I didn't like the low end roll off of the lincoln, it makes a man's voice sound nasalish and compressed (300hz-3000hz maybe). My approach was to replace the mic/line amplifier coupling capacitor C900 100nf to 220nf, which is an improvement by itself, then I replaced C570 and C571 audio modulation amplifier input coupling capacitors from 100nf to 220nf. I used a quality film capacitor vs the stock ceramics. The audio quality improvement was great, low frequency response was good down to 100hz, with tonal presence down to even 50hz. I recorded the difference between the stock radio and modified radio with enhanced low-end, better coupling capacitors. The improvement is drastic, the radio sounds so much better. The stock radio audio is maybe a 3 out of 10, modified it is now a 9 out of 10. I'm not sure why Mike is playing with the 100pf caps, the 4558 op amps sound great, cheap caps=cheap sound, the high-end frequency response on my radio was just fine up and over 4khz, which is plenty. After the modification the mic gain can be turned down to 70%, the audio circuit can now be driven to 95% modulation with as little as 10mVp-p. The xmit audio response is now excellent from ~50-4000Hz+. I did not clip, tweak or peak anything else on this radio, it really works so well. I feel Tinkering further is counter productive, Asymod is just too far for me, 3ea capacitors at 220nf is less than $10, one could even increase value of the caps for more lowend enhancement, I feel some where around 470nf would be about as far as one should go. That would maybe give too much low end audio to most listeners, rattling the loud speaks off the shelf. Hihi
Great vid...Have you messed with an Alltune of any kind? I'm trying to decide between this radio and either the Alltune 555N or 6666? And not real sure which one of those to go with but looking at the 555N what's your opinion I really would like to know thinking of ordering today hehe!! Thanks!
I thought I was going to buy one. I like the way you do the videos, if I wasn't going to get one that was good. I get one and I have to have some one look at it.
Hi Mike, great demonstration of what is possible with the high frequency response. I see i have to change C502+C525. Did you also tried to modify the low frequency response? It seems that C569 is responsible for that. I would just take it out.
Nice and informative vid. At
is this LPF modification documented anywhere? locations of the parts to change?
Amazing , thank you for sharing .
How i can make a s-meter Jack in the lincoln 2+ ?
I didn't like the low end roll off of the lincoln, it makes a man's voice sound nasalish and compressed (300hz-3000hz maybe). My approach was to replace the mic/line amplifier coupling capacitor C900 100nf to 220nf, which is an improvement by itself, then I replaced C570 and C571 audio modulation amplifier input coupling capacitors from 100nf to 220nf. I used a quality film capacitor vs the stock ceramics. The audio quality improvement was great, low frequency response was good down to 100hz, with tonal presence down to even 50hz. I recorded the difference between the stock radio and modified radio with enhanced low-end, better coupling capacitors. The improvement is drastic, the radio sounds so much better. The stock radio audio is maybe a 3 out of 10, modified it is now a 9 out of 10. I'm not sure why Mike is playing with the 100pf caps, the 4558 op amps sound great, cheap caps=cheap sound, the high-end frequency response on my radio was just fine up and over 4khz, which is plenty. After the modification the mic gain can be turned down to 70%, the audio circuit can now be driven to 95% modulation with as little as 10mVp-p. The xmit audio response is now excellent from ~50-4000Hz+. I did not clip, tweak or peak anything else on this radio, it really works so well. I feel Tinkering further is counter productive, Asymod is just too far for me, 3ea capacitors at 220nf is less than $10, one could even increase value of the caps for more lowend enhancement, I feel some where around 470nf would be about as far as one should go. That would maybe give too much low end audio to most listeners, rattling the loud speaks off the shelf. Hihi
How much for you to do this to my Lincoln 2 plus? And where are you located?
Great vid...Have you messed with an Alltune of any kind? I'm trying to decide between this radio and either the Alltune 555N or 6666? And not real sure which one of those to go with but looking at the 555N what's your opinion I really would like to know thinking of ordering today hehe!! Thanks!
Do you have a high-res photo (or cap numbers) of the offending caps? Some of us are optically challenged. LOL
Nice demonstration of how the filters work, will help a lot of people that don't know how they are done.
I thought I was going to buy one. I like the way you do the videos, if I wasn't going to get one that was good. I get one and I have to have some one look at it.
Thanx☺ for doing this video! I was considering buying this radio -now not so sure.😕
Hi Mike, great demonstration of what is possible with the high frequency response. I see i have to change C502+C525. Did you also tried to modify the low frequency response? It seems that C569 is responsible for that. I would just take it out.
Do you have fuses on both positive and negative power wires?
could anyone tell me, I did the 11 meter conversion the bands seem wrong I used 1k resister
If you needed that cap, it probably was passing +V over that pin for the electret element supply.
Couldn't you replace the Op Amp to one that produces better sound? I have upgraded them in many of my headphone amplifiers that I built.
do they make a pin compatible amp that will drop in?
Howdy Mike! What's your comment when compare the "standard" Lincoln with RF Final MRF477 with this set?
Techs are always saying how "horrible" some radios are out of the box.
Does anyone have the instructions to set the bias on the finals and driver? Thanks in advance!!