Late game, TEC have little chance of betting Advent - in multiplayer.  Since you are playing against AI, I think you just shouldn't have let the computer get that far advanced. 

My personal opinion is that Vasari (or Advent) is the best race to beat Advent.  For Vasari, getting phase missles upgraded helps a lot since Advent are shield dependant.  I would also get subverters, which will lock down all of the ships you just mentioned, minus the caps. 

As TEC and late game, you need to have a better economy and just Nova Cannon the crap out of him and keep building insane numbers of ships.  Hopefully you will win by attrition.  If you can, getting the Akkan to level 6 might help you because Armistice will make them stop firing at you, which will give you a chance to take out a few of their ships.  The support cap (can't remember the name) also has the EMP charge, which should help out immensly as well.

Get a Couple Sovas (or better yet, a fleet-load of Percherons) and tempt them to attack you. I've noticed, if you ever attack an AI Meduim or above, they attack you in turn.

Raid one of their planets and do some damage. Retreat. I suggest getting 20-50 Percherons and two or So Sovas. A Marza or two would be great to back  up the Javelis' long range abilities. Two to three Kol could be on standby. once the frigates are pummelled, move them in with frigate escort. If one of the enemy caps is a Carrier, get a dozen or so gardas to defend your caps.

A couple Dunovs with EMP Burst would be good too as stated above to cripple their frigates. Adn remember, keep your carriers and LRF's safe! If you lose just one LRF it could mean defeat. The best defense is a good offense.

And always make sure their attacking you. Home Field Advantage.

Even though they're said to be good only against AI, some Gauss Cannons can take down a dozen or so frigates.

Doing it all as fast as possible is always key. If you abolish most of the enemy fleet but your planet is still being raided, fall back to the nearest planet and recuperate. Build even more defenses, more ships, etc:.

And always be prepared to get attack and overwhelmed. I had to learn that the hard way

Yes, post your fleet composition.

Are you British?

The Bollocks Part hinted it

I see.

Anyway, the only way to beat the Advent is not just by numbers, but superior tactics and more researched techs.

12 kol battleships with upgraded gause cannons and 4 carriers should out number any battle ship fleet. this is because the advent base their numbers on unmanned fighters and bombers so when you look at the numbers they out number you.my trick is to form an alliance with the vasari early in the game because their weapons are closer to advent tech, this is because they are not projectile weapons like the tec. also vasari ships are no longer warship based because their people live on those ships which in future battles tec ships can kick their asses.

but stil its not the ships that cause the greatest damage with the advent its their large numbers of air support with all thos aeria drone hosts ive recently been using my 12 Kol battle ships (Upgraded to be heavy weapons themselfs with gause tech and i have been using them as bomber support carriers then the 4 carriers are upgraded to have increased fighter upgrades and to contain 7 figter squads each this is the stron point of the minimal fleet

(1)the fighers clear away enemy fiters/bombers from causing death and destruction

(2)our bombers then destroy key targets such as drone hosts,heavy criusers,any long-range weapons and battle carriers which later on helps divert the fighters assist the bombers in attacks

(3)the main battleships use gause upgrades and enhanced shields an weapons to give them a chance to hit them in their newly created weaknesses

if their sheilds are nocked off line upgraded armour will give atleast 10mins worth off battle time before having to leave to prevent critical damage depending on how many attack at once

(4)always have cobalt frigates and krosovs standing by ready to fight these may look weak but they have hidden talents beyond upgrades

i agree in my opinion of observig enemy movements they depend on one scource for their ships their CAP planet abit like our plans whereas if we need more closer construction areas we build more whereas they dont so thats their weakness their home world get the quikest route their avoid a standoff(create a diversion with a medium force) then obliterate their central world

CUT OFF THE DRAGONS HEAD AND IT WILL DIE FAIL YOU WILL MAKE IT WEAK BUT EVEN DEADLIER---BE WARNED

Tips:the sun masks incoming ship signitures,try worm holes,sun to sun travel,turn dead asteroids into forts with defence platforms and hangers(helps by diverting direct fleet invastions of key areas

I don't know about other versions, but in 1.05, the Sova can only field 6 squadrons at level 10...

I see a number of ways those four points can be countered, but this isn't the thread for that.

The Dunov has no abilities that disables weapons (though I suspect you're talking about Magnetize, which disables abilities and makes strike craft collide with that ship given they are close enough). Weapons that are energy based are no different than projectile weapons in terms of ease of disablement: a Hoshiko can disable a Crusader's weapons just as easily as the weapons on a Kodiak (unless that Hoshi is owned by the same player which owns the Kodiak).