I recently broke down and purchased a reissue G12-65 just to find out what the hype is about. I have tried my OTS with Celestion V30's, Hellatone V30's, G12H, G12M, G10 and an EV12L and am completely convinced that there is good reason for that hype. My OTS came alive for some reason. The single notes were round, fat and smooth and the rhythm sound was thick and meaty. The amplifier simply came to life. Its hard to explain. Many have tried especially on this forum and its a thing you have to hear and more importantly, feel for your self. The way the amp reacts with that speaker is absolutely beautiful. Taste is a personal thing I know and I have not heard this amp with every speaker out there but for me, this is it. Besides, if the tone gets any better than this, my head may explode!

I had a similar problem and it turned out to be the lack of shielding. I should have questioned it when I received the Mojo head cabinet and noticed that there was no shielding but...

I installed a piece of aluminum and all my problems went away.

Wow...not loud enough?? 

My 1987 is ear splitting loud through a 4x12 and a 2x12. I need an attenuator to tame this beast. I guess you could change the tubes but then it wouldn't really be a 1987 anymore?

I also use a 4x10 cabinet with Celestion G10's and love the tone at any volume. I have a 2x12 with a Vintage 30 and G12H30 but seem to keep going back to the 10's. The low end seems to tighten up a bit to my ears with the 10's. Either way...you cant go wrong with an OTS. 

Received mine about 3 weeks ago and cant believe how good it sounds.  I ordered it with the Brown Mods as I am going for that VH1 tone. I run it through a Weber  MASSLite 100 and have the volume set around 3 o'clock and just sounds sick. Luckily, I had a set of Mullard EL-34's that I have had sitting in a box for probably 15 years now and threw those in, biased with a BiasRite between 36 and 39 ma's and sounds amazing. Eventually, I want to try and get a set of Sylvania 6CA7's. Anyway, highly recommend this amp and cant say enough about Nik and his guys at Ceriatone. The build is quality is amazing but the sound is unbelievable.   

Nik responded to my email...see below...

 "1/2W will be fine, but perhaps use 1W"

Gonna go with a 1 watt for the hell of it.
 

Thanks for the layout Nik...question regarding the resistor...I assume that it is a 10 Ohm resistor? Also, 1/8, 1/4 or 1/2 watt? I guess I can overkill it and use a 1/2 watt but want to confirm before I buy the parts.
Thanks!

UPDATE...no bill from DHL yet. It has been 6 months.... 

I was able to get in touch with Gil Ayan and he responded with the exact placement of his mod...heres are his comments in case anyone wants to know exactly where he placed the components in the circuit:

"The resistor and cap are in parallel to one another. Interrupt the connection between the wire that comes from the relay board and the 220K resistor at the input of the overdrive, and insert the pair (4.7M//.0047uF) in series with that. So, relay to 4.7M//.0047uF, to 220K resistor. "

After playing the amp for a few days, it seems that the problem still exists even messing with the OD trimmer. Because of this, I actually removed the trimmer and placed a 100K pot where the unused ground switch was and wired it accordingly. Now I can adjust it on the fly which has really helped in dialing it in. I also lowered one of the caps in the OD channel but still seems a little funky when playing single notes in the lower registers. Since I like tinkering with this stuff,  I'm going to try Ayan's mod and cross my fingers.   

Go to: http://www.effectsconnection.com/oscommerce/index.php?cPath=30&osCsid=0d161301fd55a8707a7c007077673e09

They will have what you need and prices are great.

Good luck.

+1...I have also paired up the V30 & G12H30....installed in a repro 2x12 Fender piggyback Bandmaster style cabinet and it sounds fantastic. They are both 8 ohm speakers wired for 4 ohms and there is no absence of volume....

I have tried the OTS through an EVM and liked the tone but theres something about the Celestions that really makes this amp shine IMHO.

Great...Thank you bluesfendermanblues! This is awesome information. I will definitely watch myself inside the amp...no doubt. At least you have cleared up some doubts as to what I was looking at in the layout which is extremely helpful.

For right now...I will take your advise and mess around with the settings before getting in there and changing stuff. I have definitely noticed the range of tones available by just adjusting the input, volume and OD gains. Reminds me of my MKIIc+....

Anyway...thanks again for all the advice.

Im thinking of doing this mod myself as well...Nik sent me what we will need to complete

Belden P/N: 8216 or equivalent RG-174/U type shielded coax cable
Linear taper 100K POT

Picking up the supply's and will post pics once done....

I was finally able to mess a little more with the OTS last night. Based on the information in this forum related to the proper orientation to use when adjusting the OD Trimmer (should be looking from the input side of chassis towards the trany) mine came from factory set at 2 o'clock.   

I never messed with it because looking in the opposite direction it looked like it was at 10. I backed it off to about 10-11 and the low end issue I was having improved. It's still there but much more manageable than before. I tried to go a little lower but felt that 10-11 is where i like it best. I'm inclined not to change a thing with the cathode bypass cap but am curious about the frequency cut off detailed by bluesfendermanblues. I am going to lower one the caps a bit and see what happens...stay tuned...

UPDATE...Nik responded to my email and confirmed that he is changing the plugs to 2.1mm and they are negative center.