Funny you say that, as I was just reading a little about goldfinger hifi. Could be interesting, and if it turned out well, a keeper for sure.
It's an
"audio bandwidth increase" (1Khz?) that really takes the right microphone to take advantage of, if you only have a stock mic you won't be amazed or happy. The Astatic 636L works poorly, my Galaxy stock mic works awesome on the GoldFinger 29, & the Turner RK56 is aslo awesome.
One thing be careful with is the tantalum caps, I mis-read the board my first time and made the radio sound like absolute garbage, I can only wonder how many people have put the cap in the wrong spot and dismissed this modification as being crap when they goofed up, & in reality this mod kicks @zz!
It is enough to make you stand out from the crowd without all that swing non-sense, but don't expect a miracle, paired with the right microphone, you will have that "Big Radio Sound" without destroying the band or even the adjacent channels! (I can only imagine how well a D-104 can do w/this setup!)
I re-used caps from a few parts Cobra for my "GoldFinger 29 LTD test", it worked awesome, after I did the
'extra' cap change (C71=33uF for 29 LTD).
Postby
Goldfinger » Mon Aug 13, 2012 2:22 pm
The AMC on this chassis is slow and whippy. After the hi-fi transmit mod, the problem is even worse. Here is an quick way to make it work fast and snappy, making it easier to limit right at 100% mod on a hi-fi radio.
Change C71 (220uF 10V electrolytic) to a 33uF 16V electrolytic. (observe polarity)
On the Cobra 25 LTD the one you want to change is C91 (220uF) to a 33uF 16V electrolytic.
Cobra 25LTD Classic (TA7222AP)
Receive:
Change C32 (front center of PC board) to a 2.2uF mylar or NP electrolytic
Change C54 and C56 to 2.2uF NP electrolytic
Change C67 to a 1000uF 25 volt electrolytic
more highs? Change C151 to a .001uF disc or mylar
Transmit:
Change C90 to a 1.5uF 16-50 volt tantalum observe polarity.
Change C96 to a .001uF disc or mylar
Change C89 to a .033uF (333) green mylar
From Goldfinger:
I almost always use a mylar or polypropylene for C32. The signal levels are low there so using a high fidelity cap is a noticeable upgrade.
C54 and C56 are in a higher level area of the chain so the small/handy radial lead non-polar's are fine.
All mylar's is also fine if you can squeeze them in!
Pro Tip: Before venturing into unknown waters with modifications, it's best to start with the solid foundation of a factory radio, this removes any potential variables that can skew the results or cause unexpected failures!
For some dummy load experimentation, I would recommend this mod to even a total newbie, but not the v-mod because the v-mod can act/splatter worse than a "clipped limiter" in the wrong hands! (It often does
)
After the radio is stock, do the GoldFinger cap changes for TX, make C91=33uF, & call it a day!
If this is a decent Philly (how is the chrome?), fixed & with some new lids this radio would be worth more than what you paid!
Credits for the mod info all goes to Goldfinger of wwpdx (found online, I don't know him)
How did we start at a thread about un-hacking a radio, then go on to talking about re-hacking/improving it as a project, we skipped rite over the part when you gotta make it stock again, lol.
-LeapFrog
73
