DIY - Elektor Vocoder - General Build Thread

[Fitchie]

This build thread is for the DIY - Elektor Vocoder - 35th Anniversary Edition





General discussion thread:
https://www.muffwiggler.com/forum/viewtopic.php?t=193646&sid=e00222ae7666a4e9ce9a531164d022e6


Website:
www.vocoder.eu/index.html


Building instructions:
www.vocoder.eu/building-guide.html


BOM:
www.vocoder.eu/bom.html


PCB layouts:
www.vocoder.eu/boards.zip


Documented errors:

• 1/
  Some resistor and trimmer references are incorrect included in the initial BOM.
  Please download a recent version of the BOM (20/11/2018 or later).
  
  2/
  The offset compensation on the filter boards do not allow easy fine-tuning.
  In case of an inaccurate setting of the trimmers, the LM741 opamp immediately saturates.
  See page 11 how to easily fix this.
  
  3/
  To adjust the LM741 bias exactly to 0,00 mV on the low pass filter and high pass filter, there is a minor modification on both PCB's required.
  See page 12 how to easily fix this.

[gianni]

Does the Vocoder require 1/2 W resistors or will 1/4 W work?

[jersupereq]

Hoping someone puts together a mouser BOM

[Fitchie]

Does the Vocoder require 1/2 W resistors or will 1/4 W work?

• 1/8 W or 1/4 W resistors are perfectly suitable.
  I consciously did use 1/2 W resistors to get the old-fashioned look of the original device.

[Portabella]

did you use carbon film or metal film?

[Fitchie]

did you use carbon film or metal film?

• The MCMF50 series resistors are axial leaded precision metal film resistors with a tolerance of ±1%.
  To allow the filters to flow correctly in each other at the right frequency you need this precision resistors.

[Alfrede]

Hi Fitchie,

when i read your message i believe you say that the carbon resistors have more free elektrons which make the Sound more smother then for the metal film resistors which Sounds cold ?


But the reason because i write is because your PCB and Case which come Today are Really Really nice. thank you so much for realising this.

[Revok]

did you use carbon film or metal film?

It think Fitchie made a typo above but all of the resistors in the BOM are 1% metal film except for one 4.7M at 5%.

[Fitchie]

It think Fitchie made a typo above but all of the resistors in the BOM are 1% metal film except for one 4.7M at 5%.

Oops... My bad!
I'm completing a tube amp, and there carbon resisters are used in the input signal, so I mixed up things.

Haste makes waste, my apologies. I already edited the original post.

I did also publish an updated bom (some missing components added, silkscreen references partially added):
www.vocoder.eu/bom.html

[Vlado]

Hello,

i'm scratching my head mor and more while watching the costs for the components raising more and more.

The 21 pin connectors cost a fortune ... I managed to find 1 pair for 4,5 euro.

Coming to my question about the required OP-Amp TL084ING4.
This beast is not easy to find, but there is another one TL084IN.

Comparing the datasheets i did not find any differences.

Can I use the TL084IN insted of the TL084ING4 ?

Best regards

[Vlado]

Hello,

having trouble to get 25k trimmer potentiometers I would like to ask, if I could put in a 50k. As i have found reasonably cheap precision potentiometers with 25 turns, it would be interesting to know, if these could be used instead.

Best regards

[Vlado]

Hello,

after having a closer look at the transformer, I found an important detail, that might interest others in the group.

It is a 2x 115V to 15V transformer that is only good for US and A.

Has anyone looked up a replacement for 240V ?

Best regards

[gianni]

Hello,

after having a closer look at the transformer, I found an important detail, that might interest others in the group.

It is a 2x 115V to 15V transformer that is only good for US and A.

Has anyone looked up a replacement for 240V ?

Best regards

The transformer has two primary windings, so it can be configured for 115V or 230V. It can be configured via this little solder bridges at the bottom of the PCB.

[Fitchie]

The 21 pin connectors cost a fortune ... I managed to find 1 pair for 4,5 euro.

• TME keeps these connectors in stock, when the stock has been sold out, they are reordered very fast.
  
  Current stock:
  102E10079X - 195 pieces - 2,31 euro
  101E10099X - 51 pieces - 1,59 euro

Coming to my question about the required OP-Amp TL084ING4.
This beast is not easy to find, but there is another one TL084IN.

• Farnell has 5.128 of them in stock for 0,536 €/each.

Can I use the TL084IN insted of the TL084ING4 ?

• I did not try it out, but they are pin compatible and the specs looks the same.

[Fitchie]

Having trouble to get 25k trimmer potentiometers I would like to ask, if I could put in a 50k.
As i have found reasonably cheap precision potentiometers with 25 turns, it would be interesting to know, if these could be used instead.

• Yes you can, but the adjustment is less easy when using a 50k trimmer due to the narrower range.
  Anyhow using a multi turn trimmer facilitates this again.

[zephyrin]

For DIN 41617 Reichelt have a better price (shipping price is not expensive as TME )

FEDERLEISTE 21L (same as 102E10079X ) -> 2.01 €

STIFTL. 21W (101E10099X ) -> 1.82 €

3.83 € for 1 pair


FL14/15 Block is also avalable for 9.43 € (Farnell 13.8 € )

you can also found WAGO 243-131

[zephyrin]

For CA3080 i will try to used SMD version found on ebay with PCB converter

[Fitchie]

It is a 2x 115V to 15V transformer that is only good for US and A.
Has anyone looked up a replacement for 240V ?

• You don't need a replacement.
  Use the solder bridges to choose the right voltage.
  
  

[Fitchie]

All,

The final BOM is available here:
www.vocoder.eu/bom.html

This file will replace all previous versions.

[Vlado]

All,

The final BOM is available here:
www.vocoder.eu/bom.html

This file will replace all previous versions.

Thank you.

One thing makes me wonder.

How are the 1mm solder pins going to be used?
Isn't there a part missing (WAGO 243 Series PCB Terminal Blocks)?
I'm thinking more of one of these guys:
Datasheet connector

[Vlado]

For DIN 41617 Reichelt have a better price (shipping price is not expensive as TME )

FEDERLEISTE 21L (same as 102E10079X ) -> 2.01 €

STIFTL. 21W (101E10099X ) -> 1.82 €

3.83 € for 1 pair


FL14/15 Block is also avalable for 9.43 € (Farnell 13.8 € )

you can also found WAGO 243-131

Thank you for the effort, but ...

Concerning the DIN 41617 connectors the L means that these are soldering lugs version that can not be mounted on pcbs.
Ordering them might not be the best idea. They don't have the correct ones.
I found them at din 41617 socket for 1,78 (if you order 10+) same for the din 41617 plug for 1,30 (if you order 10+).

Oh, i miscalculated the price for a pair in my previous post ... didn' consider 15 instead of 10.

For the WAGO 243-131 solder pins you can check elpro.com (lötstifte 1mm).

I spent some time checking the transformers carefully on reichelts webpage and did not find it immediately,
because there is a wrong picture not showing FL14/15 and the price confused me, because it is different (i guess it is because of different VAT).
After checking specs at farnells it was easy. It is this transformer.

Best regards

[Fitchie]

For DIN 41617 Reichelt have a better price (shipping price is not expensive as TME ):
FEDERLEISTE 21L (same as 102E10079X ) -> 2.01 €

• DO NOT ORDER THESE CONNECTORS !
  
  Take care not to order the L (solder lugs) version, they will not fit in the backplane !
  Please see below specifications before ordering.

[zephyrin]

Oups sorry for this error

[dnode]

One temporary (only few days left!) tip for people looking for CA3080 could be:
http://www.spheremusic.com/Bargaindtl.asp?Item=17529

A bit much, in quantity and price, but maybe useful for a few people teaming up?!

(I am in no way associated with Spheremusic/VEMIA, this is just being helpful)

[Girts23]

Hi, there!
Could you, please, check the band filter BOM? R1 is mentioned 3 times there as 10k, 33k and 150ohm. And R10, R15, R200,R201 and R202 are missing in the BOM.

And on Lowpass filter there’s no R93 on the PCB

Thanks!

Girts