Nice to know, I have  a 1x12 with a Ceramic Blue Dog in it, might have to plug the Overtone in and give it a whirl 

I have had the same experience with my G12-65s and they are very much broken in. It is very noticeable when you A/B them in real time with other speakers.  Judging from many posts in this forum, that "muffled" tone sounds very good to a lot of people using the G12-65 with OTS.

The Weber Blue Dog is a great speaker. I have 10s in Bassman Clone. My amp tech does work for Emerald City Guitars in Seattle, WA and we have had the opportunity to A/B my 5F6A kit amp with three vintage '59 Bassman amps. My clone sounds remarkably better than those amps. I have to attribute this to those speakers. The Weber kit that I purchased had the cheapest, crappiest, components. I have had to replace switches, jacks, various resistors and capacitors and the power transformer, but that amp has always sounded great, due to those Weber Blues.

There are more players that like the g12-65, me included .
If your OTS is on the darkside a g12-65 might be a wrong speaker.

Hey, we obviously don’t want your head to explode, but you have to try FANE AXA12 ALNICO.

I just loaded a 2X12 cab with one Eminence Texas Heat and one Eminence Man-O-War. What a great combination. The cab did have Celestion 70/80s in it. The 70/80 speakers are just plain and lifeless. The Eminence pair have a tight, punchy bottom end with great mids and just enough highs to be clear but not tiring to the ears. Really makes my HRM shine!

I've owned my OTS for a few months now using it at many concerts and festivals. It (for me) is the perfect amp. The distortion is more smooth and less harsh, but it is not for playing heavy metal. You'd need a distortion pedal.

It's got great blues distortion, classic rock and rock sounds. With the OD Trim Pot mod, you have 3 levels of OD to play with, and it's got cahones and tone. Being able to bypass the amplifier's tone stack with a footswitch is a great touch for soloing also.

The tone controls aren't as "responsive" as some would like, but with the addition of the 3 toggle "tone" switches and a presence control, it's not really needed. I set it and forget it. You can also do internal mods to it yourself (via this forum) to shape the tone more to your liking.

The best mod I did was moving the OD Trim Pot to the back panel for "on the fly" adjustments. I also replaced the filter caps to 200mfd and added a fan on the inside of the cabinet to help cool it. Mine doesn't get that hot unless it's in the sun, and it has been a couple of times, and still performed solidly.

I purchased and have been using the Kleinulator and it's a must for this amp (or for only $120) or perfect for any amp that does not have an active effects loop. It allows me to use my wah, reverb, delay and chorus.

On some settings it's a little noisy, but what real tube amp isn't? It's still sounds every bit as good as a M******** or a T** R***, etc.,  for under half the cost. I have to admit the tone of the OTS is a little different, and owning two of them (an OTS 1x12 50w Combo and a OTS S&M 50w amp head only), they each sound a little different. But it is fat, sweet, full, rich... use whatever superlative you want.

This amp sustains (with the right guitar/pickups) forever. I use Rio Grande Texas BBQ's in a PRS Santana III and a Gibson Les Paul  Double Cutaway and I also have an Ibanez Semi-Hollow Body (with Santana III pups). They all three sustain / feedback excellently.

I use Eminence Patriot "Cannabis Rex" 12", 50w speakers in both my 1x12 cabinet and the 1x12 Combo amp. This is a great complement for the OTS. Smooth, silky highs. Very tight lows and pronounced mids (but smooth). Also it's a loud combination. Playing many large outdoor events, I've never played with the amp over 2½, and that was LOUD (soundmen get pissed at about 1½), and this is using only 1x12. Using 2x12's is really LOUD! It's not just the volume, it's the fat tone that cuts through the mix.

My bandmates make fun of me at practice because I "only" use a Mesa Boogie Lonestar Special, 1x12, 30w for rehearsals (until I bought the OTS, it was my main amp). The Lonestar is one good sounding amp, but there is a world of difference in tone, the clarity and the pure "balls" in the OTS's sound and the Lonestar just can't even touch.

You also can bias the tubes very easily if you have a Digital VOM. It takes a minute or so to do.

Also it has an impedance selector switch (4 / 8 /16 ohms) on the back and though I experimented a little with impedance mis-matching, I really couldn't hear an improvment over the 50w amp being ran through a 50w speaker.

The only thing it doesn't have is reverb built in, but I'm not complaining, it's just a fact. I use a DigiTech Hardwire RV-7 Reverb which I prefer over most reverb tanks anyway.

Cost was not an issue as the OTS S&M was $2000 less that the other amps that I thought were in the same "class". Very clean P to P wiring, good packing job when shipped. No instruction manual included, but there is this forum and the diagrams that are available from Ceriatone. If you found this amp, you don't need instructions because you've probably been playing awhile and know you want a "better" tone. You found it!

It's built heavy duty, though the amp head cabinet is actually too lightweight for the amp. I bought a heavy duty real leather handle for my cab head. The head is very solid, probably 38 pounds or so (in a light cabinet).

I'm still experimenting with different 6L6's and 5881's as the output tubes. So far I like Groove Tube 12AX7s as the preamps and the stock JJ 6L6s and Tung Sol 6L6s. I use the Tung Sol 6L6s and just carry the stock JJs with me just in case. I've not had any problems (except an initial JJ 6L6 was bad when I received the OTS S&M, but Nik sent me a new pair with all the associated resistors, caps, etc.). No problems since. Just rockin'!!!

I played many festivals/concerts this summer, all of them having used the OTS S&M head and a 1x12 cabinet. We had a large gig in Chicago on Aug. 14 at the Woodstock tribute festival and they provided the backline, so I didn't take my amp head (MISTAKE). They had a huge backline selectionn of amps. 3 Mesa Boogies, Fenders, Vox AC30 and Marshalls. NOTHING came close to the tone I'm now used to, and I was jonesing for it that night.

I got home the next afternoon and immediately went online to Ebay and purchased an ATA approved road case for it! It cost $155 or so, but is a great heavy duty case and it will protect my head since I WILL be taking it to all gigs in the future.

So overall I give the OTS S&M and the OTS a 9 out of 10, and I've owned practically every amp imaginable at one time or another (except a Dumble). The knocks are the OD Trim Pot you have to modify yourself (this feature should be a part of the stock build) and the lack of an active effects loop.

Tone: 10
Features: 8
Volume: 10
Versatility: 9
Reliability: 9 (so far all is good but can't give it a 10 there, yet...)
Price: 10

Deafcat, I like what you said about the Celestions being lifeless. To me they sound like playing through cardboard... Totally lifeless, muffled and tinny. But a majority of players use them, so it must be our ears eh? 

If you're really going for tone, and not just loud, distorted sound, I also believe that The Eminence Patriot Series offers some great alternatives.

I also tried a Tone Tubby (don't understand the fascination with them?), and Scumback (an excellent speaker, but very heavy/expensive), JBL, and Celestions (3 different types). I went through a total of 7 different speaker combinations before I decided on the Cannabis Rex. The first night I used one, it was love at first sound. Mine aren't even broken in yet and they sound great.

I actually had a Texas Heat originally but it was just too damn loud! You get into some of these festivals/casino circuits and you have to control your volume and still get the tone/sustain/feedback you need. The "Rex" is a perfect fix for that.

Plus the hemp cone in the "Rex" is a nice touch on the high end. Makes it fatter and less tinny. You can get all the bite you want, but with Celestions it was all bite all the time, even with the highs rolled back all the way.

Another bonus? The Cannabis Rex is inexpensive ($89 including shipping is what I paid on eBay) and very light.

I’m sorry but this is wrong statement.
Some celestions are not good enough for OTS but nothing compares to Blue, Gold (12” and 10”) and Century range. G12-65s need about 24 hours brake in period and after that they sound great. It’s also depends on the cabinet you use, 1x12, 2x12, open or closed back front ported and so on. To test the speaker it should be in the cab, on your face level or in the sound proof room closely miced up and auditioned from the good PA (best test).
I’ve tried almost any existing Celestion, Jensen and Eminence speakers (it is my job! We build cabinets) side by side in similar cabs with a,b,c,d switch box and best speakers FOR OTS!!!!!  Are:

1.   Fane AXA12 alnico
2.   Electro Voice
3.   Jensen Jet Tornado
4.   Celestion Gold
5.   Tone tubby
6.   Celestion Century
7.   Celestion century vintage
8.   Celestion G12-65
9.   Eminence Wizard
10.   Emi cannabis Rex

Best wishes