Accustic Art Tube Preamp II Mk2

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代友詢問Accustic Art Tube Preamp II Mk2 比對 Nagra PLL with external Power Supply Unit 是否upgrade (配AA Amp II Mk2 power amp 計)??? 两者价錢相近

但AA Tube preamp 要用4隻ECC83, 好似難配對?

http://www.musicalsounds.us/PDF/ ... e%20Preamp%20II.pdf

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tst123

師兄，拿部Nagra PLL 去AB test 便一清二楚，我準備買Nagra 時也帶它去到處比拼，試完不得不科水。

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tst123 發表於 2013-10-17 08:02
師兄，拿部Nagra PLL 去AB test 便一清二楚，我準備買Nagra 時也帶它去到處比拼，試完不得不科水。 ...

多謝師兄提点, 可能我要帶部PLL同我個friend去hifi鋪做AB test

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Just looking at their specifications:

- Nagra PLL's output impedance is 60 ohms;
- AA Tube Preamp II MK2's output impedance is 34 ohms.

Both preamps can match power amp with XLR Input Impedance of 20K or even 10K ohms very well.

Usually, the typical output impedance of preamp is around 600 ohms (e.g. Audio Research preamps).

The ratio of power amp's input impedance to preamp's output impedance should be greater than 10 times for no mismatch (i.e. no high frequency roll off)

leoking

nagramen 發表於 2013-10-17 22:24
Just looking at their specifications:

- Nagra PLL's output impedance is 60 ohms;

Output impedance of Soulution 720 preamp is only 2 ohms. Does it mean it could match with most power amps?

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leoking 發表於 2013-10-17 23:00
Output impedance of Soulution 720 preamp is only 2 ohms. Does it mean it could match with most pow ...

Yes! Ideally output impedance of preamp is zero

But output impedance of preamp varies with frequency, e.g. Nagra PLL has 36 ohms across most of the audioband as measured by Stereophile:

"The unbalanced output impedance was 36 ohms across most of the audioband, this increasing slightly to 125 ohms at 20Hz. The balanced figures, from the optional transformer-coupled XLR output, were 63 ohms at 1kHz, 66 ohms at 20kHz, and 158 ohms at 20kHz."

http://www.stereophile.com/conte ... lifier-measurements

Law記

ECC83 matched quad比較少見，可能要等耐d