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DIY Stompboxes => Building your own stompbox => Topic started by: AS74 on December 17, 2017, 09:46:22 AM

Title: Dyna Comp Brightness.
Post by: AS74 on December 17, 2017, 09:46:22 AM
Hello to all who have compressor knowledge and are willing to share and teach...   :-* :icon_biggrin:

I've just put together a Dyna Comp build and I find it is brightening things up too much for my liking.

I've heard it being referred to as being a dark.  I don't find that at all.

This seems at odds with experiences of other chasing Jangly sounds.

To the point : do the Ross additions tame the eq?

I believe there is compensating filter, maybe to fiddle with values to lessen brightness?

Maybe it's the wrong circuit for me but I have it built and would rather try to get it more to my liking than build anew.

It's only that it changes my tone to the bright side.

Thanks to all in advance

Cheers

Adam
Title: Re: Dyna Comp Brightness.
Post by: thermionix on December 17, 2017, 04:19:03 PM
The Ross has a 220pF cap from input to ground that takes off a bit of high end.
Title: Re: Dyna Comp Brightness.
Post by: PRR on December 17, 2017, 05:03:23 PM
The usual complaint is that a limiter takes the bright off. Maybe by cutting the initial attacks which tend to be bright.

That you have the other observation suggests you re-check all your cap values. A small coupling cap reduces bass, which makes the tone bright. A large rectifier cap delays the action on attack, letting attacks clip brightly.
Title: Re: Dyna Comp Brightness.
Post by: AS74 on December 17, 2017, 09:15:36 PM
Thank you
I have replaced all 0.01uF caps with 0.022uF after initial impressions and doing some online investigations.  Also replaced the 0.05uF on the output with 0.1uF.
These changes are positive.
Listening to some videos, my dynacomp is as should be.  Maybe it's not a brightness thing but something lacking in the lower/mid frequencies?
Title: Re: Dyna Comp Brightness.
Post by: AS74 on December 19, 2017, 12:06:57 AM
To bring this post to a satifactory end and a reminder to others (again)  :-[  I have today discovered that ALL the transistors were backwards.

I noticed a little distortion, not too unpleasant.  Started to check with audio probe and schematic in hand and there you have it.
 :icon_redface:

Must have been past my bed time as I always check pinout with the hfe socket on my meter.

Sounds much better now.

Thanks to all.
Title: Re: Dyna Comp Brightness.
Post by: duck_arse on December 19, 2017, 08:42:02 AM
this is why we allays ask "can we see photos?" and "what transistors are you using?"

is it too late to ask what transistors you are using?
Title: Re: Dyna Comp Brightness.
Post by: AS74 on December 19, 2017, 08:56:54 AM
Transistors are 2n3904's.

It's all good and lesson learned
 :icon_idea:    Don't take beddy-byes tablets and build afterwards.   :icon_biggrin: 8)
Title: Re: Dyna Comp Brightness.
Post by: PRR on December 19, 2017, 06:57:43 PM
> ALL the transistors were backwards.

That may "work". Not very well.

Backward, a Si BJT has very low hFE and breaks-down at 7V. Here, no stage is super critical for hFE, and going up to 7V is near as good as going to 9V. The low hFE will make a difference; though I am not inclined to work out what.