The Raven - CKD

[Meat&Beer]

The Raven – CKD (Crush Kill Destroy)

Warning; I’m one wordy bugger.

Hey guys!

So after the many “what is that thing??” ’s I received when I posted the amp in progress to a thread about faceplates, I guess I won’t wait till it’s done, so here it is. I may (most likely) need to ask for some assistance still, so an early start on its introduction certainly won’t hurt!

This is my first build. Why so complicated??? Well, I didn’t know any better when we were developing it, never had built an amp before. My tech that took me under his wing just kept saying, “We can do this, or we could add this..” etc. Not knowing any better, my response was, Hell yeah!

Oh boy.

Now there’s this. Been about 2 ½ years in the making, prototyped/breadboarded and the whole nine in the beginning. I don’t live where my tech dood does anymore, so its progress is difficult and slow moving. The finish line is very near, methinks.

What’s wrong with it now;

We implemented a voltage regulator for the two final stages, as one was acting up when a certain control was adjusted. (Labled “Spazz” on this unit. See B.K. Butler Real Tube RT-902 schematic attached. The last stage of one of the [two] channels is essentially this.) Both last stages (One envelope each) run at about 110v, opposed to around 310v’s on all others. With the control in question at zero, B+ is normal, at full, B+ almost doubles. This behavior was inherent in the original BK unit, I own it and checked for myself. Mr. Technician thought this was very un-cool, so he designed the neon bulb voltage regulator to fix it.

I have a dozen little neon bulbs to audition for the regulator, hoping to find one as near to exactly what is needed. I do this tonight hopefully…
The other problem, unstable ground noise/fluctuating weird sounding unhappiness. I’m almost certain I need to re-flow the grounds on the buss bar (Will never use this grounding scheme again!) because some of them look like crap, and I am very close to positive that I have a bad/cold ground connection somewhere, judging by this now familiar sound.

That’s the skinny on my issues. Here’s what she be;

My tech goes by a moniker, “Raven” is the last name of his alter ego, as he calls it. He’s kinda well known for his neon glass bending. I pretty much named this amp after him. The guy is as friggen rad as it gets. “CKD” stands for “Crush, Kill Destroy”.

Yes, this is a very metal/high gain amp.

Two fully independent channels, and a “trick” that is like another channel, per say. I just say it has 2 ½ channels. Top row, is Kill, my favourite. No cathode caps, just one on the first stage that’s switchable. Five stages, one 12AX7, one 6av6, and one 12AU7 at the end in one dual rocking formation.

Bottom row is “Destroy”, and it has more gain than is humanly necessary. Cathode caps all along, two 12AX7’s, one 6AV6, and one 12AU7 (Buffers). The second stage (AX 1B) uses the first half of the AU as a buffer, and you can switch it so it sends it directly to the PI, yielding a Marshall Plexi type circuit. This little cuitie, the “Trick”, the ½, is called Crush. And man, it sounds purdy...

Center input jack allows you to select either channel, or both simultaneously with a 3 position rotary. (12AX7 mixer right before a 12AU7 PI)

There’s a 6AU6 for the FX loop return. It has a colour organ, which detects your playing dynamics and flickers the 12 LED lights to your playing. It can be full/solid on, off, or “strobe”, as I labeled it on the back, using 3-way rotary. It’s all transistor, on its own board side mounted. It feeds straight from the input jack.

5U4 rectumzapper. Much controversy over these envelopes here! I think I’d prefer a 5AR4, but not in a position to mess with it yet. 2x6L6GC. Gonna convert to EL34 in the end, I really suspect... Then I can play with 5881’s, 6CA7’s, KT88’s… Right? Dude told me I could, I better be able to! (After a bias adjust, of course.)

I really REALLY want to show the head enclosure I made for it. I’m in the process of trying to get a copyright for it. First time ‘round, they called it a “Useful Article” and denied me. Well, of course it is, how silly of me. I’ll try a new one, remove the plexi front, not mention anything about it being an enclosure, and just call it a wooden sculpture. What I do with and put inside of my wooded sculptures is MY business! More to come on that subject in a few months, Copyrights take a while to go through…

I did have this working, mostly without issues, then, the ground problem developed over a short time. So much has gone on with it, I can’t even really talk about its present operations at the moment. 1st order, get B+ to behave. 2nd order, re-flow ground connections. Then, so much more work to do...

Cheers!

Chris

[Cliff Schecht]

That gut shot is what amp builders see when they have nightmares..

[M Fowler]

Fun project for sure.

Sometimes too much is just too much. How the heck would a guy know how to operate all those knobs and switches.

I've always wanted to build a multi channel preamp but then I say no keep it simple.

Thanks for sharing.

Mark

[MCK]

Would love to hear it. You certainly get an A for effort. Great job persevering.

[Structo]

Man, that's a lot of pots and stuff.

[EtherealWidow]

Well if this is your first build,I think by the second you'll be ready to move onto a Mesa Road King clone. 6 12AX7's, 4 6L6's, 2 EL34's and 2 5U4's. Your PT hates you.

[VacuumVoodoo]

Set up your video cam. Turn the "amp" on for the first time. It rises into the air. You tweak a couple knobs and switches. It moves in circles and up and down. You realize you have built an antigravity propulsion device and you want to prevent it from getting weaponized. You turn it off and disassemble. You can't replicate it. There's only this 1 minute clip on youtube.

[Leo_Gnardo]

Wooden sculpture - HA! I love that!

Better luck with the copyright office.

[Meat&Beer]

How the heck would a guy know how to operate all those knobs and switches.

When one has built this amp about 3 times over like I have, I get to know them pretty well. Seriously, there are two switchable tone stacks per channel, a lot of them are tone controls, the yellow lines help navigate also. When the day comes you get to see a video of it in action, it's surprisingly easy to navigate.

VacuumVoodoo; the first time we fired it up, it actually became self aware. We had to remove a sliver from the tri-force so it would stop shooting lightning bolts out of my pickups and electrocuting the dog.

The first time I breadboarded the preamp, it was a SWEET tone oscillator...

[Meat&Beer]

Your PT hates you.

Yes.

[NickC]

^^^


Note To Self: No! No! No! .............. don't even think about it!

[Meat&Beer]

Well wuddya know, I need help already.

I mentioned we're using a neon bulb as a regulator. When Mr. tech sent me the circuit, it was pre-done. I hooked it all up, and saw about 62vdc where we wanted approx 125vdc.

He discovered his meter was acting up, and since sent it out to be serviced. Great. So he had me order more bulbs to be screened for the right voltage. I got them, and auditioned them. Still, getting mid 60's out of them.

The bulb in question is a, NE-2H. See the Mouser sheet here;

http://www.mouser.com/ProductDetail/Chi ... YyVqklb04W

To test them, the voltage feed is ~360vdc. A 470k resistor on one leg of the bulb, and the other leg to chassis ground. B+ is applied to the 470k, and I read at the node of the 470k and the bulb.

Pretty sure I need a different bulb for this. Could someone tell me what would yield double what this one is, in this situation?

Yes, I would ask the man himself, but he is in mourning. I think he wants to be left alone for a bit while he deals with the situation. Can't say I blame him, poor guy.

Suggestions? I have no knowledge of neon lamps. Operating supply voltage on the sheet says 135dc. Do I want a lamp with double this figure??

As always, thank you for your support.

Cheers!
Chris

[xtian]

I love the star ground in the shape of a star!

You are an ambitious builder. More power.

[shoggoth]

Maybe use two bulbs in series? Or a Zener diode?

[Meat&Beer]

Maybe use two bulbs in series? Or a Zener diode?

Yes of course! The thought crossed my mind after making the post... I didn't think of a zener though. I'll give it a shot tonight after work, thanks much!