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Old 11th April 2013, 04:46 PM   #37951
SY is offline SY  United States
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Quote:
Originally Posted by simon7000 View Post
No they are output transformers!
That's a pity.
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Old 11th April 2013, 05:37 PM   #37952
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Quote:
Originally Posted by gpapag View Post
strong in innovating.
Also the first commercial echo sounder for fishing vessels (Fischlupe)
The echo-sounder was also a German invention, 1918.

(Elac/Electroacustic started out as Signalgesellschaft, a company that developed sound apparatuses for submarines)
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Old 11th April 2013, 07:21 PM   #37953
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Originally Posted by bcarso View Post
I worked on such a design for a while, mostly as a stunt, until distracted by more immediately remunerative pursuits. A lot of the work was on the efficient but low noise power conversion.
The well-regarded Royer R-122 still uses a matching transformer, but they may not need the whole 1:50 stepup. Pretty certain they didn't include DC-to-DC conversion either, but still a solid and practical commercial compromise. (That's *not* a bad word.)

I once calculated the number of 12AX7 triodes it would take for 3dB noise figure from a nominally 3 Ohm Coles. IIRC it was 853, but can't remember if that was triodes or whole (two triodes each) 12AX7's. And ignored excess noise. And ignored the wire resistance from the ribbon to the electronics. Yikes!

Thanks, as always,
Chris
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Old 11th April 2013, 10:01 PM   #37954
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Quote:
Originally Posted by jacco vermeulen View Post
Signalgesellschaft, a company that developed sound apparatuses for submarines)
I traced 32 patents (*) of them on this topic, which were known in UK during 1920-1921.

George

>Edit: (*) patent applications
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Last edited by gpapag; 11th April 2013 at 10:13 PM.
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Old 11th April 2013, 10:32 PM   #37955
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Is everybody finished with the first layer of criticisms of the passive line amp? If so, we might go forward.
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Old 11th April 2013, 10:58 PM   #37956
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Originally Posted by john curl View Post
Is everybody finished with the first layer of criticisms of the passive line amp? If so, we might go forward.

i'm not completely comfortable with the colour of the sleeving and would prefer clear zip-ties the vast empty space could be smaller also
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Old 11th April 2013, 10:58 PM   #37957
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One more. Get rid of all the wires, squash everything down to the tightest, most compact configuration. Of course, then there is no excuse for the bling enclosure, sized appropriately ...
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Old 11th April 2013, 11:33 PM   #37958
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Critics should send their suggestions to Herr Hartwig:

Passive Vorstufe mit High-End Leitplastikpoti

Would love to read his answer
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Old 12th April 2013, 12:02 AM   #37959
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Vicious ... 700 Euro for the TKD pot alone ...
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Old 12th April 2013, 01:02 AM   #37960
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well OK i'm not surprised at the freyed blue sleeving now, the website is loud and covered in that blue. I particularly love this one

Click the image to open in full size.

love the heatsinks...

I guess the cases are designed to make them look more substantial, or match other components, but its still pretty funny, I wonder if they are extra

Last edited by qusp; 12th April 2013 at 01:08 AM.
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