RE: A few things to consider

Posted by Russ57 (A) on September 17, 2015 at 15:52:34

In Reply to: Resistor Questions posted by mark.korda@myfairpoint.net on September 14, 2015 at 07:47:10:

A higher than needed wattage resistor might offer "safety factor" for the resistor.....but it offers less protetion for more important items like tubes. It is like using a 30 amp circuit breaker on 20 amp wire. Nice for the breaker but not nice for the wire.

Metal oxides suck. On most vintage schematics all resistors are 1/2 watt unless noted. 510 ohm is a standard resistor value so nothing special needed there.

That preamp isn't such a great one. I kinda hate to see you put boutique parts in it. A normal quality carbon film resistor such as you get from mouser/digikey/allied and orange drop caps are more than good enough. PEC pots are fine for volume control. Save the Percy parts for a high quality design. The PAM circuit isn't going to know the difference. Better to splurge on telefunken tubes for it.

The downfall of most vintage preamps are all the tone control circuits and rotary switches. They also tend to have way too much gain. If you don't have a turntable most preamps these days need to have negative gain!

A preamp is so easy to make from scratch. Phono stages are a different matter. The original Foreplay from Bottlehead is a decent cheap starting point....and WAY better than the PAM-1. Again only saying this because I hate to see you dump money into a loser.

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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 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: A few things to consider

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