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Jurgen Haible Frequency Shifter (JH FS-1a) Build Thread
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Author Jurgen Haible Frequency Shifter (JH FS-1a) Build Thread
tommy.york
glennfin wrote:
Just a couple of questions about this project,

Can this be adapted to run off of standard eurorack power? +12 -12v ?

Is there a PCB available? I have a few mc1496's I can put to use cool

Thanks


Adapting the FS-1a will require some sort of step-up solution, because it very much needs 15v. This is discussed here. Right now, there's a breadboarded solution with a DC/DC converter sduck recommended. Cost is <$20. Thinking about a cheaper solution involving a cheaper chip, but it'll be more complex.

The PCB is available, from either Modular Addict in the US or Random*Source in the EU.
glennfin
Thanks for the info. I don't want to mess around with stepping up voltages just to run this board. I'll probably end up designing my own circuit around the 1496 that will be 12v friendly. cool



tommy.york wrote:
glennfin wrote:
Just a couple of questions about this project,

Can this be adapted to run off of standard eurorack power? +12 -12v ?

Is there a PCB available? I have a few mc1496's I can put to use cool

Thanks


Adapting the FS-1a will require some sort of step-up solution, because it very much needs 15v. This is discussed here. Right now, there's a breadboarded solution with a DC/DC converter sduck recommended. Cost is <$20. Thinking about a cheaper solution involving a cheaper chip, but it'll be more complex.

The PCB is available, from either Modular Addict in the US or Random*Source in the EU.
Cheradenine
Finished building one, in Modcan A format.
I left out the dry/wet mixing to fit everything on a 1U wide module...that can be done elsewhere in a modular synth
The signal LED and fine exp control were also omitted...needed space for the mandatory big knob Mr. Green





The calibrating was fun...sort of eek!


And now I have two more ready to be wired... MY ASS IS BLEEDING
pix
beautiful!! we're not worthy
Zaibach
Hey Guys, I just completed the wiring two days ago, when I encountered magic smoke on first power-up. After searching for a while looking for the short on pcb two I saw this:



The trace near the APF section is connected to the ground plane?? Could someone take a look at your board and confirm that this is normal - or is it a production error?
Cheradenine
This trace is -15V, it should absolutely not be connected to the ground plane.
I checked on 3 differents boards I have, there's no connection here.
This is definitly a production error, and can explain your magic smoke...that's a direct short between -15V and GND eek!

PWM
Never mind. Better answer typed faster. :

Always check unpopulated boards for errors!
Starspawn
Error, not so on mine.
Zaibach
Wow, thank you guys for your super-fast replies! thumbs up I will cut the connection and hopefully have this thing up and running very soon!
pix
OK, my fears came true...just plugged mine in for the first time and it's not working properly.

basically the only thing I hear in for the sum and diff outs is the internal oscillator. I can pitch it up and down fine, and my input signal shows up in the DryOut output so it's getting to board 1. But it's not being shifted after that.

I'm a bit overwhelmed by the complexity of the circuit, are there a couple of obvious things I should look for?

thanks!
Cheradenine
Do you have jumpers in the right places ? Before attempting to hear anything, you should follow the calibration procedure.
pix
thanks! I did have the jumpers set up properly but had wired the comp outs incorrectly.

It's working fine now, what a fantastic module. the feedback possibilities are insane and the sound quality is so good.

here are some pictures. Thanks again to Tommy for the panel layout. Also, I'm still waiting for the LED lens to arrive and still need to wire the output with the summed diff and sum outputs.


Zaibach
Finally got my Shifter working!



After scoring an old analogue oscilloscope on eBay to calibrate it properly, I ran into more problems, which I finally was able to fix. There was a bad solder joint at a transistor, which was my fault, but there were FOUR more manufacturing errors on pcb 2, all of which sent the signal at different places in the dome filter to the ground plane, never to be seen again. I mean, the signal is present at one side of a resistor, and at the other side it's gone? At first it looked like a measly 680R resistor dropped a 5Vpp signal down to nothing? Damn! That was causing me headaches... I should have been more suspicious after the first error on the pcb (a few posts up) where the -15V trace was connected to the ground plane... But it's working now. I already sent my voice through it - loads of fun!

Oh, and I think I mislabeled the feedback switch - it doesn't switch the feedback on or off, but switches between sum out and difference out for the feedback? So "Feedback mode" should be appropriate...
PWM
Zaibach Great looking build!

Always check over PCBs before populating, with a MM (continuity between power rails/ground) and with the power of sight.
I had some terrible trouble shooting experiences becouse I didn't.
Zaibach
PWM wrote:
Zaibach Great looking build!

Always check over PCBs before populating, with a MM (continuity between power rails/ground) and with the power of sight.
I had some terrible trouble shooting experiences becouse I didn't.


Thank you!
Well, I never had any problems with manufacturing errors so far, so I guess I just took it for granted that everything is ok. This one taught me! hihi
tommy.york


Here's the step-up converter on... I don't even know what this kind of board is called. It's not strip board, right? Because the back doesn't have strips?

I'm still getting settled after the move and after buying a bunch of connectors realized that I don't have the little metal things that you crimp onto the wires at the end. I've soldered everything in and now just need to get the thing wired.

One thing though: pix, where did you get those right angle connectors? Mine are all just straight, and that looks like it might be a better call in this situation.
pix
I got them from mouser I can look up the catalog#. But keep in mind I had to bend most of the cables coming out of the main board anyway.

also I'll send the panels sometime this week.
sanders
tommy.york wrote:
I'm using polystyrene (where available from Mouser) + C0G ceramics for the dome filter. Not 1% - will calculate resistor values for the dome filter.

Tayda polyester + electrolytic + tantalum everywhere else. Trying to do this project on a budget. waah


I've had this FS1 PCB set for years; bought it when it was first offered and put it aside until I figured out what to do with it. I didn't have the cash on hand when Zthee offered his Buchla-format kit; but now this thread has inspired me to dig it out and get started on a Eurorack assembly.

Was wondering though if anyone has a cart or list of the parts they ordered (particularly the selected dome filter cap/resistors and the 15v step-up components)?
sanders
Cheradenine wrote:

I left out the dry/wet mixing to fit everything on a 1U wide module...that can be done elsewhere in a modular synth
The signal LED and fine exp control were also omitted...needed space for the mandatory big knob Mr. Green


Most of the vintage Frequency Shifters, Bode, 360 Ststems, Buchla, Serge I've looked at for panel inspiration use a minimum of controls, mostly dominated by one Frequency Shift pot.

I guess I need to just build the FS1 and try it out with a dummy panel; But it's hard for me to imagine using all of the controls offered on this PCB. Particularly in the context of a little eurorack panel.

Can FS1 users speak to this? Most of the builds I've seen seem to incorporate all the controls; do any of them get used less than others? Are any of the controls never used? I'd like to scale down this Frequency Shifter to the most essential controls, but I also don't want to leave out some incredible feature I didn't know about.
Luka
i used all of the controls smile
sanders
I know Luka, I think I've seen your build. Excellent job.

But I'm just wondering-- when you 'play' it-- do you find that you utilize all of the inputs and knobs?
tommy.york
Question: the modularsynthesis.com instructions call for a number of modifications. Because my design is based on his, I'll need to do these. I have a question about the first instruction:
Quote:
I eliminated the exp polarity switch and modified the expo cv attenuator to a reversing style. On board1 I changed R2 from 51K to 36K, added an additional 36K resistor to pin 6 of U1, and wired the attenuator similar to the linear cv control circuit.

The first part is easy. But the second part - adding an additional 36k resistor to pin6 u1, is confusing. Clearly, I'd solder one end of the resistor to pin 6. Does the second pin to to pin 1 or pin 7 (both of which connect to pin 6, albeit differently, one through a 100k resistor, the other through a capacitor + resistor in parallel)? Or maybe it goes to ground?

This is why I bought Horowitz + Hill, but hey, I'm working up to it.

edit: also a bit confused by:
Quote:
I added a separate feedback attenuation control to pins 1 and 2 of the Mic_Level connector. The bypass switches route the input to the respective outputs but they do not affect the feedback control so the output may still be shifted.

Would like to know how any of you builders out there interpreted that.
sduck
tommy.york wrote:
But the second part - adding an additional 36k resistor to pin6 u1, is confusing. Clearly, I'd solder one end of the resistor to pin 6. Does the second pin to to pin 1 or pin 7 (both of which connect to pin 6, albeit differently, one through a 100k resistor, the other through a capacitor + resistor in parallel)? Or maybe it goes to ground?


Take a look at his modified schematics - http://www.modularsynthesis.com/jhaible/shifter/DJB-Frequency%20Shifte r%20schematic%20mods.pdf - that 36K resistor is between pin 6 and the expo FM pot

tommy.york wrote:
edit: also a bit confused by:
Quote:
I added a separate feedback attenuation control to pins 1 and 2 of the Mic_Level connector. The bypass switches route the input to the respective outputs but they do not affect the feedback control so the output may still be shifted.

Would like to know how any of you builders out there interpreted that.


I didn't do that one. And I seem to recall there was something wrong with Dave's input 2/FB knob, although he may have updated it - mine went into feedback way too fast, and was uncontrollable - I ended up changing to JH's pot value and adding a resistor to the feedback line. I think I documented this in the electro-music.com thread, or maybe not.
tommy.york
sduck wrote:
tommy.york wrote:
But the second part - adding an additional 36k resistor to pin6 u1, is confusing. Clearly, I'd solder one end of the resistor to pin 6. Does the second pin to to pin 1 or pin 7 (both of which connect to pin 6, albeit differently, one through a 100k resistor, the other through a capacitor + resistor in parallel)? Or maybe it goes to ground?


Take a look at his modified schematics - http://www.modularsynthesis.com/jhaible/shifter/DJB-Frequency%20Shifte r%20schematic%20mods.pdf - that 36K resistor is between pin 6 and the expo FM pot


Thank you. I'd forgotten about davebr's notes. Super useful.

I'm trying to go through and test all my connections while building them. For example, I was worried about the pot on the input as voltage divider and have been trying to test it with an oscilloscope, sending a sine wave into the input and spinning the pot. No luck yet, but I think it's a pot pinout issue. Anyone have any additional recommendations on checking the connections? Going to use a dmm to test all the other pots.
tommy.york
Alright, connections are getting there. Waiting until everything is debugged to do the exponential input, but I have a question about INV1, INV2, diffout, and sumout wiring, and an error on the frequency shifter itself I'm having:

sduck (or anyone else that did davebr's wiring): how did you wire INV1, INV2, diffout, sumout, the out jack, and the up/down A switch? I think I'm confused because they're on two different sides of the diagram. Do I just think of diffout and sumout going to both the up/down A switch and to each other, where they also run to invout and inv2?

I might just repost this with a diagram, I'm not sure my language is really clear here. No worries if you don't remember, if so I'll just take my best guess after I've got the other bugs figured out.

Second question: After wiring everything up, I don't get any wet signal. I've noticed that when running through the calibration procedures, I get messed up in the level calibration. I can get dryout to 5 Vp, but CmpOut will either be constant at like -13.6 V or show up as a square-ish wave that is 27 Vp that's only barely modified by R99. I'm looking for shorts / messed up IC pins / checking component values. Any other recommendations?
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