Topics

Morning fun - working scope with no tubes?

 

Hi Robin,
You are referring to the Long Tail Pair which is an incredibly versatile circuit that has been used for over 80 years n tube circuits, transistor circuits, and integrated circuits.

Wikipedia includes the historical background of this circuit in their article on Differential Amplifiers (the Long tail Pair is a simple differential amplifier):
https://en.wikipedia.org/wiki/Differential_amplifier

An explanation of how the vacuum tube Long Tail Pair works is given at
http://www.valvewizard.co.uk/dcltp.html

Fender (and many others) used the Long Tail Pair as a phase inverter in their guitar amplifiers:
https://www.tdpri.com/threads/how-the-long-tail-pair-phase-inverter-works.519077/

Although the Long Tail Pair circuit was originally developed for vacuum tube amplifiers it is so general it works as well for transistors. This article describes how the transistor version works and how it is used extensively in IC OpAmps and Differential Comparators:
https://www.electronics-notes.com/articles/analogue_circuits/transistor/long-tailed-pair-circuit.php

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Robin_Birch
Sent: Friday, September 20, 2019 3:44 PM

Yes,
Designing stuff so that it was, as much as possible, independent of the particular characteristics of a given device as it aged or cane from various suppliers, was one of the great skills of tube design,.



--
Dennis Tillman W7PF
TekScopes Moderator

 

Hi Tom,
I just checked on-line dictionaries from Merriam-Webster, Webster's Online Dictionary, Cambridge English Dictionary, Collins English Dictionary, and on and on. They all provide definitions for it.

Uh Oh! Did I fall for your trick and prove your point because I was gullible enough to challenge your claim? :)

Dennis Tillman W7PF

-----Original Message-----
From: TekScopes@groups.io [mailto:TekScopes@groups.io] On Behalf Of Tom Miller
Sent: Friday, September 20, 2019 5:40 PM
To: TekScopes@groups.io
Subject: Re: [TekScopes] Morning fun - working scope with no tubes?

An old saw comes to mind here. Did you know the word gullible is not in the dictionary?

Regards




--
Dennis Tillman W7PF
TekScopes Moderator

 

An old saw comes to mind here. Did you know the word gullible is not in the dictionary?

Regards

On 9/20/2019 6:05 PM, Jamie Ostrowski wrote:
Chuck, do you know if the Bugle Boy, etc, tubes were even used in the
original builds, or what brand they used originally?

On Fri, Sep 20, 2019 at 5:00 PM Chuck Harris <cfharris@...> wrote:

That is something that few people understand.

Tektronix was trying to get state of the art performance
out of fairly common vacuum tubes..... but with as long
a vacuum tube life as they could reasonably manage. There
were a lot of tubes in these scopes. If reliability was
compromised, probability is you would be replacing a tube
every few months... sort of like the old color TV's...

This required them to use configurations that had cathode
bias to very high negative voltages, to keep the currents
effectively constant, and to use each stage with fairly low
gain, making the gain up over multiple stages. Linearity
was very important to tektronix engineers.

By the time a tektronix scope tube is starting to show a
noticeable reduction in performance in a tektronix scope,
it is dead, dead, dead... for the more basic circuits used
in tube testers, and audio amplifiers. And has been for
quite a while.

This is why tektronix stated in most all of their manuals
that the best tester for the tubes in your scope, was the
scope itself. They didn't believe very highly in tube
testers.

So, many of those spiffy bugle-boy tubes, that work just fine
in a scope, have had just about every last drop of goodness
extracted from them... And, will test bad in your fancy
Hickok tester.

Just a thought.

-Chuck Harris

Mlynch001 wrote:
I don’t have a dog in the hunt here, as I buying and fixing later model
solid state TEK scopes and other gear. It seems to me that a scope that
will function correctly at the frequencies that we request of them must be
just as demanding of the tubes? If all of this audiophool nonsense is
true, none of our scopes is worth a darn. I don’t have a $2500 power
cord, $150 receptacle, cryogenic treated breakers or wire. How does my
scope function and deliver usable results? Crap in . . . Crap out! Just
thinking out loud.


 

Yes,
Designing stuff so that it was, as much as possible, independent of the particular characteristics of a given device as it aged or cane from various suppliers, was one of the great skills of tube design,

Robin

On 20 Sep 2019, at 23:22, Chuck Harris <cfharris@...> wrote:

I think BB's were, as well as most any other high quality
brand. Tektronix made scopes, not radio tubes. They
tested what they sold, and designed their circuits so that
they generally were not too dependent on the exact characteristics
of the different tubes.

Bugle Boys were just ordinary tubes that you might find at
your local drugstore, or TV repair store.

-Chuck Harris

Jamie Ostrowski wrote:
Chuck, do you know if the Bugle Boy, etc, tubes were even used in the
original builds, or what brand they used originally?

On Fri, Sep 20, 2019 at 5:00 PM Chuck Harris <cfharris@...> wrote:

That is something that few people understand.

Tektronix was trying to get state of the art performance
out of fairly common vacuum tubes..... but with as long
a vacuum tube life as they could reasonably manage. There
were a lot of tubes in these scopes. If reliability was
compromised, probability is you would be replacing a tube
every few months... sort of like the old color TV's...

This required them to use configurations that had cathode
bias to very high negative voltages, to keep the currents
effectively constant, and to use each stage with fairly low
gain, making the gain up over multiple stages. Linearity
was very important to tektronix engineers.

By the time a tektronix scope tube is starting to show a
noticeable reduction in performance in a tektronix scope,
it is dead, dead, dead... for the more basic circuits used
in tube testers, and audio amplifiers. And has been for
quite a while.

This is why tektronix stated in most all of their manuals
that the best tester for the tubes in your scope, was the
scope itself. They didn't believe very highly in tube
testers.

So, many of those spiffy bugle-boy tubes, that work just fine
in a scope, have had just about every last drop of goodness
extracted from them... And, will test bad in your fancy
Hickok tester.

Just a thought.

-Chuck Harris

Mlynch001 wrote:
I don’t have a dog in the hunt here, as I buying and fixing later model
solid state TEK scopes and other gear. It seems to me that a scope that
will function correctly at the frequencies that we request of them must be
just as demanding of the tubes? If all of this audiophool nonsense is
true, none of our scopes is worth a darn. I don’t have a $2500 power
cord, $150 receptacle, cryogenic treated breakers or wire. How does my
scope function and deliver usable results? Crap in . . . Crap out! Just
thinking out loud.





Mlynch001
 

Chuck,

As always, I enjoy all information that you bring out in your posts.

Thanks!

--
Michael Lynch
Dardanelle, AR

Jamie Ostrowski
 

Thanks for all the info, Chuck. Very informative.

On Fri, Sep 20, 2019 at 5:17 PM Chuck Harris <cfharris@...> wrote:

In some uses, the tube type was pretty important.
Heathkit was forever banning this brand, or that from
use in their amateur radio equipment. This was because
there were subtle differences in inter-electrode capacitances,
and gain curves between the different maker's same numbered
tubes. A GE 12AX7 might not work, but an Amperex might. It
was also because they were working the tubes pretty hard.

Audio amplifiers work their tubes pretty hard too, and often
have been cheapened in ways that make them rely on the quirky
characteristics of certain brands of tubes. Only certain
makers of 6V6's would sound right in the old Fender amplifiers.
And, that was in the 50's and 60's.. tube's hay day. Most of
the newer Russian copies won't work right with the simple biasing
methods Fender used. They don't distort right at the right
setting of the volume controls.

Remember, the different makers did not get their tube designs
from the originator of the tube type. They designed their
own to match the original maker's specs, and to work well with
their manufacturing capabilities. Some were better than others.

Many brands actually bought their tubes from other vendors. For
instance Silvertone never made a single vacuum tube, and yet they
sold millions under their brand

I think there were fewer than a dozen tube manufacturers in the
peak of tube usage. And those that were there often filled out
their line by buying from other makers.

-Chuck Harris

Jamie Ostrowski wrote:
Yes I think that is a good question.

I asked a similar question about a month ago to this group if I needed to
be concerned about whether the say, 12AX7 with the special D getter,
black
plate, et al 12AX7's being sold on ebay were equal to a standard GE 12AX7
in one of my oscilloscopes, and the answer I got from some of the
brightest
minds here was that there was no difference. I could use any 12AX7.
(Granted I would stay away from the Chinese stuff).

We could probably be sure of the answer to that if we knew what brand of
tubes were used in these scopes when they were manufactured. If the
answer
was GE, RCA, Sylvania tubes, then we would know right away that there
could
be no negative impact.

But most of these scopes have had their tubes replaced throughout the
years. I don't know what tube brands were originally installed.



Chuck Harris
 

I think BB's were, as well as most any other high quality
brand. Tektronix made scopes, not radio tubes. They
tested what they sold, and designed their circuits so that
they generally were not too dependent on the exact characteristics
of the different tubes.

Bugle Boys were just ordinary tubes that you might find at
your local drugstore, or TV repair store.

-Chuck Harris

Jamie Ostrowski wrote:

Chuck, do you know if the Bugle Boy, etc, tubes were even used in the
original builds, or what brand they used originally?

On Fri, Sep 20, 2019 at 5:00 PM Chuck Harris <cfharris@...> wrote:

That is something that few people understand.

Tektronix was trying to get state of the art performance
out of fairly common vacuum tubes..... but with as long
a vacuum tube life as they could reasonably manage. There
were a lot of tubes in these scopes. If reliability was
compromised, probability is you would be replacing a tube
every few months... sort of like the old color TV's...

This required them to use configurations that had cathode
bias to very high negative voltages, to keep the currents
effectively constant, and to use each stage with fairly low
gain, making the gain up over multiple stages. Linearity
was very important to tektronix engineers.

By the time a tektronix scope tube is starting to show a
noticeable reduction in performance in a tektronix scope,
it is dead, dead, dead... for the more basic circuits used
in tube testers, and audio amplifiers. And has been for
quite a while.

This is why tektronix stated in most all of their manuals
that the best tester for the tubes in your scope, was the
scope itself. They didn't believe very highly in tube
testers.

So, many of those spiffy bugle-boy tubes, that work just fine
in a scope, have had just about every last drop of goodness
extracted from them... And, will test bad in your fancy
Hickok tester.

Just a thought.

-Chuck Harris

Mlynch001 wrote:
I don’t have a dog in the hunt here, as I buying and fixing later model
solid state TEK scopes and other gear. It seems to me that a scope that
will function correctly at the frequencies that we request of them must be
just as demanding of the tubes? If all of this audiophool nonsense is
true, none of our scopes is worth a darn. I don’t have a $2500 power
cord, $150 receptacle, cryogenic treated breakers or wire. How does my
scope function and deliver usable results? Crap in . . . Crap out! Just
thinking out loud.




Chuck Harris
 

In some uses, the tube type was pretty important.
Heathkit was forever banning this brand, or that from
use in their amateur radio equipment. This was because
there were subtle differences in inter-electrode capacitances,
and gain curves between the different maker's same numbered
tubes. A GE 12AX7 might not work, but an Amperex might. It
was also because they were working the tubes pretty hard.

Audio amplifiers work their tubes pretty hard too, and often
have been cheapened in ways that make them rely on the quirky
characteristics of certain brands of tubes. Only certain
makers of 6V6's would sound right in the old Fender amplifiers.
And, that was in the 50's and 60's.. tube's hay day. Most of
the newer Russian copies won't work right with the simple biasing
methods Fender used. They don't distort right at the right
setting of the volume controls.

Remember, the different makers did not get their tube designs
from the originator of the tube type. They designed their
own to match the original maker's specs, and to work well with
their manufacturing capabilities. Some were better than others.

Many brands actually bought their tubes from other vendors. For
instance Silvertone never made a single vacuum tube, and yet they
sold millions under their brand

I think there were fewer than a dozen tube manufacturers in the
peak of tube usage. And those that were there often filled out
their line by buying from other makers.

-Chuck Harris

Jamie Ostrowski wrote:

Yes I think that is a good question.

I asked a similar question about a month ago to this group if I needed to
be concerned about whether the say, 12AX7 with the special D getter, black
plate, et al 12AX7's being sold on ebay were equal to a standard GE 12AX7
in one of my oscilloscopes, and the answer I got from some of the brightest
minds here was that there was no difference. I could use any 12AX7.
(Granted I would stay away from the Chinese stuff).

We could probably be sure of the answer to that if we knew what brand of
tubes were used in these scopes when they were manufactured. If the answer
was GE, RCA, Sylvania tubes, then we would know right away that there could
be no negative impact.

But most of these scopes have had their tubes replaced throughout the
years. I don't know what tube brands were originally installed.

Jamie Ostrowski
 

Chuck, do you know if the Bugle Boy, etc, tubes were even used in the
original builds, or what brand they used originally?

On Fri, Sep 20, 2019 at 5:00 PM Chuck Harris <cfharris@...> wrote:

That is something that few people understand.

Tektronix was trying to get state of the art performance
out of fairly common vacuum tubes..... but with as long
a vacuum tube life as they could reasonably manage. There
were a lot of tubes in these scopes. If reliability was
compromised, probability is you would be replacing a tube
every few months... sort of like the old color TV's...

This required them to use configurations that had cathode
bias to very high negative voltages, to keep the currents
effectively constant, and to use each stage with fairly low
gain, making the gain up over multiple stages. Linearity
was very important to tektronix engineers.

By the time a tektronix scope tube is starting to show a
noticeable reduction in performance in a tektronix scope,
it is dead, dead, dead... for the more basic circuits used
in tube testers, and audio amplifiers. And has been for
quite a while.

This is why tektronix stated in most all of their manuals
that the best tester for the tubes in your scope, was the
scope itself. They didn't believe very highly in tube
testers.

So, many of those spiffy bugle-boy tubes, that work just fine
in a scope, have had just about every last drop of goodness
extracted from them... And, will test bad in your fancy
Hickok tester.

Just a thought.

-Chuck Harris

Mlynch001 wrote:
I don’t have a dog in the hunt here, as I buying and fixing later model
solid state TEK scopes and other gear. It seems to me that a scope that
will function correctly at the frequencies that we request of them must be
just as demanding of the tubes? If all of this audiophool nonsense is
true, none of our scopes is worth a darn. I don’t have a $2500 power
cord, $150 receptacle, cryogenic treated breakers or wire. How does my
scope function and deliver usable results? Crap in . . . Crap out! Just
thinking out loud.


Chuck Harris
 

That is something that few people understand.

Tektronix was trying to get state of the art performance
out of fairly common vacuum tubes..... but with as long
a vacuum tube life as they could reasonably manage. There
were a lot of tubes in these scopes. If reliability was
compromised, probability is you would be replacing a tube
every few months... sort of like the old color TV's...

This required them to use configurations that had cathode
bias to very high negative voltages, to keep the currents
effectively constant, and to use each stage with fairly low
gain, making the gain up over multiple stages. Linearity
was very important to tektronix engineers.

By the time a tektronix scope tube is starting to show a
noticeable reduction in performance in a tektronix scope,
it is dead, dead, dead... for the more basic circuits used
in tube testers, and audio amplifiers. And has been for
quite a while.

This is why tektronix stated in most all of their manuals
that the best tester for the tubes in your scope, was the
scope itself. They didn't believe very highly in tube
testers.

So, many of those spiffy bugle-boy tubes, that work just fine
in a scope, have had just about every last drop of goodness
extracted from them... And, will test bad in your fancy
Hickok tester.

Just a thought.

-Chuck Harris

Mlynch001 wrote:

I don’t have a dog in the hunt here, as I buying and fixing later model solid state TEK scopes and other gear. It seems to me that a scope that will function correctly at the frequencies that we request of them must be just as demanding of the tubes? If all of this audiophool nonsense is true, none of our scopes is worth a darn. I don’t have a $2500 power cord, $150 receptacle, cryogenic treated breakers or wire. How does my scope function and deliver usable results? Crap in . . . Crap out! Just thinking out loud.

Jamie Ostrowski
 

Yes I think that is a good question.

I asked a similar question about a month ago to this group if I needed to
be concerned about whether the say, 12AX7 with the special D getter, black
plate, et al 12AX7's being sold on ebay were equal to a standard GE 12AX7
in one of my oscilloscopes, and the answer I got from some of the brightest
minds here was that there was no difference. I could use any 12AX7.
(Granted I would stay away from the Chinese stuff).

We could probably be sure of the answer to that if we knew what brand of
tubes were used in these scopes when they were manufactured. If the answer
was GE, RCA, Sylvania tubes, then we would know right away that there could
be no negative impact.

But most of these scopes have had their tubes replaced throughout the
years. I don't know what tube brands were originally installed.

On Fri, Sep 20, 2019 at 12:43 PM Mlynch001 <@mlynch001> wrote:

I don’t have a dog in the hunt here, as I buying and fixing later model
solid state TEK scopes and other gear. It seems to me that a scope that
will function correctly at the frequencies that we request of them must be
just as demanding of the tubes? If all of this audiophool nonsense is
true, none of our scopes is worth a darn. I don’t have a $2500 power
cord, $150 receptacle, cryogenic treated breakers or wire. How does my
scope function and deliver usable results? Crap in . . . Crap out! Just
thinking out loud.

--
Michael Lynch
Dardanelle, AR



Mlynch001
 

I don’t have a dog in the hunt here, as I buying and fixing later model solid state TEK scopes and other gear. It seems to me that a scope that will function correctly at the frequencies that we request of them must be just as demanding of the tubes? If all of this audiophool nonsense is true, none of our scopes is worth a darn. I don’t have a $2500 power cord, $150 receptacle, cryogenic treated breakers or wire. How does my scope function and deliver usable results? Crap in . . . Crap out! Just thinking out loud.

--
Michael Lynch
Dardanelle, AR

Harvey White
 

I'm not sure that this group is a significant source of tube type anything (let alone oscilloscopes) to the audio market.

If you're going to do such a thing, then at least keep the matched and selected pairs where they were.

Harvey

On 9/19/2019 9:27 PM, Jamie Ostrowski wrote:
If I'm understanding your solution correctly, you're suggesting we all
raise the price on our oscilloscopes we sell to a price that is equal to
the cost of the individual components in the unit all together. We may as
well consider the transformers, because in audiophool circles they value
these, despite the problems with the epoxy-based transformers being a huge
problem. They tout them as "extremely reliable". I suppose because they're
big and heavy(?)

In the solution I proposed, you could just as well take out the Telefunken
tubes and sell them separately for a higher price, and replace them with GE
or RCA tubes, which are no lesser the tube in an oscilloscope. You would
increase your own profit, and create at the same time a trend in the market
- that the Tektronix oscilloscopes do not have the tubes favored by
audiophiles. If you have a concern your oscilloscope will go to a party
with ill-intent, you could even state that in the advertisement. They will
quit buying them for scrapping, you will increase your own profit, and more
old oscilloscopes will live to see tomorrow. There is a significant price
difference between some GE tubes and some Telefunkens, without any
performance cost to the scope as far as I'm aware of.











On Thu, Sep 19, 2019 at 7:59 PM Chuck Harris <cfharris@...> wrote:

Ok, come up with your own solution.

The less valuable tubes that never sell on ebay don't
sell for much, and as such don't add much to the price
model.

I once calculated it out for a 585A, and came up with
$300 for ebay completed auction prices.

The 585A has a forest of 6DJ8's, which the audiofools
value quite highly, even though they are very common.

One $0.50 6AL5 doesn't skew the model enough to even
comment about.

-Chuck Harris

Jamie Ostrowski wrote:
I don't think that formula for calculating the price of the oscilloscope
makes any sense. There isn't much demand for most of the tubes in that
oscilloscope. All harvesters are interested in is the audio tubes. The
remaining tubes in that oscilloscope will sit on ebay for years and years
and years. In other words, they're mostly worthless.



Alberto I2PHD
 

The mother of idiots is always pregnant...

Dave Seiter
 

I passed on a 5xx scope at an estate sale back in the spring for $10;  it had been offered for $150 two days earlier.  It was an X/Y, so I wasn't really interested.  In retrospect, for the price I should have grabbed it.  
-Dave

On Thursday, September 19, 2019, 08:41:17 PM PDT, Jamie Ostrowski <jamie.ostrowski@...> wrote:

Yeah this has been an interesting conversation. It has given me some new
perspectives on things. I think that is a very fair suggestion. I'd love to
see more cooperation between the audiophools and scope guys. I wouldn't
mind buying a cheap scope without tubes and loading it myself. I just hate
to see them tossed out.

For the record, I don't expect to buy any Tek scope for $50, although from
time to time they appear. A few months ago I purchased a 531A for $75 with
a cart. Granted I drove a couple hundred miles to pick it up but I enjoyed
the road trip!

The 500 series scopes selling on ebay, fb, et al, for $200+ dollars sit
there for months before they vanish with "best offer accepted" or get
re-listed over and over again. This does seem to be growing trend. Based on
what I have seen, a lot of the scopes seem to be sold by people who don't
know what an oscilloscope is, but they inherited it, and they are using the
ebay listed prices as a baseline.


On Thu, Sep 19, 2019 at 10:19 PM Chuck Harris <cfharris@...> wrote:

My suggestion is when you see a tube harvester
that has separated the scope from the tubes, make
him an offer that is high enough to encourage him
to sell the scope to you with tubes... assuming
you really want the scope.

We all like bargains, but a $50 535 doesn't match
the reality of the value of the parts anymore.

If you think it does, then you are demonstrably
mistaken, and really have no cause to complain.

-Chuck Harris

Jamie Ostrowski wrote:
If I'm understanding your solution correctly, you're suggesting we all
raise the price on our oscilloscopes we sell to a price that is equal to
the cost of the individual components in the unit all together. We may as
well consider the transformers, because in audiophool circles they value
these, despite the problems with the epoxy-based transformers being a
huge
problem. They tout them as "extremely reliable". I suppose because
they're
big and heavy(?)

In the solution I proposed, you could just as well take out the
Telefunken
tubes and sell them separately for a higher price, and replace them with
GE
or RCA tubes, which are no lesser the tube in an oscilloscope. You would
increase your own profit, and create at the same time a trend in the
market
- that the Tektronix oscilloscopes do not have the tubes favored by
audiophiles. If you have a concern your oscilloscope will go to a party
with ill-intent, you could even state that in the advertisement. They
will
quit buying them for scrapping, you will increase your own profit, and
more
old oscilloscopes will live to see tomorrow. There is a significant price
difference between some GE tubes and some Telefunkens, without any
performance cost to the scope as far as I'm aware of.











On Thu, Sep 19, 2019 at 7:59 PM Chuck Harris <cfharris@...> wrote:

Ok, come up with your own solution.

The less valuable tubes that never sell on ebay don't
sell for much, and as such don't add much to the price
model.

I once calculated it out for a 585A, and came up with
$300 for ebay completed auction prices.

The 585A has a forest of 6DJ8's, which the audiofools
value quite highly, even though they are very common.

One $0.50 6AL5 doesn't skew the model enough to even
comment about.

-Chuck Harris

Jamie Ostrowski wrote:
I don't think that formula for calculating the price of the
oscilloscope
makes any sense. There isn't much demand for most of the tubes in that
oscilloscope. All harvesters are interested in is the audio tubes. The
remaining tubes in that oscilloscope will sit on ebay for years and
years
and years. In other words, they're mostly worthless.







Jamie Ostrowski
 

Well look on ebay for 12AX7 and sort by price, lowest first. There's a lot
of GE tubes on there for a lot less than the Amperex or Telefunken tubes.

Have a forest of them in your old scope? Sell them on ebay and put in a set
of GE's, RCA's, or Sylvanias. Pocket the difference. Your scope will be
just as happy, audiophools will have a new flood of their precious tubes on
ebay, and everyone will be happy.

On Thu, Sep 19, 2019 at 11:28 PM ykochcal <Kochcal@...> wrote:


Now for real audio you have to go all the way

" My circuit breakers have been cryo'ed and yes you can hear the
difference."
https://www.audioasylum.com/cgi/vt.mpl?f=tweaks&m=199820&VT=T


.....


Now for audio, which is best to buy, hydro, coal, Natural gas, solar or
nuclear electricity?

Now seriously:

I have some 500 scopes that were scrapped for tubes plus misc, have some
that I paid $20-$30 for (in California) just so they would not be scrapped,
some I don't have that were trashed before I made that offer.

You can't save every scope.

And I know there is no truth to it but I presume a lot of us have too
"many"
already.
Or from an outsiders perspective is that a similar but different sort of
obsession as cryo'ed audio.

Now if I ran across a pair of those gold plated horn boy tubes with just
the
right getter and plates, I would possibly be tempted pull them and replace
it with a good old tube or one of the new manufactured Eastern tubes.

Has anyone tried new "eastern" tubes in a scope?

If scopes in your area are more then $20 -30 you could look at buying,
pulling the "good audio tubes" selling and replacing them with the scope
good/audio bad tubes.

Could you come out ahead?
If so it would solve the problem.
If not, unhappy scope people need to fork over more cash.

So far I have other stuff I have always done first.

John
P.S. Thanks all for some entertainment tonight





ykochcal
 

Now for real audio you have to go all the way

" My circuit breakers have been cryo'ed and yes you can hear the
difference."
https://www.audioasylum.com/cgi/vt.mpl?f=tweaks&m=199820&VT=T


.....


Now for audio, which is best to buy, hydro, coal, Natural gas, solar or
nuclear electricity?

Now seriously:

I have some 500 scopes that were scrapped for tubes plus misc, have some
that I paid $20-$30 for (in California) just so they would not be scrapped,
some I don't have that were trashed before I made that offer.

You can't save every scope.

And I know there is no truth to it but I presume a lot of us have too "many"
already.
Or from an outsiders perspective is that a similar but different sort of
obsession as cryo'ed audio.

Now if I ran across a pair of those gold plated horn boy tubes with just the
right getter and plates, I would possibly be tempted pull them and replace
it with a good old tube or one of the new manufactured Eastern tubes.

Has anyone tried new "eastern" tubes in a scope?

If scopes in your area are more then $20 -30 you could look at buying,
pulling the "good audio tubes" selling and replacing them with the scope
good/audio bad tubes.

Could you come out ahead?
If so it would solve the problem.
If not, unhappy scope people need to fork over more cash.

So far I have other stuff I have always done first.

John
P.S. Thanks all for some entertainment tonight

Jamie Ostrowski
 

Well, it looks like the mailman may have stripped my image:
http://www.packetry.com/546.png

If I was less naive and watching my wife's spending, I would not have to be
so frugal, but circumstances dictate my financial stretch for the time
being. Lessons learned.

On Thu, Sep 19, 2019 at 11:03 PM Jamie Ostrowski via Groups.Io
<jamie.ostrowski=gmail.com@groups.io> wrote:

I also picked up this 546 for $35 a couple of months ago...complete, but it
is going to need some work. That's ok! What fun is a puzzle that's already
assembled? :-)

[image: image.png]

On Thu, Sep 19, 2019 at 10:41 PM Jamie Ostrowski via Groups.Io
<jamie.ostrowski=gmail.com@groups.io> wrote:

Yeah this has been an interesting conversation. It has given me some new
perspectives on things. I think that is a very fair suggestion. I'd love
to
see more cooperation between the audiophools and scope guys. I wouldn't
mind buying a cheap scope without tubes and loading it myself. I just
hate
to see them tossed out.

For the record, I don't expect to buy any Tek scope for $50, although
from
time to time they appear. A few months ago I purchased a 531A for $75
with
a cart. Granted I drove a couple hundred miles to pick it up but I
enjoyed
the road trip!

The 500 series scopes selling on ebay, fb, et al, for $200+ dollars sit
there for months before they vanish with "best offer accepted" or get
re-listed over and over again. This does seem to be growing trend. Based
on
what I have seen, a lot of the scopes seem to be sold by people who don't
know what an oscilloscope is, but they inherited it, and they are using
the
ebay listed prices as a baseline.


On Thu, Sep 19, 2019 at 10:19 PM Chuck Harris <cfharris@...>
wrote:

My suggestion is when you see a tube harvester
that has separated the scope from the tubes, make
him an offer that is high enough to encourage him
to sell the scope to you with tubes... assuming
you really want the scope.

We all like bargains, but a $50 535 doesn't match
the reality of the value of the parts anymore.

If you think it does, then you are demonstrably
mistaken, and really have no cause to complain.

-Chuck Harris

Jamie Ostrowski wrote:
If I'm understanding your solution correctly, you're suggesting we
all
raise the price on our oscilloscopes we sell to a price that is equal
to
the cost of the individual components in the unit all together. We
may
as
well consider the transformers, because in audiophool circles they
value
these, despite the problems with the epoxy-based transformers being a
huge
problem. They tout them as "extremely reliable". I suppose because
they're
big and heavy(?)

In the solution I proposed, you could just as well take out the
Telefunken
tubes and sell them separately for a higher price, and replace them
with
GE
or RCA tubes, which are no lesser the tube in an oscilloscope. You
would
increase your own profit, and create at the same time a trend in the
market
- that the Tektronix oscilloscopes do not have the tubes favored by
audiophiles. If you have a concern your oscilloscope will go to a
party
with ill-intent, you could even state that in the advertisement. They
will
quit buying them for scrapping, you will increase your own profit,
and
more
old oscilloscopes will live to see tomorrow. There is a significant
price
difference between some GE tubes and some Telefunkens, without any
performance cost to the scope as far as I'm aware of.











On Thu, Sep 19, 2019 at 7:59 PM Chuck Harris <cfharris@...>
wrote:

Ok, come up with your own solution.

The less valuable tubes that never sell on ebay don't
sell for much, and as such don't add much to the price
model.

I once calculated it out for a 585A, and came up with
$300 for ebay completed auction prices.

The 585A has a forest of 6DJ8's, which the audiofools
value quite highly, even though they are very common.

One $0.50 6AL5 doesn't skew the model enough to even
comment about.

-Chuck Harris

Jamie Ostrowski wrote:
I don't think that formula for calculating the price of the
oscilloscope
makes any sense. There isn't much demand for most of the tubes in
that
oscilloscope. All harvesters are interested in is the audio tubes.
The
remaining tubes in that oscilloscope will sit on ebay for years and
years
and years. In other words, they're mostly worthless.











Jamie Ostrowski
 

I also picked up this 546 for $35 a couple of months ago...complete, but it
is going to need some work. That's ok! What fun is a puzzle that's already
assembled? :-)

[image: image.png]

On Thu, Sep 19, 2019 at 10:41 PM Jamie Ostrowski via Groups.Io
<jamie.ostrowski=gmail.com@groups.io> wrote:

Yeah this has been an interesting conversation. It has given me some new
perspectives on things. I think that is a very fair suggestion. I'd love to
see more cooperation between the audiophools and scope guys. I wouldn't
mind buying a cheap scope without tubes and loading it myself. I just hate
to see them tossed out.

For the record, I don't expect to buy any Tek scope for $50, although from
time to time they appear. A few months ago I purchased a 531A for $75 with
a cart. Granted I drove a couple hundred miles to pick it up but I enjoyed
the road trip!

The 500 series scopes selling on ebay, fb, et al, for $200+ dollars sit
there for months before they vanish with "best offer accepted" or get
re-listed over and over again. This does seem to be growing trend. Based on
what I have seen, a lot of the scopes seem to be sold by people who don't
know what an oscilloscope is, but they inherited it, and they are using the
ebay listed prices as a baseline.


On Thu, Sep 19, 2019 at 10:19 PM Chuck Harris <cfharris@...> wrote:

My suggestion is when you see a tube harvester
that has separated the scope from the tubes, make
him an offer that is high enough to encourage him
to sell the scope to you with tubes... assuming
you really want the scope.

We all like bargains, but a $50 535 doesn't match
the reality of the value of the parts anymore.

If you think it does, then you are demonstrably
mistaken, and really have no cause to complain.

-Chuck Harris

Jamie Ostrowski wrote:
If I'm understanding your solution correctly, you're suggesting we all
raise the price on our oscilloscopes we sell to a price that is equal
to
the cost of the individual components in the unit all together. We may
as
well consider the transformers, because in audiophool circles they
value
these, despite the problems with the epoxy-based transformers being a
huge
problem. They tout them as "extremely reliable". I suppose because
they're
big and heavy(?)

In the solution I proposed, you could just as well take out the
Telefunken
tubes and sell them separately for a higher price, and replace them
with
GE
or RCA tubes, which are no lesser the tube in an oscilloscope. You
would
increase your own profit, and create at the same time a trend in the
market
- that the Tektronix oscilloscopes do not have the tubes favored by
audiophiles. If you have a concern your oscilloscope will go to a party
with ill-intent, you could even state that in the advertisement. They
will
quit buying them for scrapping, you will increase your own profit, and
more
old oscilloscopes will live to see tomorrow. There is a significant
price
difference between some GE tubes and some Telefunkens, without any
performance cost to the scope as far as I'm aware of.











On Thu, Sep 19, 2019 at 7:59 PM Chuck Harris <cfharris@...>
wrote:

Ok, come up with your own solution.

The less valuable tubes that never sell on ebay don't
sell for much, and as such don't add much to the price
model.

I once calculated it out for a 585A, and came up with
$300 for ebay completed auction prices.

The 585A has a forest of 6DJ8's, which the audiofools
value quite highly, even though they are very common.

One $0.50 6AL5 doesn't skew the model enough to even
comment about.

-Chuck Harris

Jamie Ostrowski wrote:
I don't think that formula for calculating the price of the
oscilloscope
makes any sense. There isn't much demand for most of the tubes in
that
oscilloscope. All harvesters are interested in is the audio tubes.
The
remaining tubes in that oscilloscope will sit on ebay for years and
years
and years. In other words, they're mostly worthless.









Jamie Ostrowski
 

Yeah this has been an interesting conversation. It has given me some new
perspectives on things. I think that is a very fair suggestion. I'd love to
see more cooperation between the audiophools and scope guys. I wouldn't
mind buying a cheap scope without tubes and loading it myself. I just hate
to see them tossed out.

For the record, I don't expect to buy any Tek scope for $50, although from
time to time they appear. A few months ago I purchased a 531A for $75 with
a cart. Granted I drove a couple hundred miles to pick it up but I enjoyed
the road trip!

The 500 series scopes selling on ebay, fb, et al, for $200+ dollars sit
there for months before they vanish with "best offer accepted" or get
re-listed over and over again. This does seem to be growing trend. Based on
what I have seen, a lot of the scopes seem to be sold by people who don't
know what an oscilloscope is, but they inherited it, and they are using the
ebay listed prices as a baseline.

On Thu, Sep 19, 2019 at 10:19 PM Chuck Harris <cfharris@...> wrote:

My suggestion is when you see a tube harvester
that has separated the scope from the tubes, make
him an offer that is high enough to encourage him
to sell the scope to you with tubes... assuming
you really want the scope.

We all like bargains, but a $50 535 doesn't match
the reality of the value of the parts anymore.

If you think it does, then you are demonstrably
mistaken, and really have no cause to complain.

-Chuck Harris

Jamie Ostrowski wrote:
If I'm understanding your solution correctly, you're suggesting we all
raise the price on our oscilloscopes we sell to a price that is equal to
the cost of the individual components in the unit all together. We may as
well consider the transformers, because in audiophool circles they value
these, despite the problems with the epoxy-based transformers being a
huge
problem. They tout them as "extremely reliable". I suppose because
they're
big and heavy(?)

In the solution I proposed, you could just as well take out the
Telefunken
tubes and sell them separately for a higher price, and replace them with
GE
or RCA tubes, which are no lesser the tube in an oscilloscope. You would
increase your own profit, and create at the same time a trend in the
market
- that the Tektronix oscilloscopes do not have the tubes favored by
audiophiles. If you have a concern your oscilloscope will go to a party
with ill-intent, you could even state that in the advertisement. They
will
quit buying them for scrapping, you will increase your own profit, and
more
old oscilloscopes will live to see tomorrow. There is a significant price
difference between some GE tubes and some Telefunkens, without any
performance cost to the scope as far as I'm aware of.











On Thu, Sep 19, 2019 at 7:59 PM Chuck Harris <cfharris@...> wrote:

Ok, come up with your own solution.

The less valuable tubes that never sell on ebay don't
sell for much, and as such don't add much to the price
model.

I once calculated it out for a 585A, and came up with
$300 for ebay completed auction prices.

The 585A has a forest of 6DJ8's, which the audiofools
value quite highly, even though they are very common.

One $0.50 6AL5 doesn't skew the model enough to even
comment about.

-Chuck Harris

Jamie Ostrowski wrote:
I don't think that formula for calculating the price of the
oscilloscope
makes any sense. There isn't much demand for most of the tubes in that
oscilloscope. All harvesters are interested in is the audio tubes. The
remaining tubes in that oscilloscope will sit on ebay for years and
years
and years. In other words, they're mostly worthless.