Buchla 100 system diy build

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bluedonkey
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Post by bluedonkey » Sun Apr 15, 2018 3:20 pm

Hey all,

I found a great way fo making panels cheap. Using a service like this

https://uk.whitewall.com/photo-lab/alu- ... um-backing

Anything white will just be aluminium. I made a Serge panel this way. I cant remember how much it was, but I think around the £10 mark.

Dibond is a sandwich of aluminium plastic and aluminium. Its a bit softer than normal ally, BUT the graphics are good and very durable.



Image

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aonghus
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Post by aonghus » Sun Apr 15, 2018 6:59 pm

A question regarding power:

Do you have to build your own power supply for these 100 series modules, or is there a modern one you can use?

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Peake
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Post by Peake » Sun Apr 15, 2018 9:05 pm

Depending upon the number of modules you want, and which ones you want, a 1A to 1.5A or larger +15V supply is mandatory. Some 3rd party module adaptations can add features requiring a -15V rail, and some modules such as the 190 dual reverb require a +24V rail. It's perfectly fine to add a 500ma or larger linear or wall wart +24V supply to a +15V supply and wire them into the distro. More amperage is better, and it's good to have reserves.

I've completed a pair of 100 Series module which use +24V and I've used pin 10 on the EDAC for it so the owner can add a +24V line into their distro on pin 10 and add other +24V modules later as they please.
Last edited by Peake on Mon Apr 23, 2018 2:44 am, edited 1 time in total.
This is not the place I'd imagined it to be.

moogboy010
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Post by moogboy010 » Thu Apr 19, 2018 2:50 am

Buchla-clone model 158A (Saw/Sine-Generator)- build.This is peakes' Ebolatone-board!
The etch turned-out really nice!The matched pair of transistors',at the front of board are (TIS-97s');The (emitter and collector)are reversed,compared with a pair of (2N3904s)'!ImageImage
Last edited by moogboy010 on Tue May 01, 2018 5:53 am, edited 1 time in total.

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Peake
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Post by Peake » Thu Apr 19, 2018 12:00 pm

Good etch!

I haven't updated my page yet but use the original 1K5 resistors in the sine shaper, not a pair of trimpots, but DO use a trimpot in place of the 470r resistor to ground just before the sine shaper. Pre55ure says this is the place to trim for a good sine wave.
This is not the place I'd imagined it to be.

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Hi Peake

Post by moogboy010 » Thu Apr 19, 2018 1:25 pm

O.K.,I will try that!The oscillator is working in range with a(U147) in the osc.section .
I have a fairly pure-tone,with a (2N4339) and the trims' tuned?Have to look at it on my scope?All is good,so far! :banana:

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158A

Post by moogboy010 » Thu Apr 19, 2018 1:30 pm

Here is a pic,so far.(10K-pot) needs' cleaned.I will replace this with a new-pot!
:tu: Picture file

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158A build

Post by moogboy010 » Fri Apr 20, 2018 6:36 am

Everything is working well.Have not decided about the sine-wave?Image
Image

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APETECHNOLOGY
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Post by APETECHNOLOGY » Sat Apr 21, 2018 2:47 am

Peake wrote:Good etch!

I haven't updated my page yet but use the original 1K5 resistors in the sine shaper, not a pair of trimpots, but DO use a trimpot in place of the 470r resistor to ground just before the sine shaper. Pre55ure says this is the place to trim for a good sine wave.
Peake, its the 3.3k next to the 470 ohm i remember from a while back...
but changing the 1k5's to trimmers has no bearing on the performance?
i already have them installed, i guess i will find out tomorrow ,

thanks for the info!
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APETECHNOLOGY
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Post by APETECHNOLOGY » Sat Apr 21, 2018 2:48 am

and nice work moogboy010!
crushing it!
:hail:

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Peake
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Post by Peake » Sat Apr 21, 2018 11:40 am

Do I keep getting that wrong? Sorry. The 1K5s definitely influence performance but Pre55ure said the other resistor is much more important.
This is not the place I'd imagined it to be.

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Post by moogboy010 » Sat Apr 21, 2018 12:58 pm

Thanks' for the compliment,Apetechnology!
I will leave the (1K) trim-pots' in place,for (Sine-Symmetry),but will change the 3.3K
resistor to a (5K,or higher) trim-pot.Makes' sense.You are controlling the bias,thus gain of that transistor,lowering(signal-input) to the (Sine-Shaper). Should reduce distortion of (sine-wave-form). :tu:
Thanks' for the revision,Pre55ure and Apetechnology! :yay:
Last edited by moogboy010 on Sat Apr 21, 2018 10:12 pm, edited 1 time in total.

Jarno
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Post by Jarno » Sat Apr 21, 2018 4:07 pm

Coming back to the 144 (or other projects that need a P-chan FET), Peake, did you try 2N3820 for the P-chan FET instead of U147?
It seems to be pretty similar to 2N5020, where 2N5460 has higher Idss.

By the way, on the board for the 144 I changed everything to 3904 and 3906 footprint. Will order boards next week.

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Post by moogboy010 » Sat Apr 21, 2018 6:36 pm

I made some (J175s') work,in the model#144. Unfortunately The U147(Very difficult to find,if at all) is a natural! All (4) of mine worked in Peakes' 144 board! :hmm:
Btw; From what I have been able to learn,I think the gain of the matched pair have as much to do with which (Jfet )will work,as anything.Might take a lower(hfe-matched-pair),for a different transistor.As I stated before,I used (TIS97s'),with a gain around (hfe=505).A set of (2N3904s' ),with lower(hfe) might work better,for other(P-channel-jfets')? I had a wider range of tuning control,with the(1K trim-pots')and the (U147),using the (TIS97-matched-pair).

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Post by Jarno » Sun Apr 22, 2018 7:10 am

Interesting, so not just the jfet but rather the combination. Will try out, I have changed the board to 3904 for the matched pair, lets see if i can get some different fets and try out.

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Post by moogboy010 » Sun Apr 22, 2018 7:52 am

Sounds' good,Jarno,
Let us know your results'?
Btw,I have an original-NOS(MD708B/dual-transistor),that I picked-up in some stuff from a "Ham Radio Fest",several years' ago!I have tested the (hfe) on both sides,under different temperature conditions' and this dual-can stays around (hfe170)! I used that as my (target-value) when matching transistor pairs'.The (MD708B) was probably used in most (Pre-CBS) Buchlas'? The (IT-122) tends' to be a good-bit higher(hfe),usually (hfe-450) and up?
Not-saying that (bias-resistors') don't have a lot to do with the oscillation and performance of the (jfet),but I think that the driver-transistors'(Dual-Pair)have a large-role.
Best of luck :hmm:

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Post by hydn » Sun Apr 22, 2018 8:42 am

This is really incredible work you're doing!

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Peake
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Post by Peake » Mon Apr 23, 2018 12:11 am

The IT122 are well-matched for both voltage and gain. The MD708B is very sloppy in comparison.

I have not used anything to substitute but 5020 and J175.
This is not the place I'd imagined it to be.

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Post by APETECHNOLOGY » Mon Apr 23, 2018 1:44 am

so i fired up a couple 158's the wave shapes were ass shaped, the one in the picture is actually not that bad,
i replaced the 3.3k with a 5k trimmer
and i was able to adjust out the "ass"!
thank you Pre55ure for the tip!
the new question is, how much should the saw look like a saw?
i did not take a pic of my saw, my 252e is giving the 158 a work out and it sounds nice!
thank you Peake for the hard work!
ImageImage

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Post by moogboy010 » Mon Apr 23, 2018 10:57 am

Beautiful job,Apetechnology.
Nice,clean board! Sine-wave looks' very-symmetrical!
Congrats' on a quality build! :bananaguitar:

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Peake
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Post by Peake » Tue Apr 24, 2018 12:56 am

Loving everyone's builds! Thanks for confirming the best way to get a sine in the 158! That's some 2nd harmonic right there. Trim out all the ass!

Image
This is not the place I'd imagined it to be.

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cygmu
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Post by cygmu » Tue Apr 24, 2018 3:30 am

Peake wrote:Loving everyone's builds! Thanks for confirming the best way to get a sine in the 158! That's some 2nd harmonic right there. Trim out all the ass!
Yes, this is very interesting and quite possibly pertinent to other JFET sine shaper sections.

I guess the thing being trimmed is the peak-to-peak level of the triangle going in?

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Post by moogboy010 » Tue Apr 24, 2018 9:02 am

HI Peake,
Love the GIF,Hilarious!
:lol: Here are some (Dinosaur-screen-shots') of the wave-forms' from the 158A and 144.
A little blurred.Got to change the exposure time on damn-camera! :mad:
ImageImageImageImage

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Peake
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Post by Peake » Tue Apr 24, 2018 12:02 pm

cygmu wrote:
Peake wrote:Loving everyone's builds! Thanks for confirming the best way to get a sine in the 158! That's some 2nd harmonic right there. Trim out all the ass!
Yes, this is very interesting and quite possibly pertinent to other JFET sine shaper sections.

I guess the thing being trimmed is the peak-to-peak level of the triangle going in?
I believe that's what Pre55ure said, makes sense.
This is not the place I'd imagined it to be.

moogboy010
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140 pulse pictures'

Post by moogboy010 » Wed Apr 25, 2018 12:44 am

Here are some (Dino-scope)-shots' of the (140 pulse generator),with various pulse-widths'Picture filePicture filePicture filePicture filePicture file

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