Quad 405 mod

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B

Blue

Member
Joined 2004
none.donthave.one
Caps off

Will the real JC please stand up... please stand up

With over 1500 postings and a handle like analog-SA do YOU really want to know the answer ??

In short, when you dc bias a bipolar you won't half get a good capacitor, in fact you will.

BLUE

"There are an infinite number of octaves between dc and 20Hz but less than 10 between 20Hz and 20kHz"
 
K

kaj2

Member
Joined 2004
Blue said:
KAJ2:

There's more to modify on a QUAD 405 than simply fitting overpriced capacitors....


http://www.dc-daylight.ltd.uk/Valve-Audio-Interest/QUAD/QUAD-405-Modification/QUAD-405-Mods.html


Never fit a bipolar capacitor when there is a dc voltage across it !


BLUE
Click to expand...

Hallo Blue

As far as I can see there is more than overpriced capacitors to the NET-audio modification, as far as i can see they do more or less the same as in the dc-daylight link.
I do not know mutch about elektronic then. The good thing about NET-audio is that youcan send them the amp board and they do the modification.
Do you think that the amp will sound worse after the NET-audio modification?

Kaj
 
B

Blue

Member
Joined 2004
none.donthave.one
Kaj

I think the Keith Snook mod to the front end and the correct placing of C8 in the bridge after upgrading the class A transistors is an original and cool move, also it looks like a hobby site, not commercial although proffessional.

As you say Net Audio will do the mod for you, that takes a lot because the amp could be in any state so they must be serious players.

I thought this was DIY? not let some company do it, I have done the Keith Snook mod to a MK2 and it is truley amazing and like him I have not done any thing to the current limiters yet as they have not been caught out to date.

I will not be posting much much more as I have had some bad feedback for expressing my opinions on other DIY Audio threads so good luck and..

ENJOY THE MUSIC

Blue
 
iTiberius

iTiberius

Member
Joined 2005
Zombie said:
Do you still have the current limiting in? Seems like the CCD to the class A is a good idea...
Have you implemented your changes on a 405 original board or made your own?
Cheers
tom
Click to expand...

I also think that a CCD for class A stage will improve sound quality.

All modifications have been made on an original board (copy). The amplifier is a clone.
With all modifications (see rev.2 picture), the amplifier is very stable and sounds excellent. :)

What do you think about a cascode stage after op. amp. ?

Cheers,
tibi
 
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