Home › Forums › Help/Technical Questions › trimpot calibration for Stereo Polychorus (reissue)
- This topic has 13 replies, 7 voices, and was last updated 13 years, 9 months ago by gibsonrd.
-
AuthorPosts
-
November 19, 2009 at 4:20 pm #79345jwny72Member
I’m trying to equalize the output volumes between my Stereo Polychorus’s engaged and disengaged status. There are 8 internal trimpots. Does anyone know what they all do?
November 19, 2009 at 4:22 pm #103922The EH ManModeratorDidn’t I already answer this question for you?
November 19, 2009 at 7:09 pm #103931jwny72MemberAlmost, but not entirely. Adjustments to TP3 did alter the delay/chorus effect intensity (clockwise rotation reduced the amount of feedback and the volume of the repeats). Adjustments to TP2 produced no result whatsoever that I could detect. Before moving on to adjust other trimpots at random, I was hoping to get input about what they’re all supposed to do.
November 19, 2009 at 7:16 pm #103932The EH ManModeratorDon’t touch the others as they’re for delay IC bias and other things.
November 20, 2009 at 6:35 pm #103989Howard DavisMemberThe trimpot alignment of a pedal of this complexity should not be undertaken by anyone that is not an experienced technician. You need an oscilloscope, an audio signal generator, a diagram showing the locations of the trimpots and their functions,and the proper procedure. Without all these things, you will probably just worsen the misalignment.
Howard Davis, EE – Designer of the Stereo Polychorus
Guitar pedal design engineering, repairs, and custom mods:
http://howard.davis2.home.att.net/November 23, 2009 at 2:39 pm #104109KriceMemberSo, is it possible to adjust the output volume from any of the trim pots or not? Simple answer would be nice.
November 23, 2009 at 2:50 pm #104111The EH ManModeratorQuote:So, is it possible to adjust the output volume from any of the trim pots or not? Simple answer would be nice.Short answer: no
November 23, 2009 at 3:24 pm #104112KriceMemberIt could be just me, but I think the volume boost of Polychorus is somewhat annoying. It’s noticeable. Is there something you can do about it?
November 23, 2009 at 5:53 pm #104118Howard DavisMemberQuote:So, is it possible to adjust the output volume from any of the trim pots or not? Simple answer would be nice.Yes, but there is more than one trimpot that affects output level.
November 23, 2009 at 6:48 pm #104121nightravenMemberbasically – get howard to fix it :p
November 24, 2009 at 8:30 am #104147KriceMemberIs there a reason why trim pots aren’t explained in the manual already? They usually are if a pedal has them.
November 24, 2009 at 7:39 pm #104184Howard DavisMemberQuote:Is there a reason why trim pots aren’t explained in the manual already? They usually are if a pedal has them.Trimpots are for adjustment by a qualified service tech only. To encourage anyone else to tamper with them is to encourage people misaligning or even damaging their pedals. As far as I know, there are no service manuals issued for EH pedals.
November 24, 2009 at 11:36 pm #104197electro-melxModeratorQuote:Is there a reason why trim pots aren’t explained in the manual already? They usually are if a pedal has them.Is there a reason that the pots are inside the pedal rather than stuck on the front with knobs on?
….answer, yes!
November 4, 2010 at 6:33 pm #112390gibsonrdMemberHey everyone! So I have a reissue polychorus I picked up. I am having the same issues with mine as listed above with the loud volume increase when engaged. I tried ajusting the trim 2 and 3 with no results and now the pedal is not functioning properly. The chorus is coming out of the flange setting, and the flange is coming from the filter matrix setting. Can someone take a pic of their trimpots and post it for me? Or can someone post a better explanation of what each trimpot is used for? Any help would be greatly appreciated and thanks.
-
AuthorPosts
- You must be logged in to reply to this topic.