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1  Ceriatone / Overtone / Re: Serial Tone Killer on: May 01, 2020, 05:04:06 PM
The HUM FIGHT is OVER !  Chair Dance

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 !


2  Community / Chit Chat / The Desert... on: August 24, 2019, 04:48:53 PM
The Desert...

It seems that http://ceriatoneforum.com looks like this to me...  Huh?

Really too bad !  Sad

Cheers !  Wink
3  Ceriatone / Overtone / Re: Serial Tone Killer on: August 24, 2019, 04:04:39 AM
Footswitch built... And working fine at the 1st time : no adverse noise, no clicks.   Smiley

I just have to design and engrave a top plate, though.

It controls : Overdrive / PAB / Reverb / FX Loop.

Additional feature of the Serial Tone Killer :

Assuming you want to use up to 4 stompboxes in the FX Loop and want to put it on the top of the amp (well, at least, it's what I plan to do  Undecided), the integrated 4X 9VDC
supply can power those stompboxes directly  Wink :

Next step : expected end of the hum fight...  Wink

Wait and See !
4  Ceriatone / Overtone / Re: Serial Tone Killer on: August 21, 2019, 08:31:06 AM
Improvements finished...  Smiley

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

Next step = footswitch  Wink

And still the hum sprinkler transformer !  Angry

5  Ceriatone / Overtone / Re: Serial Tone Killer on: August 20, 2019, 04:53:33 PM
For the moment, I'm experimenting improvements on the tone-corrector and the PAB to make that amp sound deeper and less systematically "in your face".

Wait and See !

6  Ceriatone / Overtone / Re: OTS boost on: August 20, 2019, 04:46:02 PM
Is there a way to make the boost on the OTS fatter and less harsh?   It's too thin and pretty much worthless.

Yes. I think that I have found a way to do that : I'm experimenting it on my Serial Tone Killer amp now.

7  Ceriatone / Overtone / Re: Serial Tone Killer on: August 19, 2019, 05:41:42 PM
I am approaching the end of the build and the tuning of the circuits of my Serial Tone Killer...  Smiley

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.  Shocked
The Jazz setting was nearly useless, everything seemed to be only Rock / Hard Rock-orientated.  Undecided

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...  Cool

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  Angry - despite its lightweight and excellent power performances.  Sad
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 !  Wink

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

Wait and See...

8  Ceriatone / Overtone / Re: Built In Effects Loop - Tube Town on: August 19, 2019, 05:16:24 PM
Sorry for the very late answer...  Embarrassed

It is powered by the plate voltage derived from +B4 via an additional RC filter.

9  Ceriatone / Overtone / Re: OTS boost on: August 19, 2019, 05:11:59 PM
I'm thinking about that too. But I did not searched a solution yet... Wink

10  Ceriatone / Overtone / Re: Serial Tone Killer on: August 02, 2019, 02:56:42 PM
The story has not ended - simply in waiting...

Warning: this topic has not been posted in for at least 120 days.
Unless you're sure you want to reply, please consider starting a new topic.

So yes, when the Serial Tone Killer will be fully oprational, I'll start a new thread  Wink

Wait ans See !
11  Ceriatone / Overtone / Re: Serial Tone Killer on: October 02, 2018, 09:39:34 AM
I was being sarcastic about the churches and the Louvre.

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 !


12  Ceriatone / Overtone / Re: Schematic for OTS Mini 20 Preamp on: September 27, 2018, 04:45:06 PM
Hi nocturnus,

I think that this is the schematic of the OTS Mini Lunchbox 20W, where you have the preamp section separate from the power section :

AFAIK, the OTS20 and 50/100 shares nearly the same preamp section.

For more accurate information, the best is to contact Nik at ceriatone.

Cheers !
13  Ceriatone / Overtone / Re: Serial Tone Killer on: September 27, 2018, 04:28:25 PM
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 !  Wink

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...  Undecided

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 ?  Shocked - At least, your strength won't have problems for carrying your amp and speaker cab !  Grin

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 voilą, 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  Angry... Otherwise, the Serial Tone Killer works as it should  Cool, and I'm sure that you will be rewarded by the tone both in clean and overdriven modes when your amp will be ready  Smiley


---> A+!
14  Ceriatone / Overtone / Re: Built In Effects Loop - Tube Town on: September 27, 2018, 03:02:11 PM
Hi Phil,

Sorry I did not tested the tube version but the LND150 FET version from TT, and it works.

I integrated it after the master volume of my modified OTS "Serial Tone Killer". You can see it in the center of the chassis, along with FX loop and reverb switching relays :

I think that the tube version has its proper complementary B+ like the FET version, so you just have to connect it to B4 or B5 on an OTS schematic.

Cheers !

15  Ceriatone / Overtone / Re: Just Ordered - 50 Watt FMME w CLator Kit on: September 20, 2018, 04:13:52 PM
Hey Joe & thanks !

I think I took pictures of the OD relay configuration and I draw a schematic. Let me retrieve (or redraw it) so I can post it here if you intend to do that little easy mod too.

About the "wheel diodes" (= "diodes de roue libre" in French) : it seems that it's called "flyback diodes" in US/UK. In a few words : a flyback diode is installed in // with the coil of a relay in order to null the flyback current ("extra courant de rupture" in French) due to the coil relay switching. That flyback current is responsible for the annoying to very loud "pop" noises that arises when you switch that relay on and off, and the diode is here to null it by shorting it. As this kind of current is a short but ample impulsion, you need a fast (high speed) diode for best cancellation. Here I used 1n5819 diodes.

You should easily find much complete litterature on flyback diodes in English on the web ! i.e. : https://en.wikipedia.org/wiki/Flyback_diode

My Serial Tone Killer is not a Twin, it's a modified OTS100, on which I added :
- a footswitchable digital EHX reverb unit with deported pot.
- a footswitchable integrated FX Loop able to deal directly with guitar FX pedals.
- a 1W "HOME" single ended EL84 switchable output stage.
- an integrated 4x9VDC regulated power supply for in-llop stompboxes.
- an extra filtering on the HV voltage.

I'm facing issues with the 1W facility : the prototype tested on my Boogie MKIIA worked amazingly well, but it sounds awfull on the STK, no matter the attempts that I made to cure the problem. Well... It's a bad wedding, so to speak... I will dismantle it, I think, and replace it by something else : I'm studying the possibilities.

IMHO, If you target to DIY a Twin-Reverb, do not choose the OTS route : the circuit is much different from the TR. Ceriatone probably have an offer in that field.

Also, considering that it's only your 2nd DIY tube amp, I'm really afraid that you would face many other issues by "following exactly my footprints", so to speak, with all my respect. I mean : assemble a kit is not the same as designing mods or a whole amp. If you finish and debug your OTS and C-Lator satisfactorily - not to say perfectly - let me tell you that you'll have taken a big step !

And for more detailed pics about the Serial Tone Killer, you can have a look to my Serial Tone Killer subject on the forum.

And yes, it seems that we are here like two survivors...  Grin

I'm located near the city of Lyon.

Cheers !
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