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Subject: Re: vco preparation

From: "J. Larry Hendry" <jlarryh@...
Date: 1999-03-25

> From: Gur Milstein <gur-m@...>
> hi list.
> well its about time for me to prepare for the vco.
> i need to buy a scope but my question is how the tune caliberation
> is gone be,is the scope is the best way to tune your vco,
> or do i need to go for a freq counter ?
> allso can you guys give some tips on what is importent when going
> to buy a second hand scope,and what is a good price for 50Mhz ,
> and a good manufecture name..... ?
> its gone be hard for me to find where
> i leave the old TEK scope as Paul once suggest.
> thanx
> Gur Milstein

Here is a post from a while back from Paul in case you didn't happen to see
it or save it.
From: "Paul Schreiber" <synth1@...>

Since the VCO kit really requires a scope to really check it out, I went to and searched the current scope offerings. There were over 75
95% would work for analog synth poking around.

Here is a quick guide:

1) 50Mhz is all you need. 40 is OK, 20 is too slow, even for audio. Buy Tek
if you can (Tektronics).
2) Avoid the following:

HP: the HP17xx scopes are easily the worse product line in the history of
HP. ∗trust me∗
military: requires 4 people to lift it.
Dumont: tubes
Heathkit or Eico: crappy & more crappy

3) Good buys: Philips (vastly underrated scopes), B&K Precision (had one
8 years)

Note that 99% of these DO NOT come with probes. Meduim quality, 50Mhz
are about $35 ea.
and you will need 2.

4) Best solution if you have LOTS of room: Tek 7000 series. In the mid-80s
this was TEK's "flagship" line.
You get a 'mainframe' (power supply and CRT) with room for 'plug-ins'
(usually 4-wide). A dual-channel,
150Mhz delayed-sweep 7000 was $12,500 in 1984. Today, you can get the
∗exact∗ same configuration for $400!!

What's the catch??? Well, they are ∗BIG∗. About the size of 1 drawer in a
filing cabinet. In other words, they
are ∗DEEP∗. I mean like 28 inches deep. But, if you have the space
(depth-wise) these puppies rock the scope world.

I use a TEK TAS250 (2 ch, 50Mhz, no delayed sweep) for all MOTM check-out.
This is a smaller, lightweight portable
scope. I bought a "demo" unit off the web from a liquidator for $400. It
∗brand new in the box∗! This was a $1300 new
scope. I also have a TEK TDS380 2Ghz , 450Mhz sampling scope. I won't say
how much THAT cost: let's say that
∗replacement∗ probes are $395 each!!!

I you find something, and want me to go look at it, send me the URL of the
page (ebay has a cute feature that does this).

Paul Schreiber