Amp Build: Ceriatone Kraken 50

[mikepukmel]

Hi FourT6and2,
What kind of lead bending tool do you use?
Thanks,
Mike

[FourT6and2]

Hi FourT6and2,
What kind of lead bending tool do you use?
Thanks,
Mike

I use these:

1. https://tubedepot.com/products/1-4-1-2-watt-lead-bender
2. https://www.doreenbeads.com/stainles...UaAqjaEALw_wcB

[FourT6and2]

A bit more today. Having routed a bunch of stuff now, I'm making some notes about how to do it better the next time around. And by better, I mean more OCD lol.

[mikepukmel]

I use these:

1. https://tubedepot.com/products/1-4-1-2-watt-lead-bender
2. https://www.doreenbeads.com/stainles...UaAqjaEALw_wcB

Thanks FourT6and2!

[FourT6and2]

Preamp tubes all done. In the home stretch now.

[mikepukmel]

General lead dress question if you don't mind: In most tube amps I notice that the wiring going to the vacuum tubes always goes first down to the chassis, across the chassis, then up to the socket pins, except for the AC heater wiring. OK I understand the reason for twisting the Ac heater wiring, and keeping them up and away from the signal and power leads. But why do the leads to/from the tube pins run along the chassis? Thanks, MP.

[Justin Thomas]

Hey Mike,

I've seen it said that it helps shield the signal wires from picking up stray fields that aren't heaters. Personally, I just think it looks neater (not that I use it, with all of my point-to-pointedness... also may help keep wiring from getting fatigued over many decades and breaking/sagging?

Just my own threories...

Justin

[FourT6and2]

General lead dress question if you don't mind: In most tube amps I notice that the wiring going to the vacuum tubes always goes first down to the chassis, across the chassis, then up to the socket pins, except for the AC heater wiring. OK I understand the reason for twisting the Ac heater wiring, and keeping them up and away from the signal and power leads. But why do the leads to/from the tube pins run along the chassis? Thanks, MP.

How else would you do it? The wires come out the bottom of the turret board. What are you going to do? Bring them down and out from the turret board, then arch them up in the air over the socket? I guess you could do it that way. Here's another build I did a while back. You can see that the wires exit from the TOP of the board, instead of the bottom. And because of that, it made more sense to arch them up and over, then down to the socket. Another reason for this in that build is because I ran a bus bar for the filaments. And this way keeps the leads nice and out of their way.

[mikepukmel]

How else would you do it? The wires come out the bottom of the turret board. What are you going to do? Bring them down and out from the turret board, then arch them up in the air over the socket? I guess you could do it that way. Here's another build I did a while back. You can see that the wires exit from the TOP of the board, instead of the bottom. And because of that, it made more sense to arch them up and over, then down to the socket. Another reason for this in that build is because I ran a bus bar for the filaments. And this way keeps the leads nice and out of their way.

Eek, not complaining at all, just trying to learn stuff. Fumbling my way, all 4 thumbs, though a first amp build. I started off trying to figure out what to do by scouring the web for photos of the chassis of the old amp I want to build. Most of the images are from higher production, mid 60's to 80's fender amps. The wiring/lead dress on most of the amps I found photos of ranges from just below acceptable to hideous. The wiring on your amp looks absolutely awesome. So, thought to ask what the electrical ramifications are for running the wires a certain way.

This clip is from one of the better specimens I found.


The lead dress is OK, but the wiring does get attached from the top, then humps down over the side of the fiberboard down onto the chassis.

[mikepukmel]

lead dress vs parasitic oscillations

The main reason for asking around pro amp builders about lead dress was that I found some blog posts here and there talking about parasitic oscillation, but not good detailed explanations on exactly what causes it to occur or not. The main comments were: leads too long, general 'bad' lead dress issues. Since the amp Im working on is from off the shelf parts, the dimensions are going to be different from the original AB763 design. What I don't know, and would like to have some idea: is 1/4" extra lead length overall going to cause a problem, e.g. my fiberglass eyelet board is mounted on little standoffs, so the wiring is going to be uniformly different than if I had a fiberboard screwed to the chassis. If I put the wiring out the bottom of the board or over the top, will it be better one way? If my board is a non reverb board but its mounted in a reverb chassis, I can put the circuit board closer to the output tubes or closer to the preamp tubes, which would be better. etc, etc..

Thanks
Mike

[Justin Thomas]

You posted while I was writing. In answer to your question, no, I doubt 1/4" will matter much. The main thing with "bad" lead dress is keeping low-level AD away from heaters & power supply. One thing that can help is to keep any wires from running parallel to each other, and if they have to cross, try to do it at 90°. But when you're building from scratch, there is just a LOT of experimenting involved.

... The wiring/lead dress on most of the amps I found photos of ranges from just below acceptable to hideous...

You should see one of mine!
http://music-electronics-forum.com/a...6-dscn6402.jpg

I think there are a lot of factors involved with why manufacturers do it the way they do, mostly having to do with cost and time. Most of the amps you're looking at are probably from factories. The rule is, crank them out as fast as possible and as good-sounding as possible. The amp shown meets the criteria for noise-free open operation, and nothing more. I bet when they designed, they experimented til they found a layout that worked. Once they got it, quick, draw a picture and do ALL of them like that! For us, building one at a time, we can afford to take the time to both make it noise-free AND aesthetically pleasing. For a real treat, Google a Fender Super Twin Reverb.

The other thing is, a Fender or a classic Marshall (pre-800) is a low-gain circuit. And so, it's really not as big a deal to position each wire to the precise millimeter. Start talking Mesa, 5150, SLO, etc, it's a bit more important.

I've also seen beautifully wired amps that screech like banshees, because the aesthetic layout violated the electrical principles that get rid of noise. One thing I do like about an old Fender is that there's some extra length if I need to trim a wire for any reason.

There's a whole other Trainwreck thread of three pages that mentions routing wiring wrong ON PURPOSE in pursuit of certain artifacts and interactions. It really is a great big old can of worms.

Justin

[mikepukmel]

Another fantastic build, thanks for the photo.

[mikepukmel]

Hey Mike,

I've seen it said that it helps shield the signal wires from picking up stray fields that aren't heaters. Personally, I just think it looks neater (not that I use it, with all of my point-to-pointedness... also may help keep wiring from getting fatigued over many decades and breaking/sagging?

Just my own theories...

Justin

Thanks Justin

[FourT6and2]

All done!

Just doing some testing now. I'm using a 47K 5W pot wired as a variable dropping resistor. This way, I just clip it to the filter cap and I can tune all the voltages in the amp. Typical value is 10K. I set it to 18K, which is what the Yeti uses (higher voltages). And my B+ is a whopping 515vdc! That's without power tubes though. Once I stick some in, it'll probably come down a bit. I don't really have a set goal in mind. But I'll play it with a few of the resistor values I have on hand and figure out which one to use.

I also got some new Tefzel hookup wire in some fancy colors for the next build. And I'm going to try to make the lead dress a little better next time around. I wanted to get this one done so I can start testing a few things first, tone wise.

Current voltages with no power tubes and 18K dropping resistor:

MAINS: 124.4VAC
AC FILAMENTS: 3.47VAC
DC FILAMENTS: 6.09VDC
BIAS/PI SPLITTERS: -50 to -36VDC
PT SECONDARY: 375VAC

V1:
1: 151VDC
2: SIGNAL
3: 1.47VDC
4: FILAMENT
5: FILAMENT
6: 274VDC
7: SIGNAL
8: 2.47VDC
9: FILAMENT

V2:
1: 226.1VDC
2: SIGNAL
3: 1.26VDC
4: FILAMENT
5: FILAMENT
6: 381.5VDC
7: 226.1
8: 228VDC
9: FILAMENT

V3:
1: 257.3VDC
2: 26.2VDC
3: 42.24VDC
4: FILAMENT
5: FILAMENT
6: 245.2VDC
7: 27.6VDC
8: 42.24VDC
9: FILAMENT

V4/V5:
1: 0
2: FILAMENT
3: 511VDC - 515VDC
4: 509VDC
5: -50VDC
6: 509VDC
7: FILAMENT
8: 0

B+: 515VDC
SECOND CAP AFTER DROPPER (18K): 381VDC
BOARD CAP AFTER DROPPER: 366.8VDC
V1a: 151.7VDC
V1b: 274VDC

[FourT6and2]

Here's a clip. This is with a 10K dropping resistor. Probably my favorite value so far. The volume is as loud as I can get it without clipping the mic on my laptop, sorry lol. I'm working to upload the other clips with different voltages too. But it takes a long time for YT to process 'em. I'm still toying with a few parts here and there.