Amp Build: Ceriatone Kraken 50

[SavageRiffer]

Sounds better than the first video. I like the low mid range presence. Badass build man.

 

[FourT6and2]

Sounds better than the first video. I like the low mid range presence. Badass build man.

Thanks

The next one will be cool, too. Maybe a slightly different voicing. We'll see.

 

[SavageRiffer]

Sounds better than the first video. I like the low mid range presence. Badass build man.

Thanks

The next one will be cool, too. Maybe a slightly different voicing. We'll see.

Good idea. Sell this one to me dirt cheap and build a new one.

 

[FourT6and2]

Sounds better than the first video. I like the low mid range presence. Badass build man.

Thanks

The next one will be cool, too. Maybe a slightly different voicing. We'll see.

Good idea. Sell this one to me dirt cheap and build a new one.

It's for sale! But not cheap lol.

 

[SpiderWars]

haha! yeah at some point I gotta say enough is enough lol

Yup, you could tweak for days. I get ear fatigue pretty quickly and can't do many mods before my ears are shot. I've often thought that I tend to 'mod it until it sounds bad' lol.

TBH, I'd be surprised if you can hear the difference between 1k5 and 5k6 on the grids of the power tubes. I've always read that it could be way higher with no noticable difference but will admit to not doing any real tests.

From our good friend Randall Aiken:

The grid resistor value typically varies from as low as 1.5K to as high as 470K.
Most output stages use relatively small grid resistors, such as the 1.5K seen on the grids of 6L6 tubes in most Fenders, and the 5.6K seen on the grids of EL34 tubes in most Marshalls. In general, the grid resistor at the grid of the power tubes can be as high as 56K to 100K before any noticeable loss of high frequencies occurs. Higher values can help in reducing "blocking" distortion as noted above, and can also take some of the "edge" off of an overly brittle sounding output stage. If the resistor value is made too low, it may not be enough to prevent parasitic oscillations, and the amplifier may exhibit instability in the higher frequency range. This may or may not be audible. Symptoms of oscillations include: high-pitched "squeal", glowing plates at "safe" bias currents, harsh treble response, lack of power, undesirable overtones, and unusual frequency response which makes the amp sound funny. Note that power tubes have a specification for maximum resistance that can be in series with the grid terminal before the tube becomes unstable due to grid current. The maximum allowable resistance is larger in cathode biased circuits than it is in fixed bias circuits because the cathode bias provides some "self-limiting" protection against bias runaway. The total resistance is the sum of the series grid resistor and the bias feed or "grid-to-ground" resistances, so if the max spec is 300K, for example, and there is a 220K bias feed resistor, the largest grid resistance that can safely be used is 80K. Of course, in practice, tubes should not be run that close to the edge of their specifications, to insure reliability.

 

[CrazyNutz]

haha! yeah at some point I gotta say enough is enough lol

Yup, you could tweak for days. I get ear fatigue pretty quickly and can't do many mods before my ears are shot. I've often thought that I tend to 'mod it until it sounds bad' lol.

TBH, I'd be surprised if you can hear the difference between 1k5 and 5k6 on the grids of the power tubes. I've always read that it could be way higher with no noticable difference but will admit to not doing any real tests.

From our good friend Randall Aiken:

The grid resistor value typically varies from as low as 1.5K to as high as 470K.
Most output stages use relatively small grid resistors, such as the 1.5K seen on the grids of 6L6 tubes in most Fenders, and the 5.6K seen on the grids of EL34 tubes in most Marshalls. In general, the grid resistor at the grid of the power tubes can be as high as 56K to 100K before any noticeable loss of high frequencies occurs. Higher values can help in reducing "blocking" distortion as noted above, and can also take some of the "edge" off of an overly brittle sounding output stage. If the resistor value is made too low, it may not be enough to prevent parasitic oscillations, and the amplifier may exhibit instability in the higher frequency range. This may or may not be audible. Symptoms of oscillations include: high-pitched "squeal", glowing plates at "safe" bias currents, harsh treble response, lack of power, undesirable overtones, and unusual frequency response which makes the amp sound funny. Note that power tubes have a specification for maximum resistance that can be in series with the grid terminal before the tube becomes unstable due to grid current. The maximum allowable resistance is larger in cathode biased circuits than it is in fixed bias circuits because the cathode bias provides some "self-limiting" protection against bias runaway. The total resistance is the sum of the series grid resistor and the bias feed or "grid-to-ground" resistances, so if the max spec is 300K, for example, and there is a 220K bias feed resistor, the largest grid resistance that can safely be used is 80K. Of course, in practice, tubes should not be run that close to the edge of their specifications, to insure reliability.

I've read that before, and because of that I used to overlook this as a spot to tweak, however experimentation tells me something different. In some builds (and mods) I've done, it made the difference from being a bit flubby and dark, to tight and open. It's more of an icing on the cake thing I suppose.

 

[FourT6and2]

A friendly guy PM'd me to point out something I overlooked. I corrected that small mistake and made a few more tweaks and I think a lot of the aggression and Marshall flavor is there now. I removed a small cap on V1b grid and I've been playing with the slope resistor.

Here are some clips, what do y'all think? I'm listening through powered headphones/speakers, so not sure how it'll sound through regular headphones or like computer speakers or anything. But man... I'm really happy with how this turned out. Just gotta decide on a slope resistor and it's finally done-done.

This amp absolutely rips now. I think I've accomplished what I set out to do. It's got the snarl and aggression of the Chupacabra, but with a MUCH more punchy attack and the low-end stays nice and tight without any flub. Hard to get that across in a YT video. But it shakes the house for sure and really has that hollow thud that hits you in the chest. This is NOT just a Chupacabra/Yeti hybrid. I've re-voiced much of the circuit by now. Definitely the best high-gain Marshall I've played. It's a keeper for sure.

33K:

35K:

39K:

47K:

 

[jsp]

Sounds great. That last vid sounds especially mean.

 

[FourT6and2]

Sounds great. That last vid sounds especially mean.

Yeah, you know... looking at my notes, I think I had the other diodes engaged for that one. The other vids had the lower-gain clippers engaged. So the other slope resistor values can get that level of aggression too.

 

[psychodave]

Sounds great.

 

[FourT6and2]

Sounds great.

Does one of those sound better than another to you?

 

[duesentrieb]

Congrats Mike. Looks awesome (neater than a Larry lol) and sounds great.

 

[FourT6and2]

Congrats Mike. Looks awesome (neater than a Larry lol) and sounds great.

Thanks, Olaf. That means a lot coming from you! Your builds are awesome. I really like your Noir et Blanc. Sounds great.

Do you have a preference with any of the slope resistor clips I posted above? I wired up a pot so I can just play around with it, but I can't decide. They all sound good in the room haha.

 

[duesentrieb]

I haven't heard all of them, will do Mike.

You desperately need better Cs than these Micas though, go with Muratas instead.

Personally I often use 39k for most dist. channels, no scientific approach, just preference over all the builds I've done.

 

[FourT6and2]

I haven't heard all of them, will do Mike.

You desperately need better Cs than these Micas though, go with Muratas instead.

Personally I often use 39k for most dist. channels, no scientific approach, just preference over all the builds I've done.

Which Muratas? Any specific part number/series/voltage?

 

[marcus262]

As for slope resistor values, 33k, 35k, 39k sound good with different flavours,
I just don't like 47k very much, sounds too modern and scooped for my taste.

1nF cap with a 150k resistor makes a low pass filter around 1kHz, so without 1nf cap you would have much more frequencies beyond 1khz, and so also
more agression and gain. The only problem I can think of here is that it may sound great on medium gain settings but higher gain setting may start to get fizzy, don't know if you tried.

so, 1nf acts like a snubber cap, and many amp with 3 or more gain stages that have cathode bypass capacitor on all stages utilize some sort of snubber from values of 100pf, 470pf, 1nf, ex. Diezel Vh4, Bogner Shiva, Friedman BE100... to help with the fizz.

 

[CrazyNutz]

Sounds better. I like either 33k, or 39k for the slope. 33k sounds more marshally, and not surprisingly 39k sounds more VH4'ish. Put'em on a switch!

BTW I agree with what duesentrieb said about the mica caps. I find myself liking ceramics better (in almost all circuits) ceramics really add some pleasant grit, and dimension.

 

[FourT6and2]

As for slope resistor values, 33k, 35k, 39k sound good with different flavours,
I just don't like 47k very much, sounds too modern and scooped for my taste.

1nF cap with a 150k resistor makes a low pass filter around 1kHz, so without 1nf cap you would have much more frequencies beyond 1khz, and so also
more agression and gain. The only problem I can think of here is that it may sound great on medium gain settings but higher gain setting may start to get fizzy, don't know if you tried.

so, 1nf acts like a snubber cap, and many amp with 3 or more gain stages that have cathode bypass capacitor on all stages utilize some sort of snubber from values of 100pf, 470pf, 1nf, ex. Diezel Vh4, Bogner Shiva, Friedman BE100... to help with the fizz.

Yup. So I have a 1nF cap on the board in series with the V1 coupling cap to ground, before the gain control. Which I think does a similar thing. I might try putting the cap on the grid back and removing the one on the board as well. Turns out these amps (not just Ceriatone) usually have one or the other. But I mistakenly used both lol.

As far as gain, the clips I posted are with all the EQ/tone controls at 12:00. The gains are also around 12:00 - 1:00.

And yeah, I see now... looking at the Cameron Aldrich... that there is a 100pF cap from pin 1 to 3 on V1, whereas some others use a 1nF on the grid-to-ground of V1b to form a low-pass with the grid resistor. Fortin uses the 1nF to ground after the coupling cap. Interesting.

 

[FourT6and2]

Sounds better. I like either 33k, or 39k for the slope. 33k sounds more marshally, and not surprisingly 39k sounds more VH4'ish. Put'em on a switch!

BTW I agree with what duesentrieb said about the mica caps. I find myself liking ceramics better (in almost all circuits) ceramics really add some pleasant grit, and dimension.

I was thinking of installing a little trim pot on the board for the slope. But I'm not positive. A switch would be cool, too.

Just a guess, but I think Olaf might not like micas because of some people encountering ones that leak DC? I think I'm going to use those Philips KP caps. I seem to recall Larry and Aiken and a few other builders liking those. I have some in 100pF, 510pP, 470pF, and 560pF. I'll use the 100pF as the fizz cap and I haven't decided on treble cap values yet. The clips above are with 500pF treble peaker and 560pF tone stack treble cap.

 

[CrazyNutz]

I was thinking of installing a little trim pot on the board for the slope. But I'm not positive. A switch would be cool, too.

A trim pot on board would be neat.

I've done a slope pot on the front panel before, and drove myself crazy with the "fine tweekability", haha. I like the choices, but not that many, plus I prefer the exact indexing the switch provides.