PreAmp Math

Your amps input impedance needs to be a minimum of ten times what the output impedance of your preamp is if you don't want to lose signal quality. More is better but it also depends on the preamp. On my Audio Research the output impedance is 600 ohms balanced yet ARC recommends a minimum of 20k.

Sounds like Warnerwh has a good rule of thumb. The other day, I was looking at input and output impedance ratings for CD players/preamps/amps. This is an example of one company's top of the line CD player, preamp, and amplifier ratings. (All ratings are for unbalanced in/out.) You can see the pattern from these values that Warnerwh was talking about. The input impedances are many times higher than the output impedances.

CD player output impedance = 50 Ohms

Preamp input impedance = 47,000 Ohms
Preamp output impedance < 600 Ohms

Lower priced preamp input impedance = 25,000 Ohms
Lower priced preamp output impedance = 100 Ohms

Amplifier input impedance = 105,000 Ohms

Lower priced amplifier input impedance = 49,900 Ohms

I would recommend the B&K PT-3 or 5. The 3 can be had for 2 or 3 hundred used and sounds great.

The craftmanship is excellent, often the parts are excellent, and the sound is excellent, and the price of dirt.

I purchased a highly customized BEZ pre, oil caps, hand wired stepped volume, point to point wiring, etc. All for less than $400. It outclassed my T-hold pre-amp by a margin, but, it also comes with limited in's and outs, and NO REMOTE.

I won't keep it, but it has clearly put me on a quest for a very good toob pre, with volume, and the Orient has now offered me a nice pre with 4 inputs, switched via remote, and volume via remote.

NA look out, the Asians are coming, and coming fast.

Note: old NOS toobs are still needed to sound the best.

loon