Since this is where the experts are--
Is there any way to improve the splatter on my TS830s (low s/n) with RCA
6146B's?
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).
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. The mics I have tried are Shure 444 (desk) and
404c (mobile) and they both do the same thing. 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.
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.
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.
Jim, ac6tk
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