Mine arrived today, and here is the short version, don't try to run 6bg6ga in a SSS, they don't work in it at all.  Do not try.  Don't even think about it.  They work great in my 50w HRM and OTS builds, just not the SSS, so I got lots of spare pairs available.  How do you describe the sounds of  oscillation?  Ouch!

Stuck in a tightly matched quad of Svetlana 6l6gc, biased them a tad hot at 39mv, sounds great!  

V1 RCA labeled Tungsram NOS 12ax7
V2 CBS longplate 12ax7
V3 Sylvania black plate 12at7
V4 CBS longplate 12ax7
V5 Raytheon long blackplate rectangular getter halo 12ax7

schweeeet!

most recent update...

One good thing about waiting for a new amp to arrive has been the opportunity to research more about the amp itself and to do some tube experiments in similar operating environments, which recently caused me to rethink...

"It's my belief that my D-circuits require for bias to be set above a certain minimum, and that the tubes in them also have their own ranges depending on type. My ears say that if the tube can handle the circuit's bias needs that the sound is going to be very very good."

I was wrong...

Was playing out a few nights ago through my 50wOTS with a pair of GE blackplate 6bg6ga's, using a bassy 2/12 hempcone cab, was sitting in and standing a bit too close to the amp, could not use overdrive channel because of excessive feedback.... even standing to the gitbody side of the cab was not working. I had set the bias up to an average of 37mv current draw, and the amp was uncontrollable in anything much more than clean and clean PAB.  

Perfect storm of low power output tubes biased too hot, bassy cab, clean hearoom used up, underpowered power section wanted to distort and sustain, and guitar too close to the speakers.  I turned knobs front and back of the amp, found workable settings.  The stage volume was very, very loud, and since I was sitting in, I just rode in the bubble with it, we all had a great time.

A couple days later at home I sat across the room from a very loud, well warmed up amp, bias probes socketed, dropped to an average of 27mv, 65%-ish, tone was crisper and very sweet.  Sustain was excellent with much better control playing the floating block hollowbody gitbox that was so uncontrollable the night of fun.  The cleans gained  detail to the point of sounding HIFI in a very good way with gain knob at 4-ish and stayed fairly clean at a high volume.   Got low gain as well as Marshall-y lead tones, sustain was great bit also controllable, bloom was very very sweet, something very special about the GE tone here.  This is the tube I would use for a hollow, or semi hollow guitar.  I'd use the punchier, bassier Sylvanias for solid body guitars.  Rock/jazz switch, rock/jazz tubes, hmmm.  

I learned from the sesh not to bias to an a set point figure based on a self generated mistaken belief, the tube data proved to work better at high volume settings.  The missing headroom and amp control are back.  I know that the tubes are happier, the tones are just amazing, and now have a gorgeous sounding 30-ish watt amp as well as 50 without having to buy or attempt a separate low power build... in the time it takes to swap two tubes and rebias.  

While doing that I also assembled a tight pair of the higher horsepower family mutant Sylvania 6bg6ga's,  I got semi-prototypic "ODS build" tones using those repinned 7581a's with a plate cap.  According to my ears at loud or room volumes they could be biased a tad cooler than calculated, about 3mv down from the calculated 55%.  But I have a cheap DVM, could be some instrument error.  These tubes have bigger, punchier bottom end than the super sweet GE's and a nice crisp top, The Syl's offer up very Fendery cleans.  Preamp detail in OD comes through very crisply, great note and harmonic definition.  They come in gray and black plate, both types fairly similar in tone.

Finally, put the 19-22w GE's back in, rebiased, ear set the PI trimmer, and buttoned up.  Sweet, sweet ride.  Pleased by what I learned, glad to correct my mistake while sharing.  

SSS should arrive in a couple weeks...ready!

Thank you very much for your prompt and helpful reply.  Safety precaution needs noted.  I have a way to drain the caps to below dangerous levels before taking the chassis out of the headshell and will follow up with additional precaustions.

Once I got a finger across the OT primary terminals by mistake in my Frank-en-Champ very early on in my tinkering while the amp was running, burned a tiny hole all the way througgh the skin right into the meat, didn't bleed because wound was cauterized as it was being bored by the arc of rampant b+... and my stupidity.

Thanks again, will look at both layouts.  Then get to most carefully researching and then source the part(s). 

I use a volume pedal. works fantastically.  Don't get the kind that use a potentiometer to reduce volume, they suck tone badly at less than full volumes unless modified. 

'scuse the intrusion but...

Wow!  I learned some really nice stuff here.  I ordered my OTS and HRM 50 watters prebuilt.  However, I'm not averse to picking up my pencil, braid, and solder to try something new.   I'm not as familiar as the forum's builders, I am not famliar with where such obvious tagnames are located.  I'd like to try it.  Man, if someone could shoot me a PM with maybe a chunk of the layout with notes on this that would be so appreciated... 

It's within a couple weeks of NAD, so still getting ready...

OCD lives! Gotta have the power section glass ready for the newest mail order bride's arrival. Glass GAS is defintely a pocketbook hazard along with the other NAD-dy new gear addictions among the tube weenie tribes. It's often codependently and cooincidentally suffered when waiting for a custom build mojo juju amp to arrive from its birther.

...and...ummm, I learned that I was mistaken about a brand in a tube type. So now the yet to arrive SSS's power section has two (tight for now) quads of of 6bg6ga waiting. A tightly matched NOS pair of Sylvania 6l6gc go for 200-300 bills today, so 400-600 was my personally chosen par price to beat for a single matched quad.

After getting the Japanese GE's, I picked up a few more one at a time ebay BIN's for Sylvania. The adapters showed up, the yet to arrive tube coolers are coming in through US customs Canada Post. Now I knew that the Sylvanias were monsters, and I thought the GE's were 30 watt 6l6GC type guts, but careful build examination and in circuit performance show that they are closer to 19-22 watts than 30. With that said, i ended up with 5 out of 8 that drew within 3 mv or each other, so first tight quad comes from those, and they were absolutely fabulous while playing music through them. Then on to the Sylvanias. Average price for those singly was 10-15-ish delivered. I tested six in black plate and six in grayplate, all 35 watt monsters with the 7581a guts. Ended up with a quad of two black and two gray within 3mv. So the GE set is like a small block Chevy engine while the Sylvanias are definitely the big block units. Both types sound amazing and have their own voice. The GE's can handle the el34 range of bias settings, and the Sylvanias need to be set 5-10 mv higher than 6l6gc settings. So by virtue of low unit cost i was able to accumulate a decent quantity of very, very nice sounding glass, two tight quads of two diffrerent types and power ratings. The others left over can be used as spares, and a few pairs exist among them for my 50 watt d-clones. It's my belief that my D-cirdcuits require for bias to be set above a certain minimum, and that the tubes in them also have their own ranges depending on type. My ears say that if the tube can handle the circuit's bias needs that the sound is going to be very very good. The GE's are running at 85% max to get that done, and act like they are not breaking a sweat, tone is well defined and complex. The tube coolers will be essential to use them. The harmonic bloom is incredibly musical. They want to compress and sing for days. Sylvanias are a tad brighter on top, bigger bottom, and very punchy. Both quads draw similarly at similar bias settings.

There was an interesting texture in the mids when I mixed a low max power tube and high power tube together in a 50 watt amp, they had a matched idle current draw to one another. Sound was very good overall. I set the bias knob to a working setting, ran all the tubes from both types through the amp and wrote results on each bulb with a sharpie as I tested. I also tested all of the new adapters as well, all worked perfectly, but the plate caps were cheesy in the metal insert, had to tweak a couple of them with a needlenose to get them to grip right.

just do it.   

Updating...

Updating...

In anticpation of the amp arrival I snagged 2 quads of true NOS GE Japan (hopefully Matsushita) 6bg6ga from one vendor, and a quad of adapters from another, all on fleabay delivered for less than 165 bucks for the eight tubes and four adapters. 

From my experience with pre, rec, and power tubes, the build on Japanese tooling, whether originating from Mullard or otherwise, provided wonderful sound and durability, clearly superior to most current production offerings as well as favorably competing for same in their production era.

Why 2 quads? For more flexibility to deliver a particularly chosen current draw application.  Can have inner and outers' pairs biased hot and cold a la Mesa simulclass via natural current draw, or choose from all eight for the tightest possible match and swap in and out as drifting occurs during butn in, which is common for any powerful pentode, new production build and new old stock.

Congratulations!  Fun to get yur own tones!

I love to tinker with a soldering iron myself.  But there are more pounds of parts stuffed in a D-clone chassis than Dolly's boobs in one of her industrial strength over the shoulder boulder holders.

I had mine delivered fully assembled.  Bluesmaster?  Plasticvonaband has one.  The HRM has IMHO such a wide variety of tone palette, with V1 tube rolling you can get some of that BF sound,  Sylvania long grayplate, 12ax7,  and it would be ignorant to ignore the GE shortplate 12ax7a/7025, a fave of HAD's.    The classic Fender BF V1 is going to be either an RCA 7025 type or 12ax7a/7025.  All bets are off in a combo, the head setup is the one to use old glass in, don't need to shake the grids like a belly dancer with a combo setup's speaker providing extra excitation...

There are two fave speaker types of his in his cabs in the thread about the HAD modded Primceton head thread at TAG.   It sits on a pair of 2/12's. one with JBL D120f and Altec 417 b or c model cabs. Those are both very wide range, big diameter VC, like 3 inches, have great cone control with both of those Jim Lansing designs.  Lansing was in a league with HAD, he was the speaker genius of all time IMHO.  I prefer his later designs, the JBL MI-12 and g125 are my fave d-clone speakers in 12, and the MI-15 and g135 are my choices in 15's.  The MI series is particularly nice because they are not heavy speakers, great for my (getting older) back.  And they sound just plain wonderful in 12 or 15.

Mine has not arrived yet, am going all VOS when it does, ordered it shipped without tubes.   Will NOT be using 6l6 or el34 in power section...and will be doing some tube rolling for the pre section.   Am searching/chasing for no one's tones,  but will do what I always do, roll tubes until I am satisfied with that circuit's tones, play and occasionally leave on 100 hours for breakin, then check for bias drift and roll pre tubes all over again.   It's like being picked for a sports team, every tube position's socket muct be tried out for,  like the positions on any sports team.  Sometimes I roll up to ten different tubes for a spot before I am satisfied that I have found something appropriate.  And even though my ears know how the basic types of VOS 12ax7's all sound, I try my best to not stereotype before choosing and listening like a good equal opportunity employer!    For instance, the ultra rare Euro 12ax7 in V1 of my 50w HRM was kicked out of v1 (at least temporarily) by a Philips ECG (think Sylvania long ribbed gray plate.)  This tube has a top end that is just about as sweet as a Tungsram, and a fat, Mullard-y  mid and huge bottom.  This tube, like all syl's of this type, is slightly microphonic, but by the time I added the tube cooler and the red O=rings wrapped around it to hold it in place, no microphonic problem in that spot.  It's a little more spendy than a typical syl, being mil stock, but the sound is very good in this circuit.  I think that it will be an excellent candidate for the "Slow dancing in a burning rrom" tone type.

I'm not sure how many have actually spent the money yet to start an order on this amp, I'd be surprised if there were more than 20 at this time.   There is a feeling over at the ampgarage among some members  that the C-tone SSS is not the real thing because it lacks the post PI driver tube, with one very prominent and vell informed member posting that as far as he knew, all SSS's had that driver tube.  Driver tube, Shmiver tube, I could care less about whether that tube was there or not, the tones in the clips display both the SSS sweetness and a very versatile tone palette, which in the real world of stage performing is helpful to say the least.  I'd be pleased to know the serial # on mine, hopefully it's in the first ten!  I'm not gonna bother Nik with any trivial questions about that, he's already busy as a one legged man in an ass kicking contest.

That's just plain awesome!  I know what you mean to dial an amp in from what is stuffed into the cab back to the input jack.  have done that with 50w HRM and 50w OTS.  Gonna get to do it all over again when the SSS arrives with no tubes in it by my request... 

There is a lot of herd following on the EV thang as well as the Celestion g12-65.  Great speakers for sure, but I have other preferences.  Keep working on your VOS tube collection.  Niiiiice!

I have both OTS and HRM circuits in 50 watt sizes, and absolutely love the tones I am getting with both of them, as heads.   I have found that the HRM's clean channel can tolerate a more agressive pick attack without mushing out or distor4ting right at the attack, the OTS is more prone to that, I run it at a lower clean gain setting, 3-4 vs 5 1/2-7 for my HRM.  I'm using all old stock glass in these, the tones I'm getting are amazing.  6bg6ga/adapters (7581a type) in the OTS, and el34 in the HRM.  The HRM takes longer to go into harmonic bloom/feedback and is more stable once there, the OTS is more quick reacting.  OTS has a bit more bounce in the dirty channel for what sounds like a similar gain setting, HRM, is smoother and tighter in the bottom.  Both amps have a very sweet clean channel.  I like that I can adjust the dirty channel tonestack in the HRM very much, can tune that amp's OD voice for a particular guitar and/or cab situation.  OTS has strong mid in dirty channel.  I prefer to run the OTS with no c-lator, prefer the HRM with.   C-lator has old glass in it too.  If you know your 12ax7's from the golden years, you can easily voice either preamp via tube rolling to get exactly what you want.   

Gonna be fuuuuuun when that SSS arrives.