Have you still got it? I had one of these in the 60's but had to part with it. Although I'm now in my eighties I still do some work with valves and would love such an instrument. I live in Mid Wales.(Llanidloes)

Colin Walsh

In on 10 Nov 2009 09:45:09 -0500, in
rec.radio.amateur.boatanchors, 'Scott Dorsey' wrote:

Dave J. wrote:
If it measures characteristics of which I have only the faintest working
knowledge then by my standards it's complex enough.

What makes it complex is the fact that tubes all have different pinouts.
There are three or four controls on there that set voltages and loading for
the tube, and the rest of the controls just are for selecting the pinout.

If the 'curve tracers' you mention are the sort of tool I imagine from the
name then in those (pre d - a / computer) days they must have been
beautiful designs.

The curve tracer is basically a device like what you have, except that it
makes one parameter adjustable and displays a plot on a CRT of the plate
current with respect to that parameter. Some of them make two parameters
adjustable and display a family of curves.

Anything you can do with a curve tracer you can also do by hand with a
transconductance tester like you have, and a sheet of graph paper, and a
lot of labour making individual measurements and plotting the curve.
The transconductance tester is normally used for simple go/no go tests, and
for matching tubes based on their plate current at a single point in the
curve.


Yes, that sounds close to what I was picturing. Perhaps a LF oscillator
providing input(s) and a synchronised scope as a readout?

These days I imagine you'd produce a reasonable semblance by knocking up a
two way interface between a sound card and some breadboarded testkit?
Although preferably with a decent linear opto-isolator somewhere in
between

A PC makes quite a handy substitute for an audio 'scope. I'm slowly
meandering toward digging up the right 'back to basics' video capture card
to give me something that'll work at lowish RF. (maybe a few MHz) My
lifelong love of the tinkering perpetually exceeds my budget by a couple
of orders of magnitude.. ;-{

[..]

Hadn't thought of a guitar shop, though I'm surprised your average guitar
amp's all that fussy WRT valve specification? I'd have imagined more the
sort of pass/fail testing I'd cobble together as a psu/pot/avo birds-nest
on my workbench.

The guitar shops usually aren't too worried about that, but everyone would
rather have nice test equipment than poor test equipment.

Bit expensive for a pass/fail piece of kit I'd have thought. Although, I
s'pose it'd be one of those investments that won't drop in value too
quickly .


Thanks and apols for time-warped reply

Dave J.

In on Sun, 8 Nov 2009 10:49:54 +1100,
in rec.radio.amateur.boatanchors, 'MoiInAust' wrote:

"Dave J." wrote in message
...

I'm wondering if there's anyone here, local(ish) to me, who'd be
interested in an Avo Valve Characteristic Meter. My Dad recently passed
away and I've inherited it, along with a beautiful CR100 ex-Navy comms
receiver.

Are you prepared to deliver to Australia? G

Gladly!

If you'll pay the air fare ;-)

Baggage'd cost more than the ticket - it's a lovely old thing but probably
weighs more than me..

For that matter, if you'll include my better half, a boat ticket'd do the
job grin

Dave J.

"Dave J." wrote in message
...
In on Sun, 8 Nov 2009 10:49:54 +1100,
in rec.radio.amateur.boatanchors, 'MoiInAust' wrote:

"Dave J." wrote in message
...

I'm wondering if there's anyone here, local(ish) to me, who'd be
interested in an Avo Valve Characteristic Meter. My Dad recently passed
away and I've inherited it, along with a beautiful CR100 ex-Navy comms
receiver.

Are you prepared to deliver to Australia? G

Gladly!

If you'll pay the air fare ;-)

Baggage'd cost more than the ticket - it's a lovely old thing but probably
weighs more than me..

For that matter, if you'll include my better half, a boat ticket'd do the
job grin

Dave J.

Well, ship is how we came out here (at full cost I may say). The 6 week line
voyage was a wonderful experience. If I had the money I would gladly ask you
and your wife to bring the tester... but you might pass me going the other
way!

"MoiInAust" wrote in message
...

"Dave J." wrote in message
...
In on Sun, 8 Nov 2009 10:49:54 +1100,
in rec.radio.amateur.boatanchors, 'MoiInAust' wrote:

"Dave J." wrote in message
...

I'm wondering if there's anyone here, local(ish) to me, who'd be
interested in an Avo Valve Characteristic Meter. My Dad recently passed
away and I've inherited it, along with a beautiful CR100 ex-Navy comms
receiver.

Are you prepared to deliver to Australia? G

Gladly!

If you'll pay the air fare ;-)

Baggage'd cost more than the ticket - it's a lovely old thing but
probably
weighs more than me..

For that matter, if you'll include my better half, a boat ticket'd do the
job grin

Dave J.

Well, ship is how we came out here (at full cost I may say). The 6 week
line voyage was a wonderful experience. If I had the money I would gladly
ask you and your wife to bring the tester... but you might pass me going
the other way!
And by the way Dave, I don't think the AVO Mk 4 is all that heavy. What I
call heavy is my old AR88 at 100 lbs (or approx 45 Kilos!).

In on Mon, 30 Nov 2009 10:25:32 +1100,
in rec.radio.amateur.boatanchors, 'MoiInAust' wrote:


"MoiInAust" wrote in message
...

"Dave J." wrote in message
...
In on Sun, 8 Nov 2009 10:49:54 +1100,
in rec.radio.amateur.boatanchors, 'MoiInAust' wrote:

"Dave J." wrote in message
...

I'm wondering if there's anyone here, local(ish) to me, who'd be
interested in an Avo Valve Characteristic Meter. My Dad recently passed
away and I've inherited it, along with a beautiful CR100 ex-Navy comms
receiver.

Are you prepared to deliver to Australia? G

Gladly!

If you'll pay the air fare ;-)

Baggage'd cost more than the ticket - it's a lovely old thing but
probably
weighs more than me..

For that matter, if you'll include my better half, a boat ticket'd do the
job grin

Dave J.

Well, ship is how we came out here (at full cost I may say). The 6 week
line voyage was a wonderful experience.

Yes, that's roughly what I was thinking as I made the post, that as long
as I could bring the lovely lady I'd actually *prefer* to travel that way.

Aircraft seem too much like teleport, no real experience of how far you're
travelling.

If I had the money I would gladly
ask you and your wife to bring the tester... but you might pass me going
the other way!

Well, thanks for the thought :-) Her Ladyship has a brother over there and
he seems to prefer it overall. Apparently, the seasons seeming so skewed
is the only main drawback compared to this wet little island.

And by the way Dave, I don't think the AVO Mk 4 is all that heavy. What I
call heavy is my old AR88 at 100 lbs (or approx 45 Kilos!).

(Two posts for the price of one :-))

I've just looked it up and yes, that definitely appears to make the grade
as a full-fledged boatanchor!

I wonder what the CR100 weighs in at, it's heavier than the Avo. As an
aside, there seems to be a real commonality of appearance between
equipment from those days. I think it's just the control knobs/switches
plus the slightly yellowing meter movements.

I've just finished checking out what my Dad left me and I've found he or
my Mum binned (yes fricken BINNED) a large green box jam packed with
valves that I remember from my childhood. So I have some spares for the
comms box and nothing else :-(( They moved house to much smaller premises
and I guess storage cost outweighed memory. I just wish he'd warned me

Real shame as this newsgroup's poked my mind into daydreaming back to
childhood, playing with is it a 6SA7, 6ST7 maybe? Octal double triode
anyhow, along with some sort of 9pin pentode. Built a 7meg crystal oscy, a
couple of different VFOs and a little TRF radio. All with that CR100 sat
in the background to pick up any RF I managed to stick into the air

Ah, one day, one day. I'll get a chunk of workbench set aside for valve
experiments again. Trouble is that I first need a supply of valves. Some
of the above triodes, perhaps a few ecc83s (81s?) some old line-out valves
for some oomph and a 6V6 or two. Yeah, that'd do it... Amongst the
chuck-aways were a couple of 807s too.. :-( /daydream mode

Dave J.