MOTM

Except for Dave "The Rocket" Bradley has anyone got a VCO up?

How are the instructions?

Like the new switches??

TEST those power cables!!

Paul S.

Hah! Great minds think alike!

I definitely like the new switches better. Finer threads on the barrel and a
backing nut to help protect against torque monsters (you know who you are!)

One thing in the instructions that gave me pause for a second was when they
casually ask you to solder the vias. I asked myself "Is he really asking me
to put solder in ALL the via holes?" After I thought for a second, I figured
that since it was a high performance circuit, soldering all the vias was in
fact justified. That's what I did, since it can't hurt anything.

Dave Bradley
Principal Software Engineer
Engineering Animation, Inc.
daveb@...

> -----Original Message-----
> From: Paul Schreiber [mailto:synth1@...]
> Sent: Friday, May 07, 1999 3:14 PM
> To: MOTM listserv
> Subject: [motm] VCO's wiggling yet?
>
>
> From: "Paul Schreiber" <synth1@...>
>
> Except for Dave "The Rocket" Bradley has anyone got a VCO up?
>
> How are the instructions?
>
> Like the new switches??
>
> TEST those power cables!!
>
> Paul S.
>
>
>
> ------------------------------------------------------------------------
> Wanting to get back in touch with old friends?
> http://www.onelist.com
> Reunite through a ONElist community.
>

Hi All:

I did get my VCO working yesterday but spent an inordinate amount of time
calibrating it. I really love the instructions (especially the theory of
operation). Yes, I had problems with the power cable and that added to the
time it took to calibrate it; I was able to fix the pins on it properly.

I do have a question for Paul and other VCO users: I'm experiencing a
frequency drop when I switch from soft to hard sync (with nothing at the sync
input!). At 1440 Hz in the hard sync position, it drops to about 1360 Hz in
soft sync. I don't hear a pitch drop at around 90 Hz (I don't trust my freq
counter at this low freq), so it seems to scale differently in the hard and
soft sync positions. Does anyone else notice this behavior?

Oh yeah! Filter 12 -- the filter that filters out all JB's bad jokes while
passing the incredibly small amount of content on the MOTM Onelist. Its
called a Low Brow filter. I've never used a Serge Variable Slope filter, but
Serge T. had said that it would be the best compliment to the Extended Range
Filter I already have -- an interesting filter concept if nothing else.

JB

>I did get my VCO working yesterday but spent an inordinate amount of time
>calibrating it. I really love the instructions (especially the theory of
>operation). Yes, I had problems with the power cable and that added to the
>time it took to calibrate it; I was able to fix the pins on it properly.

1) If you are use a freq counter, then use the SYNC I/O jack with the switch
set to SOFT.
This seems to make my freq counter the "happiest": ie not bouncing the
digits.

2) I take it you eventually were happy with the calibration.

3) Using a Pro2000 and a freq counter, I start in the middle of the pot
rotation and
can get to tracking point in about 1 minute. How long did it tke? What was
the
input device?

>
>I do have a question for Paul and other VCO users: I'm experiencing a
>frequency drop when I switch from soft to hard sync (with nothing at the

sync

>input!). At 1440 Hz in the hard sync position, it drops to about 1360 Hz in
>soft sync. I don't hear a pitch drop at around 90 Hz (I don't trust my freq
>counter at this low freq), so it seems to scale differently in the hard and
>soft sync positions. Does anyone else notice this behavior?

Look at the schematic. In SOFT mode, the sync pulse is feeding back into the
VCO.
So, it would not surprise me if it dropped some because of delays in the
circuit.

I haven't paid much attention to this: I will investigate.

The soft sync is a little "touchy" and I may need to adjust a R or C.

99% of the time, HARD sync is what you will use.

Paul S.

At 11:55 PM 5/7/99 -0400, you wrote:

>From: JWBarlow@...

>I do have a question for Paul and other VCO users: I'm experiencing a
>frequency drop when I switch from soft to hard sync (with nothing at the

sync

>input!). At 1440 Hz in the hard sync position, it drops to about 1360 Hz in
>soft sync. I don't hear a pitch drop at around 90 Hz (I don't trust my freq
>counter at this low freq), so it seems to scale differently in the hard and
>soft sync positions. Does anyone else notice this behavior?

I do not see frequency shifts when I switch the sync switch back and forth
in the two VCOs I've completed. I do see a drop if I switch to Lin and DC,
but that is documented.

Rocket Man

Thought! John: make sure you don't have the switches *reversed*!!

Paul Schreiber

-----Original Message-----
From: Dave Bradley <daveb@...>
To: motm@onelist.com <motm@onelist.com>
Date: Saturday, May 08, 1999 1:38 AM
Subject: Re: [motm] VCO's wiggling yet?

>From: Dave Bradley <daveb@...>
>
>At 11:55 PM 5/7/99 -0400, you wrote:
>>From: JWBarlow@...
>
>>I do have a question for Paul and other VCO users: I'm experiencing a
>>frequency drop when I switch from soft to hard sync (with nothing at the
>sync
>>input!). At 1440 Hz in the hard sync position, it drops to about 1360 Hz

in

>>soft sync. I don't hear a pitch drop at around 90 Hz (I don't trust my

freq

>>counter at this low freq), so it seems to scale differently in the hard

and

>>soft sync positions. Does anyone else notice this behavior?
>
>I do not see frequency shifts when I switch the sync switch back and forth
>in the two VCOs I've completed. I do see a drop if I switch to Lin and DC,
>but that is documented.
>
>Rocket Man
>
>------------------------------------------------------------------------
>ONElist: the best source for group communications.
>http://www.onelist.com
>Join today!
>

Thanks to Paul and Dave for checking their VCOs. As usual, it was my fault in
that I'd misconnected two of the wires to the sync switch at the PCB.
Apparently it isn't enough to read the directions, you have to follow them as
well! Damn! It's always somethin'. Everything is working properly now with no
significant pitch drop between the sync positions.

Even after taking it apart, and resoldering a few other places on the PCB, it
only needed a slight tweak to rescale it. I think the VCO has raised the
(already high) standard for MOTM kits!

But I still hate that heat sink compound!
JB

1) Whew! I can cross *that* off my list of worries!

2) Like I said before: heat-sink coumpound is NASTY to wash out.

Paul S.
still pole-vaulting

-----Original Message-----
From: JWBarlow@... <JWBarlow@...>
To: motm@onelist.com <motm@onelist.com>
Date: Saturday, May 08, 1999 2:51 PM
Subject: Re: [motm] VCO's wiggling yet?

>From: JWBarlow@...
>
>Thanks to Paul and Dave for checking their VCOs. As usual, it was my fault

in

>that I'd misconnected two of the wires to the sync switch at the PCB.
>Apparently it isn't enough to read the directions, you have to follow them

as

>well! Damn! It's always somethin'. Everything is working properly now with

no

>significant pitch drop between the sync positions.
>
>Even after taking it apart, and resoldering a few other places on the PCB,

it

>only needed a slight tweak to rescale it. I think the VCO has raised the
>(already high) standard for MOTM kits!
>
>But I still hate that heat sink compound!
>JB
>
>------------------------------------------------------------------------
>ONElist: the best source for group communications.
>http://www.onelist.com
>Join today!
>

Via holes are holes in the circuit board that you don't put component leads
in. They are there to connect a track on one side of the board to another.
The electrical connection is made by a layer of plating that gets deposited
in the holes during the board fabrication process. Look inside the holes in
a board to see this layer. However, it's microscopically thin, and it is
even possible to have hairline cracks that cause the connection to be broken.

Anyway, all those tinier than normal holes left over should be filled with
solder, but not the ones for the pots, the tempco resistor, or the wires
coming from the board. Hold the board up to a light to see if you have
missed any.

Why doesn't Paul have us solder these holes for all the kits? I suspect
because this is a higher performance circuit, and a denser design, but I'm
sure he can tell you his reasons.

Dave

At 09:46 PM 5/8/99 -0500, you wrote:

>From: "J. Larry Hendry" <jlarryh@...>

>> One thing in the instructions that gave me pause for a second was when
>they
>> casually ask you to solder the vias. I asked myself "Is he really asking
>me
>> to put solder in ALL the via holes?" After I thought for a second, I
>figured
>> that since it was a high performance circuit, soldering all the vias was
>in
>> fact justified. That's what I did, since it can't hurt anything.
>
>Huh? "Splain this to be better Lucy."
>
>Larry H
>
>
>
>
>------------------------------------------------------------------------
>Always wanted to set up a book club, but can't find the time?
>http://www.onelist.com
>Create an online book club through ONElist.
>

> I definitely like the new switches better. Finer threads on the barrel

and a

> backing nut to help protect against torque monsters (you know who you

are!)

I personally resemble that remark Dave.

> One thing in the instructions that gave me pause for a second was when

they

> casually ask you to solder the vias. I asked myself "Is he really asking

me

> to put solder in ALL the via holes?" After I thought for a second, I

figured

> that since it was a high performance circuit, soldering all the vias was

in

> fact justified. That's what I did, since it can't hurt anything.

Huh? "Splain this to be better Lucy."

Larry H

>
>Why doesn't Paul have us solder these holes for all the kits? I suspect
>because this is a higher performance circuit, and a denser design, but I'm
>sure he can tell you his reasons.

How about: "I always do this by habit but thought that others may need to be
instructed speciffically"

Or the Steve Martin version: "I FORGOT. EXCUUUUUUUUSE MEEEEEEEE!"

Paul S.
arrow through head

I have 2 up and running. Going to calibrate them tonight...

The instructions were wonderfull as usual. I especially liked the proximity
clues. One minor correction: page 2 parts list says that R52 220K is red red
orange, should be red red yellow.

The soldering of the via holes made me also think about going back and filling
my other MOTM boards. I guess one day I'll overhaul them, but not today as
they seem to be working OK.

The heat sink compound seems to be available in 2 flavors - silicon &
non-silicon. Don't know if it matters at all, as long as you do not get it on
your jeans ;-)

...jp


_______________________________________________________________________________

>From: motm@onelist.com on Fri, May 7, 1999 4:40 PM
>Subject: [motm] VCO's wiggling yet?
>To: MOTM listserv
>
>From: "Paul Schreiber" <synth1@...>
>
>Except for Dave "The Rocket" Bradley has anyone got a VCO up?
>
>How are the instructions?
>
>Like the new switches??
>
>TEST those power cables!!
>
>Paul S.
>

>The instructions were wonderfull as usual. I especially liked the proximity
>clues. One minor correction: page 2 parts list says that R52 220K is red

red

>orange, should be red red yellow.

%$@#$^@#!!

>
>The soldering of the via holes made me also think about going back and

filling

>my other MOTM boards. I guess one day I'll overhaul them, but not today as
>they seem to be working OK.

Sorry, I sort of do this on autopilot. If you go back to do this, use the
NO CLEAN solder!

>
>The heat sink compound seems to be available in 2 flavors - silicon &
>non-silicon. Don't know if it matters at all, as long as you do not get it

on

>your jeans ;-)

The silicon is better! But "goopier" and harder to clean-up.

Paul S.

> From: "Paul Schreiber" <synth1@...>
> How about: "I always do this by habit but thought that others may need to

be

> instructed speciffically"

I am one of those "may need to be instructed specifically kind of guys."
Guess now I will go back and do so with "no clean" on my previous modules.

> Or the Steve Martin version: "I FORGOT. EXCUUUUUUUUSE MEEEEEEEE!"
> Paul S.
> arrow through head

Of course he also said "I'm one wild and crazy guy." Probably because of
brain cells contstantly upset by that arrow through his head. <g>

Larry Hendry

Hey,

I finished building my VCO last night, late. Took 3 evenings, and is
definitely the most complex piece of electronics I've ever built. As usual,
I was amazed that it actually worked when I powered it up.

________________________________________________________
Dave Trenkel : improv@... : www.peak.org/~improv/

"...there will come a day when you won't have to use
gasoline. You'd simply take a cassette and put it in
your car, let it run. You'd have to have the proper
type of music. Like you take two sticks, put 'em
together, make fire. You take some notes and rub 'em
together - dum, dum, dum, dum - fire, cosmic fire."
-Sun Ra
________________________________________________________