[Boatanchors] Tube reciever design banter

[match at ece.utah.edu]

On 21 Dec 2009 at 18:26, Carl wrote:

> > Yeah, we've discussed this before, however I found another that looks
> > interesting. Have a look at the 6MU8 triode/pentode. Semi-remote cutoff,
> > 9000 uM, 3.75 W plate diss., and an extra free triode section as a bonus.
> > Designed around 1970 and I think it's a frame-grid. I like multi-section 
> > tubes
> > when it makes sense to use them. $2.43 right now at AES.
> 
> 
> There are many nice tube possibilities at the end of the era altho many are 
> the same tube with different pin outs or slightly fudged specs simply to 
> generate captive audience sales.

Yes, from about the mid 60's there was not much new, just mostly the same 
tubes repackaged to woo the TV manufacturers. 

>  However the 6MU8 pentode is a sharp cutoff 
> and the 6LM8 isnt very exciting for a high performance receiver.

Now this is very interesting! My RC-30 databook lists it to be a semi-remote 
cutoff pentode. But everywhere I can find it's specs listed online has it as a 
sharp cutoff.

Oh well. One or the other must be a misprint. Wouldn't be the first time. I 
guess the only way to find out would be to test one or break one open.

Gee, I was all set to build something like "The Simple X Super" with an 
added RF stage and AVC out of them... I guess I still could.

Marvin
KA7TPH