Your query is very vague. Ask in more detail and I think some folks here can probably help.
Difference Decca / London records
Did someone made a comparison? I did a research in the www and the general opinion is, that the SXL are better. But in the last days I listened to a lot of both and I don't think so. I never read one posting about their differences in thickness for example (they have 200gr or a bit more), you have to change the VTA for example, no one wrote about that ... and there are some more differences ...
Your impression?
Your impression?