Crack with speedball, no sound, advice/help needed (solved)

[halverson]

Hi everyone, first time posting here, be gentle

So the other day I finally got around to building my crack. I decided to just built it with the speedball from the start. I checked everything the best I could, measured ohms and everything looked good so I did a through voltage check and everything was spot on (I didn't write it down though).
The tube glows, nothing seems off.

I don't have much to plug into at the moment, what I have is my Xonar essence STX in my computer. I was hoping to test with that before I bought a proper DAC. I plugged in with RCA cables and was using HD650 headphones. At first as I turned up the volume I could hear odd feedback, and when I moved my mouse it picked up noise from that. I changed plugins for the crack and that eliminated any background noise, just blank. Although now, I can't get any sound at all, no matter what I try. Perhaps I can't actually use it with the Xonar? The second attempt I tried was plugging a Nintendo Wii into a TV with just video, then trying to connect the crack via RCA for sound, and nothing.

Perhaps I am missing something simple here? Or is there anything I should go check again and again?

Any help is greatly appreciated!

Much thanks,
-Halverson

[Paul Birkeland]

So the other day I finally got around to building my crack. I decided to just built it with the speedball from the start. I checked everything the best I could, measured ohms and everything looked good so I did a through voltage check and everything was spot on (I didn't write it down though).

Hello Halverson,

Can you go back and check/write down the voltages?   All we really need are terminals 1, 2, 4, 5, 7, and 9 to know how the amp is operating.

The noise you are experiencing from your computer is very typical, and generally due to the low quality of ATX power supplies.  Using an optical cable and external DAC will isolate you from that issue, or generally a laptop won't give you these problems.

If you no longer get sound out of the Crack, the voltages are very likely to provide some direction.

-PB

[halverson]

Hello Halverson,

Can you go back and check/write down the voltages?   All we really need are terminals 1, 2, 4, 5, 7, and 9 to know how the amp is operating.

The noise you are experiencing from your computer is very typical, and generally due to the low quality of ATX power supplies.  Using an optical cable and external DAC will isolate you from that issue, or generally a laptop won't give you these problems.

If you no longer get sound out of the Crack, the voltages are very likely to provide some direction.

-PB

Hey PB,

So I went back to check the voltages just now and write them down (well the ones you mentioned anyway). A couple were actually lower than should be, guess maybe something is a miss.

1-75
2-173
4-173
5-75
7-103
9-102

Several are just a few over, but number 1 and 5 are 15 lower than should be. Perhaps this is the issue? Should I follow the connections for 1 and 5 and check the soldering? Or are those readings not why there is no sound?

Thanks for the help.
-Halverson

[Paul Birkeland]

Your Speedball voltages are spot on.

[halverson]

Your Speedball voltages are spot on.

Alright that's a relief. So now, any idea what I should try?

[Paul Birkeland]

Can you download a 60Hz test tone, then play that into your Crack?

Set your meter for AC volts, at a low range (5-10V or thereabouts).

Turn the volume pot all the way up.

With the amp off, measure the AC voltage between ground and the center pin of each RCA jack.  Let us know what that is here.

Next, measure the AC voltage between ground and pin A2, as well as ground and A7 (you'll understand why you'd want the amp off for this one!)

Let me know what you get there, and we can continue testing.

-PB

[halverson]

Can you download a 60Hz test tone, then play that into your Crack?

Set your meter for AC volts, at a low range (5-10V or thereabouts).

Turn the volume pot all the way up.

With the amp off, measure the AC voltage between ground and the center pin of each RCA jack.  Let us know what that is here.

Next, measure the AC voltage between ground and pin A2, as well as ground and A7 (you'll understand why you'd want the amp off for this one!)

Let me know what you get there, and we can continue testing.

-PB

I put on a 60Hz test tone, but still can't get any sound. I did notice though that when I unplugged my headphones from the amp, it made an audible noise from being unplugged.

I'm not getting any readings for any of those. I'm not really great with understanding this but should I even get readings of voltage when the amp is off?

[Paul Birkeland]

Crank the volume all the way up, you can try measuring the AC voltage at the RCA cables when they aren't plugged into the Crack.

-PB

[halverson]

Crank the volume all the way up, you can try measuring the AC voltage at the RCA cables when they aren't plugged into the Crack.

-PB

Ok I understand now. The lowest I can actually set this meter to is 200 AC. When I measure the two RCA jacks with the computer volume cranked, they seem to start around 01.0 and decrease quickly down to 00.1, this is for both jacks.

[Paul Birkeland]

You will need a meter with a lower scale than 200 AC, or a source with more level.  The 60 Hz tone from your computer should make at least 0.3V, I would triple check that you don't get a stable reading, otherwise the $20 meter from Harbor Freight may be in your future.

-PB

[halverson]

Well I decided I needed to try on something other than through my soundcard on the PC. So I went out and bought an RCA to 3.5 jack to go through my laptop. Everything is working fine now. No idea why I can't get it to work through the Xonar...oh well. Time to pick up a nice DAC.

Thanks for all the help PB!