Streams envelope output levels


#1

What output levels should the envelopes generated from Streams be when no cable is inserted into the input jack?

When I view the output of the envelopes on a scope they are 0 to 3V (approx).

Stream manual states “When no jack is inserted in this input, a +8V signal is internally routed to the VCFA” but Stream Quick Start states “normalized to a constant +5V offset”.

Note: if I manually patch a 5V DC signal (from shades) into the IN of streams I get approx 0 to 5V envelopes and if I use a 8V DC signal I get approx 0 to 8V envelopes.

Thanks,
Steve


#2

IN gets +5V ; and LEVEL gets +8V.

The Quick start manual was correct, I’ve fixed the online manual.

Are you sure the VCF is fully open (if it’s closed, it can smooth the edge of envelope and prevent it to fully reach the attack level), and the response is not too much on the exponential side (otherwise it decays very fast from +5V)?

I would love to see the scope trace!


#3

Streams in Env mode:

  • Shape: approx 8 o’clock.
  • Mod: full CW.
  • Level Mod: full CCW.
  • Response: full CW (linear).

If I manually patch a 5V DC signal (from shades) into the IN of streams I get approx 0 to 5V envelopes.

Steve


#5

You needn’t bother. I hardly, if ever, use Streams to generate envelopes. I only discovered this because I was investigating another troublesome module which is behaving weird with envelopes/normalization (Quad VCA).

If I need to generate envelopes from Streams I can always use Shades to send a 1-10V DC into Stream’s IN. This will give me more control over the envelope output too. But when I use Stream’s in envelope mode, it’s with the VCA and I put the audio directly into IN.

I would however like to understand what is happening. Can you elaborate on the following: (From schematic):
LEVEL (J5) is receiving +10V AREF via jack switch (normalization). So with voltage divider:
(Vsource x R34) / (R60 + R34)
(10V x 100k) / (24.9k + 100k) ~= 8V.

IN (J2) is receiving +10V AREF via jack switch (normalization). So with voltage divider:
(Vsource x R12) / (R59 + R12)
(10V x 100k) / (100k + 100k) ~= 5V.

So where is the ~3V for IN coming from? What am I missing?

Steve


#6

The input impedance is not 100k but 50k because the input signal is fed to two circuits: the 2164 VCF through R42, and the offset/scale circuit for the ADC through R12.

So the equivalent voltage at the input is.

Vsource x R42//R12 / (R59 + R42//R12) = 3.3V


#7

Noobie doobie time

Trying to think real quick how and why to generate envelopes with Streams using 0-10V rather than sending a trig to excite?


#8

I’m afraid I don’t understand your question. If you’re not sending a trig to EXCITE, when/how should the module know it has to start the envelope?


#9

@pichenettes Thanks for explaining this. Much appreciated. :+1:

@accountboy You would still need a sufficient impulse to trigger the envelope via the Excite input but by using an external DC voltage into the IN you can change the peak envelope size. For example, using 8V DC from Shades into Streams IN would yield you an envelope which tops out roughly at 8V. (See pic I attached earlier and imagine that it goes up to 8V instead of 3.3V). This becomes interesting when you then modulate this IN signal so it varies between say 0 and 10V. You end up with envelopes which vary accordingly from off (0V = No envelope) to 10V peak.

Steve


#10

Thank you for your ptience everyone, for attempting to decipher and answer.

So this example has 8V of DC, attenuated to level from a Shades. (I have a Blinds so I expect to try this with that).

I think what I’m missing here is that a trig is different from the (entirely?) binary gate. So this example has to do with attenuating the level of a trig? Haha I’m writing this down as I’m thinking it.

What a great feeling. Thanks for having me here.


#11

In my description I’m talking about sending a DC voltage into the jack labelled “IN” on Streams but it still requires a separate trigger or gate signal going into the jack labelled “EXCITE” on Streams to start the envelope.

Attenuating a trigger or gate is not what I’m saying and doing so will only make the trigger/gate no longer register.

You might want to search the web for tutorials on gates/triggers like this one or this one.


#12

I think the misunderstanding is that Streams doesn’t output a envelope. It can use its VCA to apply an envelope to an input signal.
When you pass a steady voltage from a source like Shades to the IN port of Streams, what you effectively get on the OUT port is the shape of the envelope.


#13

Oh thank you! In and excite, they’re right there on the panel. I however was carelessly typing away on the subway. I’ll put these links to use, thank you! Next is figuring how Streams’ different modes relate to this type of patch but there’s a manual for that.


#14

So funny, I actually have a patch sitting at home made on this exact belief/fake knows/supposed premise. Using it this way I was thinking I was sending and envelope for one channel on my Veils. I’m having similar issues understanding Maths and CV Trinity and even Peaks envelopes but I watch too much tv. Problem in chair not in modular.


#15

Saying it doesn’t output an envelope is just confusing. If it looks and acts like an envelope… it is an envelope.
It’s all just control voltage. So:

“When you pass a steady voltage from a source like Shades to the IN port of Streams, what you effectively get on the OUT port is the shape of the envelope an envelope”.


#16

By the way I know almost for sure what’s happening with the Intellijel quad VCA.

Let’s assume the input impedance of their CV path is 100k per channel. They normalize each channel’s CV input to the next one, so when you patch something in channel 1’s CV input and nothing in the subsequent ones, the input impedance of the CV input is 25k. As soon as you patch something in channel 2’s CV input, it gets back to 100k.

Assuming a 1k resistor on the Quadra output, you get a voltage drop factor of 25/26 = 0.96 in the former case, 100/101 = 0.99 in the later. Is this the difference in amplitude you hear?


#17

Earlier, when you mentioned “impedance is not 100k but 50k…” I suspected something similar with the Quad VCA. However, as my knowledge on the subject is lacking (as I showed earlier) I’m still waiting a reply from Intellijel.

I’m getting a difference of approx 20dB! However, this is when response curve is exponential and the incoming CV is attenuated (via on board pot). The difference is not as perceivable when set to linear but there is a difference.

Update: The difference is approx 2dB when response is linear.


#18

I think I get it.

Sorry to hijack thread and contribute little else but confusion. But what happens to the Streams envelope when Streams’ IN receives a negative voltage from a Blinds?

Shades: able to output a steady +5V to +10V DC
Blinds: able to output a steady -5V to +5V DC
Frames: able to output a steady +5V or +10V DC (is this either/or and constant?)


#19

Well, I said earlier that an 8V DC signal in will would yield you an envelope which peaks at roughly 8V.
So guess what will happen if you use a -8V signal?

Any case why don’t you try and see for yourself?


#20

what happens to the Streams envelope when Streams’ IN receives a negative voltage from a Blinds?

You just get a negative envelope on the output.

Shades: able to output a steady +5V to +10V DC

Or -5V or -10V if you configure the channel as an attenuverter.


#21

Don’t really have the tools for examining the results, cannot comprehend what I’m hearing.

I love being able to ask so I can approximate what I’m listening to.