[WRL] WANTED 755 VFO parts unit

[Glen Zook]

The plain WRL 755 does have one tube inside the shield.  However, both the 755 that I had back in 1959 and the 755 that I have now, were/are very stable after about a 15-minute warm up.  I was the second owner of the first 755 and I don't know how many had owned my present 755.  However, both were "factory" built.  That is, not the kit version that WRL offered.  I don't know if being "factory built" has any major influence on the stability.


Of course, there are all sorts of variables and different units can certainly act differently due to all sorts of things.  I haven't tried replacing the 6AU6 with a 6AH6.  Doing so would probably increase the stability even more like in the Heath VF-1 and Johnson 122.

 Glen, K9STH 
 Website: http://k9sth.net

 

      From: Kenneth G. Gordon <kgordon2006 at frontier.com>
 To: Glen Zook via WRL <wrl at mailman.qth.net> 
 Sent: Thursday, January 21, 2016 6:56 PM
 Subject: Re: [WRL] WANTED 755 VFO parts unit
   
On 21 Jan 2016 at 21:43, Glen Zook via WRL wrote:

> The WRL 755 VFO is not that common nor is the WRL 755A VFO.  The 755 is an
> excellent VFO (very stable).  Finding one is going to be difficult. 

Yes. I had a GK-500C many years ago, and it was very stable and output 
very nice AM and CW. I also had a 755-A VFO and used it with several 
rigs. It was very stable too.

The difference between the 755-non-A and the 755-A is that WRL moved all 
the tubes outside of the VFO tuning box in the "A" model, while there was 
at least one tube inside that box in the non-A model.

I have both a 755-A and a 755 now. The "A" model drifts a lot less than 
the non-A model.

I consider the WRL-755A to be about the very best VFO of that time 
period.

Both models include a separate buffer tube, which neither the Johnson 122 
nor the Heathkit VF-1 have.