Hearthpwn

Only played a few games, and I'm already feeling the pain and frustration of trying to get the combo set up. Aggro is quite prevalent lately, and I find myself using up both Hellfires due to the lack of Defile, or simply having no other early answers to the board. Many times both Voidlords are drawn before a single Lackey shows up, and many times Lackeys remain in the hand without Dark Pact to destroy them. Summon a Lackey anyway, it gets immediately silenced. 

Still, it has proven to be a fun challenge to attempt to win, with or without the combo. Currently only one game was won, against what was some sort of Big Hunter. 

The combo seems awfully slow.

1) Play Bloodreaver Gul'dan 

- Fine.

2) Play Carnivorous Cube and cube Clockwork Automaton

- Not fine. Requires you to pass the turn, leaving the opponent with the initiative and your cube is a sitting duck for silences (which is everywhere atm) and straight out being killed or otherwise dealt with. Sap anyone ? Psychic Scream maybe ?

3) Play Prince Taldaram and copy  Carnivorous Cube

- Yes, if your really lucky and your cube has survived.

4) Play  Hellfire and then attack enemy minions with Carnivorous Cube to die

- Yes, if your really lucky and your cube somehow has survived, and there is enemy minions on the board to actually attack.

The deck does look like fun but pulling this OTK of seems hard to do.

You are right,

Can't find any replacement to speed up this combo.
Maybe just using the Automaton to double your hero power it's not as bad itself, maybe a control lock could do something using low cost demons (Vulgar,Dreadlord and voidlord) and not sticking with a cubelock recipe that couldn't work for many reason.

Just think about using Gul'dan, summoning a lot of demons and then play from the hand Automaton, healing yourself of 6. It's not bad in this view. But it coud be only a for-fun deck 

Any ideas?

You don't have to use the 48 damage to win.  You only use it against certain deck like Infinite Taunt Druid, where they don't have silence.  I beat them most of the times even with bad draw with this deck.  I usually save all combo pieces against them, because that is the only way to beat them.  That deck  can spawn waves of taunts which out-value any decks.  Also, you have a lot of minions to bait out silence, etc. before the ultimate combo, which is when both players are almost of cards.   Against aggro and tempo, don't even think about the ultimate combo.  Yo want to get your Voidlord out and as many Voidlord as possible.  That is how you beat them.  Try to time it, so that you can Faceless the Voidlord when it comes out.

1) OK

2) There is a risk, but by that time you should already bait out silence, etc.  The deck itself without the combo is already strong.  The opponent will not sit on the silence, etc. until the end of the game. 

3) Luck and knowledge

4)  Are you telling me on turn 10, there is no minion on board to attack?  They are not going to play anything on turn 10? Also, you don't need to attack if you still have a dark pact, but it's only 24 damage.  just copy the Clockwork Automation with Prince or Faceless and you get 3 Clockwork Automation.   If you want 100% sure, then you can put in Catalysm, but it will make the deck weaker.  

The deck is strong by itself without using the ultimate combo.  You can just use a 2 cards combo, Clockwork Automation and Prince Taldaram, after DKed for 12 damage/24 heal.  I beat most other decks like that, especially against other Cube/Controllock.  

I didn't use this deck to reach legend, but I went from 3000's legend to 1100's legend with it.  I reached legend before the expansion and messed around until I made this deck.  It has a fun combo, but also consistent.  The only problem is against Odd Rogue. That deck is too powerful.

Did not played this but it seems funny