RE: A few things to consider

Vintage Asylum

Classic gear from yesteryear; vintage audio standing the test of time.

Posted by Russ57 (A) on September 19, 2015 at 18:39:27

In Reply to: RE: A few things to consider posted by mark.korda@myfairpoint.net on September 19, 2015 at 07:51:28:

Consider what we need a preamp to do.

1) It picks between sources. In the past we might have had a phono, tape deck, tuner, etc. So what do you have? If only a CD/DVD why do you need a selector switch?

2) It provides enough voltage gain to allow sources to drive an amp to full power/clipping. For tube amps this was about 2 volts RMS. Many solid state amps need less. Today a CD/DVD player puts out 2 volts RMS easy.

3) It provided impedance matching. This is a little harder to understand. Best I can do. Think of voltage gain as how fast a car can go. Think of low output impedance as a measure of how fast a car/truck can go when pulling a heavy load. A porsche might do 140 MPH but it won't pull a 40 foot boat or motor home up a mountain. Typically tube amps don't need a low output impedance preamp (but it helps) whereas solid state amps do.

So think about what you need. What are your sources? How many do you have? What is their voltage and output impedance? What do your amps need? Are you building only for current amps or anything that happens in the future?

In short if your only source is CD/DVD then they have enough MPH and torque to drive your amps up the steepest mountain at any desired speed. Anything and everthing in the PAM only gets in the way and degrades performance. Better to buy a quality DAC and do volume control on the digital side (or add a pot to input of amps).

If you are a vinyl addict than you do need a preamp/phono stage. I'll wait to hear more before I say more. You have enough to consider, including why others have tried to talk you out of this path.

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Follow Ups Full Thread

Topic - Resistor Questions - mark.korda@myfairpoint.net 07:47:10 09/14/15 (13)

RE: A few things to consider - Russ57 15:52:34 09/17/15 (3)

RE: A few things to consider - mark.korda@myfairpoint.net 07:51:28 09/19/15 (2)

RE: A few things to consider - Russ57 18:39:27 09/19/15 (1)

RE: A few things to consider - mark.korda@myfairpoint.net 10:32:35 09/21/15 (0)

RE: Resistor Questions - TimeConstant 09:05:16 09/16/15 (2)

RE: Resistor Questions - mark.korda@myfairpoint.net 20:32:39 09/16/15 (1)

RE: Resistor Questions - TimeConstant 12:53:03 09/17/15 (0)

470 + 39 in series = 509 - Alpha Al 05:44:21 09/15/15 (0)

1 Watt Resistors are helpful at certain areas... - Interstage Tranny 15:41:10 09/14/15 (3)

RE: 1 Watt Resistors are helpful at certain areas... - mark.korda@myfairpoint.net 21:03:51 09/14/15 (2)

RE: 1 Watt Resistors are helpful at certain areas... - airtime 05:52:35 09/15/15 (1)

RE: 1 Watt Resistors are helpful at certain areas... - mark.korda@myfairpoint.net 11:10:38 09/15/15 (0)

RE: Resistor Questions - airtime 08:00:53 09/14/15 (0)

Follow Ups

RE: A few things to consider - Russ57 18:39:27 09/19/15 (1)

RE: A few things to consider - mark.korda@myfairpoint.net 10:32:35 09/21/15 (0)

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