How to modify Ross Compressor with attack and release switch ?

[astley]

any one can help me how to modify Ross Compressor with attack and release switch ?

[Processaurus]

Hi, search here for:  hammer ross mod
for a 3 way switch that changes the release time of the ross.  Works well.  I haven't heard of a mod that actually modifies the attack.  What most people refer to as an attack mod on this and similar designs is really the same release mod.

[astley]

thx so much~

[Mark Hammer]

That mod, and all variants, are often called "attack", but the term silk-screening on the chassis is misleading about what is going on underneath.  Many of the 3-knob compressors you might see from companies other than MXR will have an "attack" control added to what is essentially the same circuit as the Dynacomp.

We had a lengthy discussion here about that many years ago, and it became clear that the control/changes did not change the initial attack of the first note in a sequence of picked notes as a "true" attack control would in a rackmount unit (that type of control would set how quickly the gain is reduced in response to the initial pick attack, even if it was one lonely note with 20 seconds of silence on either side of it).  Rather, that change in resistor value altered how quickly gain was restored after that first initial transient.  If the first note picked resulted in a reduction in gain that only came back slowly, then other notes following in quick succession would also have their volume reduced.  Because that effectively eliminates the initial louder picking sound you get from the first note, it *sounds* like a change in attack properties, but it isn't.  Probably the best verbal description of what this accomplishes is to call it a "recovery" control/mod.

What many don't understand is that the suggested changes to that 150k resistance simply alter the time it takes for the circuit to react to the *next* note the way it reacted to the first one.  With lower resistance (e.g., 10k) values, that 10uf capacitor charges up really quickly such that you can pick another note reasonably quickly and have the unit react to notes 2, 3, 4, etc, the way it reacted to note 1.  Of course, if you pick notes slowly enough, and don't stick a lot of finger vibrato afterwards, you will be unlikely to hear any difference between slower and faster recovery settings, since the circuit always has enough time to return to max gain, regardless of how you've set it.  This is one of those mods that doesn't "impose its will" on the sound.  Rather, it simply makes some things more possible and others less possible.  If your picking style at that point does not need what the mod/setting makes possible, you won't hear it.  If your picking needs something that the setting makes impossible, you will hear it.

[pedalgrinder]

how about adding a 2 meg pot to earth to the 10uf cap as a release as a lot of compressor do so you can adjust how quickly it charges and so on or would this make the compressor to pumpy.

[merlinb]

how about adding a 2 meg pot to earth to the 10uf cap as a release as a lot of compressor do so you can adjust how quickly it charges and so on or would this make the compressor to pumpy.

Unfortunately that would simultaneously alter the threshold. There is no easy way to add a true attack control to the Ross, at least, not one that doesn't affect everything else at the same time. Would require a fairly chunky redesign of the side chain.

[merlinb]

There is no easy way to add a true attack control to the Ross, at least, not one that doesn't affect everything else at the same time.

I tell a lie, someone posted this on the other forum:

*the other forum* .org/download/file.php?id=17407&mode=view

Attack and release are somewhat interactive, but not enough that you would notice. Neat solution! (Seems obvious now... ). However, a problem is that with any feedback compressor you are likely to get overshoot with longer attack times, i.e., it overcompresses just after a loud transient and goes oddly quiet for a split second. Can be a cool effect, but not always what you're after.