Silver mica caps are considered by many amptechs to be probably the best general purpose caps around.  I upgraded to them on the slope resistor, bright switch, treble cap, and negative feedback loop (also swithched the val. of feedback loop cap to 500 which is the stock Dumble val. according to the dumble schematic that I have access to.  I liked this value better) The silver micas noticeably smoothed out the tone and best of all they are only like a dollar a piece.  When people try to tell you things on this forum like "if its good enough for Dumble then it should be good enough for you" just remember that you decide for yourself what is good enough for you.  Also, this amp isn't a Dumble.  The magic of Dumbles was that they were built by him and tweaked by him specifically for each client.  He is a one of a kind master builder and could probably make a transistor radio sound amazing.  Good luck, have fun, and remember the sky is the limit.  My OTS sounds incredible.

I do not have the S&M model, mine is the OTS 100 watt, and I did my own mods following a combination of traditonal fender values and original dumble values.  I originally had the J. Zucker mods and that sounded like cotton in my ears.  Pure midrange.  Now it sounds real cool.  I would try, in lieu of tweeks to the tone stack or anything, turning the midboost off and the bright off.  They seem to deffeat the purpose of tone knobs on my amp.  I have no use for them.  Also, this OTS tone stack has a lot of mids that funnel their way into the highs and lows  so it really isn't "super" responsive.  Try treb. bass. and mid. at 0.  Then turn your mids up first.  Then add treble and bass and listen for the changes.  That will be the jist of the range you will be able to get and its a good way to prep your ear.  I'm sure you will find what you are looking for, though.  Good luck.

I agree that there are many things that affect the tone from situation to situation, but I play this amp in a variety of settings and I just felt that there was a lack of note separation and a brittleness that was always there, especially when I was driving the power section.  With great pickups, tubes and varying speaker combinations, adjusting the ratio to my taste as well, I just felt that the tone was not as "pretty" or sweet and chiming as I thought that it should be.  I talked to a couple of different amptechs that I have worked with in the past and they both recommended a output transformer upgrade.  So I did and the problem was solved. I did not mean to upset anyone at Ceriatone by suggesting that the transformers were cheap and crappy, but I do believe that the output trans. in my OTS at least, was at best adequate.  The Mercury Magnetics just simply blew it away, and I was trying to be emphatic.  But mostly  I am just trying to share positive tonal discoveries with you all.  If you want to find a great sound in your amp or any amp for that matter, I suggest looking at the output transformer first.  I know that I will from now on.  It would have saved me a lot of shop time.  Its like taking a highly tuned V-8 engine and only putting a 2 barrel on it instead of dual 4's if you catch my meaning. Ciao for now.

It is really only the output transformer that I am commenting on.  We are talking about 100 to 200 dollars max.  It made a very noticeable difference. Whether it is a Mercury Magnetics or a great old fender.  Maybe for most people it doesnt matter, but for me and everyone who had a chance to A B the two sounds it did.  They could not ignore the beautiful shimmering tone that now comes out of this very cool amp.  My ears dont lie and I have nothing to gain by sharing this discovery with you all except the joy that it has brought me.  Silver mica caps on the neg. feedback loop and on the bright switch noticeably smoothed out the tone and sweetened it slightly more.  As soon as I am able I will share some sound clips and you can be the judge.  Thankyou.

I use nos tubes ranging from RCA blackplates to amperex to GE, Mullard...you get the point,  Marshall cab, celestion, Weber, Jensen...(my fav. is the Marshall 4x10 cab closed back, killer man and I mean killer),  but with out a doubt, the most exhilerating upgrade I made to this very cool OTS is the transformer.  In my opinion this amp deserves nothing more than a first rate transformer.  I put in a Mercury Magnetics transformer upon their sales reps reccommendation (he has sold several transformers to Mr. Dumble himself, or he is a liar).  Brother when I hit that first chord, nice and loud, it was like the clouds parted and REAL Godlike tone came shimmering down from the heavens.  Yes, it was just like that!  Do not do a freakin' thing to that amp until you get that crappy cheap output transformer out of there.  Dont get me wrong, the amps all sound good, but that is just it, they sound good not truly great, and it is beause the transformer is not adequate to make truly great tone.  Another good thing to do is to upgrade some of the cheaper capacitors, that will make a slight but noticeable improvement...but the transformer, dude the transformer...upgrade it to Mercury Magnetics, you will always be glad that you did.

Hey, just thought I'd share with you all my recent discovery.  I just picked up a Marshall 4x10 cab from my local music store that deals with a lot of consignment pieces and cool vintage stuff.  It is the model 1965A that was sold during the 80's.  It has 4x35 watt 10 inch celestions about 25 years old at this point.  This cab is a sleeper as far as the sometimes "overpriced" vintage scene is concerned, kind of under the radar if you catch my drift.  I paid 400 dollars for it with speakers, cab and all and kids it really sounds great!!  Totally blows away my 2x12 Weber set up.  It is so warm and open and balanced and CHEAP!  My webers are for sale.  If you have the option to try one out I seriously recommend it.  Its also quite lite and easy to transport.  It truly is an awesome compliment to the OTS.   

I use matched PI's.  they push the power section more evenly.  AT7s give a more of a glassier feel, thats why I like them.  They "sparkle" more.

I use a les paul with humbuckers primarily, and a strat with single coils about 20% of the time.  They both have Jason Lollars.  I highly recommend.

I use NOS Mullard AT7.  The best AT7 I've ever heard.  It opens up the high end in a sweet almost glassy way.  Like a Fender Twin but without any shrillness.  Anyone concur?  What others have you all tried and to what avail?  Thanks.

I guess I mean the input channel.  The first tube.  The original cap was rated at 5 or .5 or something with a 5.  My amp guy and I tried some different values and settled on 10 or whatever twice the value was of the original.  It sounded a little more balanced.  By the way, check me out on youtube.com under Brian Feist Blues or Randy Oxford.  You will see me in some live situations.  All the clips are with different amps though.  I will post soon with the OTS.  You will all be quite pleased.  It sounds sweet and ferocious and unlike anyone else, which is why I bought the amp.  The OTS is a great amp to find your own unique voice.  The crowd response has been amazing. 

I use two Weber 30 watt Blue Dog alnicos in a custom built pine wood open back cab.  I run a nos GE 12ay7 in the overdrive circuit.  With a Tom Scholz power soak I drive the power section so that the power tubes are full-blooming and beginning to break up.  The sound is fantastic.  Like an old fender tweed but smoother.  Then I hit the overdrive circuit and the ay7 adds just the right sizzle.  I found that a 12axy in the overdrive circuit was just too much distortion for my style.  I like Mike Bloomfield tone, early Clapton, and all the great Chicago bluesmen.  This setup works really well.  Anyone else going for a more "vintage sound" with there OTS? If so, how are you achieving it.  Thanks.  Oh yeah I also changed the input cap from 5 to 10 it felt a little more balanced.