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Old 18th June 2014, 09:00 PM   #41
sonnya is offline sonnya  Denmark
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I use an an passive preamp. But in general a low zout buffer is better.

The frontend of the TSA V1.7 is a CFP design which produce an minimum of current fluctuation on the input.

The DCB1 from Salas is an good design as you have such an low zout buffer without feedback.
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Old 18th June 2014, 09:06 PM   #42
sonnya is offline sonnya  Denmark
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An current feedback amp produce a large step on the input because of its nature. (Low Z feedback network produces high peak currents in buffer frontend in an CFB amp)

An diamond buffer has two stages, this TSSA V1.7 has two stages made with the CFP pairs. The SSA variant only has one stage buffer -> fluctuation currents on the input is beta factor times higher on the SSA than on the diamond buffer or the TSSA CFP input pair. With BC850C/860C that would give you currents that are ~600x higher on the input that the preamp has to drive!

So there you need a low Zout preamp with very wide bandwidth.
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Old 18th June 2014, 09:25 PM   #43
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Well I must admit that you lost me there....

Unfortunately I am a man of practice and not the theory ....in the past this has resulted in very expensive errors...(maybe thats the reason for the sudden crisis mmmhh). So these days I go with the advice of the experts...
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Old 18th June 2014, 09:27 PM   #44
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Quote:
Originally Posted by Xerxes75 View Post
Well I must admit that you lost me there....

Unfortunately I am a man of practice and not the theory ....in the past this has resulted in very expensive errors...(maybe thats the reason for the sudden crisis mmmhh). So these days I go with the advice of the experts...
Short: Use an passive preamp but the DCB1 is better for the job, and has no feedback.
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Old 18th June 2014, 09:40 PM   #45
sonnya is offline sonnya  Denmark
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Quote:
Originally Posted by Salas View Post
But are there through hole external resistors for fixing the gain and instructions in V1.7 as in the previous amp?
There is one trimmer less and trim range is much better.
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Old 18th June 2014, 09:56 PM   #46
Salas is online now Salas  Greece
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Quote:
Originally Posted by sonnya View Post
Short: Use an passive preamp but the DCB1 is better for the job, and has no feedback.
It is indeed wide bandwidth single stage that has 100% self feedback being a JFET source follower buffer, but I would think you refer to the absence of an external and reactive multistage feedback loop.
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Old 18th June 2014, 10:08 PM   #47
sonnya is offline sonnya  Denmark
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That is right. That is what i mean.


Sent from my iPhone using Tapatalk
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Old 24th June 2014, 06:16 AM   #48
sonnya is offline sonnya  Denmark
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We have made an user interface for an customer with an TFT display. More or less all the software and hardware can be reused for a user interface for an preamp.

I have set Kristian my colleague on the Job changing it to something usefull for an preamp.

The display is 240 x 160 x 24bit.

Let me know if this has any interrest?
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File Type: jpg tft display.jpg (51.5 KB, 309 views)
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Old 4th July 2014, 10:24 AM   #49
sonnya is offline sonnya  Denmark
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Hi all.

Sorry for the long delay.

I have got this message today.

"TSSA V1.7 boards finished, however, we made the mistake with soldermask color, we made them as green soldermask, however, you ordered them as black, if green soldermask acceptable? Or we will arrange remaking and it takes about 6-8 days for remaking."

So we need to add 6 - 8 days. As i want them to be black. They look the best this way.

Sorry for the inconvenience it causes!
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Old 9th July 2014, 02:49 PM   #50
pdb is offline pdb  Denmark
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Originally Posted by sonnya View Post
Per, what we Can do is to build it for you. We have a case already that we could use. Simelar to the one on the pictures.
Thank you for the kind offer - very tempting indeed. Send me a PM with the details and costs. Thanks again. All the best, Per
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