Goldmund Mimesis 3 Clone, World's Best Amplifier!!!!

[NagysAudio]

Final Schematic Notes:

 

[bluevas]

Can 2N5565 replaced with 2SK389 or dual jfet NPD5565? thank you guys.

 

[finwbu]

Mimesis 3

Hi NagysAudio,

what is the size from the board ?

regards
Walter

 

[NagysAudio]

Bluevas - No. 2N5565 can only be replaced by a 2N5564. There are no other equivalents.

Walter Burkhard - The board is approximately 24cm X 13cm.

 

[finwbu]

Thanks NagysAudio,

i can arrange to get 2N5565 or 64 from Vishay.

regards
Walter

 

[jtwrace]

Hi NagysAudio,

what is the size from the board ?

regards
Walter

In Post #61 within the parts list that Nagy posted it says 9.4" X 5.0".

EDIT: I see that Nagy has posted for you already.

 

[NagysAudio]

Little update showing the correct mains fuse rating:

 

[smartx21]

So many times this circuit has appeared and no one has complained till now about the "magic" 56V output WITHOUT any filtering capacitor... But talking about large pics is fine...

 

[Boscoe]

Are there any single sided designs out there?

 

[Lee Knatta]

So many times this circuit has appeared and no one has complained till now about the "magic" 56V output WITHOUT any filtering capacitor... But talking about large pics is fine...

Since Norbert will prototype the amp prior to selling boards this time I haven't much to complain about.


Without the caps on the amp pcb there's only rectified AC, okay.

What one could complain about is that nobody noticed he forgot to subtract the diode drop.

 

[NagysAudio]

Smartx21 - What magic 56V are you talking about? Do you not see the ginormous 10,000-15,000uF capacitors on the PCB?

 

[PCKING]

I think he is refering to adding small filtering caps of say 0.01uF across the 4 rectifying diodes.

Smartx21 - What magic 56V are you talking about? Do you not see the ginormous 10,000-15,000uF capacitors on the PCB?

 

[smartx21]

Smartx21 - What magic 56V are you talking about? Do you not see the ginormous 10,000-15,000uF capacitors on the PCB?

Well, 40VAV and 56.65V are not values, are connection references, OK, I see.
But, if you look only to the power supply, and not to amplifier main schematics, so only by magic you would have 56.65V at that point...

 

[NagysAudio]

Pcking - Why would the diodes need small caps across them?

Smartx21 - Caps, or no caps, you would still have +/- 56.56V at those points...

 

[PCKING]

It's supposed to filter noise generated across the diodes. Schematics as ashown below:

An externally hosted image should be here but it was not working when we last tested it.

Pcking - Why would the diodes need small caps across them?

 

[NagysAudio]

Pcking - Those are not necessary. If you're going to add any small value caps, they should be as close as possible to the output MOSFETS.

 

[Luke]

Pcking - Those are not necessary. If you're going to add any small value caps, they should be as close as possible to the output MOSFETS.

Not so, its common practice to put a snubber or cap across the diode to dampen the switching noise it generates, get a scope and see for yourself.

 

[NagysAudio]

It doesn't matter, it will make no difference. The sensitive input stage has it's own power supply which already addresses all of that. Small caps on the rectifier bridge are simply a waste of time I'm afraid.

 

[ostripper]

It doesn't matter, it will make no difference. The sensitive input stage has it's own power supply which already addresses all of that. Small caps on the rectifier bridge are simply a waste of time I'm afraid.

But the big power supply caps might last longer , especially if the power supply is under heavy load. If you do quiet listening ..no , but for a "party amp" , the snubbers have a very beneficial effect (VERY oblivious on scope).

The secondary supply , even with it minor loading , would also benefit from cheap 10c .01uf/400v snubbers. This is common on the PS bridge of even the cheapest walmart surround receiver , is the goldmund not worthy of these additions ??

OS

 

[NagysAudio]

Sorry, not needed guys