Author Topic: Do you have any test equipment in your lab that uses vacuum tubes?  (Read 3549 times)

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Offline 5065AGuru

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Do you have any test equipment in your lab that uses vacuum tubes?
« on: September 09, 2019, 04:57:22 am »
Hi,

Just wondered. The only vacuum tube test equipment I have is an HP 428B clip on Ammeter. It is one of my favorite instruments and warms up in less than 30 Seconds!

Cheers,

Corby Dawson
 


Offline Berni

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #2 on: September 09, 2019, 05:41:41 am »
While most of my equipment is rather old it still tends to have at least early ceramic DIP ICs in it.

The one i do have is a Fluke 410B (Precision HV Power supply)
https://testequipment.center/Products/Fluke-410B

It is modern enough for its control circuit and reference to be silicon, but it still uses incandescent lamps as indicators on the front panel. But since this thing can output up to 10kV they couldn't get a transistor to handle that, so there is a big fist sized vacuum tube inside working as a linear pass element to regulate the output.

You would know the thing has vacuum tubes inside without even opening it up because the heater on this tube runs so hot that you can see the bright orange light shining out of all the vent holes in the back area.
 

Offline Smith

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #3 on: September 09, 2019, 06:01:35 am »
I regularely use the HP 412B 2kV HV supply, basicly a 2kv version of the 410B. Its so easy to use, and verry precise. It only needed a new cap for the internal reference a few years back. The downside is the 32mA output, almost 32mA more than 1 need. The output is in series with a relay that should eventually kick in above the 32mA. Colleague got a shock from the his 3kV version once (415B), he was not amused.
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Offline fourfathom

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #4 on: September 09, 2019, 06:30:17 am »
Do Nixie tubes count?  My old HP  freq counter has these.  I also have a variable high-voltage power supply with some big vacuum tubes, but I haven't plugged it in for a very long time.
 

Offline Henrik_V

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #5 on: September 09, 2019, 06:41:24 am »
In my lab yes, however beside nixies (WG, HP and GR counter, and a V543 DMM) I use a Kepco 2kV Powersupply with a beam power pentode. My museum doesn't count, but in rare situations I use a TeraOhmMeter with a electrometer tube build by Jahre (maybe known as a mica Cap producer) just because it's working and the only gage if have at home for that range.
Greetings from Germany
Henrik

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Offline Berni

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #6 on: September 09, 2019, 06:45:58 am »
I regularely use the HP 412B 2kV HV supply, basicly a 2kv version of the 410B. Its so easy to use, and verry precise. It only needed a new cap for the internal reference a few years back. The downside is the 32mA output, almost 32mA more than 1 need. The output is in series with a relay that should eventually kick in above the 32mA. Colleague got a shock from the his 3kV version once (415B), he was not amused.

I have not yet found out what is it like to touch the output of mine, but i really don't want to feel it. The last time i had the output of it arc over to ground it resulted in a loud pop and flash while the protection shut it down.

Mine is a bit whimper at 10mA, but all that appears to be is a relay kicking in at that threshold, nothing actually limiting the output current, so when a short happens the thing just dumps its internal capacitors right out hence why it makes a loud pop when it arcs over, as there is likely amps of current flowing for a brief moment. My solution to that is to add a physicaly large resistor in series with the output so that there is at least something limiting the current.
 

Online TheSteve

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #7 on: September 09, 2019, 06:54:25 am »
Only VFD's, CRT's, Nixie's and Panaplex displays. I had some spare tubes(and CRT's) but they all went home with Mr Carlson a while back.
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Offline Berni

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #8 on: September 09, 2019, 07:58:12 am »
Oh and where is the line for it being considered a vacuum tube.

Since quite a few of my equipment still has CRTs and even more has VFDs and those are technically vacuum tubes since they all fire electrons off a heater trough vacuum. Nixie tubes are different since they are essentially glorified neon bulbs (Much prettier to look at tho).

Then you have weird 'tubes' like a traveling wave tube (old high performance RF amplifiers) or things like magnetrons or klystrons that also fit the working principle of a vacuum tube (Tho i don't think you find the last two in test gear).
 

Offline Bart1965

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #9 on: September 09, 2019, 09:23:35 am »
I own a Philips GM4140-00 ("Philoscoop") measurement bridge from 1938. Inside are an EZ 40 rectifier, an EF 40 pentode (another Dutch invention) and the EM 34 "magic eye".
 

Online BravoV

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #10 on: September 09, 2019, 09:30:51 am »
The only one in the house, Heathkit vacuum tube voltmeter, a freebie meter.


Offline Psi

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #11 on: September 09, 2019, 09:58:51 am »
I have an old graph paper servo plotter that uses tubes around somewhere.

And i saved a magic eye valve from going to the rubbish tip a while back.
Not sure what project i'll use it in.
Greek letter 'Psi' (not Pounds per Square Inch)
 

Online tautech

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #12 on: September 09, 2019, 10:08:03 am »

And i saved a magic eye valve from going to the rubbish tip a while back.
Not sure what project i'll use it in.
Gave the only one I've ever had to member Neo in the US as I'll never use it.
He had some project but has never disclosed what.  :-//

Still got a box of assorted tubes that I really must throw out unless you want them ?
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Offline Psi

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #13 on: September 09, 2019, 10:18:41 am »

And i saved a magic eye valve from going to the rubbish tip a while back.
Not sure what project i'll use it in.
Gave the only one I've ever had to member Neo in the US as I'll never use it.
He had some project but has never disclosed what.  :-//

Still got a box of assorted tubes that I really must throw out unless you want them ?

Only if there's some 12AX7  or EL34 in there.  ;D
« Last Edit: September 09, 2019, 10:21:13 am by Psi »
Greek letter 'Psi' (not Pounds per Square Inch)
 

Online amspire

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #14 on: September 09, 2019, 10:26:22 am »
I have an ESI precision capacitor measuring transformer bridge that uses valves in the tracking oscillator and null detector. The null detector has a sharp bandpass filter that tracks the oscillator over a range of about 20Hz to 20KHz.

Some of the vacuum tubes do not seem to be easily available.

If it starts to fail, I think I might keep the meters, dials, resonant passive components and precision coupling transformers, but replace the valves with a solid state circuits. Maybe make it battery powered.

I also have an old 5MHz BWD oscilloscope that is a transistor-valve hybrid - haven't used it in decades. It was my first scope and I just never felt like getting rid of it. Fantastic triggering.

A basic valve RF oscillator and Vacuum Tube Voltmeter.  They could end up being converted to solid state.

Richard.
« Last Edit: September 09, 2019, 10:31:54 am by amspire »
 

Offline factory

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #15 on: September 09, 2019, 10:28:02 am »
I regularely use the HP 412B 2kV HV supply, basicly a 2kv version of the 410B. Its so easy to use, and verry precise. It only needed a new cap for the internal reference a few years back. The downside is the 32mA output, almost 32mA more than 1 need. The output is in series with a relay that should eventually kick in above the 32mA. Colleague got a shock from the his 3kV version once (415B), he was not amused.

Did you mean a Fluke 412B? the HP 41x Series are all meters not HV supplies.

I have loads of test gear with vacuum tubes in my collection, mostly HP, but I also have a Farnell E350, Advance SC1 and a few older ones from Taylor.

David
 

Online tautech

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #16 on: September 09, 2019, 10:29:21 am »

And i saved a magic eye valve from going to the rubbish tip a while back.
Not sure what project i'll use it in.
Gave the only one I've ever had to member Neo in the US as I'll never use it.
He had some project but has never disclosed what.  :-//

Still got a box of assorted tubes that I really must throw out unless you want them ?

Only if there's some 12AX7  or EL34 in there.  ;D
I think there might be, I'll look tomorrow and PM you.
There's all sorts of old shite, some was Dads from the '40's but most were scrounged from old tele and radio sets.
There's a few bases too, 4, 5 and 8 pin along with some later mini 8 pin bases.
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Offline aix

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #17 on: September 09, 2019, 10:58:45 am »
I have a Keithley 240A power supply.  I don't get to use it very often, but love the fact that it goes up to eleven!
 
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Online med6753

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #18 on: September 09, 2019, 11:25:48 am »
Besides numerous analog scopes with CRT's I have:

Tektronix Type 191 Signal Generator
Heathkit V-5 VTVM
Heathkit V-7A VTVM
Heathkit S-3 Electronic Switch
Heatthkit AG-9A Audio Generator
Heathkit OL-1 Oscilloscope

All are in working order.
 
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Offline tggzzz

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #19 on: September 09, 2019, 12:55:55 pm »
My Tek time mark generator contains half a dozen or so. Here are pics of two of them:





FFI see https://www.eevblog.com/forum/testgear/test-equipment-anonymous-(tea)-group-therapy-thread/msg2196288/#msg2196288 and subsequent posts.
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Offline ferdieCX

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #20 on: September 09, 2019, 01:01:05 pm »
Heathkit IG-42 RF generator - in use
Tek 310A scope - in work condition, but not in use
 

Offline T3sl4co1l

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #21 on: September 09, 2019, 03:41:45 pm »
CRTs -- a few.  Aside from those, not anything that I use regularly.  I have the same VTVM BravoV shared, I think a later model; an RCA "high sensitivity AC VTVM" with a DC mod, and Eico 377 audio and 322 RF generators.  Some audio amps about rounds it out.

I suppose the distributed amplifier counts; haven't had much cause to use it, but it's an original. https://www.seventransistorlabs.com/Images/DistAmp2.jpg

Tim
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Offline KrudyZ

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #22 on: September 09, 2019, 04:04:19 pm »
I have a HP214B pulse generator.
It uses tubes in the output section to deliver 100V into 50 Ohm with 15 ns transition times.
Can't say that it sees a lot of use though...
 

Online schmitt trigger

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #23 on: September 09, 2019, 04:13:25 pm »




Gorgeous!
Nuvistors and metal-can transistors coexisting peacefully within inches of each other.
 

Offline Dwaine

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Re: Do you have any test equipment in your lab that uses vacuum tubes?
« Reply #24 on: September 09, 2019, 05:00:18 pm »
Yep.  Heathkits...  cap checker and vtvm.  Love them...
 


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