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Old 17th June 2011, 05:17 AM   #31
sonnya is offline sonnya  Denmark
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You added the gatestoppers i have forgotten.

The offset-pot i also placed at a good position.

But basicly, this version lineup have made would be easy for all to make even if they have no SMT experience.

The opamp, makes it possible to use an passive preamp section.

Last edited by sonnya; 17th June 2011 at 05:21 AM.
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Old 18th June 2011, 06:16 PM   #32
sonnya is offline sonnya  Denmark
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Default modified for noninverted with high input impedance.

Hi WuiYt, Lineup and other.

I have attached the schematic where it is modified for noninverting with an gain of 26.4dB.

Compared to the original schematic it has 3 more resistors and 4 more bjt's.

By adjusting the r6 with an potentiometer offset can be removed as per lineup.
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File Type: pdf simpleamp v11 noninverted loopg.pdf (15.2 KB, 271 views)
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Old 18th June 2011, 07:03 PM   #33
lineup is offline lineup  Sweden
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Looks real nice.
Must be very low THD now.
It is now Diamond input. Like Hiraga used in his famous amplifiers.
And Current feedback
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Old 18th June 2011, 10:42 PM   #34
sonnya is offline sonnya  Denmark
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2. and 3. is down to 100dB at 1KHz and 1W into 8 Ohm.
2. and 3. is down to 90dB at 1KHz and 10W into 8 Ohm.

Funny enough. They are equal in level.

I talked to my brother this evening, and we wants to build a version with 3 channels on a heatsink.

This HT amp will be running on two cosel L150 SMPS made for medical use. The put out 36V but can be adjusted +/-5V. They can in 10 second give 280W.

He wanted an amp with lower idle current to save on the bill.

The voltage gain stage uses only 6mA.

I am going to make another version also which has powersupply on board like the one SWF and Hugh had made.

Not to copy them. But they actually lead me to use those mosfet, and it turned out that they are easier to get stable than BJT's and need no driverstage for a little amp.

Thanks for getting me to think it over twice
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Old 18th June 2011, 11:20 PM   #35
sonnya is offline sonnya  Denmark
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Distortion is at 1W,10W 0.001269% and 0.004907%.

This is at an idle of 1A.

At 150mA idle the thd is up to 10 times higher at 10W. But at 1W the THD is 50 times higher.

At 500mA 10W is still high but 1W is equal to 1A.

To obtain low thd at a relative low idle it is neccesary to use BJT output stage.
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Old 19th June 2011, 09:08 AM   #36
WuYit is offline WuYit  Sweden
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Hi,
Quote:
This HT amp will be running on two cosel L150 SMPS made for medical use.
No applause from me.
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Old 19th June 2011, 09:27 AM   #37
sonnya is offline sonnya  Denmark
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I did not expect it either.

I was just telling about the progress.

Besides if you do not test it, it is unknown land.
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Old 19th June 2011, 09:35 AM   #38
WuYit is offline WuYit  Sweden
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It`s a well-known land, has no place in audio.
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Old 19th June 2011, 09:37 AM   #39
sonnya is offline sonnya  Denmark
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So you have actually listen to the Cosel LEP150F yourself?
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Old 19th June 2011, 09:49 AM   #40
Piersma is offline Piersma  Netherlands
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Default PSRR

hi Sonnya,

Nice circuit that will provide nice THD figures.

Did you check the PSRR?
By nature the current feedback configuration results in a poor PSRR.

I would run the front end from a regulated supply.

regards,
Piersma
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