EB 1190/123 Idle Current adjustment

[Erlend Sæterdal]

Hi I just finished a EB 1190/123 . Now I discovered I miss the paper with explanation how to adjust the Iddle and where to measure. I guess I should use the P2.

Anybody can help ?

[GaryB]

Originally Posted by Erlend Sæterdal

Anybody can help ?

Take a look here:
http://web.archive.org/web/200408061...com/classa.htm

[Erlend Sæterdal]

Originally Posted by GaryB

Take a look here:
http://web.archive.org/web/200408061...com/classa.htm

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.

[homemodder]

In another thread I read that Borberly could be contacted via facebook. Its his design and who better to help out.

[GaryB]

Originally Posted by Erlend Sæterdal

Thank You very much Gary. But I have those papers and there is nothing about how to adjust P 2.

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.

[Erlend Sæterdal]

Hurray ! Fantastic how helpful people can be !

Thank you very much !

[Erlend Sæterdal]

I was not able to adjust the Current higher than 2,75 / 100 = 27,5 ma for one of the Channels but I consider that as OK !

[GaryB]

Originally Posted by Erlend Sæterdal

I was not able to adjust the Current higher than 2,75 / 100 = 27,5 ma for one of the Channels but I consider that as OK !

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

[ticknpop]

Yes Borbely IV is very , very good

[Erlend Sæterdal]

Originally Posted by GaryB

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

Change all metalfilm resistors to Takman Carbon.