Jürgen Haible Krautrock phaser BUILD THREAD

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the bad producer
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Post by the bad producer » Mon Feb 05, 2018 8:57 am

You are right, 6 x 10uf... I think the mysterious 100uf are a relic of JH's original BOM which had those listed but no amount:

http://jhaible.com/legacy/compact_clone ... er_bom.pdf

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LektroiD
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Post by LektroiD » Mon Feb 05, 2018 10:17 pm

megaohm wrote:
baouftou wrote:I've covered the lamps on the PCB with duck tape to seal from ambient light but still no luck.
Duct tape may be conductive and could be shorting out the LDR leads if touching.

I used bicycle inner tubes cut an inch or so longer than the lamp.
Fold over a small portion at the top and clamp with a cloths pin or similar.
It's quick and you can remove it easily. Once the module is fully going zip tie the tube to the base of the lamp.
I got the inner tube idea from someone else in this thread or a website somewhere.

Hope you guys get them running!
I used black heat shrink tubing, works perfectly.

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Post by nologin » Wed Mar 28, 2018 8:41 am

I built 2 of these phasers, there are one, i connected a big transformer of 46VA. It works very well.
The 2nd i tried with a transformer 10VA, it works poorly, the phaser saturates and has a non-conforming modulation, I tested with the 46VA, it's OK. So it takes a pretty big voltage transformer, the question how much of VA minimum?

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hamildad
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Post by hamildad » Fri May 18, 2018 4:06 am

which of the 10U caps are Tantal?

the BOM says nearer the voltage regulator... but I dont really want to guess...

nearing the end of this build...just hoping that I haven't lost the LM1458...
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hamildad
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Post by hamildad » Thu May 31, 2018 4:26 am

got this all up and running with lamps flashing and all that.

there is one tiny snag.... it doesn't seem to actually be doing any phasing...

I think this might have been my completely made up wiring of the stage choice part of the PCB, I have the OnOnOn switch wired up according to Youtube, but then pretty much guessed the PCB wiring.

any tips on how to actually make the unit phase?

Or I might leave it as a blinkenlights module... and sell it to DeadMau5 as a secret sauce plug in effect.
My Synth Instagram here * My Synth videos here
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External PSUs and DC jacks are the hallmarks of toys. - Graham Hinton.
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I am one of the "tiny fraction of a percentage of oversensitive idiots" who feels the name of this site sends the wrong message.
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This is primarily for melody and historical educational purposes - Analogue Music

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soup
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Post by soup » Sun Jun 24, 2018 8:52 pm

Image
:miley:

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Post by Jumbuktu » Thu Jun 28, 2018 8:11 pm

I recently bought one (possibly the last one) of the boards from Thonk. I have always wanted to build one of these - I wish I had bought when the partial kits were still available.

Anyway, I can easily source the majority of the components, either from our local retail suppliers (Jaycar in Australia) or eBay for some of the rarer parts. But of course, the key LDR components are long obsolete. There are one or two being hawked on eBay for exorbitant prices, but it's time someone tried an alternative more readily available source.

After scouring spec sheets, I have hit on one that I think is a pretty close match. It's Mouser part #485-161, described as 'Adafruit Accessories Photo Cell CdS Photoresistor'. I am attaching the Mouser data sheet (photocells-932884.pdf), which is more of a user guide. It in turn refers to the data sheet (attached as PDV-P8001.pdf) for a listed commercial product. I am also attaching the data sheet for the original M9960 11A for comparison (PERKS00452-1.pdf). The key characteristics look to be a pretty close match - especially if you compare some other common LDRs, for which the resistance numbers are radically different. More recent products seem to have much better characteristics in terms of very high dark resistance, which suggests they wouldn't work for this project.

Anyway, I am going to try these LDRs and I will report back here when I get some results. I can source the actual PDV-P8001 from Digikey if necessary, but as I will be getting some other stuff for this project from Mouser, I will try the Adafruit option first.
Attachments
PERKS00452-1.pdf
(81.03 KiB) Downloaded 19 times
photocells-932884.pdf
(693.81 KiB) Downloaded 22 times
PDV-P8001.pdf
(93.71 KiB) Downloaded 24 times

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Jumbuktu
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Post by Jumbuktu » Fri Jun 29, 2018 1:55 am

hamildad wrote: I think this might have been my completely made up wiring of the stage choice part of the PCB, I have the OnOnOn switch wired up according to Youtube, but then pretty much guessed the PCB wiring.
Why not unsolder the switch and solder a link on one of the phase stage selectors? If it works then you know it's the switch wiring that is the problem. If it doesn't it's something else.

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hamildad
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Post by hamildad » Fri Jun 29, 2018 5:47 am

was going to do this, but then when I got it out, it now doesnt turn on...

so there is obviously something else which has just appeared.

will keep at it.... at least I have seen the lamps glow...
My Synth Instagram here * My Synth videos here
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External PSUs and DC jacks are the hallmarks of toys. - Graham Hinton.
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I am one of the "tiny fraction of a percentage of oversensitive idiots" who feels the name of this site sends the wrong message.
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This is primarily for melody and historical educational purposes - Analogue Music

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the bad producer
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Post by the bad producer » Fri Jun 29, 2018 5:51 am

hamildad when you tested it did you make sure the bulbs / LDR's were sealed from light interference? I remember on my first one not doing this, and of course it didn't work!

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Post by IID_nrebs » Mon Jul 02, 2018 1:34 am

soup wrote:Image
:miley:
how do you manage to fit all the stuff into such a small box? Especially the lamps. can you tell me which casing is that? thanks...

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soup
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Post by soup » Tue Jul 03, 2018 7:58 pm

IID_nrebs wrote:how do you manage to fit all the stuff into such a small box? Especially the lamps. can you tell me which casing is that? thanks...
It's not a small box! It's the 1550g, the monster truck of pedals...

Image

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keninverse
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Post by keninverse » Mon Jul 09, 2018 10:28 am

Anyone know where to get these photocells?

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Jumbuktu
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Post by Jumbuktu » Mon Jul 09, 2018 11:02 pm

keninverse wrote:Anyone know where to get these photocells?
See my post about 4 back.

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Post by Jumbuktu » Thu Jul 26, 2018 7:20 am

Just an update on the use of Adafruit LDRs. I just finished enough of my build to be able to test the phaser, and these LDRs seem to work. I say 'seem' because I have nothing to compare the sound against, other than a few demos and my old copy of Phaedra. I noticed a discussion in the old Electro-music forum where someone asked Jurgen if he could use another type of LDR. Jurgen remarked that the phaser would probably work in some way with almost any LDR, but it would probably not have the unique sweep of the original. He said he had spent 'weeks' trying different components before he decided on the Elmer-Perkins ones. I also noticed that he had sockets for the LDRs on his prototype. Anyway, the specs of the Adafruit LDRs look very similar on paper, and I am happy with the results.

I am still waiting for a proper plug for my external power supply, and some suitable knobs, and I need to paint the enclosure (I used the same one as Soup). I will post some shots and build tips when I get it finished.

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the bad producer
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Post by the bad producer » Thu Jul 26, 2018 8:11 am

Thanks for trying those Jumbuktu, I have a new one to build with no LDRs so I will go for these and - if I remember - do an A-B comparison with the old one.

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Jumbuktu
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Post by Jumbuktu » Thu Jul 26, 2018 8:19 am

the bad producer wrote:Thanks for trying those Jumbuktu, I have a new one to build with no LDRs so I will go for these and - if I remember - do an A-B comparison with the old one.
Cool! Why not install sockets in case you want to try something different as well?

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Post by keninverse » Thu Jul 26, 2018 9:36 am

Jumbuktu wrote:Just an update on the use of Adafruit LDRs. I just finished enough of my build to be able to test the phaser, and these LDRs seem to work.
Thanks for posting your results!

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Post by Jumbuktu » Tue Aug 07, 2018 12:07 am

I would like to better understand the actual phaser section of the circuit.

The 'stages select' pads on the pcb and the associated switch are generally coded as 2, 4 or 6 stages. When I look at the schematic, I see 8 identical sections, each built around a LM741 chip. So is it really 2, 4 or 8 stages, or are two of the LM741s doing something else?

It's not marked on the schematic, but I would like to know exactly where the stage selection switch taps in on each stage (both pads). Main reason for asking is that I want to explore a slightly simpler solution for the stage selection switch.

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Post by hamildad » Sun Nov 11, 2018 5:50 pm

hamildad wrote:was going to do this, but then when I got it out, it now doesnt turn on...
This turned out to be just fuses.... replaced and removed the stage select switch and simply jumpered the 4 stage points.

but still no phasing.... lovely lights, but no difference to the sound.... I put the lights under their bike tube hoods and nothing.... I am passing through audio ok, and the sound seems filtered, but no movement at all...

desperately trying to kill my backlog before 2019, so on a mission to get this sorted.

:bang:
My Synth Instagram here * My Synth videos here
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External PSUs and DC jacks are the hallmarks of toys. - Graham Hinton.
-
I am one of the "tiny fraction of a percentage of oversensitive idiots" who feels the name of this site sends the wrong message.
-
This is primarily for melody and historical educational purposes - Analogue Music

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soup
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Post by soup » Sun Nov 11, 2018 6:03 pm

Are you getting +/-15V at the MOTM footprint?

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Post by aabbcc » Mon Nov 12, 2018 4:03 am

I've been looking for the correct LDR's for ages now but they seem unobtainable :bang:

Does anyone here have spares enough for 1 unit that I could buy? :hail:

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Post by Bamboombaps » Sat Nov 24, 2018 3:55 pm

I'm also looking for the proper ldrs :eyes:

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Post by Reese P. Dubin » Sat Nov 24, 2018 4:34 pm

soup wrote:
IID_nrebs wrote:
Image
just wanted to say no one else commented on the Klaus Schulze double LP in this photo yet

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Post by vandaal » Fri Nov 30, 2018 1:16 am

Built and designed a case for the beast.
Sounds great on synths and beats. Really fun!
Fitted a 15VA transformer inside. So just plug it to the wall.
Pots are 24mm Alpha.
Red illuminated Bypass switch on the front and footswitch on the back.
The toggle switch on the back is Manual/Auto.
Additional hole for what ever mod was left inside.
I though I would put lfo off-set bias pot there, but I cant seem to get it to work correctly.

Image

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Last edited by vandaal on Mon Dec 03, 2018 1:30 am, edited 1 time in total.

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