2. amps-preamps
  3. 1113688410

PreAmp Math

I'm looking for an inexpensive preamp to run with my Aragon 4004 mark II amp. I've run my cp players direct to this amp for the past 4 years and just want to try a different arrangement.

The Aragon's output is a relatively low 22K ohms. One active preamp I was looking at suggested a minimum of 50k ohms input. To my ears I've got good sound from using my cd players as preamps and I can't believe this active unit would suggest such a high value.

How important is it that mathematically your preamp matches your amp?

Thanks - Jack
gooddomino
bufus
149 posts
 
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
rwwear
2,873 posts
 
I would recommend the B&K PT-3 or 5. The 3 can be had for 2 or 3 hundred used and sounds great.
loontoon
301 posts
 
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
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