Search found 88 matches

by ilya
Tue Jul 25, 2023 6:22 pm
Forum: Test, Measurement and Repair
Topic: Intermittent scratches/distortion/level changes in preamp
Replies: 10
Views: 12936

Re: Intermittent scratches/distortion/level changes in preamp

I can’t tell because I don’t recognize the exact brand of the button. My bet is they are silver.
by ilya
Tue Jul 25, 2023 4:49 pm
Forum: Test, Measurement and Repair
Topic: Intermittent scratches/distortion/level changes in preamp
Replies: 10
Views: 12936

Re: Intermittent scratches/distortion/level changes in preamp

I think I found the culprit. It's the buttons. Wayne, you were right. The manufacturer solution is very questionable. Basically, this is a single input preamp that is pretending to be able to take line levels. But in fact, what "Line in" button does is insertion of the 36dB pad. This is no...
by ilya
Wed Jul 19, 2023 8:33 am
Forum: Test, Measurement and Repair
Topic: Intermittent scratches/distortion/level changes in preamp
Replies: 10
Views: 12936

Re: Intermittent scratches/distortion/level changes in preamp

As expected, hair dryer did not make anything break. I've tried cleaning switches, but there's a ton of components and wires dangling on these buttons (at both sides!), so I didn't dare to unsolder it all and disassemble the buttons. I hope that all the chemistry I used managed to get inside the but...
by ilya
Tue Jul 18, 2023 7:27 am
Forum: Test, Measurement and Repair
Topic: Intermittent scratches/distortion/level changes in preamp
Replies: 10
Views: 12936

Re: Intermittent scratches/distortion/level changes in preamp

Tried the freezer. No dice. The next is a hair dryer. But I doubt it will show anything. Another suspects are the push buttons, which are a type of multipole (ala dialistat, but modern) thingies. I tried to make them produce the fault that I described and I sort of succeeded. Sort of, because it’s r...
by ilya
Sat Jul 15, 2023 11:34 am
Forum: Test, Measurement and Repair
Topic: Intermittent scratches/distortion/level changes in preamp
Replies: 10
Views: 12936

Re: Intermittent scratches/distortion/level changes in preamp

mediatechnology wrote: Wed Jul 12, 2023 7:23 am I would try freeze spray.
I don't have a lot of experience with freezer. Is it safe to use it on live circuit? Or should I power it down, apply freezer and then power up again?
by ilya
Wed Jul 12, 2023 7:18 am
Forum: Test, Measurement and Repair
Topic: Intermittent scratches/distortion/level changes in preamp
Replies: 10
Views: 12936

Intermittent scratches/distortion/level changes in preamp

I'm repairing the BAE preamp (that is a copy of Neve 1073 mic preamp section). It has very unpleasant and difficult to trace problem. Once in a while the sound becomes distorted and changes in level (although the change is not drastic, my estimate is 2-4dB), and after some short time everything gets...
by ilya
Wed Jul 12, 2023 7:02 am
Forum: Pro Audio Design
Topic: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 142
Views: 353350

Re: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp

I've been wanting to use the ZTX851 or ZTX1053 in a mic preamp. Both are exceptional. Me too! However, given current situation in our region, it's very difficult to get parts from the outside. And I do have a ton of 44xx that I can play with. I'll see, maybe I will provide additional footprint for ...
by ilya
Wed Jul 12, 2023 5:12 am
Forum: Pro Audio Design
Topic: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 142
Views: 353350

Re: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp

I’m thinking about this flying concept and applying it to some other preamp. I was planning to build Cohen type preamp at some point anyway. And this whole flying rails concept makes the project much more fun. I suppose that THAT chips are based on the same topology, so there should be no problem wi...
by ilya
Mon Jul 10, 2023 12:10 pm
Forum: Pro Audio Design
Topic: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 142
Views: 353350

Re: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp

This discussion has sparked a new wave of my interest. Might get to building the Wayne version at some point.
by ilya
Sun Jul 09, 2023 3:35 pm
Forum: Pro Audio Design
Topic: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp
Replies: 142
Views: 353350

Re: New: A Direct-Coupled Input-Capacitorless Active Mic Preamp

I've just stumbled upon this:
https://audioxpress.com/news/acoustics- ... ugust-2022

Article by Michel Nieuwenhuizen looks a lot like Waynes work.