BUILD THREAD: 266-style PCBs

jbaken · Post by **jbaken** » Tue Sep 18, 2012 12:00 am

@L-1
it looks like you didn't connect board 1 to board 2 with the thru connection (next to euro connector). also looks like your ribbon cable is upside down?

L-1 · Post by **L-1** » Tue Sep 18, 2012 12:41 am

Ribbon cables are correct.
V+ connected via ribbon cable from board1 to board3 and then to board2.
V- connected via ribbon cable between board3 and 2 but not connected to board1 where is power. It is an error. I've connected V- from board1 to 3 via wire, as it must to be.

camelneck · Post by **camelneck** » Sun Sep 23, 2012 10:40 pm

Roman's BOM for the 266 (Buchla & Euro Formats only) lists Small Bear as a parts source for the five B10K potentiometers. They cost $1.95 each.

Has anyone bought and used these pots (or equivalents) from Mouser?
If so, do they fit on the PCB properly?
Can you list (or verify) the Mouser or Alpha part number for these pots?

I'm almost sure that I have found the same Alpha pots (or equivalents) on the Mouser website for $1.11 each, but I'd like to know if someone can verify this for me. (Although I think Small Bear is a great company, buying them from Mouser would save me from having to place a second order and having to pay a 2nd shipping charge. The pots at Mouser are also considerably cheaper than those from Small Bear.)

Here is the part number and other information about these pots from Mouser.

Mouser Part #: 317-2090F-10K
Manufacturer Part #: RV09AF-40-20K-B10K (Alpha)
Type: miniature, vertical mount snap-in
Shaft Diameter: 6 mm
Shaft Length: 12.7 m
Resistance: 10 KOhms (0.1 Watt)
Shaft Type: Knurled / Serrated with 40 teeth
Termination Style: Snap In, Pin
Voltage Rating: 50 Volts
Datasheet: http://www.mouser.com/catalog/specsheets/TW-700167.pdf

I measured the pot pads on the PCB and compared these measurements with the dimensions listed on the datasheet and these pots look like they should fit on the PCB just fine. (This includes the 3 pot pins and the 2 mounting pins).

The only difference I see between these Mouser pots and the one pictured on the Small Bear website is the Small Bear pot appears to have a smooth shaft, whereas the Mouser pot is knurled or serrated. However, there are 40 teeth on the shaft (which is a lot more than most knurled shafts have) so I don't think it will be a major problem if you are using the Buchla-style (Davies) knobs. (Since these knobs have set screws they work best with smooth shafts.)

There were no specs on the Small Bear website except for the description:
Alpha Single-Gang 9mm Right-Angle PC Mount
Otherwise, if they had given the Alpha part number I would know for certain if this is the same pot.
http://www.smallbearelec.com/servlet/Detail?no=1139

ringstone · Post by **ringstone** » Sun Sep 23, 2012 10:51 pm

camelneck wrote:Roman's BOM for the 266 (Buchla & Euro Formats only) lists Small Bear as a parts source for the five B10K potentiometers. They cost $1.95 each.

Has anyone bought and used these pots (or equivalents) from Mouser?
If so, do they fit on the PCB properly?
Can you list (or verify) the Mouser or Alpha part number for these pots?

I'm almost sure that I have found the same Alpha pots (or equivalents) on the Mouser website for $1.11 each, but I'd like to know if someone can verify this for me. (Although I think Small Bear is a great company, buying them from Mouser would save me from having to place a second order and having to pay a 2nd shipping charge. The pots at Mouser are also considerably cheaper than those from Small Bear.)

Here is the part number and other information about these pots from Mouser.

Mouser Part #: 317-2090F-10K
Manufacturer Part #: RV09AF-40-20K-B10K (Alpha)
Type: miniature, vertical mount snap-in
Shaft Diameter: 6 mm
Shaft Length: 12.7 m
Resistance: 10 KOhms (0.1 Watt)
Shaft Type: Knurled / Serrated with 40 teeth
Termination Style: Snap In, Pin
Voltage Rating: 50 Volts
Datasheet: http://www.mouser.com/catalog/specsheets/TW-700167.pdf

I measured the pot pads on the PCB and compared these measurements with the dimensions listed on the datasheet and these pots look like they should fit on the PCB just fine. (This includes the 3 pot pins and the 2 mounting pins).

The only difference I see between these Mouser pots and the one pictured on the Small Bear website is the Small Bear pot appears to have a smooth shaft, whereas the Mouser pot is knurled or serrated. However, there are 40 teeth on the shaft (which is a lot more than most knurled shafts have) so I don't think it will be a major problem if you are using the Buchla-style (Davies) knobs. (Since these knobs have set screws they work best with smooth shafts.)

There were no specs on the Small Bear website except for the description:
Alpha Single-Gang 9mm Right-Angle PC Mount
Otherwise, if they had given the Alpha part number I would know for certain if this is the same pot.
http://www.smallbearelec.com/servlet/Detail?no=1139

I'm not sure Mouser even carry these pots (specified in the 266 BOM). They do carry the non right-angle version, but at $4.73 each, so over double the cost of Small Bear. Plus they only carry a few of the most common values.

The pot you are looking at on Mouser is probably a plastic shaft pot with no mounting hardware. It may well be fine, but I'd check the specs very carefully.

I find that buying pots for around 10+ projects at a time from Small Bear is the best way to go. You gain more advantage from price breaks that way.

Cheers
Blair

EDIT: Looking at that PDF you posted confirms these have no sleeve for mounting to the panel. I'm pretty sure these are the plastic shafts intended to have no knob, as you can see from the technical drawing there is a tick mark on the end of the shaft itself. In my experience you might have a problem finding a knob to fit on the shaft, even set screw.

camelneck · Post by **camelneck** » Sun Sep 23, 2012 11:31 pm

I have a few questions about LEDs.

1) I still haven't made up my mind whether to use the red LEDs as the older 266 modules used or blue LEDs as the 266e modules use. The red LEDs look more authentic, but personally, I prefer the look of blue LEDs.

Does anybody have a Mouser part number for a 3mm blue LED that they would recommend?

2) All 6 of the 266's LED drivers consists of a 2N1711 transistor and a 100 ohm resistor. The 100 ohm resistor seems a bit low in value (which means the LED current is probably too high) for modern day LED's.

Has anybody experimented with different transistors and/or resistor values as far as the LED driver circuits are concerned?

3) I know this is off-topic, but does anybody know the LED colors for a Buchla 281 (not a 281e)? I'm sure the 4 output LEDs are red, but are the other 4 LEDs, which are lit when the FGs are in Quadrature mode, suppose to be red or orange in color?

camelneck · Post by **camelneck** » Mon Sep 24, 2012 12:36 am

ringstone wrote:
EDIT: Looking at that PDF you posted confirms these have no sleeve for mounting to the panel. I'm pretty sure these are the plastic shafts intended to have no knob, as you can see from the technical drawing there is a tick mark on the end of the shaft itself. In my experience you might have a problem finding a knob to fit on the shaft, even set screw.

Thanks for the help Blair. You are absolutely right--these pots don't have a sleeve so there is no way to screw them to the front panel. I can't believe that I overlooked that! The shaft might be a little short, also. So scratch that idea!

Do you have the Alpha pot number for these pots?

If Mouser is charging $4.73 for the right-angled (horizontal) pots, the vertical pots are probably about the same price. So I guess it would be cheaper to buy them from Small Bear even if I have to pay a 2nd shipping charge.

Thanks again.

ringstone · Post by **ringstone** » Mon Sep 24, 2012 1:58 am

camelneck wrote:
ringstone wrote:
EDIT: Looking at that PDF you posted confirms these have no sleeve for mounting to the panel. I'm pretty sure these are the plastic shafts intended to have no knob, as you can see from the technical drawing there is a tick mark on the end of the shaft itself. In my experience you might have a problem finding a knob to fit on the shaft, even set screw.
Thanks for the help Blair. You are absolutely right--these pots don't have a sleeve so there is no way to screw them to the front panel. I can't believe that I overlooked that! The shaft might be a little short, also. So scratch that idea!

Do you have the Alpha pot number for these pots?

If Mouser is charging $4.73 for the right-angled (horizontal) pots, the vertical pots are probably about the same price. So I guess it would be cheaper to buy them from Small Bear even if I have to pay a 2nd shipping charge.

Thanks again.

No problems! I have been down this path myself before...

I'm not sure of the part no. of those vertical pots, a trawl through the Alpha web site might turn them up - but I've not found another supplier who actually stocks them with the sleeve for mounting to a panel, that's cheaper than Small Bear. 9mm pots are generally more expensive than their 16mm counterparts I'm afraid.

Cheers
Blair

roman_f · Post by **roman_f** » Mon Sep 24, 2012 2:25 am

hello guys
did anyone finish the 266 for Buchla or 5U?

i'm going to upload the build docs for Euro next days - just need to make them from scratch, since i have a new laptop

roman_f · Post by **roman_f** » Mon Sep 24, 2012 2:33 am

jbaken wrote:just finished building the euro version. everything seems to be working except the sample and hold. cant seem to get any output from it.. seems like its not responding to my clock input. ive tried running it without R16 and R35 and with 47ks in both spots (based on the buchla schematic). not sure what to try now. thoughts?

are you able to make another set of ribbon cables?
due to my experience there's a very high amount of bad cables
i'll never do any more project with ribbons - only with PLDs

i have 1 working unit on my desk and ready to help anyone with scoping

cleaninglady · Post by **cleaninglady** » Mon Sep 24, 2012 3:47 am

I've finished the build but this does not fit into a Doepfer box.

I'm not talking about depth here either ; the PCB's actually won't even fit between the rails.

I'm seriously bummed about his.

nickster · Post by **nickster** » Mon Sep 24, 2012 3:55 am

Edit question already answered sorry!

L-1 · Post by **L-1** » Mon Sep 24, 2012 4:22 am

cleaninglady wrote:I've finished the build but this does not fit into a Doepfer box.

I'm not talking about depth here either ; the PCB's actually won't even fit between the rails.

I'm seriously bummed about his.

It's easy to solve:

Don't fit:

Remove about 0.2mm from each side:

Now fit:

cleaninglady · Post by **cleaninglady** » Mon Sep 24, 2012 4:29 am

Thanks !! It would have been good to know before i finished the build.

Much appreciated , nonetheless...

marvkaye · Post by **marvkaye** » Mon Sep 24, 2012 7:12 am

Just curious what folks did for the 910pF capacitors that are called for? Couldn't find them in poly or mylar, decided to attach leads to some SMT 0805 MLCC NP0(C0G) hoping they'll be appropriate. Any thoughts?

<marv>

ringstone · Post by **ringstone** » Mon Sep 24, 2012 7:15 am

marvkaye wrote:Just curious what folks did for the 910pF capacitors that are called for? Couldn't find them in poly or mylar, decided to attach leads to some SMT 0805 MLCC NP0(C0G) hoping they'll be appropriate. Any thoughts?

<marv>

The BOM actually substituted 1nF ceramic ML caps.

Cheers
Blair

raisinbag · Post by **raisinbag** » Mon Sep 24, 2012 7:24 am

Is there a different bom than that one I have that calls for 910pf and there is a mouser number for it. I haven't built yet as I'm waiting for an official build doc for the euro. If I can use a 1n that would be easier as I have lots if those.

marvkaye · Post by **marvkaye** » Mon Sep 24, 2012 7:27 am

ringstone wrote:
marvkaye wrote:Just curious what folks did for the 910pF capacitors that are called for? Couldn't find them in poly or mylar, decided to attach leads to some SMT 0805 MLCC NP0(C0G) hoping they'll be appropriate. Any thoughts?

<marv>
The BOM actually substituted 1nF ceramic ML caps.

Cheers
Blair

Thanx, Blair... the 5U BOM still calls out the 910pF but the Mouser part number that goes with it actually references a 1nF poly. I hadn't noticed that before. I need to pay closer attention to those part lists.

<marv>

J3RK · Post by **J3RK** » Mon Sep 24, 2012 11:15 am

You can get 910pF in styrene from anywhere that sells them. I have them. I can't remember for sure, but I think I got them at Mouser.

J3RK · Post by **J3RK** » Mon Sep 24, 2012 11:16 am

roman_f wrote:hello guys
did anyone finish the 266 for Buchla or 5U?

i'm going to upload the build docs for Euro next days - just need to make them from scratch, since i have a new laptop

Good to see you're back up and running!

spotta · Post by **spotta** » Mon Sep 24, 2012 12:42 pm

cleaninglady wrote:I've finished the build but this does not fit into a Doepfer box.

I've just checked mine (I got worried!) and they go in fine on my Doepfer 9u low cost wood case.

Weird.

marvkaye · Post by **marvkaye** » Mon Sep 24, 2012 1:21 pm

J3RK wrote:You can get 910pF in styrene from anywhere that sells them. I have them. I can't remember for sure, but I think I got them at Mouser.

I've been looking (Mouser, DigiKey, etc, etc) and that's simply not a very popular value in the usual operating voltages we use (ie, less than 100V).. lots out there for 630V or 1KV (mica) but they're huge and expensive. There was a place mentioned here awhile back in another thread that seemed to have a great stock of all kinds of caps at reasonable prices, but I can't for the life of me remember exactly where I saw it. And "capacitor" surely isn't the most useful search term to try to narrow things down in the forums.......

Anyway, I'm gonna keep looking and if all else faiils I'll just fade back to that 1nF value, seems to be acceptable.

<Marv>

J3RK · Post by **J3RK** » Mon Sep 24, 2012 1:27 pm

Posted incorrect link. See below for the correct one.

J3RK · Post by **J3RK** » Mon Sep 24, 2012 1:27 pm

http://www.mouser.com/ProductDetail/Kem ... d6I59rw%3d

It looks like they don't have them in the styrene variety anymore.

marvkaye · Post by **marvkaye** » Mon Sep 24, 2012 2:48 pm

J3RK wrote:http://www.mouser.com/ProductDetail/Kem ... d6I59rw%3d

It looks like they don't have them in the styrene variety anymore.

Yes, that's a fact. Plus, $2.78 is kinda pricey, which is why I thought I'd make up my own using 0805 SMT ones. These guys are 1% and are only 32c apiece... I know adding leads is a PITA, but for $2,50/cap I would be willing to suffer through. Also, West Florida Components has 560pF and 350pF styrene for 25c apiece... those guys in parallel would work too.

<marv>

cleaninglady · Post by **cleaninglady** » Mon Sep 24, 2012 6:04 pm

spotta wrote:
cleaninglady wrote:I've finished the build but this does not fit into a Doepfer box.
I've just checked mine (I got worried!) and they go in fine on my Doepfer 9u low cost wood case.

Weird.

Yeah , go figure...

MUFF WIGGLER

MUFF WIGGLER

BUILD THREAD: 266-style PCBs