.

 

[masood]

dear apex(),
i want the ful form of SGND and PGND?AND MEANIG ALSO?
AND SECOND ONE WHAT IS FULL FORM OF CFA AND VFA?
THANKS

 

[masood]

dear apex(MILE),
i want the ful form of SGND and PGND?AND MEANIG ALSO?
AND SECOND ONE WHAT IS FULL FORM OF CFA AND VFA?
THANKS

 

[apexaudio]

A33

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[olafk]

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