To boldly go, where I haven't gone before....

[digi2t]

It's more or less done. Waiting on some knobs, and some decent tubes, but sounds pretty good. No video just yet, but here's some pics.











Nice clean boost, and the Klip dirt is nice too. Top boost can really push the top end nicely, but I like the lower end chunk with a single coil. All in all, I'm pleased with it.

[Jdansti]

Looks great! 

[bluebunny]

I'm with John.  That looks pretty cool - inside and out.

[digi2t]

Thanks guys. First time I've ever built with tagboard.

I'll try to get a vid out soon. I'm just waiting on some decent tubes right now.

[wildebelor]

I've been considering this project for quite some time!
I recently purchased a Laney AOR (which is the son of the klipp) and was really hoping to hear a few samples before I embark on this!
Well done on the build, looks very neat 

[digi2t]

I've taken the liberty to mod the original schematic. It not only reflects the gutshots that I've seen on the net, but also adds the resistors to the transformer I've used, to get the two 3.15v lines.

[idiot savant]

I've taken the liberty to mod the original schematic. It not only reflects the gutshots that I've seen on the net, but also adds the resistors to the transformer I've used, to get the two 3.15v lines.

Maybe it's just me, but you really don't want those 100r filament resistors there. The other 33r resistors form a center tap that is referenced to a positive voltage node made by the 330K -100K divider. It's set up that way to ensure the filament to cathode voltage of the LTP isn't too big.

[digi2t]

Maybe it's just me, but you really don't want those 100r filament resistors there. The other 33r resistors form a center tap that is referenced to a positive voltage node made by the 330K -100K divider. It's set up that way to ensure the filament to cathode voltage of the LTP isn't too big.

OK, I'm a real noob at this tube stuff, so bear with me. The reason I put the 100R's there was because the transfo I'm using only put out 6.3v. From my reading, this was a preferred method for reducing the 0v - 6.3v down to two 3.15v lines, as shown in the original schematic. Of course, I never thought to consider the 33R's in that equation, I was simply "painting by numbers", so to speak. 

So, can I just pull the two 100R's, and test to see what happens? Will that create a problem elsewhere? I mean, I am getting the 3.15v on each line right now.

[davent]

The two 100r's and the two 33r's are serving the same purpose, an artificial center tap for the heater winding so... one or the other. Elevating the heaters (dc stand-off) with the vdc from the high voltage line should give you quieter operation. If your transformer had a center tappped heater winding you'd just connect the HV from the voltage divider to it rather then grounding the center tap. Either resistor pair could be used with dc stand-off.

[Gus]

As others have posted get rid of the 100 ohms you are causes issues using them.  Use ohms law and work out what is going on.  Measure voltages at the power supply nodes B+, 100K 33K node etc. with the 100ohm center grounded and the center lifted from ground

The two 33 ohms seem a little low but then might also be a 66 ohm load on the filament supply to lower the filament voltage with the transformer used by faustone.  Maybe the filament AC voltage was too high with two 100 ohms (200 ohm extra load)and they dropped the value to two 33ohms(66 ohms).  The 100 ohm is not a law you can use different value matched resistors

The power supply C4 at 100uf is kind of high and you might not even need the C4

If I was to build this I would have used a 80 to 100VDC B+ get rid of the gain stage R5, R6 and C4 and adjusted the first tube gain stage for a lower B+ voltage

The AC wiring looks unsafe.

[italianguy63]

It is WAY cool.  Great exectution!  Don't drop it!   

[davent]

And a great site for guitars and tubes intro, you might recognize the site's author.
http://www.valvewizard.co.uk/heater.html

And... very nice looking build there!

[Gus]

Does anyone see the danger in the wiring besides me?

[digi2t]

And a great site for guitars and tubes intro, you might recognize the site's author.
http://www.valvewizard.co.uk/heater.html

And... very nice looking build there!

That is exactly the site that I got my info for the two 100R's from. I've bookmarked the site. Lots of great reading there.

Does anyone see the danger in the wiring besides me?

Everything is properly grounded, and I have a fuse first in line. What am I missing Gus?

EDIT:

Took the two 100R's out, and I started getting oscillation when the Klipp pot is maxed. The oscillation however, disappeared when I changed the V2, so I'm chalking that up to a bad tube. My heater voltages are off now, about 1.8v on one side, and 2.4v on the other, to ground. With the 100R's in there, my heater voltages are 3.15v, as originally shown on the schematic.

Soundwise, it sounds a bit chunkier now. Little more bite. Hmmmmm.......

[Gus]

It looks like exposed AC connections at the IEC and fuse, no green bonding wire to each 1/2 of the enclosure.

The heater voltages at 1.8VAC and 2.4VAC read like something is not correct

You don't want the filament supply referenced to ground if you are building the first schematic in this thread.  You want the middle of the 33 ohms at about 1/4 of the way from ground  to B+  100K and 330K is 430 K so the 100K 330k and middle of the 33 ohms node is about 1/4 of the way to the B+

The two 100 ohm wiring is not elevated but a kind of center tapped transformer substitute.  Remove the two 33 ohms. 100K, 330K 100uf they do nothing if you add the two 100 ohms.  The 100 ohm center node to ground does not allow the filaments to be elevated above ground.

Maybe the transformer had a much higher heater current than needed and was meant to heat more than two 12ax7 tubes and it needed to be loaded more to bring down the voltage . The two 33 ohms for a 66 ohm load

Look up elevated filaments you need to mindful of the cathode to filament breakdown voltage this is in the specifications of tubes

[digi2t]

It looks like exposed AC connections at the IEC and fuse, no green bonding wire to each 1/2 of the enclosure.

Argh!! You're right, only the bottom potion is bonded (transformer foot). I'll branch one to the top half as well. Oversight on my part, thanks for the heads up.

You don't want the filament supply referenced to ground if you are building the first schematic in this thread.  You want the middle of the 33 ohms at about 1/4 of the way from ground  to B+  100K and 330K is 430 K so the 100K 330k and middle of the 33 ohms node is about 1/4 of the way to the B+

OK. I thought that was to ground. I'll check it the way that you've pointed out. Like I mentioned before, I never considered the role of the 33R's, I was just too focused on the voltage marked on the schematic. That's when I went off on the voltage divider path with the 100R's. 

Going to check my voltages again....

Yup.... that's why this young grasshopper is a loooong way from snatching the grain of rice from your hand. Without the 100R's, from the middle of the 33R's, 3.15v on each side. Another big fat learning curve. This is why I come here.

[R.G.]

OK, time for some AC safety comments. Digi, we want you to be around for a good, long time.

First: I can't possibly write down all the stuff involved in making safe AC power wiring. All I can do is write down some things that I've picked up that AC safety inspectors have told me. Even the inspectors will not tell you what IS safe, only what they find that they conclude is not. This is a compendium of things they have told me. It's a minimum.

- The incoming AC safety ground must be attached to the metal chassis by a single bolt, used for nothing else. It used to be thought OK to use the transformer mounting foot bolt for this, but is no longer. So - single bolt, not the trannie mounting bolt.
- The two halves of the chassis need a ground bonding wire that does not depend on the screws that hold it together if there is any possibility of powering it with a cover removed. In your case, as Gus says, the simplest thing is a ground wire from the safety ground bolt location to a similar location on the top half.
- At the safety ground bolt location, sand a clear space through paint down to bright, shiny metal. Put the bolt through, then stack, in order, a spring-toothed washer to bite into the chassis, then the ring terminal on the ground lead (and there must be such a ring terminal, not wrapped wires), then an optional washer, then a toothed washer and then the securing nut. This setup lets the ground ring terminal be bonded to the chassis by enough high pressure contact points that it will sustain 25A of ground current, which is viewed as mandatory.
- AC mains wiring must be done with wire rated for more than the incoming AC voltage, and higher temps than the box will ever have. Fortunately, 300VAC + wire and 85C to 100C wire is cheap. Don't use non-rated zip cord.
- Use UL/CE/CSA/TUV/etc. stamped and rated components for the incoming AC inlet, wiring, power switch and fuse holder.
- Proper AC incoming wire runs the line or hot wire first to the fuse holder, then from the fuse to the AC switch. From the AC switch it can go to the transformer primary. The neutral/cold wire can go directly to the trannie primaries; but it's safer to use a double pole AC switch and break both sides in case it's plugged into a backwards-wired wall socket.
- the AC line and neutral wires should be appreciably shorter than the safety ground wire so they break first if mechanically pulled out.
- It's far safer for subsequent technicians (that'll probably include you ...) if you use heat shrink over the bare soldered AC terminals for the AC wiring. Heat shrink is not all that useful for passing formal safety inspections, but it might keep you from accidentally touching a hot wire in the future.

As to hum issues:
- Ideally, there will be one and only one connection between signal ground and the chassis. This completely prevents hum and ground loop flows on the chassis, and lets the chassis be an RF shield. The location is not terribly critical, and probably should be one of the input jack or the mains safety point ( bolted on top of the nut already there for ground safety, a second nut).
- The connection from the rectifier setup negative side must go to the negative of the first filter cap(s) only, no where else. Otherwise the ground will carry rectifier ground noise into your circuit.
- Filament/heater supplies must be referenced to ground somewhere. The CT on most of them is for grounding. It may be lower hum to use two 100R resistors across the heater winding and ground the center than using the CT, as all CTs are not perfectly centered.

There is a huge compendium of more of this. I may have left stuff out. Ask questions.

[digi2t]

Having read through your list of safety criteria, I seem to have most of the points covered. More importantly, I appreciate the fact that your expecting me to be around for a while. I'm truly touched.

All my wire is 300v rated, so I've got that covered.

The dedicated screw for the AC ground is absolutely correct. It's on the to do list. I'm using grounding ring connectors, with integrated toothed locking, and nylok nuts. Should bite great into the aluminium box, so mechanical loosening shouldn't be an issue.

As for heatshrinking the AC wires, I must admit, it did cross my mind. In the end, decided to forego the process. As this effect will never ever be sold, and will live in my studio, I'm not worried about any hazard from this, let alone formal inspections. My baby, I can live with that one.

Neutrals are shorter than grounds. That one I knew about. As an added precaution, AC ground wire is one gauge larger than the other AC wires.

The AC jack, fuse holder, and switch are certified. Switch is a single pole though, but the order is correct.

As for hum issues, all the grounds (other than the AC grounds) are starred together at one point. I really haven't noticed any appreciable hum to speak off, but I haven't really cranked the thing through my Ampeg yet, so the jury is still out.

- The connection from the rectifier setup negative side must go to the negative of the first filter cap(s) only, no where else. Otherwise the ground will carry rectifier ground noise into your circuit.

The rectifier negative only goes to the caps, with one wire to the star ground. Is that OK? On the schematic, it shows going to ground, so....

- Filament/heater supplies must be referenced to ground somewhere. The CT on most of them is for grounding. It may be lower hum to use two 100R resistors across the heater winding and ground the center than using the CT, as all CTs are not perfectly centered.

I removed the two 100R, and as Gus pointed out, from the center of the two 33R's, my heater voltage is balanced. As there is no CT on the 6.3v side of this transformer, it seems that the artificial CT network is working properly.

Going to fix the AC ground connections tomorrow.

[digi2t]

FINALLY got a video done of this puppy. It was a camera busy day for me today. Here's a test drive of the Klipper. Enjoy.

Many, many thanks (again) to all that contributed info, POV's, scoldings, etc. to my build.