Mod Questions

[BZ58]

I have a C-X7 inductor. I’ve read that it needs to be grounded. How do I go about “grounding” it?

 

[buldogge]

Assuming you are mounting the choke at the back of the top plate, behind the transformer...Just run a wire from the frame of the choke (under the standoff screw, most likely) to the grounding lug on the top plate (by the IEC housing).

Good, cheap, easy mod.

-Mark in St. Louis

 

[BZ58]

Wow that’s easy. Thanks, Mark.

I grew up in the 60’s and 70’s in Florissant, MO.

 

[buldogge]

I'm not a native...Came here from Boston in 1986 for WashU...met a girl...started a business...and the rest is history.

Always lived on the SouthSide, except for a semester in the dorms...been in Tower Grove for ~25 years.

Good luck...

-Mark

Wow that’s easy. Thanks, Mark.

I grew up in the 60’s and 70’s in Florissant, MO.

 

[BZ58]

What is the large cap I’ve seen in pictures that is above the transformer? It is the same size cap as the two output capacitors on each side of the speedball.

 

[buldogge]

When you install a choke, you can replace the final PS electrolytic cap with a film of a smaller size...in most cases, 100uf.

I simply chose to bypass the 2nd and last PS caps with Solen 2.2uf films.

I'm down to my last mod...gonna try double bypassing the Dayton 100uf films (that are bypassed with 1.5uf Mundorf silver/oil) with Russian .015uf teflons.

-Mark

What is the large cap I’ve seen in pictures that is above the transformer? It is the same size cap as the two output capacitors on each side of the speedball.

 

[BZ58]

Here is a picture as it looks before the C-X7. I attached a film capacitor 250V 2.2 uF. So I could replace it in the future with one that is 100 uF? I haven't seen any pictures of a crack wired up this way, but it's working fine.

 

[buldogge]

That's how mine is, as well...other than being a Solens.

After you install the choke, you can remove both that 2.2uf film and the 220uf electrolytic...replacing both with a 100uf FILM.

-Mark

Here is a picture as it looks before the C-X7. I attached a film capacitor 250V 2.2 uF. So I could replace it in the future with one that is 100 uF? I haven't seen any pictures of a crack wired up this way, but it's working fine.

 

[BZ58]

Here’s a picture with the Cree diodes attached.

So I can replace the 2.2 film and 250V 2.2uF with 100uF film that are identical to the two Daytons I’ve already installed?

If I wanted to “bypass” the existing Daytons I have, do I take one of the wires from the Dayton and connect it to another cap, then from that cap continue it on to either 6U or 7U? I’ve been looking at pictures people have posted, but it’s difficult to see where the wires lead. So when you say you’re double bypassing, you’re adding another cap to the chain? I feel like I’m answering my own questions.

You said that you chose to bypass the 2nd and last PS cap, so you left the existing caps in?

I’m not sure what is meant by bypassing. Also going to search and read about the difference between film, silver/oil, and Teflon caps.

I’ve also installed the choke. I’ll post a picture of it later. It’s sounding great!

 

[buldogge]

Here’s a picture with the Cree diodes attached.

So I can replace the 2.2 film and 250V 2.2uF with 100uF film that are identical to the two Daytons I’ve already installed?

As long as the choke is installed you can go straight to using a film for the last ps cap...and a 100uf is just fine.

If I wanted to “bypass” the existing Daytons I have, do I take one of the wires from the Dayton and connect it to another cap, then from that cap continue it on to either 6U or 7U? I’ve been looking at pictures people have posted, but it’s difficult to see where the wires lead. So when you say you’re double bypassing, you’re adding another cap to the chain? I feel like I’m answering my own questions.

A bypass is exactly as the WIMA cap you already installed on the last ps cap.  A double bypass just add another cap, same way, in parallel.  In my case, chose to use a 100uf Dayton >1.5uf Mundorf > .015 Russian K72 Teflon.

You said that you chose to bypass the 2nd and last PS cap, so you left the existing caps in?

Yes.

I’m not sure what is meant by bypassing. Also going to search and read about the difference between film, silver/oil, and Teflon caps.

I’ve also installed the choke. I’ll post a picture of it later. It’s sounding great!

Congrats!

-Mark in St. Louis

 

[shrapnel]

So any impressions on how all these changes affected the sound? Thanks!

 

[BZ58]

Impressions are the same as others have reported. To my ears it sounds a lot better. The bass is stronger, which is what I was going for.

 

[BZ58]

I need to fix some connections because I’m getting some static that must be from faulty soldering. When I rewet the connection it doesn’t seem to get hot enough to make it shine.

In another recent thread Doc B mentioned that "around here we crank the iron up all the way (like 800F)" and Caucasian Blackplate adds "the only components that you could possibly damage from excess soldering are the LEDs".

I need to rewet some of the joints, and want to be clear on this. You were referring to all the soldering connections, even before the speedball? Should I always wet the iron tip before rewetting the connection? At a higher temperature than 650 would it effect the iron tip? I have a Hakko FX-888D.

 

[Paul Birkeland]

I have the same iron and I crank it up all the way.  I will mention that it's very easy to think that you're turning the temperature up, but in fact you may be adjusting the iron instead so that the maximum temperature is decreased significantly.  I would suggest reading over the manual before doing any additional soldering.

 

[BZ58]

Finally got around to poking around to fix the static. Found a loose connection. Added some solder to OA and OB.

Also noticed that when I pull up and down from the top of the right RCA plug (that connects to the DAC) it has about 1/8” give. The nuts on the bottom are tight. I can pull up and down on the soldered connection from the bottom also. Is there any way to tighten this?

Then checked the resistance at OB and OA. They both read 0. Maybe I should not have added solder? Maybe I’m not reading the multimeter correctly?

 

[BZ58]

Here's a couple more views. The yellow wire is from the C-X7 inductor soldered to the safety ground lug.

 

[Paul Birkeland]

Did you read up about how the temperature is adjusted on your solder iron?  As I mentioned before, I have the same iron, and it's easy to end up thinking you're cranking up the temp when you're actually calibrating the soldering iron by accident.  This is consistent with your complaints about not being able to heat the joints up enough, and it looks like maybe the flux still isn't flowing all the way. 

 

[BZ58]

Yes, thanks, I did read up on that and as a result I touched up some connections.

From the pictures I provided, does everything look ok?

Do I have the right settings on the multimeter to read the resistance?

Does the fact that I have 0 resistance point to any particular connections?

 

[Paul Birkeland]

A short between ground and either OA or OB usually indicates that the TIP50 transistors are not properly mounted to the heatshiks.

A reading of "OL" would be OK though.

 

[BZ58]

Everything looks good, voltages correct, all led’s glowing, but when listening there is no sound in the right channel.

I’ve discovered that when I pull up and down from the top of the right RCA plug (that connects to the DAC) it has about 1/8” give. The nuts on the bottom are tight. I can pull up and down on the soldered connection from the bottom also. Does that make any difference? Is it somewhat normal? If not is there any way to tighten this? Might this be the reason for no sound in the right channel?