Crack wiring options and tube socket PCB useage.

[jrihs]

Hello,
I got 8 feet of silver/gold hook-up wire from e-bay. I figured that would be just enough to cover the signal portion of the Crack (more on that later) and leave the copper for the power. Life was good, a decision had been made. Then I decided to get another 8 feet just in case I got it wrong, or accidents. So now I got enough for the whole project right, why not just do it all? The thing is, this z-wire is no longer made so perhaps I should save some for the signal path of my next maybe project (preamp?), or not...

So, my questions are:

1) Anyone ever notice a sonic difference between an all silver (for example) wire project and a silver in the signal path only project?

2) If I just do the signal section, should I end it at the transformer (do all the heater wiring)?

ALSO...This should be a separate post but while I'm embarrassing myself...I got teflon tube sockets on e-bay and then waited over a month for the tube socket PCB's to arrive from a well known parts internet store. So the 8-pin was easy and probably the most necessary of the two from a soldering perspective. However, the eight pin will not slide down onto the fattest part of the pin where I ASSUME it needs to be. Should I give up and solder where it is, or just chuck it and solder the 9-pin point-to-point. Wouldn't that be the best from a sonic perspective anyways?

 

[Grainger49]

I like silver signal wire.  I haven't spent a long time done A/B comparisons but whenever I put it in the signal path I like it.

I see no reason for any of the AC or DC power wire to be silver.  Maybe I'm wrong.  The improvement I would suggest is heavy gauge, therefore low impedance AC and DC power supply wiring. 

Heavy gauge is not practical for heater wires since they have such small connections.

 

[Doc B]

Are you saying that you are going to mount PC boards with copper traces to the tube sockets? We use terminal strips and point to point wire components from them to the tube sockets to keep the signal voltages away from any copper traces that run on PC board material. If the goal is to get away from the stock T strips we supply I would suggest buying turret strips. Perhaps this is what you are actually getting - a phenolic board with turret strips that mounts to the socket, like the IAG boards - in which case I should think it would be fine.

 

[jrihs]

No, though I did consider the Yamimoto terminal strips. They are basically the same tube socket PCBs as you see here: http://www.bottlehead.com/smf/index.php/topic,977.0.html, but blue. Probably from the same manufacturer in china no doubt. Though easier for soldering, they do add some lesser quality conductor between the PCC copper tube socket pins and the silver/gold hook-up wire.
Thanks.

 

[jrebman]

jrihs,

Don't worry about the availability of silver/gold wire -- mundorf makesit in 3 gauges.  If you strip off the teflon (best done with a heat stripper) and slide some cotton insulation ove it, it makes excellent signal path wiring.

In the crack if using it from the RCAs to the volume pot, I'd shield it with some copper brad and ground the braid at the RCA end to the grounding point at the back of the chassis.  Silver wire has much greater magnetic susceptibility than copper, so the run past the power transformer is probably better shielded.

HTH,

Jim

P.S. -- don't know why you'd want to use really good wire an then pc boards -- aside from the lower quality conductor, you are adding solder joints.

 

[jrihs]

Thanks! I just finished the rca's with the loose fitted teflon this wire came with (no need to strip it, it fits real loose). Not sure if its an alloy or gold plated silver...Mundorf is 1% AU...probably plated. Would it be really worth Going with cotton?
Also, i was told that for the 8-pin the pcb would be needed to ease the soldering issues with the teflon tube socket upgrade...perhaps not then?

 

[jrebman]

Mundorf is actually an alloy, and the cotton is probably more a matter of personal taste, and certainly not a necessity.

The 9 pin teflon sockets can get quite tight, but I'm blind and can manage them -- though with real care and patience.  The octals are no problem at all.

Just take your time, inspect very closely for solder bridges and protrusions, etc., and file or nip away any excess and you should be fine.

-- Jim

 

[jrihs]

Thanks again Jim, Can you describe the sonic differences using cotton? I almost ordered some, but could not find a good descriptive comparison. Cheers!

 

[Grainger49]

Where does the cotton "sock" come from.  That is, who stocks it.  I have some silver left over from a previous abandoned project.

 

[jrebman]

Grainger, PCX now stocks a variety of cotton and silk tubing, and I believe Michael Percy does too.

As for the sonics, it's more that teflon can tend to make things a bit harsh to my ears in the upper  frequencies, and the cotton eliminates this.  It may also have a damping effect, but I won't swear to that.  You can also buy cotton insulated copper and silver wire from Jupiter (also carried by PCX and others.)  I'd suggest using the pre-made copper/cotton wire so one doesn't contaminate the copper with your fingers, unless you apply a coat of 100% pro gold to it before threading the cotton tubing on.  Also, this takes patience to do, and in really long lengths can drive you nuts.

-- Jim

 

[Grainger49]

So, what I am getting is that the cotton goes on the wire like a Chinese finger torture?

 

[jrebman]

Yes, basically, but it just more or less slips on once you get it started. 
A long, straight upholstery needle helps to get things started.

-- Jim

 

[Grainger49]

Thanks Jim!

 

[HF9]

I used the PCBs with the teflon tube sockets on both. For whatever reason, they don't make the teflon tube sockets with pins that have solder holes. The octal should be okay to solder directly to the little pins, but the noval socket would be a lot more trouble.

I feel like the tradeoff of having the signal routed through a short trace on a PCB is worth it for those quality teflon sockets. You can see my Crack here: http://www.bottlehead.com/smf/index.php/topic,977.0.html .

The little pins don't stick out too far from the PCB, as you can kinda see from the photos.

 

[jrihs]

Thanks guys,
I think I may remove the octal I soldered and not do the 9-pin...guess I need a solder sucker! Perhaps a trade for 2 PCB's?

So How far do i take the signal / silver wire? through the heater wires to terminal 3,4 (?) on the transformer? Or just to the octal?

Jim, I take it silk would be slightly better than cotton both sonically and from a construction perspective (harder to poke through a little perhaps)?

ALSO, Jim, do I get the 1/2" shield to go over the braid, or the smallest to go over the wire and tubing and then braid it? AND, could I get by with just sheilding half the run (near the transformer). I'd like to use as little sheilding as possible.

 

[jrebman]

jrihs,

I am not sure I'm following you -- the transformer, pins 3 and 4 of the 9 pin socket are heater wires and those I wouldn't do silver or silver alloys with.  Copper 22 or 24 awg should be fine for the heater wiring.  Absolutely nothing wrong with the wire that comes with the kit.

As for silk, again, sme people don't like it as much as cotton and say it tends to sound more forward and can add glare, but I don't know because when I've used it, it was on top of cotton and mostly for some extra toughness as you say.  You can still easily poke the wire through it though.

As for the shielding, I myself wouldn't go that large, and I also don't know what covering half the signal wiring would be like.  A good opportunity for an experiement though.  Let us know how it goes .

Hey, I have yet to wire my crack inputs to the pot, and I really haven't decided what I'm going to do, but I'm leaning toward the cryo'ed mundorf silver/gold with cotton insulation, a silk jacket over those, and a length of 1/8" tin plated copper ground braid.

One more day of cleanup on my office/listening room/workshop, and I'll be ready to get the tools out again and get this puppy finished.

-- Jim

 

[Grainger49]

Thanks guys,

. . .  

So how far do I take the signal / silver wire? through the heater wires to terminal 3,4 (?) on the transformer? Or just to the octal?  .  .  .    

The heater wires are not signal wires.  On the 12AU7 terminals 3 and 4 (As Beefy appropriately points out below heaters are 4 & 5, 3 is the first triode's cathode) are the heaters.  Don't waste silver wire there.

I don't have a Crack manual so I can't talk terminal numbers.  I'm looking at the picture of the Crack wiring.  The signal wire comes from the input RCA jacks (three braided) to the volume control, from the volume control to the 12AU7 driver tube grids (pins 2 and 7), from the plates (pins 1 and 6) of the driver tube to the grids of the output tube (don't know pins) and finally from the plates (correction, Cathodes) of the output tube through the output caps to the headphone output.  

I hope that is a leg up on identifying the signal wires.

 

[Beefy]

On the 12AU7 terminals 3 and 4 are the heaters.

That would be 4 and 5, plus 9 for the centre tap

 

[Paul Joppa]

And it's a cathode follower output, so the cathodes (not the plates) go to the output caps.

 

[Grainger49]

On the 12AU7 terminals 3 and 4 are the heaters.

That would be 4 and 5, plus 9 for the center tap

Yes, I left for something this morning and didn't have enough coffee to count terminals.  Thanks!

And thanks PJ, like I said I didn't know the circuit.