API 512c strange issue

[fuoriporta]

Hi. I own 4 APIs 512c, bought new (2 pre a few months later than the first 2) and fitted in the same 6U lunchbox.

Today I was trying a Royer SF-24 and I found the 2nd pair (don't remember if they're the first or the last bought) sound darker, with less highs, less definied, than the other couple.

I noticed it comparing the SF-24 to a matched pair of U87Ai: the 87s seemed so much brighter than I supposed there was something in the pres.

I switched the mics on the pres, and compairing the previous recording with the new, Sf-24 sounded with more high freq.

Do you have any ideas on the reason why the 512 seem to sound different (by pairs...)?

[TonyBelmont]

Originally Posted by fuoriporta

Hi. I own 4 APIs 512c, bought new (2 pre a few months later than the first 2) and fitted in the same 6U lunchbox.

Today I was trying a Royer SF-24 and I found the 2nd pair (don't remember if they're the first or the last bought) sound darker, with less highs, less definied, than the other couple.

I noticed it comparing the SF-24 to a matched pair of U87Ai: the 87s seemed so much brighter than I supposed there was something in the pres.

I switched the mics on the pres, and compairing the previous recording with the new, Sf-24 sounded with more high freq.

Do you have any ideas on the reason why the 512 seem to sound different (by pairs...)?

What about the U87? Does it sound the same on both sets of pre's?

[fuoriporta]

Originally Posted by TonyBelmont

What about the U87? Does it sound the same on both sets of pre's?

Seems a bit darker, but not how the Royer gains on highs with the "brighter" APIs pair.

[superburtm]

Originally Posted by fuoriporta

Hi. I own 4 APIs 512c, bought new (2 pre a few months later than the first 2) and fitted in the same 6U lunchbox.

Today I was trying a Royer SF-24 and I found the 2nd pair (don't remember if they're the first or the last bought) sound darker, with less highs, less definied, than the other couple.

I noticed it comparing the SF-24 to a matched pair of U87Ai: the 87s seemed so much brighter than I supposed there was something in the pres.

I switched the mics on the pres, and compairing the previous recording with the new, Sf-24 sounded with more high freq.

Do you have any ideas on the reason why the 512 seem to sound different (by pairs...)?

First place I would look is the Lunchbox itself. I had a few suspect LB's. The slots that the modules fit into were not kosher. Like slot six would be quieter and intermittent, all kinda of issues. So I'd swap the modules into other slots and see if the problem follows or not.

[fuoriporta]

Thank you Burt, I'll try in the next days. Before friday I should do all the tests.