Older Texas Star D.C. 350 ssb delay

[walterjn]

I have a question or three about the delay on my older dx 350.
Amp info, older Bi-lateral 4 power (Texas Star) dx350. It does have 4 power levels, on AM, on ssb it has 2. Ssb power levels are the 2 lowest of the 4.
My thoughts, I'd like to have a permanent/ automatic ssb delay. Thereby having acces to all 4 power levels while on ssb.
Is this possible? It looks like I could run a wire from the power switch to the positive leg of C4. That way when the amp is on the delay works.
I want to double check with the brilliant minds here before I do any damage. I'm including pcb layout & pcb traces & schematics from cbtricks before y'all ask.
Thank you for your time.
Walterjn.

 

[ExitThirteen]

Unsolder C4, and place it across D1, by the relay. Place the negative (-) lead of C4 to the non-banded side of D1, and place the positive (+) lead of C4 at the junction of D1 and L1. You'll have "automatic" SSB delay in all modes. If you want to make it switchable, insert a switch between the negative lead of the capacitor and the non-banded side of D1. Hope this helps.


~Cheers~

 

[walterjn]

Thank you! Now, by moving C4 to D1 we have effectively bypassed D1. Would it be acceptable to remove D1 while I'm in there. Or should I just leave it in place, not worry about it & use it as a 'spacer to solder C4 onto?

 

[ExitThirteen]

Just leave it in place. Just strap the capacitor over it.



~Cheers~

 

[walterjn]

Thank you oh wise & grumpy one!

 

[walterjn]

Ok, I just pulled it out & opened it up to take a good look @ the amount of room I have to work with, & the location of all the screws I will have to remove. While I was doing so I realized that I posted the wrong layout, trace, & schematics. I remembered that this amp has 2 of the 2sc2879s, as the dx 350 shows in the parts list.
The bi-lateral dx 350 doesn't show 2sc2879 transistors at all in the parts list. It shows a MRF-455 driving 2 transistors that have the same equivalent as the MRF-455. I do apologize for not making sure as to what I actually have. Now as far as the ssb delay issue that I desire to change that looks the same. I am posting the correct info so as to make it easier on the next person...
One other item is that the Bi-lateral dx 350 has a different board than the Dx350 does. There is a trace cut from the factory.

 

[9C1Driver]

Before you do all that work why not just adjust the input drive SSB watts from the variable power on your radio? So you will have two power settings on the amp and almost infinite setting by variable RF power on the radio.

 

[walterjn]

Before you do all that work why not just adjust the input drive SSB watts from the variable power on your radio? So you will have two power settings on the amp and almost infinite setting by variable RF power on the radio.

Because I do not have a variable power on my uniden Grant xl dead key is set for 2 watts, let the amp do the rest. Pumping more than 2 watt dk will create a crappy sounding signal. Running ssb w/o the delay makes the relay chatter,which would make the relay burn out sooner.
I've had this amp for 20+ years. When I first hooked it up I had a 4 watt dk & I tried to get as much out of it as possible, all radio checks came back to shut the amp off, that I sounded better w/o it. Turned the dk down & tried again, all reports were asking me where I was as I sounded clean, clear, & loud.

 

[loosecannon]

in SSB mode, the mic gain is the variable RF power control.
LC

 

[9C1Driver]

I see. If you talk AM and SSB you won't be happy with auto SSB delay when on AM, you will miss the first half a word people say. With that radio something like 1.75-2 watt AM dead key with 8-10 watts peak should sound great on AM. And on SSB with the switched SSB delay on and a peak input of 10-14 watts once again should sound superb with that radio/amp combo. I guess I don't see the point of switching that over to full time auto delay. Anyway it's all good and it's your amp so if you think that's what needs done.

 

[walterjn]

in SSB mode, the mic gain is the variable RF power control.
LC

Honestly, I just set that & leave it alone. Half the time I'm running down the road & just don't need the hassle of messing with Mic gain from channel to channel, or conversation to conversation.
I get a trusted operator or three to give me honest reports as to how it sounds get everything set to where all agree that it sounds best let it be. & yes, operators are at different locations & distances from me. I like simple.

 

[walterjn]

I see. If you talk AM and SSB you won't be happy with auto SSB delay when on AM, you will miss the first half a word people say. With that radio something like 1.75-2 watt AM dead key with 8-10 watts peak should sound great on AM. And on SSB with the switched SSB delay on and a peak input of 10-14 watts once again should sound superb with that radio/amp combo. I guess I don't see the point of switching that over to full time auto delay. Anyway it's all good and it's your amp so if you think that's what needs done.

I picked this amp up 20+ years ago when I did spend most of my time on AM. Any more I'm on ssb 99% of the time. I originally paired this amp with my original Grant XL & everyone told me to never change anything. All agreed that it was clear, clean & loud.
As for the full time delay, I'd like to be able to use all 4 power levels on ssb. I'm not sure that I'll be able to connect with the bases that are 60-80+ miles away. I can hear them well enough, they can only hear me if I'm about 20 miles away. If I don't like the way it works out, well I can always put it back to stock, or add a small switch to the mix. If I add a switch it will be to something I can easily replace. I kinda like the fact that this amp is kinda rare, & I don't want to screw it up too much.

 

[walterjn]

Unsolder C4, and place it across D1, by the relay. Place the negative (-) lead of C4 to the non-banded side of D1, and place the positive (+) lead of C4 at the junction of D1 and L1. You'll have "automatic" SSB delay in all modes. If you want to make it switchable, insert a switch between the negative lead of the capacitor and the non-banded side of D1. Hope this helps.


~Cheers~

I just wanted to say thank you again ExitThirteen. That modification works beautifully!

 

[ExitThirteen]

Sure thing. Glad I could help.


~Cheers~

 

[SteveSteve]

Unsolder C4, and place it across D1, by the relay. Place the negative (-) lead of C4 to the non-banded side of D1, and place the positive (+) lead of C4 at the junction of D1 and L1. You'll have "automatic" SSB delay in all modes. If you want to make it switchable, insert a switch between the negative lead of the capacitor and the non-banded side of D1. Hope this helps.


~Cheers~

Would this be the same procedure for a dx 500? I'd like to also have full power output and not loose 200 watts when I push in the delay button for ssb?