1BIT Multitap Delay by FEEDBACK [UPDATE]

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tassie tiger
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Post by tassie tiger » Wed Feb 07, 2018 10:01 pm

Anton,

Your picture doesn't look correct to me.

Anode of D1 does need to go to middle terminal of J8 (Loop gate jack) as you've shown.
Cathode of D1 needs to go to the top connection of RL (1K ohm resistor) so that a connection is maintained to Pin 1 of connector 6b.

Anode of D2 does need to go to bottom terminal of SW6 (Momentary loop switch) as you've shown.
Cathode of D2, like cathode of D1, also needs to go to the top connection of RL (1K ohm resistor).

You must break the traces either side of the bottom terminal of SW6 (Momentary loop switch).

J

AntonWoldhek
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Post by AntonWoldhek » Mon Feb 12, 2018 4:07 am

Thanks Tassie!

That explains a few things. I didn't notice the extra connection from one of the diodes but not the other one. d'oh! (The other one is also not easy to see in the photo of the mod).

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Post by AntonWoldhek » Tue Feb 27, 2018 7:19 am

Thanks to Andrei I have a working module now. Maybe good to know for other folks interested in feedback modules, the amount of support Andrei gives builders is very high.

Did my first play session with this module yesterday and had a serious amount of fun.
:yay:

[video][/video]

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strat-1
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Post by strat-1 » Sun Mar 25, 2018 4:36 am

UPDATE :
The pcbs are updated to rev 1.3. I included the two diodes required for gate path on the front panel board.
I also described the modifications required for rev1.0 and 1.1 boards, at the end of the new manual.

Image

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thetwlo
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tron23
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Post by tron23 » Fri Apr 13, 2018 5:59 am

Sounds like it, reminds me a lot of the Bel BD-80! :guinness:

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maltemark
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Post by maltemark » Sun Apr 15, 2018 7:33 am

Does anyone know where I can find the manual? On the website it points to the muffwiggler thread, and maybe I'm half-blind or something, for in the thread I can only find references to the manual. I could imagine it still being written on since this is a one-man gig, but I'm not sure if this is the case ...?

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mush
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Post by mush » Sun Apr 15, 2018 9:14 am

maltemark wrote:Does anyone know where I can find the manual? On the website it points to the muffwiggler thread, and maybe I'm half-blind or something, for in the thread I can only find references to the manual. I could imagine it still being written on since this is a one-man gig, but I'm not sure if this is the case ...?
User manual 1.0 pdf is attached in the first post of this thread...
In for weird music, nice pictures and retro videos? Follow me at Instagram: https://www.instagram.com/cphmush/

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strat-1
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Post by strat-1 » Sat May 12, 2018 12:04 am

UPDATE :
Feedback range improvement.
After building many delay units, I discovered every lot of LM13700 have a different maximum gain. I knew that, but I considered it's not important in this project.
Because of this, with some LM13700s, you will already have some feedback with feedback pot at minimum.
If you have this problem, just install a wire in place of R17, R34 highlighted in the picture. These resistors were put exactly for this purpose. (or you can trimm them from 0 to 4k7 until you are satisfied with the minimum feedback setting)
If you already built the project, you can short them on the back of the board, without removing the front panel.

Image

alsec

Excellent

Post by alsec » Sat May 12, 2018 3:56 am

Just what I was looking for.

guestt

Post by guestt » Mon May 14, 2018 12:24 pm

Finally arrived today - just want to concur the this looks amazing, really looking forward to getting stuck in to the build!

Oh and the build manual is glorious - once of the nicest I have ever seen - just beautiful! Really excellent work!!

Thank you strat-1 :tu:

raph36
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Post by raph36 » Thu May 17, 2018 6:53 am

I'm currently building 3 of those 1 bit delays and wondered before i purchase some memory chips if the ram speed has any influence on the sound ,

it seems to me that these Tesla MHB4164 should work fine

https://www.ebay.co.uk/itm/Tesla-MHB416 ... SwiONYNWN5

however different 4164 seem to have different response times , going from 100ns to 250ns and those tesla chips are on the slow side. does it matter in this application ?

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strat-1
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Post by strat-1 » Fri May 18, 2018 4:30 pm

raph36 wrote:I'm currently building 3 of those 1 bit delays and wondered before i purchase some memory chips if the ram speed has any influence on the sound ,

it seems to me that these Tesla MHB4164 should work fine

https://www.ebay.co.uk/itm/Tesla-MHB416 ... SwiONYNWN5

however different 4164 seem to have different response times , going from 100ns to 250ns and those tesla chips are on the slow side. does it matter in this application ?
It will work fine, as long as it will have the same pinout.

guestt

Post by guestt » Sun May 20, 2018 7:19 am

I have a question about the static discharge, just how careful do I need to be? Are these any more sensitive than any other chip?

I ask because I knowI don't generate static electricity to any noticeable degree, I mean I have handled thousands, of chips and never had any problem.

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strat-1
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Post by strat-1 » Sun May 20, 2018 9:39 am

Baddcr wrote:I have a question about the static discharge, just how careful do I need to be? Are these any more sensitive than any other chip?

I ask because I knowI don't generate static electricity to any noticeable degree, I mean I have handled thousands, of chips and never had any problem.

Try to touch a home radiator before handling them, something metallic grounded to earth.

guestt

Post by guestt » Sun May 20, 2018 9:41 am

Okay, thanks :)

I don't have radiators, but I do have a metal post in the ground outside my little home that holds a little lamp, I will reach out and touch that before I touch the chips!

edit: just looked up grounding rods and I don't think my metal post goes, anywhere near, deep enough :doh:

Maybe I will just buy one of those grounding wrist band things - probably easier in the long run that taking any risks with particularly sensitive components.

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Check Mate
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Post by Check Mate » Tue May 22, 2018 1:50 pm

Hello Strat,

I just discoverd something strange and I don't know if it is supposed to be like that or not.

If I put a signal into the input and just monitor the output of TAP2 and turn up the FEEDBACK 2 knob, there is no feedback at all. If I trun up the FEEDBACK 1 knob there is a feedback loop audible at TAP 2 output. Twisting the FEEDBACk 2 knob still doesn't do anything.
I already changed all the TL072s but with no success.
Do you have any idea where to look to get FEEDBACK 2 working?

Thank you very much!

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strat-1
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Post by strat-1 » Wed May 23, 2018 2:01 am

Check Mate wrote:Hello Strat,

I just discoverd something strange and I don't know if it is supposed to be like that or not.

If I put a signal into the input and just monitor the output of TAP2 and turn up the FEEDBACK 2 knob, there is no feedback at all. If I trun up the FEEDBACK 1 knob there is a feedback loop audible at TAP 2 output. Twisting the FEEDBACk 2 knob still doesn't do anything.
I already changed all the TL072s but with no success.
Do you have any idea where to look to get FEEDBACK 2 working?

Thank you very much!
I can't tell you, without checking the signal path with a scope. If you have a scope, try to check the signal on LM13700.
The feedback from channel 1 present on channel 2 is normal, because both feedback mix in the same place.

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Check Mate
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Post by Check Mate » Wed May 23, 2018 2:50 pm

Dear Strat,

The signal from the input is present on the LM13700 as well as on the 311.
Interestingly the signal on pin 5 of the LM13700 is louder than on Pin 12.

I hear the incoming signal at TAP2 out just that there is no feedback with the Tap2 pot.
I already checked all resistors and caps twice and switched all the TLs without success.

P.S.: TAP2 works when switching positions but there is just no feedback loop building when turning up the TAP2-feedback pot.

ookrsia
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Post by ookrsia » Wed Jun 13, 2018 8:15 am

Would it be a (reasonable) possibility to add a mod to the module so that at least one of the feedback paths would have a send&return somehow?

Thanks

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strat-1
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Post by strat-1 » Sat Jun 16, 2018 3:49 am

ookrsia wrote:Would it be a (reasonable) possibility to add a mod to the module so that at least one of the feedback paths would have a send&return somehow?

Thanks
It will be hard to implement a send-return path, that's why I didn't include one.
The feedback send is before the output high-freq cut filter, so clock frequency is present over the signal.
Also the feedback level is between 0-2vpp.
You can try to desolder R57 at one end, and insert before it a send-return path, but the results will not be good.

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Post by Jop » Wed Jul 11, 2018 1:57 pm

Almost finished my build and not sure about the orientation of the push switch. I do not see green paint but red on my switch. Should this side facing the dot on the board?

ThxImage

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$XxxxX$
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Post by $XxxxX$ » Sat Jul 14, 2018 2:25 am

Found this beautiful module and noticed that KIT1s and 2s are sold out.

Any chance there is coming more in some point?
"An error doesn't become a mistake until you refuse to correct it."

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strat-1
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Post by strat-1 » Sun Jul 15, 2018 2:41 pm

Jop wrote:Almost finished my build and not sure about the orientation of the push switch. I do not see green paint but red on my switch. Should this side facing the dot on the board?

ThxImage
Yes, the dot matters. It means it's a red led, I don't always find green switches in stock.

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strat-1
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Post by strat-1 » Sun Jul 15, 2018 2:41 pm

$XxxxX$ wrote:Found this beautiful module and noticed that KIT1s and 2s are sold out.

Any chance there is coming more in some point?
Yes, the kits are back in stock.

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