Search found 88 matches
- Mon Jan 04, 2021 10:56 am
- Forum: Pro Audio Design
- Topic: Cohen/Transamp output stage
- Replies: 30
- Views: 80151
Re: Cohen/Transamp output stage
The first QuantAsylum was unbalanced so pretty useless for pro audio. The ne one is balanced but uses a pair of BNC’s for the connection. It doesn’t inspire confidence. What a stupid choice. I'd argue that's not that stupid. First, you can easily make an XLR to double BNCs break-out. Second, there'...
- Mon Jan 04, 2021 10:12 am
- Forum: Pro Audio Design
- Topic: Cohen/Transamp output stage
- Replies: 30
- Views: 80151
Re: Cohen/Transamp output stage
AD2, while useful, is not that low noise (but ok for general purpose work).
You may check QuantAsylum QA401. This is the most affordable and versatile analyzer that I found (and use regularly).
You may check QuantAsylum QA401. This is the most affordable and versatile analyzer that I found (and use regularly).
- Sat Jan 02, 2021 7:40 am
- Forum: Pro Audio Design
- Topic: Cohen/Transamp output stage
- Replies: 30
- Views: 80151
Re: Cohen/Transamp output stage
Very interesting discussion!
While we're wandering around the subject, I've got one more question. In TA documents, Valley recommend to use tantalums as phantom blocking caps. What's the reason behind this? Why tantalums?
While we're wandering around the subject, I've got one more question. In TA documents, Valley recommend to use tantalums as phantom blocking caps. What's the reason behind this? Why tantalums?
- Wed Dec 30, 2020 3:49 pm
- Forum: Pro Audio Design
- Topic: Cohen/Transamp output stage
- Replies: 30
- Views: 80151
Re: Cohen/Transamp output stage
Well, of course! For some reason I thought those were inverting stages. Doh!mediatechnology wrote: ↑Wed Dec 30, 2020 3:44 pm That's it though the polarities on the 1606 are reversed.
The top one is 1606 positive.
Thanks for spotting this!
- Wed Dec 30, 2020 3:36 pm
- Forum: Pro Audio Design
- Topic: Cohen/Transamp output stage
- Replies: 30
- Views: 80151
Re: Cohen/Transamp output stage
So to make sure I did that correctly, here's the crude scheme attached. Is it how 1606 should be connected to the Cohen circuit?
- Tue Dec 29, 2020 1:21 pm
- Forum: Pro Audio Design
- Topic: Cohen/Transamp output stage
- Replies: 30
- Views: 80151
Re: Cohen/Transamp output stage
What was the load on the 1510 ICs during the tests? Was it buffered? It was pretty much the circuit from the datasheet. I think the output was buffered and sent to 1646 driver. This was quite some time ago, so I can't remember the exact details. John, I know that you're not a fan of uncontrolled li...
- Tue Dec 29, 2020 1:03 pm
- Forum: Pro Audio Design
- Topic: Cohen/Transamp output stage
- Replies: 30
- Views: 80151
Re: Cohen/Transamp output stage
Thanks, JR. Yes, I know about their mic preamp chips. Although, we did a comparison between different preamps in our studio, and the 1510 type preamp was the total looser sonic-wise. I have no idea why that happened. It surely measured just fine on the bench. Maybe because of the lack of "color...
- Tue Dec 29, 2020 11:45 am
- Forum: Pro Audio Design
- Topic: Cohen/Transamp output stage
- Replies: 30
- Views: 80151
Cohen/Transamp output stage
I'm researching the pure discrete mic preamp circuits and I think I'll settle on either Transamp (by Paul Buff) or Cohen type topology. Looking at the output stage, I often see the floating source output that resembles D. Pontis work (from an old HP journal). I'm thinking to replace this stage with ...
- Tue Jun 23, 2020 5:37 am
- Forum: Pro Audio Design
- Topic: Method for testing thermal coupling
- Replies: 9
- Views: 30402
Re: Method for testing thermal coupling
Can you tell more about what you want to thermal couple and why ? JR nailed it. Yes, that's for coupling transistors in LTP, current mirrors etc. Maybe I'll get to the discrete VCA (JR will probably laugh at that). It's still not clear to me how to measure the amount of tracking between the coupled...
- Sun Jun 21, 2020 5:54 am
- Forum: Pro Audio Design
- Topic: Method for testing thermal coupling
- Replies: 9
- Views: 30402
Re: Method for testing thermal coupling
Thanks!
Sometimes the correct search phrase is important. I tried searching for "thermal coupling" and got no useful information. That's why I posted here.
I'll check out the Netional stuff and see what the "thermal resistance" brings.
Sometimes the correct search phrase is important. I tried searching for "thermal coupling" and got no useful information. That's why I posted here.
I'll check out the Netional stuff and see what the "thermal resistance" brings.