Total Recall – hiss on repeats?

[benlanc]

I can't seem to dial out some of the hiss behind the repeats on my Total Recall build.

I'm 99% certain it's coming from the BBDs (Xvive) – even with the delay time wound back so the clock noise is outside of audible frequencies, there's definitely hiss coming from pins 3 & 4 of the BBDs that is much more prominent than on the way out of the NE570N.

I'm pretty confident that the BBDs are biased as well as they can be, and the GAIN trimmers are set so I'm happy with the behaviour of the repeats and the point of oscillation. Voltages are all fine too.

Is there a low pass filter on the way out of the delay that I could tweak? I looked at R27 + C21, and also R25 + C19 thinking that they were low pass filters, but the values give cutoff frequencies way outside the audible range I think (1/2piRC, right?)

[daleykd]

I just wanted to chime in and say the same thing happened in my build.  An ever-so-subtle hiss occurs on the repeats.  I, too, am using XVIVE 3005.  (Now, when I speak of my hiss, I'm talking about the true output; not when using the audio probe.)

Have you had any success/update on this?

[benlanc]

Nope, still a bit fizzy on mine. I'm kinda curious to try it out with some original MN3005s but I'm loathe to take the risk in buying some

[Scruffie]

Did you see... can't remember the users thread (linconlc?) where I pointed out the build doc is wrong regards the setting of gain trim 2? That will increase the noise significantly.

Don't blame the BBD's yet.

[benlanc]

this one?

[Scruffie]

That'd do it.