I know you inspected the solder joints but did you re-flow them?  Sounds like a bad tube to me.  Swap v1 and v2 valves.  If no change sub in other pre's, first v1 and test, then v2 and test.  Post back.

+1  Yep, Nik would probably have to find an attorney....

SPM,

Another great clip.  I like both but I think I prefer the first clips meatiness slightly.  However, that controlled feedback on the second clip is stellar.

I'd pre-order 5 of those.....how bout it Nik.

I use pine for all my cabs.  I love the way pine cabs resonate.  At volume the sound seems to radiate from the entire cab not just from the baffle.  I built a "bare" 5E3 head and 1x12 cab for a fellow and he was so thrilled that he could not put a glass of beer on the cab as it would "bounce" off.  Most high end builders these days use Baltic Birch Ply.  I would too, but I can't get it.

Junction,

I know what you're sayin.  I've come to realize that when SL compares apples and oranges it's more like spartans vs golden delicious......oranges aren't even a part of the conversation.       

Scott Lerner is a very accomplished authority on all things Dumble.   He has first hand knowledge and experience with most if not all the Dumble voiced amps out there.  If you want that sound it is in your best interest to listen to him.  He certainly speaks with.....um.... confidence...lol.. but he has been chasing this tone for years and has earned the right.   If he says that an amp sounds bad it isn't necessarily "bad" just not in line with the tone he is focused on reproducing. Monster player, too....but sometimes I wish he would just dumb it down a little and play a simple 1,4,5....lol.

ChrisL

Gunner,
  I would just get the amp as is and mod it to your taste later.  I really does sound pretty damned good as is.  But for interest sake I will make a mod thread soon once I experiment a little more with the Overtone and D'Lite.

Hey Rui,

You still waiting for the Overtone??  The mods are in line with some of the mods being done to the D'lite.  Basically, just bringing some of the components back to typically accepted Dumble values.  I've been hampered with my parts supplier taking three weeks off but he's back to work so I'm putting in an order today.

ChrisL

spm,

Sounds great and nice playing man.  Cool vid.  Yep, those are the tones I'm getting with mine...very pleasing.  Once I get done and satisfied with the mods I'm doing I will post some clips.  You have some other nice "hardware" I see.   Overtone sitting on the Fuchs.....had a chuckle.  Lovely angels, too.

ChrisL

Yes, try some different pre's.  Like the 18watt amps and tweeds (5E3) where most of the goods are given up below 2 oclock and anything after that is just mud,, the Expression is similar.  Putting some lower gain pres and rolling off the guitar are the only ways to tame the mayhem when cranked.

Roe,

I've been looking over that layout and thinking of building it for a while now.  I haven't found a schematic and I don't like building with just a layout.  Please post pics and your thoughts of the circuit when you're done.

Wow, I like that guys playing, very tasty.  "Room at the back" has a great tone. Sure, the Overtone can do those tones but a lot of amps can get there as well with a guy of that calibre playing them.  Between my 73 Super Reverb and Overtone I think I could have most of what I hear covered. 
I haven't gotten into the Overtone's clean channel all that much with regards to the Carlton pushed cleans.  Tweaking the OD has me pretty much consumed at the moment.

Post the inside dims of the cab (in metric if possible...I'm lazy about converting) and I will tell you.

Happy holidays everyone.  All the best to you Nik in the new year.