advertisement


Deltec / DPA

It's one of the smaller, more portable and easy to use Tek scopes. Only 30 valves and 42lb weight... $860 in 1963..

The seller of the ebay one says it's been re-valved, had a new CRT and been calibrated. Obviously as with old valve amps 'scopes of this age will usually need various caps and resistors replacing and then re-calibration but hopefully this one has had some of those things sorted.

I guess if wanting a vintage scope you need to decide how much work you can do on it yourself, how much to farm out, how much prospective hassle in getting sorted etc, whether to pay a bit more for a restored or at least guaranteed working one. There are various SH test gear companies such as Stewarts of Reading which will charge rather more but usually give a 3 month guarantee. They're unlikely to have anything as vintage as that Tek though but likely a few SS ones from '70's.
'Scopes (and indeed lots of test instruments) are one of those things where more modern mainly gets you lighter in weight and smaller in size rather than better performance...
 
Spotted.

IMG_0104.JPG
 
In the real world that photo is correctly oriented, so what happens if I tip it on its size before uploading? Who cares.
 
Nice. TNMOC?

PS There are some bloody huge old valve scopes in our store room at MOSI. Real Quatermass-era stuff!
 
Arkless Electronics said:
Oh you tease!:D
Click to expand...

I’ll take a pic next time I’m in there. There is a couple of them, huge old things on massive wheeled tubular-steel frame trolley stands. No idea if they work or not. We have a couple of scopes in regular use, but they are much later ones like the one in Martin’s pic upthread (one identical, one slightly different).
 
xgr3d said:
Is there a firmware update for the PDM3? Or just for the USB exit?
Click to expand...

Neither as far as I’m aware. I’ve no idea if it is firmware updatable at all, there is no reference or specification suggesting it is, but Deltec ceased to exist (again) several years ago now so nothing will be coming. The USB spec is pretty basic, but that doesn’t stop it being a great sounding DAC. I never use the USB, mine is hooked to the transport via coax and I use the optical in if I want to hook it to the MacBook or Airport Express.
 
Tony L said:
Neither as far as I’m aware. I’ve no idea if it is firmware updatable at all, there is no reference or specification suggesting it is, but Deltec ceased to exist (again) several years ago now so nothing will be coming. The USB spec is pretty basic, but that doesn’t stop it being a great sounding DAC. I never use the USB, mine is hooked to the transport via coax and I use the optical in if I want to hook it to the MacBook or Airport Express.
Click to expand...
Thank you for the answer Tony,
Currently I have only a nuc PC connected to usb, I want to enjoy a higher resolution and so I wanted to update the USB Socket.
The coaxial rca socket is faltering (I added a demo video and it was like that from day one) and I do not know how to connect the computer to the optical input.
By the way, someone else has the same problem with the coaxial entrance? Do you know how to fix it?


https://drive.google.com/open?id=1f67XUmWC0PavL_qvjxrgSYBAFJRw-28Y
https://wetransfer.com/downloads/47...0e9670564a831dfd947bdab520180325085829/7817a0
 
IIRC there is something very fragile/sensitive about the way Deltec implement that which means you should never plug/unplug the inputs with the DAC powered up, i.e. if your issue isn’t physical (dry joint or whatever) then there is a chance you’ve fried a chip somewhere. Martin Clark will have a far better explanation as to what exactly and how to fix it, but I’m certainly aware Deltec DACs are somewhat notorious for this and I approach mine with great caution. It is actually one reason I only use optical to hook up computer stuff and there is no electrical made or broken connection that way. I just leave the optical cable plugged in the back when not in use.
 
Tony L said:
I’ll take a pic next time I’m in there. There is a couple of them, huge old things on massive wheeled tubular-steel frame trolley stands. No idea if they work or not. We have a couple of scopes in regular use, but they are much later ones like the one in Martin’s pic upthread (one identical, one slightly different).
Click to expand...

I'll guess Cossor:)
 
Tony L said:
Nice. TNMOC?

PS There are some bloody huge old valve scopes in our store room at MOSI. Real Quatermass-era stuff!
Click to expand...
Indeed. AGM thing yesterday. There are some crusty old devices lurking, but this was sat out. It looks like it might be assumed to be useful...

A nice OT sub-thread.
 
That reminds me... I have some very rare computer plug in PCB's from the mid '60's which I promised to TNMOC about 2 years ago and never got round to sending... :oops:
 
Thought you said really old and huge... hence the Cossor guess:D

Those are lovely beautiful Tek's of the type I'd sell my granny for (if she was still with us), especially the 543B. The "B" means it's a later one (1965 ish maybe) with a few transistors in it... but not many. Probably 40+ valves in it. Both take plug in modules which slide into the front panel and make them incredibly versatile. Have a look inside if you want to see something that will make even Leaks' construction look like it was thrown together by Amstrad on a Friday afternoon;)
All soldering is with silver loaded solder and the parts are fitted to white ceramic "tag strips" (not a good description but will have to do) which can be damaged by non silver solder and so they all came with a small reel of Tek approved silver solder stashed inside for the service guy to find...
 
Classic Tektronix stuff is utterly beautiful in a form-follows-function way; the way they were put together, the utterly-brilliant engineering that went into them (the hybrid T circuits and other magic to extend and flatten bandwidths and responses is just the work of genii*); the internal build is eye-popping as Jez states; and to top it all - they have the most usable-intuitive interfaces of an analogue tool imaginable: total end-to-end engineering.

The late Jim Williams - the applications engineer of Linear Tech, and a wonderful technical writer always worth reading - commented often on Tek kit in his various essays and appendices to his longer application notes ** Anyway - one of his chief musings was not understanding why classic Tek scopes hadn't appreciated as well as other contemporary design classics that cost around the same new, his choice example being a 60-s Mercedes SL
(- now look up the price of a 'Pagoda' merc - and be sitting down at the time!)

*and completed by hand before general purpose brute-force computing remember...
** For example - Linear Tech AN-47 is a masterpiece, as I've posted before in DIY here: it totally describes the subject of how to use and build and finesse fast amplifiers - and then follows-up with at least as much material again just in throw-away appendices on how to really measure what you are doing... yet a joy to read whatever your level of understanding. It's also deeply funny in places, which helps.
 
Last edited:
martin clark said:
Classic Tektronix stuff is utterly beautiful in a form-follows-function way; the way they were put together, the utterly-brilliant engineering that went into them (the hybrid T circuits and other magic to extend and flatten bandwidths and responses is just the work of genii*); the internal build is eye-popping as Jez states; and to top it all - they have the most usable-intuitive interfaces of an analogue tool imaginable: total end-to-end engineering.

The late Jim Williams, that applications engineer of Linear tech and a wonderful technical writer always worth reading, commented often on them in his various essays and appendices to his longer tech /application notes ** Anyway - one of his chief musings was not understanding why classic Tek scopes hadn't appreciated as well as other contemporary design classics that cost around the same new, his choice example being a 60-s Mercedes SL ( - now look up the price of a 'Pagoda' merc - and be sitting down at the time!)

*and completed by hand before general purpose brute-force computing remember...
** For example - Linear Tech AN-47 is a masterpiece, as I've posted before in DIY here: it totally describes the subject of how to use and build and finesse fast amplifiers - and then follows-up with 50% as much material again in a throw-away appendices on how to really measure what you are doing... yet a joy to read whatever your level of understanding. It's also deeply funny in places, which helps.
Click to expand...

Well said!! Indeed the T coil is a work of genius and though invented by Tek around late 50's (IIRC) Tek only explained to the rest of the world how it actually works in the mid 80's!!!
Then there's the Distributed Amplifier.... some Tek scopes have maybe 20 ECC88's working together to drive the CRT at 100MHz!
Then the PDA CRT....
and the Sampling Oscilloscope that could allow 3GHz or more to be viewed back in the early sixties...
and how could we forget the thick film hybrid amplifiers which used further brand new and patented technology to allow real time scopes of 1 GHz or so to be built in the mid 80's.

Unfortunately i guess those without some electronics knowledge may just think "yeah so what it's just a scope"....

(and yeah AN-47 is required reading;))

The disaster of Bob Pease dying in a car crash in his beloved VW Beetle on the way back from Jim Williams' funeral probably put analogue electronics back 5 years and they were both great blokes and EE "heroes" to many of us:(
 
You must log in or register to reply here.


advertisement


Back
Top