Sorry, late back to this one...
Tim Gillett wrote:
Hugh Robjohns wrote:Every tape machine sounds different....
I'd imagine top competing Studer and Ampex machines for example, set up with the same tape and under equivalent conditions would sound virtually indistinguishable, both as recorders and for playback.
It was/is certainly possible to line up different machines identically on a test set, with the same reference flux, rec/rep levels, and spot frequency levels at 100Hz, 1kHz and 10k, 15kHz or whatever.
But in practice, different machine types still sound different when recording and playing programme material. In my experience there were definite audible traits with different machines that were often distinctive -- much like the differences between, say, a classic Neve and an SSL console, for example.
I think this is readily explainable since different brands and designs of tape machine obviously had different electronics (many, but not all, used input/output transformers, some were built with discrete transistor circuits, others with different grades and types of ICs, etc), and with different power rails (and thus headroom and slew rates) which all affected their sound character in small and subtle ways.
Different brands of machine, (and different formats of machine within a brand) also have quite different low end characteristics because of their different head constructions and dimensions, and the associated playback head-bump differences, creating peaks and dips at different frequencies and with different amplitudes.
Within an organisation machines tended to be aligned in very consistent ways, but even so there were inevitable engineering differences, either because of different manufacturers' recommendations and procedures, or because of end-user alignment preferences and working practices.
And all that is reliant on the machines using the same tape type, the same speed speed, the same EQ, the same tape widths and track numbers, and record to the same levels. In practice, of course, different people use different configurations and all these things made audible differences too.
So i think its fair to say that, in practice, every machine in the real world sounds slightly different to every other machine. And while I've not had much personal experience of Ampex machines, I have spent a lot of time working with Studers -- mostly A807s, A810s, A812s, A80s, B67s, Revox PR99s, Sony APR5000s, and Telefunken M15as, and they definitely all had identifiable or at least distinguishable sound characters. The later Studers were probably the most neutral and similar to each other.