Just a quick one, I have just acquired a third 11=99 and pulled the back off to find a 20μF and 40μF electrolytic and most of the remainder being mustard caps, with four papers which I have replaced, unlike my other two, one of which was all mustard (excepting the electro's) the other all papers, so surprised to find a mixture. Now the closest values I had to the 20μF & 40μF were 22μF and 47μF, which I used as replacements. Listening to the radio now, it sounds really good, loud and clear and my wife has done a marvelous job with the case, it looks and sounds like brand new. I could have used a 16μF and 33μF instead of the 20 and 40μF originals, but opted for the 22 and 47μF, thinking that more (uf) is better than less, am I correct? Or if not, why?

With capacitors, the closer you get to the original capacitance values the better. Bear in mind that most have a 20% tolerance anyway so the designers factored that in.

The very important thing is to never go below the working voltage of the original caps.

By the way, have you given us the dates and serial numbers of your 11-99 sets?

Because that was such a long-lived model in production, we keep a log of those details here on the site.

No GTC, not yet, but now you have informed me I shall pull the backs off tomorrow and record them for site records, these are a set I actually love more than most, they are great little radio's and my wife and I have one on each side of our beds, as I have been told it's not a good Idea to sleep with a valve radio, I'm too old and set in my ways to break with my habit and these sets have the lowest internal operating voltage, so would be the safest. The one on my side of the bed has a solid state rectifier, so must be newer than my other two (I presume). Really lovely little radio's with great sound! It would be interesting to know exactly when they were made! I'll never stop buying these if the price is right. I'm not sure of the dates other than guessing, but I'm sure the serials are on a piece of cardboard inside.

I don't trust old valve gear enough to leave it on when I'm not present (be that asleep or out of the house).

We usually date these via a stamp on the transformer, or from the week./year marking on original caps if there are any. Serial number should be obvious.

Yes, the later ones had solid state rectifiers.

I also have about 7 or 8 of these nice looking Kriesler 11-99 radios. On display at home I have one each of the following colours, brown, white, orange, yellow.
I found the white ones are prone to sun damage and the good white one I have on display is kept away from the sun. I've also noticed that the very last ones made have a black coloured dial and all mustard capacitors.
Regarding capacitors, I have just built the Silicon chip capacitor tester and reformer in August/Sep 2010 issue and it is a great piece of test equipment, well worth building.

If you could get the details of your 11-99's, please post them in this thread:

https://vintage-radio.com.au/default.asp?f=3&th=537&offset=7

Ok, the cream one is:
Serial No. 10835, dated 30th May 1968

My wife's pinkish maroon bedside one is:
Serial No. 10036, dated 24th MApr. 1968, these radio's I found the dates on the IF cans.

My pinkish Maroon bedside one with black dial face is:
Serial No.47874, dated 2nd July 1974
Cheers, will post this info to the link post you supplied, thanks Robbbert!

Jamie,

Presumably both of the 1968 dated sets have 6V4 rectifiers?

Yes indeed they do! And silver dial faces, 2 wire power cords, the 74 one has the "notch" and 3 wire cord, date on the pwr tranny instead of RF can. And black dial face. All really good little radio's!

Thanks. Your 1974 set is the youngest one we have recorded so far in a model run that spans nearly 10 years.

Yes, I noticed that! woo-hooo!

Someone should write a history of the 11-99.

Last valve radio. Appropriate model number.

Designed to use parts left over from TV production. Reason for use of the 6GV8 (TV vertical valve) was this valve had a high reject rate in TV production (vert osc. drift as I recall) and Philips wouldn't agree to take them back so Kriesler used the TV rejects up in the 11-99. There was more reason to do this when TV production switched to the all solid state 49-7 because there were by then so many 6GV8s in surplus stock. That's what I was told by an ex-Kriesler engineer anyway.

The 11-99 line was staffed by older assemblers who had difficulty transitioning to PCBs and transistors - a nice touch. Because the 11-99 had no paper caps, everything was under-run and there was a degree of pride of workmanship, pretty much any 11-99 you'll find is still working.

One of the things that's always fascinated me about these sets is how they got away for so long with wax-impregnated paper insulation in the mains transformer. Looking at the core stack size (this applies to their TVs as well) they were designed to run cool. I don't recall ever having to replace one.

But why the half-wave rectifier?? Anyone know? It seems a strange decision, at least before the transition from the 6V4 to a silicon diode, because it meant the mains transformer core needed to be larger to avoid saturation and the filter caps also needed to be larger. Maybe the cost saving of a single untapped winding made the difference?

Further to my last post, yes, early 11-99s had some paper caps, again because the 11-99 was used as a dumping ground (that's probably a little unkind) for surplus stock parts that couldn't be used elsewhere. They were used in non-critical locations where some leakage could be tolerated.

The 11-99 line was staffed by older assemblers who had difficulty transitioning to PCBs and transistors

The fact that it was still being made and sold in mid 1974 intrigues me. I can only think that its market was among people who still wanted a mains powered mantel, and there can't have been too many of those available at that time. (I know that all of the radios in our house at that time were battery powered potable transistor sets.)

Someone should write a history of the 11-99.

Agree. I don't think it's ever been covered in Silicon Chip's Vintage Radio section, and it's high time that it got a run there.

Yes, I believe it was the last, at least this side of the iron curtain.
Nobody else was doing it, there was still a small market left that Kriesler had to themselves.
I suspect the only reason it stopped completely was that in 1974 it was all hands on deck, 3 shifts daily for 59-01 production.