help with my maestro ring modulator? please.

[strangerock]

hello please help me,
i've been trying to get this thing working but i'm at a loss.
here are some of the measurements i took with my dmm
that don't correspond to the troubleshooting page at topopiccione:
ic #1  pin6 13.7v
         pin7 14.3v
ic #2 pin1 13.0v
ic #3 pin6 0.02v
        pin11 1.9v
        pin12 3.2v
transistor gds all 0
i'm using a 18v transformer. the parts have been checked, the board
has been checked, as has the wiring. i don't know what else to check.
when the box is on i can hear my guitar but no modulator sounds, the
pots don't seen to do anything except the volume one. any help would
be greatly appreciated. i gotta get this one going.
thank you
sr

[John Lyons]

First thing. How are your voltages at the Power board? Are you getting +/- 15 and +/- 12 volts ?
Did you use the Exact parts called for or did you substitute anything?

John

[strangerock]

the power supply seems to be okay.
i'm getting 15.1v, 11.8v, 0, -15.0 and -11.6.
the only part substitutions on the main board
are 20uf el caps instead of 22,1n5226b zener
diodes(3.3), a 2.7m 1/2 watt resistor, and a 2n3820
transistor stuck in properly. i connected all the jack wires
according to the site(i left them quite long so i could hook
them up afterward) but nothing is mentioned about the
one j5 wire. also i bought 5 mc1495p chips from ebay,
maybe the are no good?
thanks for the help.
sr

[strangerock]

well i went over the board once more and resoldered a bit.
now ic1 is good
       ic2 pin1 is 7.82
       ic3 pin6 is -0.08
            pin7 is 1.9
            pin8 is 3.2
the transistor reads g 7.06
                             d 0
                             s 0
not getting any ring modulator sounds though.

[John Lyons]

I don't have mine here to measure but I know that the transistor only controls the gating of the carrier frequency so that isn't crucial in the unit working or not.
I think that's the transistor I used as well and I had to twist the pins to get the correct order.
But you can get there latter as there seems to be something else wrong anyway.

Make sure you have no solder bridges. If you have some strong reading glasse or a jewlers loupe you can chack that no solder pads are joined that should not be. Lots of connections on that board!!!

You may want to look up the chips datasheet and see what the voltages should be. At least it will tell you what the power requirements are  and what you may expect to see.
Not a lot of folks have built this unit as far as I've seen. Me, you, and zero the hero at topopicone.. not sure anyone else that I've heard.
You may want to write the guy at topopiccone and see if he can help you.



John

[Cliff Schecht]

I've seen one or two other guys talk about their builds, it's a bitch of one though. IMO mine is much simpler and easily adaptable .

[strangerock]

IMO mine is much simpler and easily adaptable .

do you have a layout for this? i'm on a ring modulator kick these days
and would love to give it a go.

well, i'm getting some major ring modulator sounds now but major
bleedthrough aswell, guess it's just a matter of fiddling with these
trimmers. wish me luck and thank yous for your halp.
sr

[John Lyons]

Did you find a specific problem strangrock?
The Transistor is esentially a gate that cuts out the bleedthrough. Like I was saying above, I have to twist the pins on mine to get the correct order for the layout. I tried two differernt number units and one was better than the other..er...forget which though..sorry.
The trimmers are a bit hard to get right but if follow the instructions you'll get it. Did you use multiturn trimmers? They are a must!!!

Hey Cliff

I'm interested in your Ring mod layout or schem. Care to share it?

Thanks

John

[strangerock]

i resoldered some connections and played around with the trimmers(multi turn)
a bit. some of the voltages are still a bit off so there is still some debuggin' to be
done. getting awfully close though!

[Cliff Schecht]

I need to redraw the schematic in an actual capture program, what I have ain't too pretty. I used a 4558 for the buffer because at the time, that was all I had, but if I was to redo this circuit I probably would have gone with a single rail opamp. And I lied about the transformers (not sure if it was here), they are 10k:10k ones from mouser. This was my first real design and after I was finished, I went over all of the little details with my dad to be sure I had everything. Anywho, here's a little schematic I drew up and some pics and soundclips (I've posted this all before ):

www.purevolume.com/cliffsjams (denoted as ringmod abuse, soon to be adding more)

[John Lyons]

Oh, ok...I forgot that was you that posted that one Cliff. 

The one you have is a lot simpler that the maestro because yours dodes not have an oscilator or a mixer etc etc.
The maestro is a lot cleaner and has more od a fundamental tone.

I think adding your ring modulator to a stable fixed octave down up yours would be cool as it would play more in tune.
In general you need to tune the oscilator to the key or the song or whatever you are playing. But with a octive mutiplier the notes will always be in tune. 

How variable are the sounds with your unit CLiff. I think you said that you used a whammy pedal as a carrier... is that correct?

John

[Cliff Schecht]

With just the ringmod, a Whammy and a distortion I can get dozens of cool effects. It's especially nice for turning a guitar into a fuzzy sounding bass, that's probably my most used effect. The Whammy does perfect octaves, so I set it for an octave down, which gets mixed back in with the original signal, run that through an octavia (octave up) and into distortion. The result is one of the fattest sounding single line distortion/fuzz type sounds I've heard. I'll be posting some soundclips of little things I've recorded using my looper.

Like you said though, using the Whammy for the carrier lets you play perfectly in tune, but anywhere else on the treadle and you get sounds like what I posted in those sound clips, anywhere from that cool Jamaican drum sound to all sorts of cool dissonant stuff. It's also cool to use the Whammy's detune effect (which has a sort of chorusing effect by nature) and play chords, it's gives a really interesting fuzzed out chord that is still in tune. It doesn't take much to get a usable sound out of the thing and I've found this thing a permanent fixture on my pedalboard, it's perfect for when I find myself in a rut. Again, I'll try to get some more soundclips up, I think other people would really like this thing, it has a lot of usable tones.

[John Lyons]

It sounds nice cliff. I'm looking forward to the new clips.
I mean no offence but the clips you already have posted seem a bit thin and scratchy.
Hoping to hear the new stuff with variance.

Since there are no controls on the ring mod box how do you control ther blend or wet to dry modulated sound (or can you?)

There was a guy here (forgot who) was working on an octave multipier which whould work well with this one. An octave or two up and  down along with this one sounds cool! I don;t have the knowhow for the clean octaves but I can dream!

Thanks Cliff

John

[Cliff Schecht]

Now I have to think, I think I just mic'ed up a shit amp with a Shure SM57. I completely agree, those clips don't sound too good, it was just to show some people what a ring modulator sounds like. There is no blend control, you are hearing the straight modulated signal. I never even thought to add a blend control, I like how "bad" the effect sounds and how fat it can make things with some octaving. Let me get a clip recorded right quick.

[Cliff Schecht]

Recorded:
http://www.diystompboxes.com/smfforum/index.php?topic=53299.0