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Old 18th Nov 2016, 3:02 pm   #1
Bill
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Default Test gear dilemma. Bradley type 134 precision voltage calibrator.

hello All, not often I post here but a regular reader.
For a lot of years I have collected all sorts of test gear, particularly valve stuff.
Most of it lies unused and has done for many years. The time has come I think to rationalise the stock.
I will mention one piece of gear that I'm agonising about: Bradley type 134 precision voltage calibrator. This was made late 60's or early 70's , it was in a calibration lab, is very well made and voltages up to 1000v, settable by decade switches . When i last powered it up, a few years ago it seemed to work fine. Would this unit be useful as it is to members here for not very much money?
So, this the dilemma:There are two TT22 (super KT88s with 12v heaters) in it , which I suspect are worth quite a bit to the audio people. Do I break the unit(perhaps because it's useless and obsolete) and sell those valves or keep it whole for someone to cherish or even, dare I say, use? What would you do?
Bill
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Old 18th Nov 2016, 3:06 pm   #2
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

I'd give it a good home for "not very much money" to save it from being broken up, but I don't want to stand in the way of other members who might want it.

Ultimately it's up to you what you do with it.
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Old 18th Nov 2016, 4:39 pm   #3
Alistair D
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

Exactly what Graham said above. Most test equipment usually finds a new home on here.

Al
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Old 18th Nov 2016, 4:55 pm   #4
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

Bradley test equipment is well respected - and for good reasons. It is well designed, well built and long lived.

Put it in the "offered" section and someone is likely to take it off your hands. Many of our members are into test equipment and several of us have our own calibration set up.
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Old 18th Nov 2016, 5:21 pm   #5
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

A quick 'google' later and it seems the TT22s are going for seventy odd quid a piece, the cynic in me says keep the unit as a display piece and sell the valves. The vintage restoration/collector in me says sell it here or keep it. I prefer option two.
 
Old 18th Nov 2016, 5:37 pm   #6
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

This is the test equipment version of the 1930s radiogram quandry.

The benefit of good calibration is real and provable, unlike the audio beliefs. Those valves BELONG in their current home. That unit has more historic worth than some new-build amplifier.

David
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Old 18th Nov 2016, 7:03 pm   #7
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

I think the answer is offer it for whatever you think the TWO valves are worth to you?
Surely that is your best option rather than strip it just for the 2 valves? To sell for little money including these valves seems unrealistic. Just being practical with financial considerations, which affect us all.
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Old 18th Nov 2016, 8:00 pm   #8
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

Bradley 134 (became Pulsetek).
I have the manual (dated 1980), which is always an extra incentive to keep the original test equipment, as you then have the specification and circuit and can repair it. I can scan it if wanted.
Up to 1000V, at 50ma, setable to within a few millivolts.
It looks a most impressive machine. The valves used are two TT22 and a single EL360. The audio boys might not like the 12.6v heater on the TT22. TT21 is exactly the KT88. The EL360 is another big beast, a low impedance 15W dissipation pentode. I have a couple extracted from a scrapped pulse generator.
I think I have a shoe box full of KT66, KT88, EL37 and 6L6 somewhere and lots of EL34. Maybe I had better check them out and offer for sale. Perhaps swop the KT88 for the complete Bradley unit - not that I want more gear. I am trying to reduce it. wme_bill
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Old 19th Nov 2016, 8:05 pm   #9
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

Bill,
I too would recommend keeping the Bradley. Our profiles are similar, with me holding a large collection of valves, & valved test equipment, & a keen affinity for Listers. I've also acquired a number of lab grade items of test equipment. Its possible that you have the only decent Bradley Voltage Calibrator in the Manchester area.There might be Forum guys down your way who need their Voltage measurement equipment calibrated. A service you could offer at Golborne Swapmeets, possibly.
At least if you sell stuff at BVWS Swapmeets, or on this Forum site, you'll get the satisfaction that it will go to a good appreciative home. Internet sites are often trolled by mercenary wheeler-dealers & unappreciative audio-phools.

Regards, David
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Old 19th Nov 2016, 8:42 pm   #10
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

If Bill wants to keep it and offer a service to other interested parties for years to come I do not see a problem. Just needing to have the room and the time to do that would be the consideration. However, If a mercenary or audiphool offers lots of cash and it is acceptable, I do not see a problem. It does look like he wants to dispose of it though.
I have quite a bit of gear that is valuable and if wishing disposal would personally sell to the highest bidder who has the cash! I would not have the space, time or inclination to do otherwise.
Sorry, but satisfaction as to who buys it does not come into the equation. Unless it is a personal friend
maybe.
Rob
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Old 19th Nov 2016, 9:05 pm   #11
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

Just reading all posts again, perhaps wme_bill has the best solution with kt88s maybe offered?
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Old 19th Nov 2016, 10:57 pm   #12
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

If the Bradley is jolly rare & is still within calibration spec, then offering a voltage calibration service might result in earning enough dosh in a year or two to justify not selling the two TT22's.
The high standard of workmanship at Bradleys, AVOs, Wayne Kerr, HP, & so on is, I reckon, part of the ethos of the vintage electronics fraternity.
If it was a couple of decent big beam tetrodes out of a rusty & knackered old Marshall amp - then by all means - flog them. But, I submit, the practice of stripping out valves from decent working valuable items of test equipment is - an anathema to the values of many VR&R Forum/BVWS/VMARS/etc. folk, and shouldn't be encouraged.
Please follow Brian's advice. You could also perhaps contact Mike Barker, or Mark Ryding, to get an idea what the Bradley might fetch at one of the Swap Meets down south.
I have a wee Time Electronics 2003N Voltage Potentiometer, and it has proved invaluable for testing MC meters, and analogue & digital MM's for myself & other vintage radio chums nearby. I also own an immaculate specialised bespoke AVO8 originally supplied direct to Prof. RV Jones - should I strip out it's 30uA movement just to repair another bog-standard AVO8 I'm thinking of flogging on ebay ? I rest my case.

Regards, David
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Old 19th Nov 2016, 11:00 pm   #13
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

Well chaps, thank you very much for the helpful advice and interest. I posted initially to see if this thing was of any interest- it seems it is. I think you have convinced me that ripping its heart out for a couple of coveted KTs is not the way to go. The idea of running a calibration service had not occurred- wouldn't the Bradley need to be re-calibrated itself though? Thanks for the offer of the manual wme_bill, but it comes with one anyway (has that just doubled its worth?). Anyway, look out for it on the For Sale section soonish.
Can I tempt anyone with an early 1950s Samwell & Hutton TV wobbulator, with integral 6in scope, I believe it was used on the Ferranti TV production line?
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Old 20th Nov 2016, 9:19 am   #14
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Default Re: Test gear dilemma. Bradley type 134 precision voltage calibrator.

Ok Bill. At least you had something to consider.
David with the Avo 8 I am really envious. If I had an o/c heater 6v6 that was blown in person by R V Jones I would treasure it! Mustn't stray OT any more.
Rob
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