mynameisjonas: that's a really dark, buzzy sound for a HIWATT voiced amp. Can you do one with the pre gain at 1:00 w/post gain about 3:00, no overdrive or distortion pedals, so we can hear the cleaner tones? Thanks! I wonder if that pi is the reason for the overall tone of that mp3? Curious. Thanks for the clip. I'm really interested in one of these "hiwatt clones" myself.

I like the 2204 & 2550, but how about a clone of the JCM 900 2500/2100 MKIII?? The dual master volume feature is nice.   

And the clips are.............where!?!?!?!?!?

And....does it indeed sound like a Marshall 2550? Review, please.

Interesting.....the lack of response from Ceriatone owners.....(01.09.2010)

Thanks for this, really. This is very helpful yet still a little confusing as it references Dumble's time line. I am still hoping for a descriptive list of Ceriatone "d-clones" on the website. Right now it has this:
 
Overtone Special
Overtone Special 100

Overtone S&M Special

Overtone HRM
Overtone HRM 100

Overtone HRM Bluesmaster
Overtone HRM Bluesmaster 100   

Does one have a pre-gain e.q. or post-gain e.q.?
Which ones have what?
What does the stock OTS have/do?
What is difference between the stock OTS & S&M Special?
What is the difference between the stock OTS S&M Special & the HRM?
What is the difference between the HRM & HRM Bluesmaster?

As a potential buyer & one gathering information about an amp I can't put my hands on before I buy, I think each amp needs a description section. Something like....the stock Overtone Special is a 2-channel amp with 3 toggle switches which re-voice (what: 1 or both channels?). The toggle switches, located on the front of the amp, are: rock/jazz, mid-boost & bright. (are any of these foot switchable?) Tone controls are passive bass, mid & treble shared by both channels. The foot switch does.....what?     

Curious......If I had to guess, would the non-HRM classic eq on the Dumble be what Eric Johnson used on the Austin City Limits video & his Total Electric Guitar video?

I agree 100%. There needs to be a sticky or something on the main site or on this page denoting each model's function & comparison difference. 

Joe Bonamassa uses his Jubilee 2555 100/watt for a particular tone. Steve Morse used to use one, too, much the same way. Both of these guys are PLAYERS. These 2555/2550 amps aren't really "high gain" amps as most current day players may think. This is high gain for 1993. It's unique. The amp also lets you set the sensitivity level & that changes everything. I'd suggest anyone thinking about getting Nik's 2550, really think about what it is. It's not an uber-gain monster. It's a player's amp with touch control that really comes into it's voice when opened up, not at bedroom levels. And with the variable gain sensitivity, it's not a one trick pony. It's a player's amp that will reward the person who knows how to utilize it's capabilities. An awesome amp for sure. 

I'd like to see a Marshall JCM 900 SL-X model/style amp. That's the JCM 900 a master volume model with two master volumes, which gives guitar players something they need: a second master volume level for soloing !! 

So this "Granger amp" is a modded Ceriatone. Interesting.....

For clarification, the Marshall 2555 is the 100 watt head; the 2550 is the 50-watt head. These were introduced as the Silver Jubilee Series & carried over for two years after that as the Custom Tube Series. Joe Bonamassa is a 2555 Jubilee user; until recently, Steve Morse used a 2555 Jubilee as a staple in his rig. Now he has his own ENGL model. 
FYI guys.....the Marshall 2555/2550 models had half-power switches which switched between pentode & triode mode, allowing a 100-watt amp to operate @ 50-watts & the 50-watt amp to run @ 25 watts. I don't see this feature on Nik's schematic. 

Hmmm....would not the new 2550 be a high gain offering? Not Uberschall territory but more gain than the 2204 or jtm or 1987?