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#1 2013-07-14 14:15:29

nitraus
Member
Registered: 2012-02-22
Posts: 55

V4 Eq/300Hz problem.

Yesterday I did a bit of A/B playing with my buddy's non master volume V4 and my master volume V4, basically because I wanted to hear a V4 with 7027s compared with mine (with 6550s).

Apart from being pleased by the 7027s crunch and by the 6550s huge bottom end, I noticed that when the midrange freq is set on 300Hz my V4 is not boosting nor cutting anything, like the pot would not be working.

Since on 1kHz and 3kHz position it's perfectly working, do any of you guys know what could be the problem and/or what I should check and possibly repair?

Thank you.

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#2 2013-07-16 07:08:50

hangman
Banned
From: Seattle Washington
Registered: 2006-09-04
Posts: 1848

Re: V4 Eq/300Hz problem.

Two likely possibilities:

The switch is dirty and not making good contact on the 300hz setting, this is remedied by cleaning the switch.

Second possibility is that you have the later discrete inductor version of the v4,  and your inductor for that setting is dead. 
Solved by replacing the inductor.

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#3 2013-07-16 23:15:18

nitraus
Member
Registered: 2012-02-22
Posts: 55

Re: V4 Eq/300Hz problem.

I'll try cleaning the switch and see if it works.
Anyway, which is the inductor codename on the schem?
I have a '77 master volume/no distortion V4.

Thanks!

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#4 2013-07-17 02:20:57

hangman
Banned
From: Seattle Washington
Registered: 2006-09-04
Posts: 1848

Re: V4 Eq/300Hz problem.

If it is a 77 then they are discrete inductors.

Check L101. Should have a green dot on it.

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#5 2013-07-17 09:59:29

nitraus
Member
Registered: 2012-02-22
Posts: 55

Re: V4 Eq/300Hz problem.

Thank you! I'll see if I'm able to repair it by myself or bring it to my tech.

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