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R-390A Audio Mods - AM Window
http://www.amwindow.org/tech/htm/r390aud.htm
R-390A Audio Modifications. by. Chuck Rippel, WA4HHG Some of you may know that I restore R390A receivers as a hobby. Here is an easy "soft " (reversable) modification which I came up with that really improves the R390A audio by mellowing it out a bit. The audio tubes, V602A and V603 are coupled with 300V, .01mfd "Vitamin Q" type capacitors.
Chapter 11 – Upgrades, Modifications, Parts ... - r-390a.net
https://www.r-390a.net/Y2K-R3/11_Chapt_11.pdf
Capt. Lee’s Product Detector For The R-390/ R-390A – Revisited 31 AGC and Limiter mods 35 High-gain Product Detector 36 R-390A Upgrading: Panel and Frame 37 R-390A Upgrading: Audio Modifications by Chuck Rippel, WA4HHG 38 R-390A Upgrading: IF Sub-chassis 40 R-390A Upgrading: RF Amplifier Sub-chassis 40
R-390A Audio Modifications - amwindow.org
https://www.amwindow.org/tech/htm/32vac.htm
R-390A Audio Modifications. by. Chuck Rippel, WA4HHG . In troubleshooting my 32V-3, a condition occurred which bears repeating as a warning to other owners of Vintage Equipment. However, I am not an electrician so check your local situation and codes before proceeding at your own risk. My 32V-3 was blowing HV power fuses due to an internal short.
Mods for Collins R390A
http://www.redwaveradio.com/11_d897569a063558ff_1.htm
For audio mods, you'll either want to 1) pull low-level audio off the "diode load" output on the back panel or 2) make the "Klerenomos" audio mod documented in "Electric Radio" magazine (I don't remember which issue). I haven't heard mention of significant differences in the audio chassis before between the R390 and the R390A.
R-390A Rebuild Audio Module - Dash Distributing
http://www.dashdist.com/1u2u/R-390A/Audio/Audio.php
Externally, you can't tell that the R-390A's Audio-module has been changed. The R-390A simply sounds better and works better. The squelch function, that was included in the R-390A's original design but omitted from its production, is included in my conversion because it required only a few, inexpensive components.
Productions Modifications, Field Changes, and ... - R-390A
https://www.r-390a.net/Pearls/mods-fcs.pdf
Optional Modifications for the R-390A This is a consolidation of modifications from the Production Modifications as listed in the Y2K Manual, various Navy Field Changes, Hollow State News, and various other sources. RF Deck Production Mod 2: Pin 7, V201, connected to ground instead of pin 2. Production Mod 2: C275 changed from 5000 pF to 3300 ...
Dave Medley's R-390 Compendium of Knowledge
The R-390 Page < This is the top view of an R-390. Note the many differences between this and the R-390A. This is the underneath of an R-390. Again note that it is quite different to the R-390A . This is an R-391 which is very similar to the R-390. The big difference is the addition of the autotune. Not a common radio in working condition.
Antique Radio Forums • View topic - R-390A diode load into ...
https://www.antiqueradios.com/forums/viewtopic.php?t=59187
3 KC audio feeding into a good amp and speakers is still 3 KC audio. But the 5.5 KC audio on the R-390A's 8 [11] KC bandwidth filter, and especially the 8 KC audio on the 16 KC filter, is worthwhile. The diode load trick on the R-390A is a pretty common thing - pretty much ever Tom, Dick and Harriette has done this - it is very easy and works well.
Antique Radio Forums • View topic - Collins R-390 audio ...
https://antiqueradios.com/forums/viewtopic.php?t=326600
Collins R-390 audio question. I have an R-390 that I modded the local audio out amp to where the audio driver is fed to the local audio out terminal through a capacitor so it can drive the input transformer of a push pull 45 amp. The way that audio mod was done, all I have to do to put it back to original is to disconnect the wire from the ...
EB5AGV's R-390A Hints
http://www.jvgavila.com/r390a_2.htm
R-390A Diode Load How To (by Tom Marcotte, N5OFF) I got a couple of notes asking to elaborate on the use of the diode load tap on the back of the R-725 (390/390A) for audio use. The diode load screws (two) have a jumper connecting them in …
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