DL96 - Can this really be new?

[martin_m0nxp]

Whilst looking for a replacement DL96 valve Google came across this page:

https://www.conrad.com/ce/en/product...-Content-1-pcs

This seems to suggest that Conrad have found a supplier of new (not new old stock, but actually new) DL96 equivalents....

This seems very strange - I can understand somebody producing new EL84s as the demand is there, but there surely can't be demand for a low power 0.2W audio output valve or which there is plentiful old stock?

Conrad don't list a manufacturer on the page... Does anyone have any more insight?

[HamishBoxer]

Wonder if they do the rest of the 96 series?

[VT FUSE]

2p2p is its correct name,made ie Eastern bloc countries and China in Cold War times,has 1.2V 0.06A Filament.
A lot of foreign portables used it,Tesla Tourist? or sim. They had built in NiCd cells for fil power. Also extensive Mil use. Note pointy pins.
Use of these in series config Fil strings might well wreak havoc-be warned of different parameters!!

Hamish Boxer-the 1f33 is near equiv to DF96 but again note 1.2V 0.025mA fil rating. 1A2 is direct equiv of DK91,a trawl would find DK96 near equiv.

I have a few new spare DL96 here if you are stuck.
PM me if you would like a FOC new year gift.

2p2p can be found on Radiomuseum.org

Regards

Mike

[martin_m0nxp]

Hi Mike,

Thanks for your kind offer, but I've sourced one from ebay (for a whole £6 inc. postage!).... from the same place I sourced the one I broke as it happens :-( ...

Actually I'm not sure I'm totally responsible for it's demise - it developed a crack spreading from one of the pins and lost its vacuum about a day after I fitted it. I'm fairly certain I didn't handle it roughly in any way. I'm not really worried at £6 though....

Is 2P2 really the correct name? It was two centre tapped filaments at 1.4v each, so surely it's a 1xx or a 3xx?

The rest of the series are readily available NOS on ebay....

[VT FUSE]

Hi Martin, deffo 2p2p (lower case to get near cyrillic alphabet) 2p2p in cyrillic looks like 2n2n- just come off Radiomuseum. The 2P2 is the old DL92, 1l33 is the old DL91.

You fell into the deliberate trap-the pcd of the 1939 US RCA b7g was Imperial and Ruski's etc used Metric translation so some sockets apply pressure at pins and fracture the button base. It is a case of go gently and push/pull them straight with no wriggling or rocking,I suspect poor annealing qc does no good here.
The Russian Vs Czech ones were built and inspected to a far higher qc standard regarding button bases and internal build.

Offer still stands should you get another mortality!

Cheers

Mike

[mickm3for]

Hi did a search for others in this range seems they do dl96 df96 daf96 not dk96
from their website
Description

This is a brand new manufactured vacuum tube identical to the types DF 96 = 1 AJ 4. These tubes are produced to the original specifications of their type and manufacturer so can be used as replacements for originals or in high quality reproductions of classic electronics. Mick

[VT FUSE]

Hi mickm3for

Now if only this was a pub quiz....

1AJ4 is US equiv for DF96

1H35 is the eastern bloc DK96,interestingly Radiomuseum (rarely wrong) give same ratings as DK96,ie: Fil 1.4V 0.025A.

Hope that helps?

Regards

Mike

[M0FYA Andy]

I worked in Munich from 1992 to 2005. There were two Conrad stores in Munich, what fantastic shops!
Best described as a 'Super-Maplin', it was quite incredible the range of parts they stocked - I assume they still do.

Andy

[VT FUSE]

I am reminded by philips210 (Martin) in the Chinese fm receiver thread,that the 1A2 fil consumption is nominally 0.031-0.033mA thus making it the Chinese close DK96 equiv but again,beware of series fil schemes and mixing valves.

Cheers

Mike

[martin_m0nxp]

...there was me thinking cloned electronic components was a relatively new problem!

I'm happy to assume the breakage of the tube was by my own hand. It has a fairly tight fitting shield over the tube - I wonder if I broke it whilst putting that back on.

I think I may have mis-understood US / UK naming schemes... I thought the <voltage> <alpha code> <elements> scheme was a US thing, so in my original reply (where I somehow dropped the final 'p') I thought you were referring to a US equivalent, but I guess there are UK codes that also begin with a number?

I'm not worried about heater current draw as the filaments in the set I'm working on are parallel. Once I get the replacement valve and a few hours to tinker I'll do a write up in another thread of the work so far on the radio... I'm quite enjoying this one!

[martin_m0nxp]

...back to the original question - I still don't understand why a company would choose to put (some of) the 96 series back into production.... there can't be that much demand for those?

[VT FUSE]

These are not in current production but are straightforward NOS which would have been from manufacturers multi boxes. Conrad are unlikely to have a desire to mislead but their suppliers may well have implied that they are current production when in truth this is deceptive.
If nothing else,the thread shone light on alternative supplies of many dwindling b7g battery radio valves.

The US derived RETMA codes have no bearing on non US manufactured valves,the Russians & Chinese had their own system and so did we,if you consider these cloned valves,the cloning took place as far back as 1958 or so and continued to 1990. These valves are not real DL96 as stated,that nomenclature was property of Philips/ Mullard etc.

Filament currents were mentioned for downstream readers, maybe in years to follow, many series wired fils have balancing resistors to keep biasing correct and furthermore, mixing the fil current drawn along a chain would unduly stress other valves.
My mention of fil ratings was incorporated as not all scenarios will be for a single 1.5v battery derived LT.

The cracked button base issue is not confined to you alone,I got through a few b7g of differing types before I investigated and saw mention somewhere regarding it-bringing up the engineering drawings of decades back will demonstrate dimensional drift in basing pcd.
Your mention of a shield over the output valve intrigues me, rarely seen in domestic radios in my experience but often used in mil kit to rationalise sockets/holders and to ruggedise.

Mike

[paulsherwin]

The Russian electronics industry took a long time to sort out mass produced silicon planar transistor technology, so lots of valve gear remained in military use right up to the end of the USSR. As a result there are warehouses full of valves still turning up all over the former Warsaw Pact area.

...and a valve radio is fairly EMP (atomic bomb pulse) proof, unlike early semiconductor radios.

[paulsherwin]

Well, that was certainly the Soviet line, but I think there was an element of making the best of things about it.

[VT FUSE]

Probably my last posting on these Sov bloc,Warsaw Pact NOS range of valves..
the tiny dimensional changes in base pitch circle diameter often causes no issue owing to tolerances on the socket/holder in situ,I learned the lesson the hard way and found pin bending and cracks propagating away from these pins in the less well manufactured button bases.

I sourced every type of b7g & b9a Russian socket that I could find on eBay at really good prices and the quality and silver plating is really impressive.
Now when constructing,my technique is to place Sov bloc valves in Sov bloc socket/holder and not use UK or US patterns.

You can-with care, use the Eastern valves 9 times out of 10 but bear in mind the ever present miniscule differences,sometimes not attempting to fully seat the valve but leaving it proud of the socket/holder by say.0.5mm will allow the natural compliance of the pins to accommodate the "misfit" with no basal fracture.

Cheers

Mike

[martin_m0nxp]

What you say Mike fits - the valve I broke was branded 'Scoba' (which according to Google is Russian). The radio is an 'Invicta model 28', so certainly has UK bases. Oddly it doesn't feel unusually tight in the socket.

I don't fancy changing the sockets on the radio - they're PCB mounted and I don't want to run the risk of destroying the traces.

I'll make sure I'm extra careful with the replacement... maybe leave off the screening can until I'm totally done.

[VT FUSE]

Hi Martin

This all drops neatly in with my last post and demonstrates a point (or two)
Scoba was a consumer brand from USSR,a perfectly good valve,should in reality be advertised as 2p2p NOS replacement for DL96 with caveat on fil rating when used in series schemes.

Holder issue.. the biggy.. if point to point wired sockets/holders are encountered by these valves, there is, in most cases, sufficient wobble/slop/wriggle of the individual contacts to accommodate the foreigner.

Soldered to board (pcb mount) socket/holder will lock the individual contacts in rigid alignment without allowance for the required small differences and movement room alluded to. These are the situations where extra care fitting is needed and where the 0.5mm or so standoff scores.

It wasn't my suggestion that sockets/holders be changed, but indeed the case, when these type valves,be they 1.2-4V ,6.3V or 12V are used in a new construction then I am careful to use the correct and purpose built bit it plugs in to.

p.s re the screening can,maybe try without it at first? if no problem with stability or hum could always be bagged with explanatory note inside case somewhere,often the envelopes are 1-2mm taller and depending on type of screening can used, may exert excess down pressure thus inducing button base fracturing. The output b7g valve is internally screened in any case.

Mike