LFO-10 4HP lfo by FEEDBACK [NEW module]

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strat-1
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LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by strat-1 » Sun Jan 31, 2021 7:45 am

www.feedbackmodules.com

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This is the easy to use but versatile LFO your modular synth will love :) :) :)
It is a great compromise between simplicity, user friendliness and enough features to make it special.

This little module is an evolution of the LFO of the famous MS monophonic synth from the seventies, adapted to eurorack format.
The original MS LFO had a FREQUENCY knob, a WAVEFORM knob and separate outs for PULSE and TRIANGLE waveforms.
We added some features to make it even better. We extended the FREQUENCY range with a switch, making it work now from 18mHz to 24Hz. Both outputs now are buffered so they have enough current to drive more destinations at the same time (without loading and distorting the waveforms). Both outputs now have their own LEDs, red for PULSE wave and bicolour red/green for TRIANGLE wave.
The main feature of this LFO is the WAVEFORM knob that will change progressively the shape of the waveforms:
- at the TRIANGLE output from SAW (CCW) to TRIANGLE (centre position) to RAMP (CW)
- at the PULSE output from 5% (CCW) to 50% SQUARE WAVE (centre position) to 95% (CW).

Tech specs:
- 4HP width
- 35mm depth behind front panel including the power connector
- 2X control pots for FREQUENCY and WAVEFORM
- 1X FREQUENCY RANGE switch: LOW and HIGH
LOW - 18mHz (55sec) - 0,7Hz (1.4sec)
HIGH - 0,63Hz (1.6sec) - 24Hz (42msec)
- 2X outputs : SQUARE 0/10V Vpp and TRIANGLE -5V/5V Vpp
- standard 10 pin euro power +12V / -12V
- power consumption +12V 20mA , -12V 15mA


https://www.modulargrid.net/e/feedback-lfo-10

Attachments
LFO-10 - User Manual.pdf
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Last edited by strat-1 on Sat Jul 24, 2021 10:25 am, edited 2 times in total.

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Re: LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by strat-1 » Sun Feb 14, 2021 3:54 pm

I made some videos demonstrating the features of LFO-10 module.




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Re: LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by strat-1 » Sun Mar 07, 2021 9:53 am

I made a pdf manual explaining the functions of LFO-10 adsr.

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Attachments
LFO-10 - User Manual.jpg

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Re: LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by strat-1 » Sat Jul 24, 2021 10:24 am

New video for ENV-310/ENV-100/LFO10 by COLOR MY SOUND :)


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Re: LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by moremagic » Sat Jul 24, 2021 7:10 pm

positive only square wave lfo? leme say Hell Yeah, i hate playing bipolar square lfos

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Re: LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by 1Dj4P's » Tue Aug 31, 2021 2:46 pm

Hi,
I finished a DIY LFO module, it works fine. I found the forecast range of frequencies, the voltage is 0 / 10V for square but I only found -2/+2V for triangle. I tried to switch R8 with R9 (100k & 150K), but I still got 2V instead of 5V in the manual. Did someone encounter the same difference ? Any advise will be appreciate ≥ thanks

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Re: LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by kallikak » Fri Sep 03, 2021 11:39 pm

See what you measure at pin 10 of the TL074, then work out what values you need for R8 and R9 as for any non-inverting op-amp.

Check if you've shorted pins 8 and 9 so it's not amplifying maybe?

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Re: LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by 1Dj4P's » Wed Sep 08, 2021 5:19 am

Thanks for your answer kallikak,
kallikak wrote:
Fri Sep 03, 2021 11:39 pm
See what you measure at pin 10 of the TL074, then work out what values you need for R8 and R9 as for any non-inverting op-amp.

Check if you've shorted pins 8 and 9 so it's not amplifying maybe?
No short between pins 8 & 9.
I measured 3,85Vpp at pin 10 with triangle wave but I'm not sure how to calculate the R8 and R9 values. I was thinking the values from the build manual are right.

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Re: LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by 1Dj4P's » Sat Sep 11, 2021 1:04 pm

Finally, I got the answer from strat one :

"The first batch of LFO pcbs required a bridge. I made the bridge on all the boards before sending them.
Maybe I skipped the bridge on your boards ?
Make a link like in the picture.
First check with a multimeter if it's ground on both vias. If it is gnd on both vias you don't have to make
the bridge, it's the next generation of pcbs.
Al the values of the parts are correct."
Attachments
LFO-10 - GND Bridge.jpg

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Re: LFO-10 4HP lfo by FEEDBACK [NEW module]

Post by kallikak » Sat Sep 11, 2021 9:55 pm

Makes sense. The amplification factor is 1 + R8/R9, so if R9 isn't connected to ground there's no amplification (the other possibility was R8 shorted and hence 0 resistance).

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