MXR Envelope filter

[lightningfingers]

I gave up on NQ, its problematic doesnt work etc...

Anyway i'm going to build the MXR one instead, but have a Question first.:

What's with the non-standard resistor values? can I sub these? e.g can I use a 10M resistor in place of a 22M( :shock:  :shock:  :shock: )?3k3/3k9 in place of 3k6, 220k in place of 200k?

Thanks :mrgreen:

[StephenGiles]

The rule says that you MUST stick to the circuit values, otherwise it's no new fuzzbox for christmas! No, the only one I would stick to is the 22m, which is probably that value for good reason - easily done by soldering one end of 2 10m resistors in the space for the 22m, then crop the unsoldered ends and solder them together - that's 22m now.
Stephen

[brett]

Hi.
Check the build reports at Tonepad, especially concerning the two resistors setting the bias on a couple of the inverters.  Can't remember which ones, but they set the bias right at the limit of where the 4069 will work.  (62k&100k originally? Shifted closer together??)

have fun, it's a good circuit.

[lightningfingers]

Hell, you are right about that, this thing rocks

I found some old carbon comps in the odd values. Now what I want to know is how come this COMPLICATED circuit works first time, and yet I can build the Nurse Quacky about 4 times and it STILL wont quack :evil:  :evil:  :evil:

[Mark Hammer]

Well if you want the Nurse, then you need to press the little button n the OTHER side of the bed.  The button you've been pressing is to make the bed go up and down.

The NQ/DQ is not THAT difficult a circuit, but there are a couple of things that can really bugger up thew works if you don't do them right.  I've had plenty of "simple" circuits that stymied me when much more complex circuits booted up fine first time.  It happens.

[Torchy]

Hang on, you mucked around with the NQ components (shorting out pots, subbing different component values etc) then blame the design ? Now you want to do the same to another circuit ? So you sub the values and it dont work. Gonna blame the design again ?

Now heres a radical idea - build the thing exactly as the schematic says. Get it working and remember how it sounds. THEN mod it.

Ive built two NQs, using the components exactly as stated on ROG. They both worked first time. I swapped the op-amp for TL072/082/4558/1458/5532 and they ALL worked. The only problem is that the effected volume is way down on bypass volume. Booster sorts that out.

Not trying to start an argument or put anyone down, but components are relatively cheap, and you stand a better chance of success by using the original values.

[B Tremblay]

Ive built two NQs, using the components exactly as stated on ROG. They both worked first time. I swapped the op-amp for TL072/082/4558/1458/5532 and they ALL worked. The only problem is that the effected volume is way down on bypass volume. Booster sorts that out.

Thanks for the report.  I still can't get either of my Nurses to operate (heh) with anything other than a 1458/LM538.  Even with the Sensitivity at maximum, I have to smash the strings to get any sweep.  Also, I've had close to unity output when the effect is engaged.

[Torchy]

Ah, Mr Tremblay, at last I get to say "thank you" for all the ROG goodies  :oops:

Yup, my NQs all quack quite nicely but at low volume - I used the same ultra-low-current 3mm red leds that I bought for the Easyvibe. Maybe they bias the OA better ? I changed to 5n6 caps to lower the sweep, but all components as stated on the schem.

[B Tremblay]

For both of my builds, I used RadioShack grab-bag red 3mm LEDs that match within a few hundredths of a volt.

I'm at a loss to explain our differing results.

[StephenGiles]

components are relatively cheap

.........even in England!
Stephen

[Hal]

does anybody have a link to the schematic for this?

I see its on the schematics link page here, but thats dead.