++++++++++++++++++ Audio Output Port for use with digital modes See also K2 AUX J5 ++++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: "'James Fonte'" , "'Elecraft (E-mail)'" Subject: RE: [Elecraft] A "nice-to-have" for the K1/K2... Date: Sun, 17 Nov 2002 13:13:12 +0100 > -----Original Message----- > From: elecraft-admin at mailman.qth.net > On Behalf Of James Fonte > Sent: 15. november 2002 11:43 > > What do YOU think about the addition of an audio-output port > on the rear of the K1/K2...that provides a standard > line-level output... I have made an audio output from the top of the AF volume control (R3) via a 10 k resistor to the Mic connector. It is very simple to do as R13 is on the Front Panel board, almost next to the Mic connector. I just did it as an experiment, and expected the level to be too low to be useful for anything, but it turned out that the audio output is enough to drive the input of a PC. The nice thing is that it is independent of the AF pot setting. In this way I can decode PSK31 and choose to listen to it or not, without affecting the setting of the level for the PSK31 program. This output works best for K2's with the AF pot modification, otherwise I think the level will be affected by the AF pot setting. Also my mic connector is wired for the Elecraft Heil microphone and I use pin 5 for AF out. Of course this will not output my own CW or speech, that would require a 3-input mixer, but it should be fairly simple to do. 73 Sverre LA3ZA +++++++++++++++ From: "Pauli Nunez EA3BLQ" To: "Julian (G4ILO)" Cc: Subject: Re: [Elecraft] Fixed level audio output for K2 Date: Mon, 27 Jan 2003 19:04:00 +0100 Hi Julian and all, I quite recently made the AF Gain Control Mod to my K2, and following the idea posted to the reflector by Sverre Holm, LA3ZA, now I also have a low level fixed audio output on pin 8 of my mic connector. I put a jumper between pin 8 of the mic configuration head, at the Front Panel board, to the VOL 2 terminal of R3 on the same Front Panel board. I would like to remember that Sverre installed a 1k resistor between those two points. The level is fixed and quite low but you can always amplify it if needed. As to what regards my Digital Interface, Ioannis Kassotakis, SV1EQP, has recently purchased a kit and has had the idea, which we are currently considering, to install it, with minor mods, on the left side panel, between the KAF2's RTC battery and the side panel. We think it may be quite feasible and once we are satisfied, I'll upload the results and pictures to my web site so as to share them with all the K2rs community. All the best Pauli, EA3BLQ K2 # 1044/100 URL: http://www.qsl.net/ea3blq/ ea3blq at menta.net ea3blq at qsl.net "Julian (G4ILO)" wrote: : I want to add a fixed level audio output to my K2, for interfacing to a : computer. I'm looking for the simplest possible circuit, that takes the : least possible space and can be installed in a fully-loaded K2 without : conflicting with the installation of the transverter module when it becomes : available. EA3BLQ's elegant modification is out of the question as I have : the KAF2 installed, and besides, I don't need the mic audio to be : disconnected nor a separate PTT line. Any suggestions? : : 73, : -- : Julian, G4ILO. (RSGB, ARRL, G-QRP, K2 #392) : G4ILO's Shack: http://www.qsl.net/g4ilo : ++++++++++++++++++++ Date: Wed, 29 Jan 2003 09:16:22 +0000 From: "Julian (G4ILO)" Subject: RE: [Elecraft] Fixed level audio output for K2 To: la3za at qsl.net, "'Pauli Nunez EA3BLQ'" Cc: Thanks for the suggestion. The one I've implemented was sent to me off-list by Joe Levy. I've taken the output via a capacitor from the junction of R10 and Q1, 2 and 3 on the KAF2 board. There is more than ample output to drive the line input of the sound card, without any additional amplification at all. I have not noticed any hum, either. 73, -- Julian, G4ILO. (RSGB, ARRL, G-QRP, K2 #392) G4ILO's Shack: http://www.qsl.net/g4ilo +++++++++++++++++++ Reply-To: From: "Sverre Holm - LA3ZA" To: Subject: RE: [Elecraft] Fixed level audio output for K2 Date: Tue, 4 Feb 2003 20:07:50 +0100 In the process of making a fixed level audio output from the K2, I also moved my zero-beat indicator to the back of the front-panel board. One feature I like about that is that there is no need for wires to be run to any other board, so the K2's internal tidyness is kept. Previously I had the zero-beat indicator on a separate board with wires going to the RF board for +5V, gnd, and audio and a wire to the front-panel board for output to the right-most LED: My K2 page has a link to a picture of this mod: http://www.qsl.net/la3za/K2.html The amplifier is a 50x LM358 amplifier, output goes to both the zero-beat indicator and a pin on the mic plug, making both the audio output and the zero-beat indicator independent of the AF pot setting. The circuitry is made Manhattan style with a mixture of SMT and through-hole components. Sverre LA3ZA ++++++++++++++++++ From: "Pauli Nunez EA3BLQ" To: "Daniel L Brinneman" Cc: Subject: Re: [Elecraft] mic pin connections Date: Wed, 26 Mar 2003 12:37:54 +0100 Hi Daniel and all, Mind that the AUDIO OUT from the J5 Aux. AF on the RF Board is balanced audio between pins 1 and 3 and you will need to buffer it and convert it to unbalanced audio (that's what my DI PCB does through the LM386N circuit) so you'll need an additional pin. I still think that the best bet is to follow Sverre Holm's, LA3ZA, idea and take the AUDIO OUT from the VOL2 terminal of R3 on the very same Front Panel board, very close to the Mic Configuration Header, and jumper it to pin 8 of the mic's connector. (You can take pin's 8 jumper block off as it is a dup GND connection of pin 7 and keep the remaining blocks on). By doing this mod you'll have to modify your MH-2 connector's connections too, as it uses pins' 7 and 8 to ground the mike. Just desolder the cable from pin 8 and solder it to pin 7, together with the shielding braid. At the same time I have also desoldered the 5.6K resistor I had installed between pins 1 and 6 at the rear of the microphone connector on the Panel Control Board and have installed it within the MH-2 connector, between pins 1 and 6, of course. Now at pin 8 I have an unbalanced fixed level AUDIO OUT connection. Have tried buffering that AF OUT using a BC107 transistor, but I like better the use of an LM386. I use the 5 VDC present at pin 6 to feed the circuit on a proto-board and it works fb. Best 73 Pauli, EA3BLQ K2 # 1044/100 URL: http://www.qsl.net/ea3blq/ ea3blq at menta.net ea3blq at qsl.net On Wednesday, March 26, 2003 4:08 AM "Daniel L Brinneman" wote: : Hi, : : would it be wise for me to connect 12VDC and AUDIO OUT from J5 on the RF : board to the Front Panel mic connector on the unused pins? : : The unused pins being UP and DWN, I would take the jumper block off of : these pins and put a label next to it for future reference. I have the : MH-2 in use. will these voltages and audio out effect the microphone? : Does the mic, MH-2, have any connections on the UP and DWN pins holes? : : Daniel : kg4dni ++++++++++++++++++++