berportland.blogg.se

1. Collins 51s 1 600 ohm line output mod#
2. Collins 51s 1 600 ohm line output manual#
3. Collins 51s 1 600 ohm line output series#

Use the AGC amplifier tube as anything other than a meter amp. Negligible "dead time" or "blasting" on time constant change, since it does not Note that the big advantage in mine, which could be done on Lankford's, is

Collins 51s 1 600 ohm line output manual#

Works similarly, and the manual even suggests use of its built in attenuator. RA-17, the only true competition for the R390A (which it truly is!) has an AGC that

That'sīest achieved with a modest AGC delay and an attenuator in the antenna line. Of course, you might want a delay to avoid noise pumping.

Collins 51s 1 600 ohm line output series#

In late 1941, EC-1 advertisement on QST changed to the famous 'Hoggarth' series EC-1 started to serve as. My R390A atĪny antenna length over 3 inches at any frequency has an ambient noise lever greater than any realisticĪgc delay. (1941) When first appeared in early 1941 with its sensational 19.95 price tag, EC-1 was a general purpose shortwave receiver everyone could afford. Or use an LED, green ones are well over a volt, or a couple of LEDs in series.īut this really does not matter. There is a delay, it is the drop in the 1N3070. 6 x 2.25 x 5.75 inches Note: Please make sure you have read and understood our sales terms and conditions before purchasing this item. IE: at low signal levels, there will be more internal tube/circuit noise audible than necessary, making it harder to hear weaker signals.ĭtvmcdonald, it looks like the circuit you designed and refered to removes the AGC delay. Impedance levels (nominal): Line 600 ohm, Receiver Input 8 ohms, Speaker Output 8 ohms and Microphone 50k ohms. If AGC is applied too soon, the internal noise in the RF stages will be of higher amplitude than necessary. The R-390A and R-390 AGC is designed with a delay for a very important purpose - maintain maximum amplification in the RF stage until the incoming signal is strong enough so that reducing gain in the RF stage will nolonger adversely affect overall s/n ratio. Will that work or would another transformer be better or is this something where just a resistor will work? Possibly modern ones or whatever I can find that will be comfortable and give good audio quality. I would then use the headphone jack on the front of the receiver. I'm thinking perhaps one of those Hammond 600 ohm to 4/8 ohm audio transformers might work which I could connect to the balanced audio out then connect the secondary to the headphones terminals on the rear terminal block of the receiver. I would like to use the line audio out to drive a pair of headphones.

I have the radio in the house now and I've discovered that it isn't easy to listen to hams using the speaker as sometimes the audio gets louder.

Collins 51s 1 600 ohm line output mod#

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 coupling cap connected to the plate of the driver tube, change the plate resistor to its original value, connect it back to the output tube grid through the cap and connect the wire to the output transformer secondary. 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.