Search found 3714 matches

by JR.
Fri Apr 19, 2024 10:54 am
Forum: Pro Audio Design
Topic: THAT2252 RMS Detector Replacement Using A THAT300 Array
Replies: 50
Views: 52936

Re: THAT2252 RMS Detector Replacement Using A THAT300 Array

My gut feeling is that CA3086 Rbb would be higher than THAT300's. Rbb generally tracks with low ein voltage but at this point not worth losing much sleep over it unless trying to make an accurate full range dB meter. IIRC both DBX and Paul Buff made wide range dB meters back in the day. Both probabl...
by JR.
Thu Apr 18, 2024 5:42 pm
Forum: Pro Audio Design
Topic: THAT2252 RMS Detector Replacement Using A THAT300 Array
Replies: 50
Views: 52936

Re: THAT2252 RMS Detector Replacement Using A THAT300 Array

The THAT300's rbb is 32Ω typical. I'm not sure I've ever seen the rbb spec for the CA3046 or CA3086. I might be able to make an educated guess from looking at the TS-1 schematic. IIRC the error was almost 1 dB at +20dBu so because of the R it measured high, I'm currently using TL072B for the op amp...
by JR.
Thu Apr 18, 2024 3:18 pm
Forum: Pro Audio Design
Topic: THAT2252 RMS Detector Replacement Using A THAT300 Array
Replies: 50
Views: 52936

Re: THAT2252 RMS Detector Replacement Using A THAT300 Array

That is a step up from the rectifier and log convertors I made with cheap 3086 transistor arrays. In the TS-1 dB meter I used to get an error near the top of the DB range (+20dBu) from the Rbb of the logging transistor. I bet those array devices have lower Rbb and less subsequent errors related to t...
by JR.
Wed Apr 17, 2024 2:51 pm
Forum: Pro Audio Design
Topic: THAT2252 RMS Detector Replacement Using A THAT300 Array
Replies: 50
Views: 52936

Re: THAT2252 RMS Detector Replacement Using A THAT300 Array

I saw Rt but discounted it. 8.3 uA x 49.5k is down a few dB from typical 0VU (around 0.4V) discounting the parallel junctions.

Never mind...


JR
by JR.
Wed Apr 17, 2024 9:48 am
Forum: Pro Audio Design
Topic: THAT2252 RMS Detector Replacement Using A THAT300 Array
Replies: 50
Views: 52936

Re: THAT2252 RMS Detector Replacement Using A THAT300 Array

Wouldn't subtracting a reference 0VU current from the common emitters (Sym adj probe node) deliver a + and - voltage relative to 0VU threshold?

It may need an offset subtracted to account for two pairs in parallel.

JR
by JR.
Fri Apr 05, 2024 9:37 am
Forum: Pro Audio Design
Topic: A Quadrature Power-Summed Compressor Sidechain For "The Uno Compressor"
Replies: 60
Views: 31172

Re: A Quadrature Power-Summed Compressor Sidechain For "The Uno Compressor"

Thanks for the explanation, kind of like the step the old sweetening engineers performed.

JR
by JR.
Thu Apr 04, 2024 2:32 pm
Forum: Pro Audio Design
Topic: A Quadrature Power-Summed Compressor Sidechain For "The Uno Compressor"
Replies: 60
Views: 31172

Re: A Quadrature Power-Summed Compressor Sidechain For "The Uno Compressor"

Deessing in a final stereo mix is kind of after the horse has already left the barn. Generally excessive sibilance is caused by too close miking hot instruments (like cymbals). Hot HF content quickly attenuates traveling through air to a less close mic. Of course that does not help after the fact. T...
by JR.
Wed Apr 03, 2024 3:57 pm
Forum: Pro Audio Design
Topic: A Quadrature Power-Summed Compressor Sidechain For "The Uno Compressor"
Replies: 60
Views: 31172

Re: A Quadrature Power-Summed Compressor Sidechain For "The Uno Compressor"

any interest in a de-ess side chain filter? Or is that not as much of problem these days? Since this is a stereo compressor a simple de esser like a DBX900 would be inadequate for most audio program. It would need to be a much fancier side chain than a bandpass filter. Floating threshold, reacts to...
by JR.
Wed Apr 03, 2024 11:14 am
Forum: Pro Audio Design
Topic: A Quadrature Power-Summed Compressor Sidechain For "The Uno Compressor"
Replies: 60
Views: 31172

Re: A Quadrature Power-Summed Compressor Sidechain For "The Uno Compressor"

any interest in a de-ess side chain filter? Or is that not as much of problem these days?

JR
by JR.
Wed Mar 27, 2024 11:11 am
Forum: Build
Topic: Phono Transfer System Construction Information
Replies: 251
Views: 6641869

Re: Phono Transfer System Construction Information

These are working into a 14K3Ω load. Wima now have some nice 5 mm lead spaced films in the MKS2 series that go up to 6.8µF so keeping them film is do-able. Cool... I was measuring phase shift at 20kHz from a 22uF caps ESL working into a 360 ohm R. 14K should not cause an issue even with modern elec...