mistress deluxe noise

[d@vide]

Hi all
I have a EH mistress deluxe...
I forgot the stomp for (I think) 10-15years.
It's time to use it.
Now when on ... with the "color pot" at min it's ok.
But when I raise the pot above 50% there's an high noise-squeal-oscillation ( that vary with the speed pot) that appear.
Any suggestion to point me in the right direction?

[george]

I would say that the clock trimpot needs adjusting.

I built a DEM from a General Guitar Gadgets RTS board (GREAT boards btw ...) which I think is based on the actual EH DEM PCB layout (AC powered model).

The layout is here http://www.generalguitargadgets.com/diagrams/dmistlo.gif , if it's the same as your model it will help locate the clock trim.

Hth ...

[d@vide]

Thanx George
I will look at clock trim...

[sjaltenb]

How does the GGG electric mistress compare to the real thing? Is it more like the deluxe reissue or the old one? Thanks

[msurdin]

Is it possible to use the GGG mistress with 2 9v clips in stead of the 18v transformer?
Thanks

[StephenGiles]

Yes, but they won't last very long.

[msurdin]

How would I do It?

I'm not sure If this would be right at all but on the layout http://generalguitargadgets.com/diagrams/dmistlo.gif where the 2 green wires from the transformer goes would I put the red clip wires there? Then Would I put the 2 black wires to the mid of the stereo in jack?
Can someone correct me if I am wrong?

[george]

How does the GGG electric mistress compare to the real thing? Is it more like the deluxe reissue or the old one? Thanks

I have no idea.  Sounds pretty good though - I also managed to fix the volume drop by changing a resistor on the input opamp.

Speaking of the clock trim, you can get a range of different sounds before the clock noise starts bleeding through - I saw a previous post for the GGG DEM where someone had actually changed this to be a control on the outside of the pedal

[george]

Is it possible to use the GGG mistress with 2 9v clips in stead of the 18v transformer?
Thanks

I run mine on 9V and it sounds fine - the bias trimmers just need to be adjusted to suit

[msurdin]

You use the GGG layout?
Can you tell me how you wired up your 9v?

[george]

9V to where the top pin of the voltage regulator would connect
0V to where the middle pin of the voltage regulator connects.

[msurdin]

Is the top pin where the voltage regulator connects pad d1, d2? Looking at the layout I see where the power transformer goes... from what you said it sounded to me like just put it to where it says pretty much d1, d2. And then the 0v goes like the same place but above the part where the black is?

[george]

Is the top pin where the voltage regulator connects pad d1, d2?

no: I mean where the voltage regulator connects R20

And then the 0v goes like the same place but above the part where the black is?

0V goes where the middle (ground) pin of the reg would go - yes, where the black would go

[msurdin]

Do I keep the r20 part (27 ohm) still in there? If so where do you solder it(upper or lower pad?)? If I remove the 27 ohm what pad?

Thanks

[d@vide]

FYI the layout at GGG is exactly like my Deluxe Mistress.

[george]

Do I keep the r20 part (27 ohm) still in there? If so where do you solder it(upper or lower pad?)? If I remove the 27 ohm what pad?

Thanks

Leave out the voltage regulator.  Just hook up 9V to where the top pin of the regulator would go (the hole at the other end of the trace connecting to R20), and 0V to where the middle pin of the regulator would have gone.

Just bear in mind 9V might give less headroom and there may be some distortion depending on what type of guitar you have.  It works for me because I have a strat with typical relatively low output pickups.   If you use humbuckers these are higher output pickups and may distort thru the DEM if you run at 9 volts.

Hth ...

[msurdin]

I use a strat. Normal single coils...
Sometimes I bring out a humbucking guitar...but I dont use the dmm with that.

Is it possible to make this 18v with 2 battery clips? Would I just double up...or is that bad move? (I wont be using 2 batteries...I will have the battery adaptors)

I pretty much got it I believe...

[george]

Internally the DEM GGG version runs on 15V (output by the voltage regulator).  The voltage regulator needs a minimum input voltage of about 18V.

So yes you can use 18VDC, but keep the voltage regulator or else you may exceed the rating of some of the components.

[msurdin]

If I want to run It 18v, via the battery clips, how do I do the wiring if the voltage regulator is now staying there?

[alex frias]

Regarding the 9 volts Mistress project...
Is it possible to use an outboard 12 v. regulated power supply, substituing the zener diode and using a bit more gain on the IC2B in order to get more headroom and less volume drop? I thought about using an output booster, but it will obviously increase the background noise.