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by **cia** » Fri Dec 17, 2004 3:37 pm

When should I bias the ST70: immediately after turning on the amp or wait for about five minutes or wait for 15 minutes. Or should I bias after turning the amp on then again after the tubes has had time to heat amp?
Thanks

by **arnoldc** » Fri Dec 17, 2004 3:57 pm

first bias, upon turn on, second bias 15-30 minutes upon turn on, third bias 45min-1hour.

that's what i do after changing the power tubes of my previous anthem. change of input and/or driver tubes no biasing needed.

the bias should not drift for a long time (months or even years) unless there are some parts that are not holding electronically anymore.

by **cia** » Fri Dec 17, 2004 4:17 pm

Thanks Arnoldc.

I did try what you have suggested and got different reading at those three bias point times. I suppose the third bias point would be the best for the amp and sound. Thanks again.
Carlos

by **mozilla** » Fri Dec 17, 2004 7:47 pm

Make sure nothing is playing when you bias.

by **jo2** » Fri Dec 17, 2004 9:24 pm

arnoldc,

Do you put a dummy load when biasing? :idea:

by **cia** » Sat Dec 18, 2004 8:17 am

mozilla wrote:Make sure nothing is playing when you bias.

Mozilla,
I noticed when using the Mullard GZ34, the bias settings are very high initially. Upon turning on, bias has to be adjusted downward, after 15-30 minutes bias adjusted down very little, then after an hour, bias needs to be adjusted very slightly up to hit 1.56 volts.

I do not play anything when biasing.
Thanks
Carlos

by **ichabod** » Mon Dec 20, 2004 9:02 am

Carlos, you've got a lot of listening and biasing to do this holiday. Enjoy. Is that paired to your LS 3/5a? Happy xmas!

by **cia** » Mon Dec 20, 2004 10:23 am

Hi Ichabod.

You are right that I may have to do quite a bit of biasing. It seems even Meralco power fluctuations affects the bias. I guess I just have to be satisfied with a range of say 1.53 to 1.57 which frankly I cannot hear any difference in sound anyway.

I am using A Rogers LS3/5A 15 ohms "white belly". Mozilla also taught me to reseal it and that made a difference in sound quality especially bass.

Happy Holidays to you and yours.
Carlos

by **mozilla** » Mon Dec 20, 2004 11:33 am

You should do the tissue tweak on your LS next! OT na

by **ichabod** » Mon Dec 20, 2004 12:59 pm

Glad to know that you've that it's a Rogers. White belly pa ha. Mahal yan sa HK. And seldom seen. Take care of it.

Wag kang maniwala kay grant sa tissue issue, pandewang lang nyan, kailan Scotts! ha ha!

Merry Xmas din sa lahat ny familia. Malakas ang WAF ng LS mo, purong music eh lalo na pag may scotch este mali spelling scotts pala!

by **arnoldc** » Mon Dec 20, 2004 1:15 pm

jo2, yes of course. cheers.

by **jo2** » Tue Dec 21, 2004 7:29 am

arnoldc wrote:jo2, yes of course. cheers.

Could you please elaborate? What types and values?

Thanks :wink:

by **arnoldc** » Tue Dec 21, 2004 8:40 am

8 ohms, 50W wirewound or white coffin

by **jo2** » Tue Dec 21, 2004 8:43 am

arnoldc,

Great!

Thanks!

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