Hello,

Can someone please point me in the direction of where I could get hold of a Kriesler 99 series circuit diagram so I can see the 6GV8 setup.

Regards

Lloyd

The 11-99 data is on Kevin Chants website, a great asset to our community :

https://www.kevinchant.com/uploads/7/1/0/8/7108231/11-99.pdf

Harold

Thank you, Harold, very much appreciated.

Was aware of Kevin's site, absolutely a great asset, has helped me out before, did look, but must have been a man look. 🤣

regards

Lloyd

Interesting!

If you try to view the file directly from the link here or from Kevin's site, the 2nd page is blank.
If, on the other hand, you right-click on the Download link and choose "Save link as", save the file, then open it with your PDF viewer, it works just fine.

Link works fine, both pages with iPad and MacBook.
JJ

Ah, must be a Windows thing!

Just tried it here, using Windows etc, and it all works fine.

BTW, I do not know how this is going to help the 6BV7 issue, unless you're planning on replacing the 6BV7 with the 6GV8, which may not be rated for the higher voltage.

The issue is not an OS related one. It is due to the fact that PDFs aren't always true PDFs anymore. When Adobe Acrobat lost its 100% market share, dozens of other vendors started relasing PDF readers and writers. The format is so butchered these days that things don't always go to plan. It may interest everyone to note that I can rip any PDF file in Photoshop and then print again to a fresh PDF file in my $20 copy of Win2PDF. I sometimes do this when altering floor plans.

The same problem occurred years ago when Internet Explorer lost its huge market share in web browsing. Back then, it was safe to ignore the tiny number of Netscape users and just code for one browser, Internet Explorer. The influx ot other browsers since just made life hell for web developers and it stayed that way until the release of HTML5 which all browsers recognise the same way.

In regards to the 6BV7 valve, sure it was developed by AWV in the 9-pin form, but is actually based on the earlier European EBL1 and EBL21.

A possible way of getting around the scarcity of supplies is to use a 6BQ5/EL84 and couple of germanium diodes. I think Resurrection Radio used to do this years ago.

The good thing is that 6BQ5/EL84's are still being manufactured.

6GV8's run very much under their ratings in that radio, in their intended vertical deflection application they run around 2000 volts peak on the anode of the output stage. Very safe here.

Big advantage of the 6GV8 is you get an audio gain stage. Plenty of volume, something the original radio lacks.

I reckon that since you are going to partly rewire the socket to take, say, a 6BQ5, for the same amount of effort you might as well make a worthwhile improvement to the performance of the radio. 6GV8s, although no longer made, are readily available NOS for less than you'll pay for a 6BQ5.

Regards the 6BV7 being based on the EBL1 et al, no, not really. The only features it shares with the pre-war Euro valve is the two diodes and the extra gain of the pentode, which was achieved by placing G1 very close to the cathode. It was a completely blank-sheet design. A pity it didn't live up to the claims made for it.

If you look forensically at many tubes you will often find the same pentode in many & perhaps acompanied by a triode in the same envelope.

One suspicious one is 6M5. Why develop a new tube is very similar to 6CK6. 6CK6 has its suppressor on a live pin 6M5 its internally tied to the cathode.

Yes Marc, production rationalisation made it worthwhile to reuse existing designs, either in full or in part. A new pentode for example could share an exiting anode and cathode but wind the grids differently.

Has anyone seen any of those AWV-made (as distinct from relabelled Philips produced tubes) 6N3 single diode recifiers (as distinct from the Chinese 6N3 power pentode)?

They were 6CA4s with the two anodes strapped. AWV obviously must have thought it was worth doing just for the replacement market.

Not a very long-lasting tube though, 6 months was about average in my experience.