[AMPS] 6146 splatter help?

[Mark Keith]

measures wrote:

> >Is there any way to improve the splatter on my TS830s (low s/n) with RCA
> >6146B's?

Not sure what you mean..."low s/n" doesn't make sense... If you are
splattering with the ts-830, that would usually mean you are
underloaded. This is common with the old hybrid kenwoods, as many will
tune up in the "tune" mode, and not finish the job in the cw mode. You
need to fully load the radio in cw mode to ensure proper loading. The
only problem you should see with some 6146's might be a problem
neutralizing. If you have no problems doing that on 10m, they should be
fine. You are pulling the correct appx plate current.
> >
> It is already the cleanest radio ever built.  .

It's pretty good , thats for sure.
> 
> >On voice peaks (p's, t's and ch's) there are burps like key click sup and
> >down the band about -40-60 db from the intended energy.
> >It is only barley noticeable up and down with a 10+ S9 signal in another
> >rcvr (although I hear the same thing coming from my TS130
> >too).
> >

But do other people hear this? You may just be slightly overloading your
in shack rcvr.

> >It is clean from the 12BY7 on a spectrum analyzer (FM/AM 1100s).  It seems
> >that maybe the alc just isn't fast enough whenever the
> >grid starts pulling current.
> 
>  ALC is never fast enough.

I don't even pay attention to the alc on a 830. Or any other kenwood for
that matter.
> 
> >The  mics I have tried are Shure 444 (desk)
> >and 404c (mobile) and they both do the same thing.
> 
> An electret mic. makes cleaner audio.

A good dynamic even better I think. I use a audio technica dynamic mike.
I've never run across a person who says I have bad audio yet. The 444
has fairly funky audio in comparison I think, and the electrets too flat
usually. Not bad, but not near as good as the dynamics I've used.
> 
> >The
> >mic gain is critical and goes from 0 to full slam scale around 9 o'clock
> >but less so with the processor on (15 db)  about 10 or 11
> >o'clock.

In that case sounds like you have too much mike gain. I run mine about
12 oclock and still can go plenty farther. I can turn mine up all the
way, and am still not overly nasty. BTW, I run my compressor, but very
lightly at usually about 9 oclock. Doesn't even  move the compression
meter unless I started screaming. Shouldn't  need any more than that. 15
db??? uhhhhhhggg....Could sound pretty funky.
> >
> >The plate is 750v, the grid is -60v and the SG is 235.  I dropped the SG
> >down to another tap at 210v,  but there was no difference
> >in operation other than Ip went from 210ma to 180ma.  Idles at 60ma.  I
> >tried opening the grid chokes on the resistors, (47 ohm) and
> >tried a standby pair of GE 6146A's but no change at all.  The 9.00v and
> >3.60v are set after doing the power supply mods, and the
> >vbt/carrier oscilllators have been adjusted for max bandwidth (+- 1.4 kHz
> >@ -6 db) in ssb (Thanks Rich. The Fcenter on the 455k5 was
> >a wee off).   Most voltages on Q19,Q20 look good, but I can't probe the
> >alc line without messing it all up.
> >
> less ALC means less feculence.

yep, I did the Measures VBT mod on my 830. Works real nice. Also the 210
mil number just about right. It was ok the first time.
> 
> >So is there a problem with the alc or pa or am I chasing ghosts?  I love
> >this radio better than some of my newer ones.

I think you need a new mike. Or reduce the gain from the one you are
using. The mike input on the 830 is low OR high impedance. It does not
take much mike gain to drive an 830. If you are near overdrive at 9
oclock you have a problem there. I'd look at that first. Sounds like the
rest is ok to me. I bought a gold label 830 about 2 years ago. I did a
total full alignment, and then the VBT and other mods that Rich has on
his website. The rig just works fantastic. Best overall receiver I've
ever used . Period. The audio thru the headphone jack is ultra clean and
smooth. Plug the same phones into my icom for instance, and you can tell
the difference right off the bat. To the average ear, the icom would
sound fine, but compare to the 830, and it sounds fairly ragged. Also
the compressor  or "rf clipper" on the 830 one of the best ever made.
Can't hardly tell it's on when adjusted properly.  MK

-- 
http://web.wt.net/~nm5k

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