Hey Mon Frer,

I have to tell you - that cabinet build is superb.  The two colors are a beautiful match, and the execution of the Tolex application is phenomenal.

---> Thanks Joe !  

Did you apply the Tolex?  If so how did you getit so straight where the colors meet on the sides.  Are they seams?  

---> Yes, I made the cab and tolexed it by myself. It's not so difficult if you prepare and cut carefully all your sheets before AND use a good glue. The one that I use is the tubetown SG5 : https://www.tube-town.net/ttstore/Tolex-entoilage/Tolex/Tolex-Glue-SG5-500-ml::4756.html. The "joint" between the 2 colors  has been traced and cut in position, the 2 colors covering each other a bit as a margin. Below a pic showing the tracing operation, the cutting being done along with a cutter an a metallic ruler. Then you remove the extra margin of each color and you obtain a perfectly neat "joint", straight without gap.



And thank you for the photos of your build.  It doesn't do me a lot of good - your mods are pretty extensive.  You have done a great job creating space in the chassis.  The extra terminal board you mounted for the power resistor circuits are great, and the relay board in the center is very creative.  Moving the main terminal board so it sits over the Power transformer is also quite creative - pick up a ton of space with that change.

---> Right. I had to save much place to enter all that stuff !

Can you tell me the purpose of the steel flange at the foot pedal jack end of the chassis?  Hard to see what that is.

---> What you call the steel flange is a radiator plate for the 2 voltage regulators 7805 (relays supply) and 7809 (reverb and ext. pedals supply)



I do see the 9v DC jacks at the far right end of the rear of the chassis - fantastic thinking.  Where do you pick up that voltage?  Did you order your transformer with a 9 V tap?

---> Yes. I choose a transformer that had additional windings for these 2 supplies. It's this one : https://www.tube-town.net/ttstore/Transformateurs/Transformateurs-dalimentation/Noyaux-angulaires/Toroidal-273VA-VH100R::5362.html

What is the benefit of the Toroidal transformer?  It sure looks impressive.

---> I used Toroidal Xfos on several of my amps with success. In theory, they give less electromagnetic radiations (hum induction), they have less losses, are more silent and more compact and lighter than their EI counterpart (a Twin-Reverb Xfo is 5.5kg, this Toroidal is 3.0kg for the same power). But unfortunately this time, this toroidal is not the perfect match here, and is probably of a lower quality than I expected...  

Last one - what does the "Stage/Hom" switch do?  I assume "HOM" is Home or bedroom levels, but what is the purpose of that when you have a full half level switch?

---> You may have noticed the presence of a single tube at the toroidal side of the chassis : it's the HOME output stage, using a single-ended EL84/6BQ5 plus some filtering to allow early and smooth overdrive. So the HOME/STAGE SW offers the possibility of a 2x(HALF) or 4x(FULL) 6L6GC or 1x6BQ5 output stage. The prototype test that I developed using my Boogie MKIIA proved very satisfactorily, with a great volume balance and tone, but unfortunately, the results on the Serial Tone Killer are simply awful in term of overdrive tone : uneven harmonics killing sustain...Despite all my attempts to retrive the excellent sound obtained with the proto "grafted" tentatively on my MKIIA, the results definetly are not met. It's an unexpected "bad wedding"... So now the HOME stage is completely removed.

---> I plan to change the power transformer for a better quality model, which would offer 2 values of HV supply, in order to achieve a class A operation in a "LO" mode.

My build is progressing well.  I changed out the Output transformer for a Mercury Magnetics, and the choke as well.  I took your advice and removed my filament wiring - it was most assuredly getting in the way of m,any other installs.  Thanks for that advice.  I will be glad to take any other advice you may feel compelled to offer!  I am quite a big guy (6' 10 " and 400 lbs.  I shudder to think what that might be in metric values... :-)  I am a giant.  My point being it is hard to get my clubs of hands into some of these tight spaces.  It isnt a huge issue, but I can tell you that I get frustrated with the small screws.  Especially because in my package from Nik I got all straight edge screws.  I hate working with straight edge screws.  I have eventually ordered replacement phillips and hex head alternatives, but all of those little bitty screws and nuts drive me ...well...nuts!

---> Well yes ! I guess it's not easy...  6'10" is 208cm, 400lbs is 181.2kg - Giant, you said ?   - At least, your strength won't have problems for carrying your amp and speaker cab !  

I have never been to France, but I guess there isnt all that much to see.  Few old buildings, a couple of big churches, and a museum with a glass pyramid.  Cheesy  I am actually French Canadian by heritage.  Apparently way back in the 18th century my ancestors came over to make their fortune in the new world.  Apparently they spent it all, cause I sure didnt get any.  My last name is Beaulieu - just a tad French I think.  

---> My familly is French for twelve centuries, with one ancestor buried in a abbey bearing his name (Saint Guilhem), and sure, there's much more than you guess to see in France, but despite that... Is it worth ? I mean : if you intend to just go to Paris and return back, it's very questionable - see the pics by the web and voilà, you'll get it all ! Conversely, if you want to see so much diversity of ambiences and landscapes in a so small country, France is the right place to visit - if you have time to. I've been only one time in Canada at Vancouver with my wife for 2 weeks in February 2018 to meet our daughter that was studying at the University of British Columbia. It was really wonderful and worth to go. But indeed, that's a very small part of the Canada, and the rest is surely very different - at a much larger scale, if I say so, compared to France's size.

Thanks STK - I hope you are enjoying yourself with that amp as well.  I will be very interested in finding out what it sounds like.

---> For the moment, I have to cure some remaining little hum in the reverb section because I can't stand hum at all  ... Otherwise, the Serial Tone Killer works as it should  , and I'm sure that you will be rewarded by the tone both in clean and overdriven modes when your amp will be ready  

Joe

---> A+!

In no way, Joe ! Your point of view - even if it was a joke - is defendable. As a US friend told me : "there's NY and there's USA, these are 2 very different things". It's the same in France, with Paris and the rest of the country. When you go in a touristic area, you fall in the classic tourist trap, like everywhere ! and it can be finally somewhat unpleasant, you guess why...

Beside that, my Serial Tone Killer is still awaiting a new transformer. I removed the HOME circuit, that worked unsatisfactorily, no matter my attempts to cure it - the proto on my Boogie MKIIA sounded so much better...

I'm going to opt for dual plate voltage transformer for class A / class AB1 operation - I'm preparing qualification tests, so... Wait and See !

A+!

I am approaching the end of the build and the tuning of the circuits of my Serial Tone Killer... 






I reworked the tone-corrector and other tone details because I found that this amp was too bright and lacking bass extension, in one word : imbalanced in tone. 
The Jazz setting was nearly useless, everything seemed to be only Rock / Hard Rock-orientated. 

Now it can compare to my Boogie MKIIA and my SF Fender Twin-Reverb, among others : he lost his agressivity and took on deepness and smoothness, but still able to rock... 



I have to build the 4-buttons FSW (OD/PAB/Reverb/FXloop).

But I still have some unacceptable hum radiation issues with the toroidal transformer  - despite its lightweight and excellent power performances. 
I'll have to replace it by a classic EI transformer which proves to be more quiet (quick comparison test made).

Current weight of the amp = 24.3kg



Not so bad for a full tube 100W amp that integrates an EVM12L speaker, which represent 8.9kg by itself ! 

Unfortunately, the change to an EI PWR Xfo will add +2kg... So the amp will be at 26-27kg. 

Wait and See...

A+!

Improvements finished... 

The amp sound from deep to rock in clean, subtle to armageddon in OD.  :

Next step = footswitch 

And still the hum sprinkler transformer ! 

A+!

The HUM FIGHT is OVER !  




I changed the 1st toroidal Xfo  for another one : no better.
I shielded it with a cap cover : no better.
I replaced the toroidal for an EI transformer : done.
I added two lateral screens to cut the magnetic core axial radiation : exit.
I added a copper flux band grounded : end of the Hum Story.



Verdict : the amp is +2Kg heavier but HUM DEAD SILENT at any level or setting.

Morality : no more toroidal transformer. Never. They are omnidirectional hum spreaders !

Everything seems to work as expected... I have to make tests at huge volume now to confirm.

Wait and See !

A+!