MOTM

Completed MOTM-320 pix at

www.synthtech.com/demo

as well as the MP3 demos of the JH/PS VC'd 12-stage phaser!

Paul S.

In a message dated 11/28/99 5:13:25 PM, synth1@... writes:

>Completed MOTM-320 pix at
>www.synthtech.com/demo

OK, I'll bite. Why the tempco with the (presumably) non-matched pair of 
transistors?

JB

Sorry, going to have to ponder more!

Yes, it is a tempco, and yes, it is in contact with 2 transistors.

Think, Grasshopper...........

Paul S.

----- Original Message ----- 

From: <JWBarlow@...>
To: <motm@onelist.com>
Sent: Sunday, November 28, 1999 11:19 PM
Subject: Re: [motm] Yes, Virginia, there is a LFO!


> From: JWBarlow@...
> 
> 
> In a message dated 11/28/99 5:13:25 PM, synth1@... writes:
> 
> >Completed MOTM-320 pix at
> >www.synthtech.com/demo
> 
> OK, I'll bite. Why the tempco with the (presumably) non-matched pair of 
> transistors?
> 
> JB
> 
> >

In a message dated 11/28/99 10:38:39 PM, synth1@... writes:

>Sorry, going to have to ponder more!

>Yes, it is a tempco, and yes, it is in contact with 2 transistors.

>Think, Grasshopper...........

I think they may come pre-matched -- though that seems like a lot of work!

Temp stabilization of the osc (similar to the 300).
Other grass eatin' stooge.
LH

----------

> From: Paul Schreiber <synth1@...>
> To: motm@onelist.com
> Subject: Re: [motm] Yes, Virginia, there is a LFO!
> Date: Sunday, November 28, 1999 11:39 PM
> 
> From: "Paul Schreiber" <synth1@...>
> 
> Sorry, going to have to ponder more!
> 
> Yes, it is a tempco, and yes, it is in contact with 2 transistors.
> 
> Think, Grasshopper...........
> 
> Paul S.
> 
> ----- Original Message ----- 
> From: <JWBarlow@...>
> To: <motm@onelist.com>
> Sent: Sunday, November 28, 1999 11:19 PM
> Subject: Re: [motm] Yes, Virginia, there is a LFO!
> 
> 
> > From: JWBarlow@...
> > 
> > 
> > In a message dated 11/28/99 5:13:25 PM, synth1@... writes:
> > 
> > >Completed MOTM-320 pix at
> > >www.synthtech.com/demo
> > 
> > OK, I'll bite. Why the tempco with the (presumably) non-matched pair of

> > transistors?
> > 
> > JB
> > 
> > > 
> 
>

Now that I see the back of the LFO and can see that it uses a dual color LED 
with only two leads, I can't understand that $5.40 cost for LED and cable 
assembly.  I would like to think Paul has wisely scanned catalogs and knows 
what's available, but I noticed awhile back that Mouser has virtually the 
same thing for a lot less money.  Pre-wired LED cable connection + lens + LED 
would cost closer to $2.  However a dual color LED as a bypass or active 
indicator on the VC Lag module is somewhat overkill anyway.

-Elhardt

On Mon, 29 Nov 1999 Elhardt@... wrote:

> Now that I see the back of the LFO and can see that it uses a dual color LED 
> with only two leads, I can't understand that $5.40 cost for LED and cable 
> assembly.

  There is also the polarity-reversing LED drive circuit to consider.
Granted, a 74LS00 will suffice, or some comparator/opamp output that
slopes between + and - wrt gnd, but it is an added cost.  Then there is
the circuit that interfaces the LED drive to the LFO itself.  It might be
trivial or it might be a bit more complicated--need to see the schem.

  I'm curious as to what the LED jumper row is for.

  I noticed a tempco on some differential pair.  Guess that is needed to
make those 10-minute cycles stay 10 minutes. :)

  --Crow

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