My tastes have evolved some over the years.

pcrecord, post: 461167, member: 46460 wrote: I'm changing the tubes on one of them in a few weeks, I'll probably do a video on it too.. Stay tuned for that !

Oh yeeeeeaaaaaa

pcrecord, post: 461167, member: 46460 wrote: But this experience with the attenuator re-confirmed to me that the ISA is all about Clean sound, no noise, no distortion.. but still offers this nice transformer sound.

Totally. From what i understand they chose the lundhal xformer, specifically because it's one of the cleanest xformers available. Plus if you consider the isa was made for a console, with eq and compressor, it makes sense that its cleaner with tons of headroom. The ISA is one of those pres that just sounds right imho.

I would be curious to hear the attenuator in series, just to hear how the isa saturates.

kmetal, post: 461171, member: 37533 wrote: I would be curious to hear the attenuator in series, just to hear how the isa saturates.

Sufficient attenuation between the output of a pre-amp and a following ADC allows the ADC to capture either the effect of transformer saturation or the onset of clipping, whichever is appropriate for the pre-amp's output architecture.

I've done a bit more digging in the Focusrite literature, and, from what I can tell, the ISA One, Two, 428 and 828 are based on a common design that has input transformers only and no output transformers. The information is well hidden, but with these models, it looks as though the output will clip.

Boswell, post: 460601, member: 29034 wrote: Here you are:

Hey Boswell, would you be kind enough to calculate what the values for a 40db would be?
It's a question Faraz Abtahi&lc=UgzYWiXPVhZb9HSBUcp4AaABAg'">il asked on my youtube channel.

This is for the U-pad in your balanced attenuator, right? Well, 40dB is easy, as it's 100x in voltage and hence ratios. To 1%, you can use a shunt of 2R and series of 100R. Series resistors of 10K Ohms and a shunt of 200 Ohms are readily available values, and would work OK in this configuration (where OK is not a short circuit). Use two 100 Ohms in series if you can't get 200 Ohms, but if you are considering that, then 4.7K series and 2x 47 Ohm shunt would work marginally better over the range of other likely circuit impedances.

Boswell, post: 462289, member: 29034 wrote: This is for the U-pad in your balanced attenuator, right? Well, 40dB is easy, as it's 100x in voltage and hence ratios. To 1%, you can use a shunt of 2R and series of 100R. Series resistors of 10K Ohms and a shunt of 200 Ohms are readily available values, and would work OK in this configuration (where OK is not a short circuit). Use two 100 Ohms in series if you can't get 200 Ohms, but if you are considering that, then 4.7K series and 2x 47 Ohm shunt would work marginally better over the range of other likely circuit impedances.

Thanks a lot, I'll relay that answer..