Buchla 200X serie 208X build thread

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boops
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Re: Buchla 200X serie 208X build thread

Post by boops » Sat Jun 05, 2021 2:03 am

Last Build guide version available ,today,post 1.
208X 200X modules serie ,Buchla 200 upgraded viewtopic.php?f=17&t=243688&p=3444875#p3444875
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 price down atm/
HQ small case buchla psu PCB
viewtopic.php?p=3118393#3118393
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Re: Buchla 200X serie 208X build thread

Post by boops » Tue Jun 15, 2021 1:35 am

Last Build guide version 7 available ,today,post 1.
208X 200X modules serie ,Buchla 200 upgraded viewtopic.php?f=17&t=243688&p=3444875#p3444875
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 price down atm/
HQ small case buchla psu PCB
viewtopic.php?p=3118393#3118393
viewtopic.php?t=211862&highlight=

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Wed Jun 23, 2021 1:23 pm

Quick question: the switch on the tiny jack (preamp input) is there to short the input to ground when nothing is plugged in, is that correct?

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Re: Buchla 200X serie 208X build thread

Post by boops » Fri Jun 25, 2021 1:43 am

Radiance2021 wrote:
Wed Jun 23, 2021 1:23 pm
Quick question: the switch on the tiny jack (preamp input) is there to short the input to ground when nothing is plugged in, is that correct?
Yes exactly ,a classic design,then no noise from the preamp,not used .
208X 200X modules serie ,Buchla 200 upgraded viewtopic.php?f=17&t=243688&p=3444875#p3444875
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 price down atm/
HQ small case buchla psu PCB
viewtopic.php?p=3118393#3118393
viewtopic.php?t=211862&highlight=

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Mon Jul 05, 2021 11:16 am

Might want to check the build guide (7)...in the First test section some pin numbers are not correct.
Correct me if I'm wrong but this is what I'm getting.
N should be Pin 18
+15,-15 & Q are correct
+12 is not used on card 3 according to the schematic...

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Re: Buchla 200X serie 208X build thread

Post by boops » Tue Jul 06, 2021 2:01 am

I’m travelling now,no computer and 208x access,
Don’t forget to Check the 208x power /calibrations too,in the first post .
208X 200X modules serie ,Buchla 200 upgraded viewtopic.php?f=17&t=243688&p=3444875#p3444875
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 price down atm/
HQ small case buchla psu PCB
viewtopic.php?p=3118393#3118393
viewtopic.php?t=211862&highlight=

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Wed Jul 07, 2021 8:42 am

No pressure Boops ;-)

I did check both your guide, Dave's site and the schematic and thus came across the supposedly wrong pin numbers...
Anyway, powering up with cards 1 to 4 went smooth...no problems whatsoever except for some slight oscillations on the envelope output which I was able to tame with a 100pF cap across pin 12 & 14 of IC1 on card #3 as described on Dave's site....man that site is a real treasure trove!

One question: can someone explain to me what exactly happens (and the routing) when you switch between "Balanced External", "A.M Oscillator" and "F.M. Oscillator" on the MO? I'm kinda struggling to find this info in the manual.

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Sat Jul 10, 2021 11:20 am

Everything seems to be working as should, as in: basic functionality is there!
However, on card 12 the transistor array Q3,4,5,6 are getting really hot, more than 120C and I suspect this causes some audible and unexplainable weirdness...

Is it normal that these get so hot?

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Re: Buchla 200X serie 208X build thread

Post by boops » Tue Jul 13, 2021 2:27 am

Radiance2021 wrote:
Wed Jul 07, 2021 8:42 am
No pressure Boops ;-)

I did check both your guide, Dave's site and the schematic and thus came across the supposedly wrong pin numbers...
Anyway, powering up with cards 1 to 4 went smooth...no problems whatsoever except for some slight oscillations on the envelope output which I was able to tame with a 100pF cap across pin 12 & 14 of IC1 on card #3 as described on Dave's site....man that site is a real treasure trove!

One question: can someone explain to me what exactly happens (and the routing) when you switch between "Balanced External", "A.M Oscillator" and "F.M. Oscillator" on the MO? I'm kinda struggling to find this info in the manual.
Thanks for the feedback
Balanced ext :modulation by the external source in the preamp
Am :amplitude mod, mo on the co
Fm:frequency modulation

In the card 12 ,did you use the little heatsink?
Did you isolated the transistors?
208X 200X modules serie ,Buchla 200 upgraded viewtopic.php?f=17&t=243688&p=3444875#p3444875
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 price down atm/
HQ small case buchla psu PCB
viewtopic.php?p=3118393#3118393
viewtopic.php?t=211862&highlight=

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Tue Jul 13, 2021 3:22 am

Yes, I'm even using a bigger heat sink right now, and isolated the transistors off course...still getting very hot, I measure 120C but the actual temp on the transistor will be way hotter. I dare not put this into a case...Boops, how hot is a working card 12 supposed to get? How hot does yours get for example?

Also, another problem occurred. I'm not getting a triangle wave at pin 9, card 8. I suspect a blown DG200...all other IC's seem to be OK, but I don't have another DG200 to swap at the moment.

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Tue Jul 13, 2021 9:49 am

Well, swapping the LM301's I had from Banzai for ones I found at my local store fixed the triangle wave problem. Thing runs smoothly now.
Vactrols in the LPG give a very distinct sound, I clearly hear a difference between the three mode's.

As for the heat problem, it still runs HOT. Is there a way to turn the headphone amp down a little? It's going really loud now....could do with less power (and thus less heat)

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Re: Buchla 200X serie 208X build thread

Post by boops » Wed Jul 14, 2021 2:22 am

The transistors in card 12 are not really hot
Control your build,resistors value,solder joint,etc
208X 200X modules serie ,Buchla 200 upgraded viewtopic.php?f=17&t=243688&p=3444875#p3444875
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 price down atm/
HQ small case buchla psu PCB
viewtopic.php?p=3118393#3118393
viewtopic.php?t=211862&highlight=

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Wed Jul 14, 2021 7:56 am

I checked all this already, and I just did it again but everything checks out fine!...It's still getting HOT, and at this stage a schematic would be really help full
IMG_0264.JPG

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Thu Jul 15, 2021 7:29 am

I'll replace the BD437/8 ...might be fake/broken ones as well. They came, together with the faulty LM301's from Banzaiu Music.

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Sat Jul 17, 2021 5:09 am

Replaced the BD437/438, still getting hot. I powered the 12V part with my lab PSU and It's drawing 1,6 A .

Boops, can you tell me how hot yours is getting and how many amps it's drawing? This would really help.

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Tue Jul 20, 2021 9:27 am

Do the tiny jacks on the AUX card mirror the 3,5 Jacks ?

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Wed Jul 21, 2021 8:31 am

Radiance2021 wrote:
Tue Jul 20, 2021 9:27 am
Do the tiny jacks on the AUX card mirror the 3,5 Jacks ?
Ok, I figured the two tiny jack outputs out...
And as I understand, the tiny jack input is an unbuffered input that connects to the post-reverb signal of the 208.
Why would we need such an intput? Is it to sum an external signal with the post reverb signal?

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Thu Jul 22, 2021 7:04 am

Boops, no need to answer any of my questions. Figured it all out myself and with some help of Dave, who gave an very elaborate answer.

Thing is though. all this took quite some time and this could have been avoided if you just had given me the schematic.
But you did not because of (and I quote)"personal reasons" whatever that means.
I mean, what are you afraid of? It's not like you've invented something new on Card 12, it's all basic stuff which exist in the public domain.
If I was to make a copy of your design I would just scan the PCB.

Anyway, it all works now...

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Sat Jul 24, 2021 7:07 am

For the record, I thought I was having vactrols with no tail on card 11 so I swapped them for the ones (with tail) from card 10...result> no difference.
I thought this was strange so I started looking at the schematic an discovered that pin 12 & 13 from IC4, card 11 should be connected. I measured on my card 11 and discovered there was no continuity...connected the two and voila, instant bongo goodness.
Boops, is this connection missing on the PCB ? I could not find it on the picture nor on the actual board...

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Sun Jul 25, 2021 8:04 am

Is there anyone else building this project ATM? This thread is becoming a ghost town....

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Re: Buchla 200X serie 208X build thread

Post by boops » Sun Jul 25, 2021 12:00 pm

Radiance2021 wrote:
Sun Jul 25, 2021 8:04 am
Is there anyone else building this project ATM? This thread is becoming a ghost town....
As I ve written a few days ago,I travel now ,and I don’t have access to the files .Sorry.
Nice you have find your issues, Yourself .
Well done,I don’t checked the schematics,but no connection atm,on actual card 11 version,pin12/pin 13,(I have my 208X with me,)many thanks .
208X 200X modules serie ,Buchla 200 upgraded viewtopic.php?f=17&t=243688&p=3444875#p3444875
FS :custom buchla 203 style càbinet ,skiff new design,boat ,hardware for diy cabinet ,easel case ,new 1u to 10u to 56u and more. / New 208 buchla card 12 price down atm/
HQ small case buchla psu PCB
viewtopic.php?p=3118393#3118393
viewtopic.php?t=211862&highlight=

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Re: Buchla 200X serie 208X build thread

Post by Radiance2021 » Sun Jul 25, 2021 12:16 pm

I was more referring to possible other builders who have posted here before...

Have a nice vacation Boops!

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Re: Buchla 200X serie 208X build thread

Post by ikkini » Sun Jul 25, 2021 5:04 pm

Radiance2021 wrote:
Sun Jul 25, 2021 8:04 am
Is there anyone else building this project ATM? This thread is becoming a ghost town....
I've been away from home, but mine has still some issues to be fixed.

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