ADA Depot - A Forum To Support Users of ADA Amplification Gear
ADA Preamps => Original MP-1 => Topic started by: MarshallJMP on March 15, 2016, 03:44:16 PM
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So Mp1 and Mp1 classic have a serial loop either.. So why they have a different behaviour?
That's a good question.Don't really know,haven't compared them.But the circuits are a bit different,2 major differences are the mp-1 uses a dual gang pot so you have more level settings while the classic only has 2 fixed level settings.
And the switching is done with CD4053 mux/demux and the classic uses 2 fet's.
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That's interesting, I've never seen a classic so I looked it up on the old depot gear pages and it said it had a stereo loop, oh well, seems is wrong :facepalm:
(Effects loop: stereo effects loop with switchable signal levels and programmable in/out.)
(http://web.archive.org/web/20040216233940/http://www.adadepot.com/adagear/gearpages/preamps/ADA-MP-1-Classic.htm)
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No problem,can't know everything ,can you? :thumb-up:
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The classic doesn't have a parallel loop like the MP-2,it's also a serial loop since it doesn't have a mix knob.Just a line /instrument level button.
The idea of the one pot loop level in the MP-1 was quite good but it didn't work out so well in the end.Some effect work pretty good some don't.
I really wish the Classic (or the MP-1) did have a parallel effects loop, it was one of the main reasons why I purchased the MP-2. Going back many years I use to run the MP-1 straight into a rack mixer and blend in the effects from an Intellifex, avoiding the MP-1 serial effects loop altogether (because to my ears I could hear some tone loss).
Having said that, I still prefer the tone of the Mp-1 and the Classic, could we have a parallel effects loop mod please?
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Hey DR, is a good idea but has some fundamental issues ie how to make it programmable. It may be possible to make the mono loop parallel ? My understanding is the patch allows you to turn on/off the return so if you changed the loop circuit to parallel with appropriate send and return level controls you could toggle that. But being able to store separate return mix levels (ala MP2) would require firmware development/programming and associated changes, not an easy task I suspect. There was a post a while ago from a guy doing a project to upgrade the MP1 control using more modern digital bits and pieces, seems to be on hold, but IIRC he was contemplating loop changes ?
Another way to achieve a parallel loop (albeit mono) for MP1 is to use a small mixer in the loop, eg you can use the ART split mix to do it (cheaply).
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I was thinking something a bit simpler, without the programmable mix settings per patch.
From an end user perspective:
1) use existing loop On/Off facility.
2) convert rear loop level control to be a wet/dry control.
3) add a push button on the rear panel to select between line and instrument levels.
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Not a bad idea, that could work
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I split this topic off as it's going in a new direction. And also starts to extrapolate into how you patch your MP1 and FX etc.
@MJMP, how hard would it it be to do something like DR is suggesting ?, seems you'd need a mix pot after the return and feed that back into the direct signal, and not divert the direct signal only through the loop when loop in, and add a switch for line/inst (and associated resistors ?)
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I'll take a look at it.
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Just another thought ... whilst a parallel loop would be excellent for fx (and preserving valve tone), it would be a bad idea for those users wishing to run noise reduction systems, or equalisers (a serial loop would be more appropriate).
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True, so they wouldn't do the mod (should one be developed) or they could turn the mix knob to full wet ? You can turn the loop into a parallel construct with a small mixer (eg ART split mix), they cost around $100 AUD. Or use one after the main outs, which is what Mike is/was doing, he's changed it to be hybrid now so he can get the GMaj2 CC benefits/features, so he's running mostly GMaj2 with a very little stereo dry signal blended in, seems to work well.
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I never have been into the whole parallel loop thing.It has advantages and disadvantages and like DR says some effects can't be used in parallel loop.Then there is digital fx,here you need some kind of dry kill switch or you will get phasing in your sound.Also if the effect doesn't have a mix knob you actually can't use it either (like the boss CE-2,just to give an example).
Now i did some looking around how it's done in other amps (no need to reinvent the wheel) and it could be done on an mp-1 with some modding,drilling an extra hole and cutting a trace on the PCB.But the question is,is it all worth doing?
It's best leaving in the original level pot,plus it still is a mono loop,so you keep the actual loop intact so this means it keeps the disadvantages it has.If you really want to use a parallel loop get a small 19" mixer and use that.Don't see the point butchering the mp-1.
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Thanks for looking into this MJMP, much appreciated.
... based on advantages vs disadvantages I'd agree that the serial loop is the better option.
Using my old rig as a case study a single parallel loop wouldn't really have helped ... I needed a fully serial loop for noise reduction and a parallel loop for effects.
I used to run my old MP-1 into a rack mixer (Rane SM26) so that I could blend in a fully wet signal from an Intellifex, it worked really well. And in the MP-1 loop I used a Rocktron Guitar Silencer (old Rocktron model).
I had a parametric EQ somewhere in the signal chain as well, I can't remember whether it was in the loop or after the MP-1. I've still got all this gear stashed away in a room, but I think I've broken the Rane SM26 :facepalm:
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Here is a handdrawn schematic if someone wants to try it.
The // means that you have cut the trace.