Aleph gain

[wuffwaff]

Hello,

I was looking at the differences between the Aleph 5 an Aleph 60 cause I would like to have a higher impedance than 10k for the unbalanced input.
After looking for a while I got very confused

The gain for an Aleph 5 ist stated as 20dB or 10 times defined as I thought by R7 (100k) and R5 (10k)balanced and 26 dB unbalanced R7 and R5//R3.

Now looking at the volksamp the specs are 20dB balanced and unbalanced bur the resistors are very different:

R7 (100k) is the same but R6 now is 68.1k. How can this give 20dB of gain?
Unbalanced it would be 100k and 68.1//10k wich also isn´t 20dB..

can somebody explain this to me?

william

 

[Geoff]

William

A search on 'aleph AND gain' or a quick look through the Pass forum index would have have easily brought you to a previous thread which answers this question (Aleph 30 Gain).

In balanced mode it is assumed that the source is low resistance. In unbalanced mode the negative input is earthed. In both cases, R3 and R6 are in parallel giving a resultant equivalent resistance of 8.7kohm which in conjunction with R7 (100k) results in a gain of 12.5 (or a little over 20dB).

Geoff

 

[wuffwaff]

Thank you Geoff,

nice thing such a search machine!
I´ll try to use it next time.

william