IC's gain dependent?

I have been auditioning a number of IC's of late. There is one in particular that I like a good deal but when I use this IC, it requires the application of a good deal more gain to achieve the same volume level as another (all else except the cable exchange being equal). This may be a dumb question, but does anyone have an idea why this would occur?
As far as I know, it could only be because of higher resistance (compared to the other IC's you've used), but I find it surprising that there could be as big a difference in this as you report. (I'm assuming it for a given that you are not comparing a single-ended IC to balanced IC's, or a very long one to short ones.) Has anybody else experienced something like this? I sure haven't...
Z, the cables are the same length and I am using them directly from the variable outputs on my tuner to amp. Both ends are RCA terminated. The difference in gain is between, for instance, from 9:00 to 10:00 for the same level of volume.
I have found this NOT to be a problem running direct to my SACD, so this must be a tuner issue.
Well, if the tuner had an unusually high output impedance (possibly because of the variable-output feature's potentiometer?), a highish-capacitance IC could exhibit noticable HF roll-off in combination, and I suppose this could be heard as a reduction in overall level upon non-instantaneous A/B comparision...
There are some cables that have a VERY high series resistance and could literally result in a very noticeable volume drop. The first ones that come to mind are some Magnan's that run about 40,000 ohms ( if i remember correctly ) for a one meter pair. I don't think that this is what 4yanx is dealing with though based on the info provided. It simply sounds like he's experiencing a difference in tonal balance / loading that Z has mentioned.

One suggestion is to turn the "low volume" cables around. The bi-directonal diodes in them might be facing the wrong way : ) Sean
40000 Ohms are too extreame!!!
But the audiable level difference to the tens of kOhms load might start in range of high tens of Ohms or low-hundreds Ohms depending on input impedance of amplifier or next component which still too much. Even digital interconnect is rated 75Ohms.