Need help with Crack + Speed ball

[timmacy941]

Hi everyone,

I recently build a Crack + speedball, while it sounds great, there is a slight channel imbalance. I have checked on the forum, so far I tried:

- Re-do the resistance check + voltage check, all passed.
- Re-solder all the joints.
- Swapped tubes.

Then I was looking at the resistance between the input RCA and ground, I see that:
- Left: 96K
- Right: 83.5K

Although those are within spec, but it seemed like the channel imbalance could be caused by that, does any one have any other thoughts? Thanks

Some other measurements I read on forum where other people were trying to trouble shoot:
Playing 60Hz on my listening volume:
- Left: 0.58V (AC)
- Right: 0.63V (AC)

Playing 60Hz on max volume:
- Left: 7.15V (AC)
- Right: 7.42V (AC)

[Paul Birkeland]

Then I was looking at the resistance between the input RCA and ground, I see that:
- Left: 96K
- Right: 83.5K

Although those are within spec, but it seemed like the channel imbalance could be caused by that, does any one have any other thoughts? Thanks

From a typical DAC, I would expect 0.009dB of imbalance due to this difference.  Since 1dB is approximately what's an audible difference for most people, this is 100 times smaller than that.

Your source has 7V of output? 

If you are only using the first 5-10 degrees of pot rotation, I'd see items #3 and #4 in the Crack FAQ.
https://forum.bottlehead.com/index.php?topic=4295.0

[timmacy941]

Thanks. Right I only use a little bit of the volume range, I will look into adding resistors.

And yes I am using regular DAC, I think the output voltage is 2V.