Thank You very much Gary. But I have those papers and there is nothing about how to adjust P 2.
Very bad work with the layout I think . At that time they had not discovered yet, how much power supply influence on the total performance either.
I am looking forward to hear it with the Teddy Pardo supply. Maybee this will be Copenhagen HiFi Clubs new Pre.
Hope to hear from Welborne Labs later on the day.
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There was an article in Audio Amateur, issue Two/1991 that described this module and others in detail. Here are instructions from that article.
1) Connect a voltmeter across R5 (or R7) and adjust the voltage drop to 2.8-3v using P2. If you can't adjust it up to 2.8v, short out R10. If the voltage drop is more than 3v with P2 set to maximum, replace R10 with 100ohms.
2) Check the offset at the output with a DC millivoltmeter and adjust P1 for 0v.
3) For adjusting the gain accurately, install P3.
You can buy back issues of Audio Amateur here:
Audio Amateur 1991 Back Issues - Circuit Cellar, Inc.
Great - glad you were able to get it working. I recall making a preamp with these boards perhaps 10 years ago and being quite pleased with the sound. I think I've got a few of these boards still lying around in a closet some where. I may need to pull them out and use them again. Might make a good output stage for a DAC.
---Gary
Nice I found this by Google. Because I forgot P 1 is for DC adjustment. Got the Pre back from Dca for repair Brocken gnd connection but there is 5,5 mvh dc at One channel. Have to readjust IT. Gary Bale???
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