Svart
Well-known member
yessir. I dug up an old white noise generator. I found a FFT plug-in for one of my programs on the recording computer that should give me a decent semi-realtime plot of the spectrum. I haven't tested it out yet but I do have other information to report.
I changed 12 sets (out of 24) of summing resistors to 15kohm from 3k and the results are better than I had expected. with 12 channels switched in(physically connected to the bus) attenuation is around 4db and I can hear no change in audio quality. In fact, it sounds great! I'm fairly smitten with the whole setup now. It really used to be a love/hate relationship.
Another note of interest, I've found that I really love the mc33078/mc33079 opamps. They work wonderfully in gyrator EQs and unity stages. It's strange though.. They sound good but their specs are not that great. They certainly don't look good on paper compared to the opax134 and opax604 parts. I've found that I've pretty much removed all OPA parts and replaced them with 5532/5534 and mc3307X parts except for the summing amp which is the FETbloke. I've come to find that I can't seem to get the OPA "sound" to work for me. Everything just ends up shrill and sucked-out, but I digress.
I bring this up because I keep finding that my favorite gear, the gear that I keep going back to using over and over (because it sounds good to me), is gear that is considered to be colored and rather dirty and would most certainly look hideous on paper. I suppose this is exactly as PRR stated, "Occasionally I've been mostly-satisfied with the sound, then discovered some major-boo-boo like a 10dB suck-out at 9KHz-13KHz. And other times my ears say "yuk" but the meter and quick 'scoping show clean.".
Anyway, I'll check out the spectrum tomorrow after work and report back.
I changed 12 sets (out of 24) of summing resistors to 15kohm from 3k and the results are better than I had expected. with 12 channels switched in(physically connected to the bus) attenuation is around 4db and I can hear no change in audio quality. In fact, it sounds great! I'm fairly smitten with the whole setup now. It really used to be a love/hate relationship.
Another note of interest, I've found that I really love the mc33078/mc33079 opamps. They work wonderfully in gyrator EQs and unity stages. It's strange though.. They sound good but their specs are not that great. They certainly don't look good on paper compared to the opax134 and opax604 parts. I've found that I've pretty much removed all OPA parts and replaced them with 5532/5534 and mc3307X parts except for the summing amp which is the FETbloke. I've come to find that I can't seem to get the OPA "sound" to work for me. Everything just ends up shrill and sucked-out, but I digress.
I bring this up because I keep finding that my favorite gear, the gear that I keep going back to using over and over (because it sounds good to me), is gear that is considered to be colored and rather dirty and would most certainly look hideous on paper. I suppose this is exactly as PRR stated, "Occasionally I've been mostly-satisfied with the sound, then discovered some major-boo-boo like a 10dB suck-out at 9KHz-13KHz. And other times my ears say "yuk" but the meter and quick 'scoping show clean.".
Anyway, I'll check out the spectrum tomorrow after work and report back.
