passive preamp matching

thanks, was very helpful

Jameswei Read your post. Just wanted to know if it was a risk to use a TLC-1 with a B&K 2140 through 1m XLO cables. I wont have the option of changing the preamp in the near future. Also planning to use one of the tape outs to power a sub? The souuce will be a Music Hall cd 25.2. Speakers are very efficient DIY. (dont turn the volume past 10:00) on my present preamp

Well its pretty simple and I reccomend it with no reserves!!

You do need to have the right numbers for it to work properly:

First:

1-Amplifier Input sensitivity (Volts)

2-DAC (or cd player) output voltage

The Dac output must be higher than the amps sensitivity, usually a DAC will have 2 volt output and the input sensitivity will be around 0.5 volts: Thats why it works so good!!

Second:

1- Amplifier input impedance (ohms)

2- DAC (or cd player) output impedance (ohm)

This is the tricky part: You need at least 10 times lower impedance on the DAC than the Passive preamp and another 10 times lower impedance on the passive than the input impedance of the amp:
Lets say your DAC has 50 ohm output impedance,
and your amp has 15k ohm (15,000 ohm) input impedance;
You will be OK with a 1k preamp (such as EVS), But a 10k preamp will probably sound funny!

My DAC has 50 ohm output and my Amps have 1 meg ohm input.
The best sound I got was the 1K, it could work with 10k or even 100k but the volume was very hard to control (very little movement would blast the speakers) I had to go down from 100k to 10k to 5k to 1.2k and eventually settled at 1k, let me tell you the difference between 1.2k and 1k is big!!! It was fun all the way!

There are 3 types of passive preamps:
1-Carbon Volume pot based (Alps, Luminous Audio, etc.)
2-Resistor loaded (several types) (Placette, Dact, Goldpoint, etc.)
3-Transformer Volume control or TVC (Promitheus, Bent, Django etc)

I personally like the Resistor based ones better (I tried most of them).

Hope this helps

Keroo1099,

Sorry, I'm not personally familiar with the equipment you mentioned. Jsadurni's post is a pretty complete discussion of the key issues. Perhaps someone else might be able to comment on the specific gear you're asking about.

Jsadurni, many thanks for your input. Will now send time figuring out volts/impedance of various components.