Upgrade Tips?

[ChrisP]

Hi fellas, I'll be slowly upgrading my crack over the next few months and want some opinions.

My reason is to clean up the insides and might as well add a few upgrades. I've already added the speedball mod.
So here are my questions:

I have hum that appears on both channels, much more in the right, and want to fix this. This hum is variable to the volume knob and hear it after turning it 1/6th of the way (I'm using HD600s).
I added a choker which seems to have helped but I've seen around on the forums that changing the capacitors on the power supply can also help. I really want the blank background that solid states have.

Secondly, is there a more durable/snappier toggle switch that fits into the precut slot? It's a minor thing but the squishy switch bothers me a bit.

And lastly, has anyone used shielded cables on any of the internal connections? Since I'm cleaning it up, I'm thinking of either reusing the cable if it doesn't matter or using new ones. If you have, mind recommending me a good cable?

Any other determined modifications that makes a difference in absolute clean sound?

Thanks!

[fullheadofnothing]

If your hum is affected by the position of the volume pot, it has to be entering before the volume pot. It is most like your source component. Second most likely is your cabling to the Crack. Included in both of these are ground issues between the source and Crack. Least likely cause would be the wires from the input jacks to the pot, if not properly routed and braided. Changes to the power supply will not fix this; your choke solution is psychosomatic at best.

The stock switch has a relatively firm click. If it does not click, the most likely cause is it being melted during soldering. Replacement switches are available here.

[ChrisP]

If your hum is affected by the position of the volume pot, it has to be entering before the volume pot. It is most like your source component. Second most likely is your cabling to the Crack. Included in both of these are ground issues between the source and Crack. Least likely cause would be the wires from the input jacks to the pot, if not properly routed and braided. Changes to the power supply will not fix this; your choke solution is psychosomatic at best.

The stock switch has a relatively firm click. If it does not click, the most likely cause is it being melted during soldering. Replacement switches are available here.

My road to subjective audio perfection is mostly psychosomatic aha.
So it looks like the loud variable hum fixed itself after moving the Crack around. Most likely a loose cable somewhere that should be fixed after cleaning it up and really going through the solder joints.

I do want to replace the cabling though since, looking at it, some of the plastic melted off from my soldering inexperience years ago and my psychosomatic illness is getting to me when looking at it. Would any copper cable work or are there specifications I have to follow?

Also any tips on actually mounting the metal sheet to the wooden chassis? I'm a uni student constantly on the move and would like it to be more stable.

Ill be sure to buy a new switch from the site!

Thanks for the quick reply

[caffeinator]

Hi ChrisP,

On the wiring replacement, use solid core wire; it is easier to work with.

For attaching the top plate to the base, one approach is to glue small pieces of wood on the inside sides of the base where there is clearance from internal components (corners are a good spot in general, but on the Crack, this might be in the center of the back behind the power transformer and along the sides near the front) such that there is a flat space under the top plate.  Into these you will need to put some kind of threaded insert to accept a fastener.

Take a look at the image at the link - you can see in the corners, there are wood pieces with threaded inserts recessed into them.  It's fairly easy to place these - once the wood has been glued into the base, drill a pilot hole through the top plate and into the wood below.  Drill out the pilot to the size required for the insert.  Drill out the pilot in the top plate to make a clearance hole for the fastener.  You can go up a size to account for tolerances - say, a #6 fastener in a #8 hole.

http://home.earthlink.net/~aeholsten/2a3_moondog/11-05_moondog_label_1200.jpg

[kgoss]

If funds allow, Blumenstein Audio makes really nice bamboo bases that captures the top plate in a slot rather than having it in a rabbit  on the top of the base.

[Leland Hankins]

I recommend silver or single crystal copper teflon coated wire, 20,22,or 24 gage.  Always use teflon coated wire if you are looking for neatness and reminder to not nick the wire when stripping the teflon.  If you use the extremely easily melted standard wire strip the ends extra long and put a short length of heat shrink on each end, this helps to reduce or covers up the melted insulation.

I put a square or triangular piece of hard wood in each corner for strength (it also helps to keeps the corners square), the one at the AC corner is shorter for clearance or not installed.  Just thread the hole with a tap or use an insert.

[fullheadofnothing]

So it looks like the loud variable hum fixed itself after moving the Crack around. Most likely a loose cable somewhere that should be fixed after cleaning it up and really going through the solder joints.

Did it end up in the same place? Moving gear and cables is how you fix hum issues related to electromagnetic interference.

[yay]

i had a hum in the right channel sometimes that went away after i put in a different pot.
i assume it was just soldering.
but after putting in a new pot and headphone jack it was definitely quieter than before.

[ChrisP]

Did it end up in the same place? Moving gear and cables is how you fix hum issues related to electromagnetic interference.

What I meant by moving it around, I meant wiggling around the Crack and poking a few wires with some wood. So I'm guessing its a solder joint somewhere?

The only background noise I'm getting now is random bits of a scratchy sound that is unrelated to the volume. Any ideas on the cause of this or a fix?
I don't believe it's my DAC since it happens whether or not something is playing.

I'll most likely upgrade the pot to an Alps blue since I hear they're pretty recommended and not too expensive.

Thank guys

[Deluk]

Scratchy sounds can be due to dirty tube pins I believe?

[skootx]

Hi ChrisP,

On the wiring replacement, use solid core wire; it is easier to work with.

For attaching the top plate to the base, one approach is to glue small pieces of wood on the inside sides of the base where there is clearance from internal components (corners are a good spot in general, but on the Crack, this might be in the center of the back behind the power transformer and along the sides near the front) such that there is a flat space under the top plate.  Into these you will need to put some kind of threaded insert to accept a fastener.

Take a look at the image at the link - you can see in the corners, there are wood pieces with threaded inserts recessed into them.  It's fairly easy to place these - once the wood has been glued into the base, drill a pilot hole through the top plate and into the wood below.  Drill out the pilot to the size required for the insert.  Drill out the pilot in the top plate to make a clearance hole for the fastener.  You can go up a size to account for tolerances - say, a #6 fastener in a #8 hole.

http://home.earthlink.net/~aeholsten/2a3_moondog/11-05_moondog_label_1200.jpg

Thanks for this, was thinking of doing exactly this.