The AM Forum

I have a Viking 2 that I picked up a couple of years ago at a Hamfest.  Just started to  look at it, and while it is very clean, it has a u-shaped chassis on the side of the oscillator compartment vertical shield.  It protrudes over the xtal sockets and almost looks like a factory modification.  It has a 12AU7 and a pot and a four wire harness connection.  Has anyone seen any sort of modification like this on a Viking 2?  And if so, any details about what it does?  I haven't started to reverse engineer yet, as I am hoping this is something that someone knows about!

Thanks, George, K9AAL

There's a litany of audio mods for that to improve modulation quality. might be on BAMA with the book, and some may be in the old ham magazines. some on the www. the Viking I is about the same, so that can be searched for also.

I suspect this is the grid block keying unit.  The unit, if factory made, should have a brown knob. I have one on one of my Vikings.

Here is the circuit and how to use it - note it is designed to be used with a VF-122 VFO which must be modified.

While on topic of modifications, both of my current Viking IIs have stock audio (all rebuilt with new caps and resistors of course).  I get great audio reports on both and can easily obtain 100% modulation, as verified with a 2 tone test and my Heathkit HO-10 station monitor. So before you think about doing some of the 'audio' mods, try the stock audio circuit.

I like  to do a fuzz inverter mod on mine see how audio comes out so don't have worry about finding a bigger driver transformer!

Thanks to all who replied.  Looks like this is the grid  block keying mod.  I will  get this nice Viking 2 going soon!!

73, George, K9AAL

how you wanting to mod your viker2 the driver transfomer too small will not pass alot of responce

I was always fairly satisfied with the Viking I audio but it has its limits. The driver is a little on the weak side in relation to what the 807's can do. The iron is very "communications grade" and is satisfactory above 250-300Hz. Mine had no overall negative feedback when I got it. After adding it the fidelity was improved to my satisfaction.

I want to do an outboard modulator pair 811A feed that into 6146's

Triode connect the 807 modulators and feed them with outboard audio....

811s should fit in the rectifier sockets after you solit state the power supply.

yes I want use a HI-FI audio amp but don't know how many watt I need. I have a small one but not sure beefy to do the job I heard WA2CYT sounds good with his and WA1HLR Done it with a Viking 3 he calls it!

Triode connect the 807 modulators and feed them with outboard audio....

Following the ER series on the V-II (and V-I) is the way I went and the only extra expense besides some small stuff was a much better driver transformer. Since the mod iron is the remaining weak link and not wanting to blow it I keep output at 100W or less and can modulate 100%+ and increase the bandwidth a bit since the piddly little driver iron was the culprit at the low end as well as causing excessive distortion when going over about 80-85% modulation.

Carl

It has mods done to it but I don't care for it! 6au6 tubes are gone in the speach and driver but I seen and heard the audio on outboard 811A what a diffrence! I like HI-FI and when you do mods like this you can narrow up audio if you like make it sound anyway you want but when you restricted you can't!

What the heck are you talking about?

Funny  ;D
Punctuation and grammar can make all the difference in the world in understanding a post. Likewise, bastardizing of common technical nouns and verbs to make a point, or to be "cute", or to feel part of some imaginary "in-crowd" went out with the 90's.

pants on the ground

What part! 6au6 speach amp is 12ax7 and 6au6 driver tube is 12by7!

just saying if you want sound like your in drive thu fine by me but I do Not!!

Did somebody drop this guy on his head?

What on earth is he blabbering about?
Sounds like Jesse Jackson

Try English

Sorry! I was asking for help!! guess I don't know how to word it!

I can understand it just fine. I dont know what y'all are drinkin (or smokin) but I could use some.

that is pretty close to the preferred modification arrangement for a viking, a ranger, and pretty much any other 100w table top boatanchor transmitter.
I don't care for 'BY7s they have a tendancy for strange failures. But the 12AX7 speech amp with a 6C4 driver (or a 12AU7 with both sections paralleled) od OK-fine for just about anything running AB1 that doesn't need any grid current. But then again so will eliminating the driver transformer and changing over to a fuzz inverter.

http://www.amwindow.org/tech/htm/viking2.htm

If you want to push it harder for more audio, a 12B4 driver with a little beefier driver transformer will work OK-Fine if you want to tickle them with a little grid current in AB2.


Also, As far as Pete's audio goes, he always sounds like he has a clothespin on his nose ;D  ;D

Replace the interstage transformer.

 AES  (http://www.tubesandmore.com)

Under transformers search p/n P-T124E.

The PT-124E is a fine audio driver transformer,that is what I use in my vikings.I think the k6AD mods in ER Mag,110,111 and 112 should be required reading for any one interested in the viking 1 or 2.He goes into great detail about the whys and hows of his mods and the shortcomings of the vikers, also a little history on the transmitters.He goes well beyond  just modifying the front end. For example changing C46,L21 and C32 the splatter filter to different values,regulating the screen and grids of the 807 modulator tubes etc.

Thanks for info like slab's idea! ;D

As we all know, that will work perfectly as long as you don't blow up the 6146's and the rest of the viking. Dennis W5FRS used an Altec 1570B (class "b" 811's) to cathode modulate a 250TH. Worked FB. Amp idled. So sweet..

Not really. I do it to annoy sticklers and pidgeon-holers, and that activity never goes out of style.

I usually chalk it off to a persons 2 digit IQ and then simply ignore if possible.
If someone wants to sound like an urban teenager he doesnt belong on this forum.

By posting multiple times about it, you are hardly ignoring it.

I included "if possible"

You going to be at Nearfest?